46th IAH Congress - Malaga, Spain 2019

Europe/Madrid
Trade Fairs and Congress Center (FYCMA)

Trade Fairs and Congress Center (FYCMA)

Av. de José Ortega y Gasset, 201 29006 Malaga, Spain
Description

The IAH Spanish Chapter (IAH-GE) and the Center of Hydrogeology of the University of Malaga (CEHIUMA) are honored to host and invite you to the 46th IAH Congress in Malaga, Spain in 2019.

Organizing info
    • 09:00 18:00
      Courses: Pre-congress courses Research building Ada Byron

      Research building Ada Byron

      Arquitecto Francisco Peñalosa, 18 29010 Málaga
    • 09:00 18:00
      Meeting: IAH Council meeting Research building Ada Byron

      Research building Ada Byron

    • 14:00 18:00
      Meeting: IAH Commission on Transboundary Aquifers Research building Ada Byron

      Research building Ada Byron

    • 17:00 18:30
      Registration
    • 08:15 09:00
      Registration
    • 09:00 10:30
      Plenary: Opening
      • 10:00
        Managed Recharge to Restore Aquifers: Past, Present and Future 30m

        Aquifer depletion and contamination are so widespread that have become a global problem. Worse, depletion causes groundwater dependent systems to suffer and loose a portion of their environmental services. Managed Aquifer Recharge (MAR) has evolved to become the only realistic remediation option, other than stopping extractions, which is often impractical. Yet, actual implementation of MAR is hindered by numerous difficulties, both technical (clogging, maintenance, etc.) and legal (inflow quality requirements are often so strict that rainfall does not meet them). We revise how to address these difficulties. Specifically, we describe the concept of a reactive layer to enhance contaminant removal process during soil passage. We conclude that MAR should, and probably will, become a conventional step of all waterworks.

        Speaker: Jesus Carrera (Institute of Environmental Assessment and Water Research (IDAEA-CSIC))
    • 10:30 11:15
      Coffee break 45m
    • 11:15 12:45
      Parallel: Monday Morning 1: Topic 1 Conference room 2.1 ()

      Conference room 2.1

      • 11:15
        Assessing groundwater recharge and evapotranspiration in a Nordic humid region dominated by snowmelt 15m

        Groundwater recharge in Nordic humid regions is mainly dominated by snow melt. Estimating recharge rates and determining evapotranspiration by determining the influence of different vegetation types on soil water fluxes represents a significant challenge. The stable water isotopes δ18O and δ2H can be used to investigate the water fluxes in the unsaturated zone, given that the isotope ratios of precipitation and snow melt are preserved in the pore water of sediments. These water isotope ratios in unsaturated zone profiles represent an inherent fingerprint of the infiltration history. Measuring the volumetric water content in these profiles, and then correlating these profiles with the isotopic profiles, makes it possible to determine the quantity of water that has infiltrated during different periods. The objectives of this study are to (i) understand snow melt infiltration at sites experiencing thick snow coverage during winter, (ii) calculate groundwater recharge rates, and (iii) estimate evapotranspiration rates at sites presenting different land covers (bare soil, bush vegetation coverage and mature forest coverage). At the study site, we sampled sediment cores at three different locations to analyse soil water content and isotope ratios in pore water. Groundwater recharge rates were calculated using the peak shift method. Using water balance values, we were able to additionally assess evaporation and transpiration at the different sites, with and without vegetation, and also to assess the influence of the vegetation cover on evapotranspiration and recharge. This study confirms the accuracy of the peak shift method for estimating recharge and for assessing the effects of field site characteristics and soil coverage on evapotranspiration rates.

        Speaker: Mr Lamine Boumaiza (University of Quebec at Chicoutimi)
      • 11:30
        Groundwater Modeling in Integrated Water Resources Use in the Little Akaki Watershed, Ethiopia 15m

        Integrated use of surface and groundwater resources is essential to provide reliable water supply and to sustainably manage the water resources. In the Akaki watershed, groundwater pumping contributes for more than 25% of the water supply to Addis Ababa City, the capital of Ethiopia. The groundwater abstraction is significantly increased without reliable quantification of hydrologic and hydrogeological components of the water resources. In view of that, this study applied the SWAT model calibrated with SWAT-CUP for surface water simulation and MODFLOW model for groundwater simulations. The MODFLOW was calibrated using the water table and baseflow. Using the two models the surface water and groundwater potentials in the Little Akaki sub-basin under different recharge (change based on land use change) and pumping scenarios were analyzed. The combination of the two models, SWAT and MODFLOW models successfully estimated the surface water and groundwater resources and the results found were acceptable.

        Speaker: Mr Mesfin Benti Tolera ((1)Construction Environment Engineering Department, University of Science and Technology, Daejeon 34113, Korea; (2)Land and Water Resources Research Department, Korea Institute of Civil Engineering and Building Technology, Goyang 10223, Korea)
      • 11:45
        Exploration of deep groundwater systems in mega-fans - Example from Northern Namibia 15m

        Mega-fans are inland riverine deltas occuring in endorheic basins. Their potential as hosts of major aquifer systems has only been recognized rather lately.

        The Cubango Mega-fan in Northern Namibia contains three aquifer systems, of which the deep one was only found at the end of the 1990s. Due to its thickness of up to 100 m, its large size and good water quality it is a game changer for the arid North of Namibia. Its spatial distribution and sedimentological background was investigated through core drilling and both geophysical and hydrogeological techniques. Due to the large size of the system, data scarcity is a constant issue affecting the exploration and management of this resource.

        Core drilling revealed that the system comprises two major formations of Tertiary age, originating from different source Areas. The cores also contain an archive of the development of the climate of southwestern Africa. The sedimentary background defines the hydrogeological structures.

        Groundwater modeling was applied to investigate the rate and location of groundwater recharge. Recharge rates are as low as 2-3 mm/a and limit potential extraction. This needs to be considered in management plans. Remote sensing (satellite radar altimetry) was applied to confirm the recharge areas. They are found in Southern Angola, making it a transboundary aquifer system.

        Similar mega-fan systems can be found in other parts of Africa and worldwide. Their hydrogeological potential is high but needs to be investigated in the future. The Namibian case can serve as a blueprint.

        Speaker: Dr Georg J Houben (BGR)
      • 12:00
        Developing a hydrostratigraphic classification system for South Africa. 15m

        Description of hydrogeological systems traditionally relies on a few factors, such as porosity, rock type and the hydraulic parameters, transmissivity and storativity. Some studies include terms for rainfall, recharge and aquifer boundaries. Inconsistency in reporting makes it hard to compare hydrogeological units and reliance on hydraulic parameters fails to consider the assumptions in hydraulic testing theory, which are often not met.

        South Africa has a stratigraphic record spanning 3.5Ga, including world class examples of Archaean granite-greenstones, Archaean volcano-sedimentary sequences, Proterozoic metamorphic belts, the world's largest layered igneous complex, the Pan-African orogeny, a Permo-Triassic fold belt, a Phanerozoic continental foreland basin, a continental flood basalt, and extensive inland and coastal Mesozoic to Cenozoic deposits. The landscape ranges from sea level to 3500m elevation, with plains, fold mountains, the Southern-African Great Escarpment, canyons, inselbergs and other landforms. The climate ranges from Mediterranean near Cape Town with snow on the mountains in winter, through sub-tropical to tropical, with seasonal monsoon style thunderstorms or perennial advective rainfall, to desert. Annual rainfall ranges from zero often in the deserts of the north-west to over 3m in the Cape Mountains. Temperatures range from winter minimums of <0 C to summer maximums of >40 C.

        Hydrogeologists working in South Africa face this complexity when describing a hydrostratigraphic unit. Multilinguilism (11 official languages) and developing world constraints on time, money and education provide additional challenges. This paper refreshes knowledge of technical terms, promotes correct use of this terminology, highlights similarities and differences between hydrogeological units countrywide, and suggests the level of information needed to make management decisions. Terms such as soil, regolith and saprolite are defined; grading and sorting and their influence on porosity are explained; representative elementary volume, especially in context of fracture networks is also explained. The distribution and flow of water is dealt with, especially complex vadoze zone flows such as imbibition, interflow and percolation. The above factors are integrated by relating these to 5 fundamental drivers: geology, geomorphology, climate, water state and human effects. The first three of these are seen as earth system constants, unchanging on a human time scale, whereas the last two are the temporal behaviours that modify the earth system condition.

        A fixed hydrostratigraphic classification system is not proposed, as the complexity and level of uncertainty precludes this. However, 10 examples of hydrogeological settings are given, spanning the diversity found in South Africa, and applying the terminology presented. This shows how reporting of typical hydrogeological investigation results (hydraulic aquifer tests, water quality analyses) needs to be augmented with information from the 5 fundamental knowledge areas to achieve a more meaningful description of the hydrogeological units, creating more consistent descriptions and ultimately allowing hydrostratigraphic classification countrywide.

        Speaker: Dr Roger Diamond (University of Pretoria)
      • 12:15
        Re-utilizing possibilities of abandoned hydrocarbon wells in Northern Hungary 15m

        The Research Institute of Applied Earth Sciences of the University of Miskolc, together with the Faculty of Earth Science and Engineering have been working on the PULSE project since 2016. The aim of the project is to allow Hungary’s abandoned or unproductive hydrocarbon exploration wells and drillings to workfor geothermal utilization. After sorting out more than a thousand drillings into the database, they were evaluated and mapped. Thenwe concentrated on the Northern part of Hungary. It is important to examine which unused wells or drillings aresuitable for geothermal use. So, the structure of this database serves this purpose. With the help of thiswork, they can serve a new goal, either through heating or electric power generation.
        The results of the last research period are related to the following topics:
        1. Development of data collection methodology. Collecting data for wells located in Hungary, collecting spatial data, collecting data on geological heat storage.
        2. Database construction, geothermal energy recovery data analysis. The database, regional database, heat storage database.
        3. Re-evaluation of wells from the aspect of heat recovery, spatial evaluation.
        4. Simulation of industrial waste heat storage with heat transport modeling.
        Our studies in the PULSE project can have a particular interest in the already designated geothermal concession areas. The project will give additive information about the geothermal situation, but also will provide better planning conditions related to re-utilized abandoned wells. Our research can also help some future projects to reduce the costs of re-utilizing abandoned hydrocarbon wells.
        ACKNOWLEDGEMENTS
        The research was carried out in the framework of the GINOP-2.3.2-15-2016-00010 ‘Development of enhanced engineering methods with the aimat utilization of subterranean energy resources’ project of the Research Institute of Applied Earth Sciences of the University of Miskolc in the framework of the Széchenyi 2020 Plan, funded by the European Union, co- financed by the European Structural and Investment Funds.

        Speaker: Prof. Péter Szűcs (University of Miskolc, Institute of Environmental Management, MTA Geoengineering Research Group)
      • 12:30
        Isotopic and geochemical evidence of groundwater origin and salinization in multi layered coastal aquifer of India 15m

        The origin and salinization of groundwater in multi layered coastal aquifer of Sankaraparani river basin, India was studied using isotopes and geochemical signatures. Groundwater in this region occurs in shallow unconfined and deep confined aquifers. The shallow aquifer comprises of Quaternary Alluvium whereas the deeper aquifer comprises of Tertiary sandstone. Groundwater sampling from different aquifers was carried out once in three months since June 2017. Parameters such as pH, electrical conductivity, oxidation reduction potential and temperature are measured in the field whereas the concentration of major ions (Ca, Mg, Na, K, Cl, SO4, HCO3) and stable isotopes (δ18O and δD) are measured in the laboratory. Geochemical signatures such as electrical conductivity, sodium chloride ratio, base exchange index and seawater mixing index indicate that upper aquifer is affected by seawater intrusion whereas the lower aquifer contains fresh groundwater. The isotopic composition of groundwater shows that in the upper aquifer δ18O ranges from -6.8‰ to -1.3‰ and δD ranges from -43.1‰ to -13.8‰ whereas in lower aquifer, δ18O and δD ranges from -5.96‰ to -3.59‰ and -39.29‰ to -23.07‰. Enriched δ18O and δD is observed in few regions near the coast. d-excess in the groundwater of upper and lower aquifer ranges from -3.7‰ to 10.9‰ and -1.03‰ to 20.13‰. Higher d-excess and depleted δ18O shows that evaporation process dominant in this region. The relationship between δ18O and δD compared with the local meteoric water line shows that the groundwater in this region is the meteoric origin. Groundwater samples near the coast with a higher concentration of chloride and enriched δ18O indicate seawater intrusion. The origin of groundwater in the upper and lower aquifers is from rainfall recharge and the groundwater in the upper aquifer has a high concentration of ions due to seawater intrusion.

        Speaker: Mr Manivannan Vengadesan (Research Scholar)
    • 11:15 12:45
      Parallel: Monday Morning 2: Topic 1 Conference room 2.2 ()

      Conference room 2.2

      • 11:15
        Transboundary Aquifers: moving beyond boundaries to management alternatives 15m

        Over the last decade, transboundary aquifers traversing the Mexico-Texas border have generated growing interest by federal institutions on the Mexico side, and state and federal institutions on the Texas side. Notwithstanding this attention, binational efforts to understand, assess, and manage shared groundwater resources remain limited, sporadic and politically sensitive. On the Mexico side, long-standing centralized groundwater governance structures, has created institutional barriers at the local level to the expansion of knowledge and cooperation over these transboundary resources. On the Texas side, property rights related to groundwater resources limit the scope of options available for cooperative management of cross-border aquifers. This paper examines stakeholders’ perspectives on the borderland between Mexico and Texas through 44 surveys and personal interviews. Findings show that stakeholders appear to support a binational groundwater agreement as a means for assuring the sound long-term management of transboundary groundwater resources in the border region; however, the majority of stakeholders also suggest that short-term local or regional arrangements may be preferable over binational agreements as local/regional approaches may be more achievable or realistic. Second, participants identified leadership and individual personalities as key factors for success at the local level, but noted that that such influence had limited sustainability over time and limited regional-systemic effects. Third, the stakeholders indicated that water quality, rather than water quantity, is the main driver of transboundary cooperation and communication efforts in the region. Fourth, participants suggested that failures and successes in groundwater cooperation efforts are based more on fear and political lobbying than on understanding of scientific facts.

        Speaker: Dr Rosario Sanchez (Texas A&M University)
      • 11:30
        Advances in Groundwater Monitoring 15m

        Understanding groundwater resources and their informed management ask for regular monitoring of groundwater state variables, both quantity and quality. Collected observations need to be stored, processed and shared among stakeholders. The Global Groundwater Monitoring Network (GGMN) assists (already since 2007) in improving the quality and accessibility of groundwater information and eventually the understanding of the state of groundwater resources (www.un-igrac.org/ggmn). This abstract summarises some advances in data collection, processing and sharing, accounted within GGMN activities.

        Although automatic groundwater monitoring and even telemetric transmission of data are becoming widely used, manual collection of data is still present or even predominant, the choice depending on parameters and purpose of the monitoring, groundwater regime, available resources, and others. In order to facilitate data collection in the field and data transmission to the GGMN Portal, a mobile (smartphone) application is recently developed. This GGMN App enables users to geo-reference and register groundwater monitoring wells, store groundwater monitoring data in the field and (immediately or later if WIFI is not available) transfer data to GGMN and store it there. In GGMN, data can be processed and optionally shared with other data providers and stakeholders.

        One of the most effective ways to share time series data among online data portals is through an automated Sensor Observation Service (SOS). This service has been recently implemented in GGMN and tested by connecting GGMN and the Groundwater Information Network (GIN) of the Geological Survey of Canada. Since GGMN aims to serve as a global monitoring focal point, the ultimate goal is establishing the same or comparable data sharing services with as many as possible national groundwater services around the world.

        IGRAC is preparing a global overview of national groundwater services with a focus on temporal and spatial processing of groundwater observations. It is a general impression that collected observations are not processed sufficiently. On the other hand, some services exhibited creative approaches in the processing of (in particular) spatial variability of groundwater variables. These approaches will be promoted through the IGRAC global overview and some of them are considered to be implemented in GGMN soon.

        Speaker: Dr Neno Kukuric (IGRAC)
      • 11:45
        Groundwater Management - A Perspective from Alberta, Canada 15m

        Fresh groundwater is a renewable resource and must be managed. Who should manage it: users or government? Or both? How should it be managed? Is groundwater scarcity perceived or real? What will happen as the climate changes?

        To manage something means to control it. The natural groundwater cycle includes recharge to, storage in and natural discharge from an aquifer – parameters which, at best, can only be estimated. Although these natural parameters cannot be managed, the human impact on the groundwater cycle – that is, the removal of groundwater from the aquifer, and the impact of that removal on the water level – can be measured, and therefore managed.

        Meaningful groundwater monitoring is necessary in order to manage groundwater resources. Aquifer tests are a guide to the availability of groundwater at a point in time, but groundwater monitoring allows us to assess how much groundwater is available on a sustained basis and provides data to help predict the effects of climate change on the resource. Meaningful groundwater monitoring includes using calibrated instruments to measure hourly discharge and at least hourly water levels from pumped water wells, and hourly water levels from observation water wells.

        With today’s technology, meaningful groundwater monitoring is affordable, with near real-time analysis. The data, collected at low cost, are reliable and accurate – and therefore essential in the management of the groundwater resource.

        The best time to start groundwater monitoring was 50 years ago; the second-best time is TODAY.

        Examples from Alberta will be provided.

        If you don’t measure it, you can’t manage it.

        Speaker: Mr Roger Clissold (Hydrogeological Consultants Ltd.)
      • 12:00
        Squaring the cycle of groundwater processes in nutrient budgets: a socio-hydrogeological application in the Lombardy Plain (Italy) 15m

        Nutrient processes in groundwater are a well known -and widely studied- issue, often contributing to aquifer contamination in densely populated areas worldwide. Nevertheless, stakeholders now almost assume that the problem is not only present, but also difficult to resolve, despite the scientific and political efforts. Therefore, nitrate contamination is almost set aside, compared to new issues, such as emerging pollutants.
        The Lombardy Plain (Italy) is an area highly affected by nitrates contamination, due to the coexistence of intense agricultural, livestock farming, industrial sites and urban sprawling, and a complex multilayer aquifer system.
        Recent studies demonstrated that despite the thirty-year efforts to implement the European Nitrate Directive, groundwater nitrate contamination is still a serious threat potentially affecting up to 9,000,000 inhabitants, with most monitoring wells showing steady or increasing NO3 concentrations. Results hence shows that the adopted strategies are not effective, and that a new approach is required to solve this issue, taking into account both the complexity of the hydrogeological system and the socio-economic context that triggers nitrate contamination. For this reason, a socio-hydrogeological approach was adopted in the frame of the INTEGRON project (Cariplo Foundation, grant number 2015-0263), whose overall goal is to integrate the role of groundwater as sink or source of nutrients (N and P) in river basin mass balances. A classical hydrogeological and hydrogeochemical approach was adopted for aquifer characterization, to understand the timing of nutrient transfer from and to the surface, and to identify the main contamination sources. Groundwater modelling was used to obtain long term projection of the evolution of nutrients concentrations in the system.
        In addition, tools and analyses typical of social sciences were integrated in the study. A Social Network Analysis was performed at the beginning of the investigation permitting to unveil the social structure of the studied area, and to highlight both social factors and key stakeholders that would determine the success of the implementation of the new science-based actions resulting from the hydrogeological investigation outcomes. To ensure a more comprehensive understanding of the needs and emergencies faced by local water users, public engagement activities were undertaken, targeted to both capacity building and outreach. The administration of semi-structured interviews and results dissemination fostered the creation of a network of mutual trust between farmers and the research team. Finally, all the recommendations resulting from the project were discussed in an open meeting with local stakeholders, to ensure a consensus on the proposed guidelines, thus combining bottom-up and top-down approaches for water resources management.
        Prior to this investigation, socio-hydrogeology was mainly implemented in developing countries. Results of this project demonstrate the effectiveness of a such approach to support regional groundwater governance also in European contexts.

        Speaker: Dr Viviana Re (Department of Earth Sciences, University of Pisa)
      • 12:15
        Protecting a freshwater lens against sea level rise: a field experiment 15m

        In the southwestern part of The Netherlands, a 75-ha-agricultural area called Perkpolder was transformed into a tidal area to restore a salt march ecosystem. In June 2015 the open connection to the sea was realized. This transformation created an average water level increase of about 1.5m and can be seen as a local sea level rise of 1.5m and may have significant effects on the groundwater system of the adjacent lying agricultural area. Below this agricultural area, a 20-meter-thick freshwater lens surrounded by saline groundwater provides the farmers fresh groundwater for irrigating their crops. It is expected that due to this local sea level rise, hydraulic heads increase resulting in shrinkage and eventually disappearance of this precious freshwater lens.

        To protect this lens, a self-flowing seepage system called SeepCat was designed and installed to compensate effects resulting from this local sea level rise. The freshwater lens is one of the Badon-Ghyben-Herzberg type and will shrink when hydraulic heads below the lens increase. The task of the SeepCat-system is to release the increased pressure in the aquifer. The SeepCat-system consists of 61 vertical seepage wells with 5-10m long screens, installed in the aquifer at 15m depth, over a total length of 1100 m. Since the hydraulic heads in the aquifer are higher than the surface water level, the seepage wells are artesian and self-flowing. The extracted saline seepage water is discharged into a canal and pumped into the sea.

        Since 2010, hydraulic heads (30 locations) and the fresh-salt interface (15 location) are being monitored to capture the reference situation, to determine effects resulting from the development of the new tidal area and to monitor the functioning of the SeepCat-system. Time series analysis was applied to quantify the effects. From the head measurements it is concluded that the seepage system is functioning well and fully compensate the effects of the local sea level rise. No changes in the fresh-salt interface have been detected yet. However, these processes occur at a much larger time scale since salt transport is involved. To determine these long-term effects, the numerical groundwater model SEAWAT was applied. The model results show that SeepCat is successful in mitigating the effects of this local sea level rise and without SeepCat, half of the precious freshwater lens would disappear after 100 years.

        The Perkpolder case serves as a field laboratory where effects of sea level rise are measured and mitigation measures for sea level rise are tested. Since the system is technically and geohydrologically working well, it could also be applied in other coastal areas, like small ocean islands. The SeepCat-system could help to protect their vulnerable freshwater resources which are seriously threatened by the expected future sea level rise

        Speaker: Dr Perry de Louw (Deltares & Wageningen University)
      • 12:30
        Stochastic knowledge integration for groundwater exploration in data scarce areas 15m

        We have developed a systematic probabilistic framework to spatially assess the potential for sustainable groundwater development. The workflow starts by explicitly defining sustainable groundwater extraction, in our case study, a groundwater abstraction that can provide 1ML/d for 10 years with a salinity of less than 2500 mg/L without causing a drawdown of more than 5% of the saturated thickness at 1m from the borehole.
        The methodology is applied to groundwater exploration in the Anangu Pitjantjatjara Yankunytjatjara (APY) Lands in central Australia. In this arid region, a crystalline basement is covered with regolith and a vast system palaeovalleys that are filled with sediments. Both the regolith and the palaeovalley systems are known to host aquifer systems. An ensemble of interfaces that define the boundaries between the basement and the overlying weathered rocks and palaeovalley sediments is generated with a Bayesian Data Fusion methodology to ensure they are consistent with the available borehole, airborne electromagnetic and digital terrain information. The surfaces defined by these interfaces are combined with probability distributions of hydraulic conductivity and storage to create ensembles of equivalent transmissivity and storage. A similar procedure is used to generate ensembles of salinity that are consistent with the available knowledge of salinity distribution across the region.
        Gridded water balance equations, in combination with the Theis equation, allow the rapid generation of ensembles of sustainable pumping volumes from these stochastic grids of hydraulic properties and salinity. The ensembles provide the probability of locating areas where the requirements of sustainable groundwater extraction are met.
        The integration framework not only allows to rapidly identify prospective zones for sustainable groundwater extraction, it is transparent, can be iteratively and locally updated when new information becomes available.

        Speaker: Dr Luk Peeters (CSIRO Mineral Resources)
    • 11:15 12:45
      Parallel: Monday Morning 3: Topic 2 Multiuse room 2 ()

      Multiuse room 2

      • 11:15
        Impacts of Climate Change on Groundwater – results from the BINGO project 15m

        Climate change impacts on groundwater usually take a longer time-lag to occur than in surface water resources, depending on the inertia of the aquifer, which are further enlarged by land use changes, population growth, changing socio-economic conditions, hindering the sustainable management of groundwater resources, which should also take into account the ecosystems’ needs. Climate change studies usually are long term (2070 or 2100) while decision-makers define policies under short term frameworks. Trying to overcome this problem, BINGO project analysed the impacts of climate change, including extreme events, on the water cycle for time horizon 2024. The analysis of climate change impacts on the aquifers Tejo-Margem Direita & Tejo-Sado/Margem Esquerda, Aluviões do Tejo (downstream Tagus Basin), starts by using climate data from 10 climate realizations and their ensembles, generated by regional climate model MiKlip developed by FUB. These data are used by BALSEQ_MOD model to calculate recharge, which is an input data for the 3D FEFLOW aquifer’s flow model. Results are presented for maximum recharge conditions (from MiKlip R1 realisation), which show a recharge change of +49.1%, +37.6%, +29.4%, for each of the aquifers, respectively. This is translated in piezometric rises between +2 and +5 m and flooding of several areas. For the minimum recharge conditions (from MiKLIP R3 realization) recharge changes range from -10.4%, -20.6%, -11.6% respectively for the same aquifers, translated into piezometric changes between -2 and +10 m. For the ensembles recharge conditions (from MiKlip R1_R10) ranges from + 5.4%, + 4.2%, +0.2% respectively, translated into a negligible piezometric change. Once the ensembles scenario is the most likely for 2024 the results show that studies for the short range are not very useful in supporting adaptation strategies, particularly for large aquifers as in this case, and instead what is required is a policymakers’ paradigm shift from the short range to the long range when dealing with climate change. That means, act now in order to be able to cope with the changes that are in store for the future instead of relying only on short term studies.

        Speaker: Dr emilia novo (LNEC)
      • 11:30
        Fresh Groundwater Resources for the Future Generations of Yemen 15m

        Unlike most regions in the Arabian Peninsula, Yemen receives appreciable quantities of freshwater due of its position within the migration pathway of the Intertropical Convergence Zone (ITCZ). Heavy rains of around 600 mm/a on average fall over the densely populated western part of the country, denoted here as the Red Sea Zone (RSZ), where about 90% of the population live in major cities or small towns and villages scattered throughout the highland plateau areas. These precipitation events occur mainly as tropical storms during July - September when the southwesterly low-level summer monsoon winds transporting moisture from the Southern Indian Ocean sweep across the country. Heavy rains that can be as high as 1 500 mm/a in the escarpment areas, feed directly the shallow alluvial aquifers in the intermontane areas which, in turn, replenish the underlying deeper and more extensive Cretaceous Sandstones with fresh water. Further down on the coastal areas along the Red Sea, surface water runoff and flash floods descending through major wadi channels percolate into alluvial aquifers extending across the Tihama Plain. It is estimated that a total of about 3.5 billion cubic meter (BCM) per annum of renewable water resources (2 BCM surface water and 1.5 BCM groundwater) is currently generated in Yemen, mainly in the RSZ. This is a substantial volume of freshwater for a country that is predominantly arid to hyper-arid. Yet Yemen has one of the worst water crisis in the world. The very rapid increase in population since the early 1960s continues to put pressure on the availability of freshwater resources, which currently stands at 73 m3/inhab/a. This demographic pressure on the renewable water resources will be compounded by the effect of climate change in the near future since Yemen is particularly vulnerable to climate change. Climate change models predict a steady rise in temperature as well as an increase in variability and intensity of rainfall. This paper looks into the potential effect of climate change in Yemen, both negative and positive. It summarizes the different scenarios of climate change impacts proposed for the country within the context of a probable northward migration of the ITCZ, which would bring more heavy summer rains spreading throughout the entire country. Finally the paper describes the result of recent investigations that shows the occurrence of relatively shallow and unexploited non-renewable groundwater resources of excellent quality in the country, and proposes that these resources should be further explored and developed for providing the future generations in Yemen with fresh water, particularly in the heavily populated RSZ.

        Speaker: Dr Yusuf Al-Mooji (Freelance consultant)
      • 11:45
        Drivers of changes in Austrian groundwater levels – climate vs. water use 15m

        Groundwater is an important resource for public, industrial, and agricultural water use. Climate change alters the hydrological cycle and thus also the replenishment of groundwater resources by infiltrating precipitation or surface waters. In Austria, renewable freshwater resources overall exceed by far water use, but in the eastern part of the country considerably lower precipitation and thus lower groundwater recharge prevails. Warming in the Alpine region since the late 19th century was twice as high as the northern hemispheric and global average. Thus, potential impacts of climate change on Austria’s water resources warrant attention. Future changes in water or land use (which may or may not be induced by climate change) can aggravate or mitigate adverse climate change impacts on groundwater. To improve our understanding and identify potential drivers of long-term trends and short-term responses of groundwater levels, we analyze standardized time series of groundwater levels, stream stages, and precipitation in Austria. As we have recently shown (Haas and Birk, J. Hydrol.: Reg. Stud., 2019) countrywide and regional averages of groundwater levels trend downwards until the 1980s, from whereon they recover. As compared to the distinct falling trend, the subsequent rise is less pronounced. Precipitation follows this track, but the downward trend is less severe. River stages lack data for the downward trending period, but follow the upward trend too. We hypothesize that the increasing water use before the 1980s accounts for the discrepancy between average precipitation and average groundwater level in this period, especially since Austria meets its water demand mostly from groundwater and the observation wells cluster around areas with high water demand. Although Austria has a diverse and differing geography, the observed trends hold for almost all regional subsets. However, since most groundwater observation wells follow human use, large parts of the country (mainly the mountainous regions) lack long-term groundwater data. Thus, the findings of this work are representative for Austria’s populated lowland and valleys rather than for the Alpine peaks and ranges.

        Speaker: Prof. Steffen Birk (University of Graz, Institute of Earth Sciences, NAWI Graz Geocenter)
      • 12:00
        Examination of the hydrologic cycle with long-term precipitation and groundwater level data 15m

        The impact of the ever-changing climate on Earth is already evident in the emergence of weather extremes and increased water demand from the agriculture. These changes and the human responses to it can greatly change many elements of the hydrological cycle. Weather extremes all appear in the amount and intensity of the fallen precipitation, while increased water demand in many areas has led to a permanent water level decrease in mainly shallow groundwater aquifers.
        Examining the changes requires large amounts of measured data, both for rainfall and water levels. In our study, these two elements of the hydrological cycle were analyzed in the Carpathian Basin involving several sample areas.
        Changes in the amount and time distribution of the fallen precipitation were investigated across the entire Carpathian Basin by analyzing more than 100-year-long data sets, while the impact of the increased water demand was analyzed for the largest continuous agricultural area at the Hungarian Great Plain.
        The different hydrological time series were analyzed by various mathematical methods. Spectral analysis based on the Discrete Fourier transformation was used to study long-term precipitation and shallow groundwater time series, and several deterministic cycles were calculated. In both rainfall and groundwater data, we have identified 13 cycles that were found in each time series, just like the 5-year, 12-year, and 4.5-year long cycles. With the help of Wavelet analysis, we also examined the extent to which these cycles changed during the 20th century, and whether there was an increase in the stochastic effects.
        On long-term shallow groundwater time series, a complex method of factor and cluster analysis were performed based on the linear modeling of each monitoring point’s seasonality, so data sets were generated from the often incomplete time series registered in different measurement intervals, which will later meet the conditions of the spectral analysis.
        The research was carried out within the GINOP-2.3.2-15-2016-00031 "Innovative solutions for sustainable groundwater resource management" project of the Faculty of Earth Science and Engineering of the University of Miskolc in the framework of the Széchenyi 2020 Plan, funded by the European Union, co-financed by the European Structural and Investment Funds.

        Speaker: Mr Csaba Ilyés (University of Miskolc MTA-ME Geoengineering Research Group)
      • 12:15
        IMPACT OF CLIMATE CHANGE ON GROUNDWATER RECHARGE AND BASE FLOW IN THE MUDA RIVER BASIN, MALAYSIA 15m

        The impacts of climate change are significant on both surface and groundwater resources. However, little attention has been given to the effect of climate change on groundwater resources. Therefore, the present study is concerned with the effect of climate change on groundwater recharge and base flow in Muda River Basin, Malaysia. The model simulations were based on 55 years of historical rainfall and runoff data (1960-2015) while climate change scenarios were run for 50 years from 2016–2050 using different downscaled Global Climate Model projections. The future climate variables were obtained from five GCMs projection were downscaled. These GCMs include i) CanESM2 from Canadian Centre for Climate Modelling and Analysis, ii) GFDL-CM3 from Geophysical Fluid Dynamic Laboratory NOAA, iii) HadGEM2 from UK Met Office, iv) IPSL-CM5 from Institut Pierre-Simon Laplace and v) MIROC5 from Japan Agency for Marine-Earth Science and Technology Frontier Research Centre for Global Change. For each GCM downscaled projection, results for two representative concentration pathways (RCPs) have been produced, namely: RCP 4.5 and RCP 8.5. These pathways describe possible future climates depending on how much greenhouse gases are emitted in the years to come. The results indicated the average annual runoff resulting from each GCM, three future possible climate scenarios were determined as Dry (CanESM RCP4.5), Intermediate (HadGEM2 RCP8.5) and Dry (MIROC5 RCP4.5) The results of this study would help policymakers, scientists, government officials and local stakeholders in planning and management of the surface and groundwater resources in the Malaysia regions.

        Speaker: Dr Mohd Khairul Nizar Shamsuddin (Senior Research Officer)
      • 12:30
        Assessing the groundwater potential of upper and middle aquifers in the Senegalese groundnut basin region – contribution of a numerical model 15m

        Drinking water supplies in the groundnut basin region of Senegal are mainly derived from Maastrichtian confined aquifer abstraction. However, water quality in this part of the aquifer is problematic with regard to health issue due to relatively high salinity and fluoride at levels exceeding WHO standards. From this fact, Water authority (Senegalese Ministry of Water Resources DGPRE) has decided to explore the potential of upper and middle aquifers (Quaternary, Eocene and Paleocene formations) where little is known about these hydrosystems. DGPRE hence launched a study to investigate the potential of the aquifer system overlying the saline Maastrichtian aquifer in order to build catchment facilities and/or explore dilution options to supply water that meets quality standards to this large regional population.

        Field investigations including geophysical, hydrogeological, hydrochemical surveys were carried out focusing mainly on the aquifer system above the Maastrichtian formations. Results indicate moderately permeable but thick formations as well as variations in water quality from one sector to another. These investigations also reveal endorheic piezometric depressions, with a water level dropping to 30 m below sea level. This piezometric depression phenomenon is known in the Sahelian region and can be explained by several hypotheses including deep evaporation or ancient changes in sea level.

        The presence of brackish water relics and piezometric depressions near the hypersaline waters of the Saloum River has raised concerns regarding the sustainability of water abstraction from these aquifers.

        A numerical model was developed to serve as a tool for evaluating and managing this resource and for planning purposes. Various pumping scenarios were tested, in particular transferring the present water abstraction from the Maastrichtian aquifer to both upper and middle aquifers. The drawdown caused by pumping and the risk of water quality deterioration due to the migration of brackish water were evaluated in the long term. Results showed that exploiting this resource could be a pertinent solution. However, this would require preliminary field testing and increased monitoring of changes in salt concentrations during operation.

        The combination of investigations, data analysis and numerical simulations made it possible to identify favorable locations for the creation of new shallow well fields. This work must be followed by pilot site tests, in order to verify in situ variations of the water table induced by pumping operations. If these tests confirm the potential of the upper and middle aquifers, it should then be possible to diversify resources tapped for drinking water supplies and thus improve the quality of distributed water.

        The IDEV-Artelia consortium is grateful to the Senegalese Ministry of Water Resources (DGPRE) and its director, Mr Niokhor NDOUR for having accompanied the study and for his contribution to its success.

        Speaker: Mr Rémi Vigouroux (Artelia)
    • 11:15 12:45
      Parallel: Monday Morning 4: Topic 3 Conference room 1.B ()

      Conference room 1.B

      • 11:15
        Pumping response and sustainable well yield of some hard-rock aquifers 15m

        The issue of sustainable yield of some wells drilled in hard rocks of the Mediterranean Region was examined. The objective of the study was to verify which information may be obtained from the results of pumping tests in order to define the long-term well functioning. These aquifers might play a strategic role in drinking and irrigation water supplies for the Mediterranean Region in a near future.
        Data analyzed concern results of pumping tests performed in three areas with similar climate conditions, which differ in hard-rock type (intrusive, effusive and metamorphic rocks). The pumping data were interpreted with analytical techniques and commercial software. This allowed to recognize three main drawdown trends, coherent with three hydrogeological settings: i) delayed response coherent with the presence of double porosity; ii) rapid increase of drawdown coherent with the presence of a barrier boundary, iii) stabilization of the water level over time coherent with the presence of a recharge boundary. On the basis of the identified trends and hydraulic parameters, different pumping scenarios were simulated through available analytical solutions and finite difference flow model.
        The transmissivity values derived from the pumping tests cover two orders of magnitude and permit to categorize the hard rocks in the classes III and IV according to Krásný’s classification. The storativity is included in a wider range of values. The previous hydraulic properties, together with the simultaneous response to pumping of the drawdown for the piezometer (or piezometers) and the pumped well, may permit to treat the aquifer as a porous equivalent medium at the volume scale of the pumping test. All these properties, associated with an appreciable aquifer recharge, make these aquifers of interest for the local water supply. In this regard, some suggestions to define the sustainable yield of a single well may be derived from the comparison of results of pumping tests with the performed simulations. The results show that the long-term trend in the drawdown and the initial thickness of the aquifer constrain the sustainable yield of a well. In the worst cases examined, the sustainable well yield is from 1 to 2 L/s. These well discharge values are significant if compared with those found in other regions of the world.

        Speaker: Vincenzo Piscopo (Università degli Studi della Tuscia)
      • 11:30
        THE ARTIFICIAL RECHARGE OF AN URBAN DRINKING WATER AQUIFER (Udine – Italy): A DIGITAL MODEL TO GROW THE WATER FLOW FROM WELLS, PROJECT THE POLLUTION PROTECTION WORKS, OPTIMIZE THE COST-BENEFITS 15m

        THE PROBLEM

        The drinking water system (AMGA public supply company) for UDINE city (Italy) is alimented by a freatic aquifer placed near the Torre River and a pumping field (surface 1kmq). These groundwaters and the entire drinking water system (150.000 people) are menaced by 2 problems:
        1. a big decrease of piezometric levels during the summer periods (4 months/year) which forces AMGA to buy drinking water from concurrent aqueducts, paying an exagerate cost;
        2. the quality of groundwaters are constantly menaced by pollution from accidental events including chemical industrial end agriculture pollution, bad human acts against strategic water ressuources.
        The solution was to find the best artificial recharge works to grow the piezometric heads in the aquifer, to produce an increase of water flow pumped from AMGA aquifer, to guarantee during the summer a sufficient water supply for UDINE.

        THE RESULTS

        Starting from hydrogeologic numerical model for the analysys of several different options and test for calculate the recharge strategy, we found the optimal solution to build modifications in the pumping field, new hydraulic drainage works, to find the project parameters-geometry-dimensions, to find the optimized costs which eliminated all the other solutions tested by model.
        The results gave:
        1. type of works and governance actions to increase pumped water flow from aquifer, to increase the piezometric level and the drinking water availability during summer seasons:
         2 barrages in the river, 1 artificial recharge basin;
         growth of the average piezometric head in the pumping field = 0,6m;
         increase of pumping flow = 120 l/s in the summer season;
         cost savings on purchasing water from drinking water company competitor= 1 €/m3= 620.000€/year;
         gross pay back = 5 years;
         Cost = € 2,4 million.
        2. type of works and governance actions to prevent groundwater pollution crisis:
         installations to control the quality of water starting from the artificial recharge sources;
         n.7 monitoring piezometers placed in hydrogeologic optimized positions;
         arriving time of a worst possible water pollution plus intervention = 9 days;
         imposed frequence and time to complete laboratory analysis sets = 9 days;
         project of the alarm system h24 placed in the aqueduct UDINE center placed 20km from the pumping field;
         preparation of a intervention procedure and field equipment in case of water pollution crisis/emergency (diffuse, punctual, external aggression, critical events).
        3. this method can to be applied in every freatic drinking water aquifer with a recharge source available nearby.

        Speaker: Dr gian paolo droli (Studio Idrogeologico GEOECO)
      • 11:45
        How efficient energy production can be fostered in transboundary aquifers 15m

        Achieving sustainable exploitation of thermal aquifers based on good governance is a recurrent challenge faced globally. The Pannonian Basin is a clear example, where some neighbouring countries have delineated thermal groundwater bodies, which must be assessed and managed according to the EU Water Framework Directive. In most cases these thermal aquifers are transboundary, necessitating the use of common assessment methodologies, monitoring requirements, and data sharing. As the economies of these countries develop, with growing demands from competing sectors, the need for both cold groundwater and thermal water increases. Boosting the share of renewables within the energy sector generally results in increased groundwater abstraction. This has a negative impact in the transboundary zones where aquifers cross national boundaries.

        The international projects T-JAM and Transenergy assessed transboundary thermal aquifers in the Pannonian Basin, proposing improved management goals. The ongoing DARLINGe project promotes a more sustainable, governance-based exploitation of existing geothermal resources in the heating sector which will contribute to an improved energy efficiency and security in the Danube Region.

        An innovative benchmarking methodology, developed and refined within this project, provides an easily comparable, informative tool for thermal water management, and its use supports measures for more efficient energy production. The tool has been tested and evaluated in selected transboundary thermal aquifers of the Pannonian Basin using a unified and harmonised approach. Pilot sites were investigated in the Hungarian-Serbian-Romanian, Slovenian-Croatian-Hungarian and Serbian-Bosnia-Herzegovinian transboundary thermal aquifers.

        Five main stakeholder groups each with different interests can benefit from this methodology. These are: 1) management authorities, international organizations, 2) licencing authorities, 3) research organizations and universities, 4) investors in geothermal use, and 5) thermal water users. Following the identification of potential beneficiaries ten relevant criteria of the benchmarking methodology were defined.

        Five categories of benchmarking indicators are defined: 1) management, 2) technology and energy, 3) environment, 4) social, and 5) economic. The minimum data requirements and data evaluation level is specified for each indicator. The indicators related to management are: licencing procedure, monitoring requirements, monitoring setup and passive monitoring. The indicators related to technology and energy use are: operational issues, cascade use, thermal efficiency, and utilisation efficiency. Environmental issues deal with reinjection, over-exploitation, and the status of water balance indicators. Waste water management evaluation could not be applied in all partner countries due to a lack of current availability of recent monitoring data. The social indicator was tested based on public awareness at site level. An example of an economic indicator is shown on a project level.

        For ease of use the tool calculates a final benchmarking number based on indicator types and values.

        Speaker: Dr Teodóra Szőcs (Mining and Geological Survey of Hungary)
      • 12:00
        Management of groundwater-energy-food nexus for sustainability 15m

        Groundwater management is important for global and local sustainability, which is shown as large groundwater footprints through the global agricultural trade and local environmental problems due to groundwater depletion, as well as climate change impacts on groundwater resources directly and indirectly, and carbon emissions through human activities using groundwater. Groundwater, energy and food are interlinked each other beyond the boundaries of each shed as well as trans-spatially, such as local, national, and global, through the food and energy trades. Interactions between groundwater-food-energy nexus and environmental/ economical/social impacts under the conditions of climate change and urbanization, are analyzed for global and local sustainability, in terms of multi-scale integrated management and governance of the nexus by increasing synergies and reducing trade-offs. Environmental changes and degradations such as air and water pollutions, land subsidence, and others, had been occurred significantly during the Anthropocene, as tradeoff of the economic development, even though the national and local government policies had tried to make synergy of groundwater-energy-food nexus.
        To understand the relationships between social/economic developments and environmental change, some analyses have been made with the indices including self -sufficiency as a part of securities, water footprints for food production as nexus interlinkage and others, depending on the different spatial scale as transboundary of inter- and intra- connected nexus. Three databases are made with resources, interlinkage, and scenario in multi-spatial scale including Kyoto city, Kyoto prefecture, Kansai area, and Japan. A nexus model to analyze the change of the nexus structure has been developed, and assessments of the changes in three resources, carbon emission, environmental and economic impacts, are analyzed. Preference of local food production causes the decrease in energy consumption for food transports and carbon emission, on the other hand the increase in water and energy consumption in local area. Tradeoffs were found between economy and environment as well as local and national scale.

        Speaker: Makoto Taniguchi (Research Institute for Humanity and Nature)
      • 12:15
        The “hydropuls®” Process for Regeneration and Intensification of Wells 15m

        Dipl.-Ing. Toralf Fischer, Managing Director TLM hydropuls GmbH

        "hydropuls®" is a pulse process for the abrupt expansion of highly compressed gas that increases or restores the productivity of wells or helps in the development of wells. The equipment has been successfully implemented in different parts of the world showing that it improves well efficiency and, consequently, well productivity. The technique is currently used in 25 countries around the world, with important customers such Suez, Danone or the Berlin Water Group. The equipment contains a pulse generator that can produce pressure pulse trains using a valve system capable of releasing, in very short times (milliseconds), the energy accumulated in the pulse generator in the form of highly pressurized gas, producing hydraulic shock waves. At the same time a cavitation effect (hollow suction) is caused due to the sudden volume change, which leads to the formation of a "vacuum bubble", which then collapses and thereby generates a hydraulic "suction wave". “hydropuls®” is potentially interesting for all well operators and well owners as well as for professionals who have to contend with the problems of well aging.

        Speaker: Toralf Fischer (TLM hydropuls GmbH, Germany)
      • 12:30
        Development of Integrated water resources management model in the transboundary Cijevna River Basin (Montenegro – Albania) 15m

        Transboundary Cijevna River Basin is shared by two countries, upstream Albania and downstream Montenegro. Generally, Cijevna is one of the most important rivers for Montenegro, not because of its river flow but because of its water quality and principal role in recharging of aquifers used as a main source for water supply in entire Skadar basin, which is the largest in Montenegro.

        Sustainable transboundary water management is one of the highest priorities of the two countries, what is confirmed by signing of bilateral Water Management Agreement, in July 2018. Development and implementation of this Agreement have to be the key point of the established cooperation in transboundary water management. Implementation of ESPOO Convention, Helsinki Convention, as well as Water Framework Directive of the European Union, and other connected water by-laws are all part of signed agreement, and found to be a substance of integrated water resources management on a transboundary level. This Agreement consider that envisaged activities in one country with possible impacts on another, should be subject of discussion between countries, based on scientifically prepared basic data.

        The Cijevna River Basin has been previously emphasized as a priority basin for integrated water management within frame of the international GEF funded Dinaric Karst Transboundary Aquifer System project (“DIKTAS”), and its Strategic Action Program (SAP). Basically, within entire transboundary Cijevna River basin the limestone rocks are dominant, and karst and fluvio-glacial groundwater are abundant. An active hydraulic connection between surface and groundwater in this basin is a sensitive factor: Any undertaken works or river training may cause negative implications on groundwater regime, as well as water quality. Currently limited investigation and monitoring of groundwater in this basin have to be improved which will offer an opportunity to develop model for sustainable transboundary water use. Design and establishment of new groundwater monitoring network within the Cijevna transboundary river basin, which should include “early warning system”, and results of new investigations, should enable a base for further negotiations between countries, strategical planning and development of Integrated Water Resources Management. If would result with success, such an approach may be widely used for promoting efficient water management in sensitive karstic areas.

        Speaker: Mr Momčilo Blagojević (Water Management Directorate, Ministry of Agriculture and Rural Development, Montenegro)
    • 11:15 12:45
      Parallel: Monday Morning 5: Topic 3.1 Multiuse room 1 ()

      Multiuse room 1

      • 11:15
        Developing a structured groundwater database for hydrogeological interpretation as a tool for sustainable groundwater management in Guinea-Bissau (W Africa) 15m

        Guinea-Bissau is a small West African Country characterized by a tropical savannah climate and an almost flat morphology. Although the yearly rainfall is high (around 2000 mm in Bissau), about 30% of the total population has no access to safe water (2015) and several villages are not reached by mechanized drilling programs. Exploitation of groundwater is fundamental to improve this situation, but the scarcity of information and the low quality of the data limit the hydrogeological knowledge of the territory by technicians and scientists.
        The research has been developed through a positive collaboration between University of Milano-Bicocca, University of Padova, UNICEF Bissau and the national water authority (DGRH – Direção Geral dos Recursos Hidricos). Our purpose is to support DGRH in the systematic organization of the large amount of information available and in the efficient management of a well-structured groundwater database.
        Borehole-log data have been processed with specifically designed software (i.e. TANGAFRIC and spMC) that allow the extraction of hydrogeological parameters from the logs and the spatialization of the textural characteristics.
        The collaboration UNICEF-DGRH started in 2016, with the introduction of a new database structure and procedure for data collection and organization. This method is based on the web platform mWater Portal (portal.mWater.co) which allows to manage a Water, Sanitation and Hygiene (WASH) information system at national scale, with the possibility to display and monitor the inventory of water points. With the technical support of the Italian Universities, a clean dataset of about 800 litho-logs has been extracted. The stratigraphic description is standardized and organized in such a way that TANGAFRIC could process the data automatically. Through this software a limited number of standard categories, describing the lithological characteristics of each log, were assigned meter by meter. This allows the automated extraction of different textural parameters and the estimation of hydraulic conductivity at log level. In the following step TANGAFRIC’s output have been integrated into the spMC package which allows the spatial simulation and prediction needed for the lithological reconstruction of subsurface. In particular, we are looking for possible correlation between the water quality and the lithological bodies geometry and trend, focusing on the Catiò Sector (SW Guinea-Bissau), where groundwater is affected by salt intrusion and high iron concentration.
        The research is demonstrating the potentiality of a properly organized groundwater database, developed from the information available in a low income African Country. The integration of specific tools for data collection and organization, together with software for hydrogeological interpretation has made possible to improve the knowledge of the hydrogeological context at national level.
        The proposed procedure is simple, innovative and easily replicable in other African Countries where an adequate strategy for groundwater exploitation and management could contribute to improve living conditions.

        Speaker: Arianna Marcolla (Department of Geosciences, University of Padova, Italy)
      • 11:30
        Empowering Local Drillers and Training Communities To Ensure Groundwater Resource Sustainability by Adequate Self Flowing Well Design and Drilling 15m

        The Rejoso Watershed, located in Pasuruan District, East Java, Indonesia, is facing the issue of the depletion of its groundwater resource at least since 2007. The cause is related to the high number of improper drilled self-flowing wells. These low-cost wells are funded by the local communities and are mostly used for agricultural needs (paddy field, annual crops and livestock).

        These improperly drilled wells are not grouted, nor screened. As a consequence of no grouting, they lose lots of groundwater without any use, as (i) they leak through their annulus, and (ii) they flow year/day long, also when water is not used. In fact, their owner fears that valving them will reduce their productivity. This fear is partly grounded as annulus leaks may increase following valving. Moreover, due to the absence of a screen, well also collapse and their lifespan is reduced.

        In this paper the methodology developed to implement and educate both drillers and community is presented on how to drill a proper artesian well called a "good water well" that can be controlled instead of making "bad wells" flowing about 5 litres/sec for 24/7, that have been spread around 600 units in the aquifer.

        The methodology is 3 steps: (i) Drilling process, divided into drilling method, well construction, and grouting. During drilling, a hydrogeological log is elaborated from cuttings description and discharge measurements to locate the aquifer(s) and design the well. (ii) Wellhead construction design: the wellhead is equipped with an efficient valve to enable closing the well when water is not needed. (iii) Educating the local community, government, and private sector, through the implementation of the "Good water well", to the differences between "good" and "bad wells".
        This initiative successfully completed a pilot good well flowing 7 litres/sec and closed the bad well nearby with grouting. The log showed that the shallow unconfined aquifer extends down to 60 m. The confined aquifer ranges from 60 to 65 m (bottom of the well). A blind 4" PVC pipe was installed in the 8" borehole (0–60 m) and the confined aquifer was screened. The annulus of the casing from 0–60 m was grouted and the artesian flow stopped in the annulus during the grouting process. To control the wells discharge and ensure monitoring, a flow meter, a gate valve, and a ball valve were installed. A transparent acrylic pipe was also installed to convince local water users that the water is not "disappearing" when the valve of the well is closed and that the well will not collapse, as the community believed. This good water well manages to save water and change the mind-set of the community, resulting in 150 ML/year saved groundwater.

        Keywords: drilling, sustainability, artesian management

        Speaker: Mr Arif Fadillah (Danone Aqua)
      • 11:45
        Lessons learned from groundwater governance and management and capacity building programmes in the developing world 15m

        Sustainable groundwater management has become topical and thrust in the forefront of water resources development and management in recent years, buoyed by the increasing water scarcity resulting from recurrent droughts, over-exploitation and quality deterioration of groundwater resources, especially in semi-arid and arid countries of the developing world. Climate variability and change further acerbates the impact of unsustainable use and abstraction of groundwater. There is, therefore, utmost need to support developing countries water management and governance institutions to better their understanding and implementation of sustainable groundwater management.

        Technical support and capacity building in groundwater governance and management towards sustainable groundwater use and abstraction was provided to different developing countries through various programmes of the Gesellschaft für Internationale Zusammenarbeit (GIZ) over the past two decades, which included: (i) SADC Transboundary Water Management Programme - Botswana, (ii) Rehabilitation of Water Supply Systems in Western Eritrea Programme, (iii) Water Sector Reform Programme in Kenya; (iv) International Water Stewardship Programme in Pakistan and Zambia, and (v) Reform of the Water Sector and Urban Water Supply and Sanitation Programmes in Zimbabwe. A detailed account of these programmes is provided concomitantly with its objectives, achievements and lessons learned.

        Groundwater governance of each of the regions (Southern Africa: Botswana, Zambia and Zimbabwe; Eastern Africa: Eritrea and Kenya and Southern Asia: Pakistan) is compared and its impact on sustainable groundwater management evaluated with the aim to identify future governance needs and required support.

        The analysis shows that there are more similarities than differences in the shortcomings of groundwater governance and that mitigation of the shortcomings requires interventions adapted to the local circumstances. There is a critical need for developing and operationalizing legal frameworks, and strengthening of the institutional frameworks.

        Speaker: Dr Hans Beekman (GIZ-Consultant)
      • 12:00
        Water Scarcity in Pacific Island Countries; Experiences in National Water Policy Development. 15m

        One of the most rational adaptation strategies to global change in Pacific Island Countries appears to be overcoming current challenges by building on the recognised strengths and resilience of island communities, strengthening institutional structures and human resources, while maintaining or enhancing the ecosystems on which island communities depend. Aid agencies and donors have seen the development of national water policy as a key step in adaptation. This work describes experiences in assisting Kiribati, Nauru, Solomon Islands and Tokelau, Pacific countries with varying dependencies on groundwater, to develop national water policies and associated implementation plans. Existing developed world policy frame works, templates and tool kits were of little use in countries were the policy development process is rudimentary or, as in one case, non-existent, and where only one or two people are responsible for water management. Ackoff’s five phases of interactive planning was a useful, easily- understood process for identifying issues and arriving at policy and implementation plans. Because this is an adaptive, iterative process, it is fundamentally important that it is carried out with a whole-of-government and community-representative steering group, particularly with women’s group representatives. A sticking point in the development of attendant national water legislation is the traditional view that land ownership implies ownership of surface and groundwater. While success in policy development is seen as Cabinet approval of policy or plans, successful ownership and implementation of policy is more problematic, particularly in protection of water sources. Long-term mentoring of water agencies has many positive benefits.

        Speaker: Prof. Ian White (Australian National University)
      • 12:15
        Inferring groundwater recharge associations to climate, land use and geological structures using multi-decadal groundwater level observations from the semi-arid Limpopo basin of South Africa 15m

        Keywords: Episodic recharge, WTF-method, 1D-modelling, climate, Limpopo basin

        Determining the long-term sustainability of groundwater use in arid and semi-arid regions with high climate variability requires an understanding of the recharge processes that replenish the aquifers as well as their major drivers significantly affecting their temporal and spatial variability. Four hydrographs that range from 42 to 46 years in duration, each within deeply weathered gneiss, were chosen on the basis of their proximity to rain gauges, interpretability throughout, and visible evidence of recharge events in the records. Recharge is quantified using: (1) the Water Table Fluctuation method, applying an inverse approach to estimate recharge from the event-based rises in groundwater level at daily and monthly time-steps; and (2) the HYDRUS 1D model: computing recharge using a dynamic soil-moisture balance model incorporating rainfall, evapotranspiration, soil properties and vegetation characteristics. The hydrographs show that groundwater levels after each rainy season, Oct-Apr, are highly variable in terms of recovery from the previous dry season levels though large episodic recharge events disproportionately contribute to groundwater replenishment. Hence, characterising these recharge events further and their relationship to climate and land use is pivotal to understanding and predicting long-term aquifer sustainability within the wider framework of climate resilience. Correlations from our records show a tendency for episodic recharge to occur during La Niña years, but not strongly enough to act as a predictive tool for significant recharge years. Finally, we provide evidence of focused recharge from surface water bodies, likely in cases further promoted by preferential flow pathways along geological structures like fractures and dikes typical of the region.

        Speaker: John Lindle (University of Copenhagen, Denmark)
      • 12:30
        IMPACTS OF LAND-USE CHANGES AND URBANIZATION ON COASTAL GROUNDWATER RESOURCES OF LAGOS, SW-NIGERIA: Integrated Hydrogeochemical and GIS-based Assessments 15m

        Water and food security are essential to human survival and well-being vis-a-vis sustainable resources management and attainment of the SDGs. This study employed hydrogeochemical and GIS-based assessments of impacts of land use and urbanization on groundwater with emphasis on the resilience and security of coastal water supply in Lagos metropolis, SW-Nigeria.
        For the assessment of land-use changes and associated impacts on community livelihood, Spot 5 satellite imagery of 1984, 2002 and 2017 of Lagos area alongside with Landsat ETM+ and OLI were used to generate the land use / land cover (LULC) changes in ArcGIS 10.3 Software. For the hydrogeochemical quality assessment, seventy (70) water samples were collected from different household water points (wells and boreholes) within Lagos. In-situ physicochemical parameters (pH, Temperature, TDS and EC) were measured in the field followed by laboratory analyses of major cations and anions.
        GIS-based assessment revealed a significant increase in the built-up areas from 447.3km2 in 1984 to 951km2 in 2017 representing 85% increase with corresponding loss of about 5% of the forested coastal wetlands. This is a clear indication of rapid urbanization in the last three decades with attendant impacts on coastal water quality and sustainability. Hydrochemical assessment revealed elevated electrical conductivity (EC) of >1,000μS/cm alongside with elevated Na (51-230mg/l), Cl (300-980mg/l) and SO4 (36-88mg/l) concentrations in shallow wells and boreholes tapping the upper unconfined aquifer. This is a clear fingerprint of groundwater vulnerability to saline intrusion and contamination.
        Therefore, in the face of reality of impacts of anthropogenic land-use and climate-induced changes, there is the need for a clear governance structure to regulate the rate of groundwater abstraction and indiscriminate groundwater development to ensure sustainable groundwater resources management and attainment of SDG-6 and avoidance of water supply crisis. Such crisis can be avoided, if appropriate knowledge-based choices, planning / management options are employed; failure of which will likely be very costly.

        Speaker: Prof. Moshood TIJANI (University of Ibadan, Ibadan - Nigeria)
    • 11:15 12:45
      Parallel: Monday Morning 6: Topic 5 Auditorium 2 ()

      Auditorium 2

      • 11:15
        Hydrogeological modeling of the Eastern Mountain Aquifer, Israel, suggesting substantial migration of discharging springs in time 15m

        Terminal Lake levels fluctuate in time as a result of climate change and/or anthropogenic reasons. This phenomenon has recently occurred in some lakes around the world (e.g. Aral Sea in Uzbekistan, Lake Urmia in Iran, Chad Lake in Africa, Mono Lake in California, etc.), which serve as a discharge base of groundwater basins.
        In this study, the effects of extreme fluctuations of the Dead Sea and Lake Lisan Levels on the flow field of the Eastern Mountain Aquifer (EMA) were examined by a numerical hydrogeological model and found to be significant. The model was first calibrated to the current condition and then simulated the paleo and future groundwater-flow-field within the EMA. The results show that currently, 90% of the EMA water discharges in springs located at the Dead Sea shore, at an elevation of ~-430 m below sea level (mbsl), with almost no discharge north of the Dead Sea. However, when Lake Lisan stretched over a larger area within the Jordan Valley, at elevations of -160 to -250 mbsl, as much as 35% of the EMA water discharged through paleo-springs at the central Jordan Valley, north of the Dead Sea.
        The high levels of the Lake Lisan affected the groundwater flow pattern by two means: (1) The hydraulic gradient was different from the current one, thus the flow from the Samaria Mountains (north-west side of the basin) discharged in the close paleo-springs, in the central Jordan Valley; (2) The groundwater flow within deep sub-aquifers was blocked due to higher location of the fresh-saline waters interface. Furthermore, the modeling shows that as the Dead Sea level drops down to ~-550 m, as expected to occur in the next centuries, the current coastal springs will dry up and the groundwater will migrate and discharge close to the Dead Sea along delta-fans.

        Speaker: Mr Yehuda Levy (Institute of Earth Sciences, Hebrew University of Jerusalem)
      • 11:30
        How ground gets wet: physical experiments of variably saturated flow 15m

        Hydrogeology no longer only relies on understanding of phreatic systems. Highly heterogeneous and anisotropic conditions in soil and rock comprising intergranular, fractured and karstic porosity affect groundwater vulnerability, recharge rates, drainage and dewatering practices, soil corrosivity, natural attenuation of contaminants, and integrity of infrastructure, to name a few examples. Movement of water at partial and highly variable saturation is very complex, depending on very small-scale variations in ground conditions as well as very subtle changes in moisture content. In contributing to this, a number of research projects were conducted, focused around physical experiments in the laboratory or mimicked in the field, and subjected to differing conditions pertaining to gravitational acceleration to scale the vertical dimension. Studies contribute to flow mechanisms and flow regimes of variably saturated soils and rocks, as well as the interface between, and link available theoretical understanding and empirical approaches to physical experiments and field verification experiments. Where possible, hydraulic parameters are estimated to improve the quantification of said parameters at discreet scale rather than assuming single values for bulk systems. Obvious limitations and assumptions are understood to the extent that updated flow scenarios are proposed to contribute to variably saturated flow systems. Behaviour is inferred for fractures of changing orientation, changes in medium from soil to rock, and for alternation between wetting and drying of different media. Selected experiments will be presented to highlight novel findings and the way forward.

        Speaker: Dr Matthys Dippenaar (University of Pretoria)
      • 11:45
        Prediction of Groundwater Inflow Rates to Longwall Coal Panels in Central Turkey 15m

        Pre-feasibility studies at a coal basin in Central Anatolia indicate mineable resources of about 265 million tons of coal that can be extracted via underground longwall mining during a mine life of 36 years. Since dry working conditions are prerequisite for a safe and operational mining, prediction of the groundwater inflow rates to the underground panels play a critical role. This study predicts groundwater inflow rates to determine dewatering requirements of the underground panels and evaluate anticipated impacts of dewatering on the groundwater resources. To analyze these aspects, the groundwater flow regime was modeled and calibrated under steady-state conditions using the three dimensional groundwater flow model MODFLOW SURFACT. The groundwater inflow rates were evaluated at six critical panel locations. The results indicate that groundwater inflow rates to the panels range from 26 L/s to 130 L/s, based on the location and depth of the panels. The long term impacts of dewatering on groundwater resources were assessed in terms of spring discharges that supply water to local communities and base flow rates to the Porsuk Stream. As a result of dewatering, majority of village water supply springs and fountains will dry up in the area. Furthermore, no baseflow contribution to the Porsuk Stream takes place for dewatering operations conducted at the deeper panels. On the other hand, the baseflow decreases by 33-38% for dewatering of shallower panels.

        Speaker: Hasan Yazicigil (Middle East Technical University)
      • 12:00
        Optimization of pilot points distribution in inverse modelling- A case study from Qatar Aquifer 15m

        Two approaches are commonly used for model calibration, namely the zonation and the pilot-points method. While the zonation approach assumes an abrupt spatial change in parameter values, the pilot-points method produces smoothly distributed parameters, however, the number and placement of the pilot-points can be challenging.
        The objective of this study is to explore the effect of pilot-points number and locations on the calibrated parameters. The northern aquifer of Qatar is used as a case study, using a 3D groundwater flow model. A numerical model of this aquifer was developed using MODFLOW and the model was calibrated using PEST package using historical data of groundwater levels. The model was run several times using a variable number and distribution of pilot points. The Root Mean Square Error for all the runs (corresponding to different configurations of pilot-points) was maintained under a certain threshold. A statistical analysis of the calibrated parameters was then performed to evaluate how far these parameters are impacted by the pilot-point locations. Finally, a new methodology for Optimisation of pilot points locations was proposed using recharge and piezometric maps.
        The results showed that the pilot-points number, locations, and configurations have a substantial impact on the calibrated parameter, especially in the high permeable regions. The outcome of this study may help focus on areas of high uncertainty where more field data should be collected to improve model calibration. It also helps placement of pilot points for a robust calibration.

        Speaker: Prof. Husam Baalousha (Associate Professor - Hamad Bin Khalifa University)
      • 12:15
        ISOTOPES AND NOBLE GASES INVESTIGATION OF SOUSS-MASSA AQUIFER, MOROCCO. 15m

        The Souss-Massa Basin, an important agriculture area of Morocco, is located in a semi-arid area and its main water resource is the groundwater. Over the last decades, population growth, agriculture development and recurrent droughts have been increasing the pressure on the aquifers of the region.
        In the this context of climate variabilities (changes) and increasing demand for water, it is crucial to identify the origin, groundwater flow dynamics and mean residence times for sustainable management of water resources. In this study, groundwater residence time and recharge conditions of the Souss-Massa aquifer system were investigated using environmental isotopes (δ18O, δ2H, δ13C, 14C, 3H) and noble gases. The results shows that the aquifer is mainly recharged by waters derived from the High Atlas Mountains, where the precipitation rate is higher than in the study area. The spatial variations of stable and radioactive isotope concentrations indicate that active mixing of recently recharged and old groundwater within the aquifer system. The recent recharge is observed mainly along the Souss River and in the irrigated areas.

        According to radiocarbon activity, two groups of waters are defined: recent (14C activity >60 pmC) and old (<30 pmC). Groundwater plotting between these two types can be used as evidence of water mixing processes. Based on the mean regional temperature of 20°C, we can also distinguish two groups of samples: low and relative higher noble gas recharge temperature. Recent and sub-recent waters show recharge temperatures ranging from 13.5 to 24.5°C, with an average around 18.3°C, which is consistent with the monthly inter-annual average temperature of 18.75°C ± 1°C recorded at the meteorological stations Agadir and Taroudant. However, the estimated noble gas temperatures in areas located near to the recharge zones, are still about the annual average local temperatures reflecting relative low contributions of water from the high elevated areas of the Atlas Mountains. The NGT of all samples collected from shallow wells are generally midrange of their annual average temperature at each location. The Turonian water has a recharge temperature of about 18 °C with a radiocarbon age higher than 19000 years BP.
        The study clearly showed that long term recharge conditions and groundwater flow processes, are influenced by natural climatic variability and anthropogenic impacts.

        This study indicates the extent of groundwater renewability and allows establishing a scientifically-based water management model for sustainable exploitation of water resources in the Souss-Massa Basin.

        Keywords: Stable isotopes, Radiocarbon, Noble gases, Paleotemperature, Groundwater age.

        Speaker: Prof. Mohammed HSSAISOUNE (Ibn Zohr University/Sultane Moulay Slimane University)
    • 11:15 12:45
      Parallel: Monday Morning 7: Topic 5 Conference room 1.A ()

      Conference room 1.A

      • 11:15
        Similarity based approaches in Hydrogeology: basic concepts, alternative approaches, first results, potential applications, pitfalls and problems 15m

        Presently, two major types of approaches to predicting the response of groundwater resources to (climate) change are available: 1) numerical models of groundwater flow and transport, 2) conceptual hydrological models. The first category is extremely data hungry and applications are time consuming, while the second relies on data-driven calibration and usually lacks adequate descriptions of the complex three-dimensional setup of the subsurface. Numerical models may be seen as the best choice to make reliable, process- and physics-based predictions. Yet, quite often, the lack of data for parameterization and calibration will hinder meaningful applications. To overcome this dilemma, we propose an alternative and complementary approach. This approach is adjusted to typical data availability of groundwater systems, but still accounts for geological conditions and their three dimensional heterogeneous distribution. The PUB (predictions in ungauged basins) concept developed in surface water hydrology was used as a conceptual basis. The fundamental hypothesis of PUB is: similar systems respond in a similar way to similar changes. Knowledge from a system with known properties and known responses can be transferred to a similar system where responses are not known (i.e. no observations exist). Adapted to groundwater, this can be formulated as: two or more groundwater systems of a certain type will show similar responses (i.e., dynamic behavior = shape of groundwater hydrographs) when exposed to similar changes (e.g. climate change). Hence, we can make predictions for places with known geology but no observations.
        With the present contribution, we would like to summarize experiences we have gathered and results obtained in the attempt to test the applicability of the PUB hypothesis in groundwater. We explain the fundamental challenges involved and our respective findings so far. 1) Detection and quantification of similarity of groundwater systems. 2) Detection and quantification of similarity of groundwater hydrographs. 3) Detection of dependencies between “types” of groundwater systems and “types” of hydrographs. 4) Combining 1-3) into an approach that can be applied to predict responses of groundwater resources in places without groundwater observation wells.
        This contribution is based on a number of (on-going) studies carried out at the University of Gothenburg, Sweden and University of Freiburg, Germany. Our aim with this contribution is to make the underlying ideas known to a larger audience and to invite colleagues from the groundwater community to include similarity-based approaches in their research. We have seen that similarity-based approaches have clear limitations and will not replace any of the existing methods. However, a range of examples from Central and Northern Europe show that they provide a variety of new insights and tools to investigate groundwater systems. Examples will be shown in three other contributions to this conference (Haaf et al., Giese et al., Nygren et al.).

        Speaker: Prof. Roland Barthel (University of Gothenburg, Sweden)
      • 11:30
        Identification and Quantification of Spatial and Temporal Hyporheic Fluxes Using High-resolution Distributed Temperature Sensing in the First-order Alpine Stream in Taiwan 15m

        Hydrologic systems are strongly influenced by interacting processes that from pore space to watershed scale, but it remains a challenge to describe, model, and observe these processes at high resolution in the field. Recently, the Raman spectra distributed temperature sensing (DTS) for use in hydrologic application presents an opportunity for temperature measurements continuously in both space and time and provides a comprehensive picture of heterogeneity for the entire system. Chichiawan Watershed in Taiwan is the only habitat for the endangered species of Formosan land-locked salmon. However, the stream fragmentation, no surface streamflow, seriously reduced the salmon population, hampering the restoration work. Therefore, the utility of combining a high-resolution DTS with long-term monitoring data in the piezometers was to illustrate the complicated dynamics of hyporheic fluxes and to identify a suitable river restoration strategy to mitigate the effect of fragmentation on endangered salmon. The DTS measurements was conducted on the length of the 1,250 m reach covering the fragmented segment of creek from 7-13 November 2018 and seven installed piezometers provided the long-term water levels and streambed temperatures. The results showed that the propagation of stream fragmentation has been observed and the groundwater inflows has been clearly identified. The concentrated locations of groundwater inflows at the downstream confirmed the downstream channel is a perennial stream. The upwelling fluxes is differentiated from the regional groundwater and their contributed ratio vary with time and space. River restoration to mitigate the stream fragmentation can extend the habitat of salmon and the upwelling cold water can provide the thermal refuge for salmons during the summer.

        Speaker: Prof. Yung-Chia Chiu (National Taiwan Ocean University)
      • 11:45
        Lysimeter experiment on municipal landfill waste 15m

        Many landfills do not have ground seals, so that pollutants leached from waste migrate to the ground and water environment. In most cases, the exploitation of unsealed landfills has ended; however, their impact on the groundwater environment still occurs. Lysimeter studies allow us to determine the size and chemical composition of leachates as well as the leachate water balance.
        The lysimeter experiment was carried out from November 2016 until May 2017 on a 230-litre municipal waste sample. During the experiment, the lysimeter was precipitated with distilled water. In each month of the experiment, the total volume of the obtained effluents was measured and the values of specific electrolytic conductivity, temperature, pH and Eh were determined. In addition, the characteristic indicators of groundwater pollution in the area of municipal waste landfills (Na, K, Ca, Mg, Fe, Al, Mn, Ni, Cu, Sr, S, Cl, SO4, HCO3, NO3, NO2, NH4, PO4, N Kjeldahl, TOC) were monitored. Microbiological analysis and profiling of physiological population level using EcoPlateTM microarrays - were also performed in collected leachate samples.
        The maximum EC value from leachate from the lysimeter was 33 mS/cm. High concentrations of ammonium ion (up to approx. 1400 mg dm-3), chlorides (up to approx. 6800 mg dm-3) and iron (up to approx. 31 mg dm-3) were observed in the effluents. Microbiological analyses showed strong contamination of leachates with bacteria, including potential human pathogens.
        Community-level physiological profiling indicates that the activity and functional diversity of microorganisms were higher in the samples obtained in winter compared to leachates collected from lysimeters in spring.

        Speaker: Dr Dominika Dabrowska (University of Silesia, Faculty of Earth Sciences)
      • 12:00
        Integrating Fiber-optics distributed temperature sensing and electromagnetic geophysics data for multiscale characterization of GW-SW interactions in heterogeneous streambeds. 15m

        Groundwater-surface water interactions play a key role in determining accurate estimation of groundwater resources. However, the quantification of water exchanges occurring along and across multiple scales of streambeds still represents a big technical challenge. Given the difficulties to directly measure the seepage and/or infiltration volumes, indirect observation of water exchanges becomes an interesting alternative approach. Temperature profiles together with vertical hydraulic gradients of the sediment allow the calculation of vertical flux exchanges, but the values calculated from such few locations may not be representative of the spatial and temporal variability of exchanges. Conversely, distributed techniques such as fibre-optics distributed temperature sensing provide the opportunity to infer groundwater discharge and surface water infiltration based on the distinct thermal footprints they leave in the sediment-water interface. Moreover, the technique can capture not only the spatial heterogeneity of these patterns attributable to groundwater but also the areas of surface water infiltration during transient events. Electromagnetic induction geophysics can complete the exploration of heterogeneity by identifying the regions of preferential groundwater-surface water interaction based on the distribution of hydraulic conductivity values derived from electrical conductivity observations. Furthermore, the integration of the traditional point data with the high-resolution data from distributed techniques improves the performance of flow and heat transport models used for modelling groundwater-surface water interactions. The study builds a MODFLOW-MT3DMS model to simulate groundwater-surface water interactions in the same study site in East Germany where point and distributed data was collected. The FloPy python suite helps to incorporate the high-resolution data of distributed techniques into the 3D model. The study evidences how models based on distributed geophysics data outperform those defined on sediment cores. Secondly, the model validates the reliability of fibre-optics to identify groundwater-surface water exchanges based only on the spatial and temporal evolution of temperature anomalies in the sediment-water interface. Additionally, 3D flux estimates from the 3D flow and heat transport model cast doubt on the accuracy of the 1D vertical estimates of groundwater-surface water interaction obtained from point techniques. Altogether, the study enables discussing the advantages of using distributed techniques for the investigation of groundwater-surface water interactions with a multi-scale approach while showing the potential of 3D flow and heat transport models fed with this data for upscaling of local groundwater-surface water measurements.

        Speaker: Mr Jaime Gaona (Free University Berlin / Leibniz Institute of Freshwater Ecology / University of Trento)
      • 12:15
        Towards a holistic approach in characterising the water cycle in the Campine area (NE Belgium) at various temporal and spatial scales 15m

        The Neogene aquifer in the Campine area, northeastern Belgium, is a major water resource with many functions. It provides drinking water for the population, irrigation water for agriculture and water for industrial activities and recreational purposes. In addition, owing to its phreatic nature and the shallow groundwater table, it is a water supply for rivers and wetlands as baseflow. The quality and quantity of groundwater, and the geometry of the groundwater body is not only influenced by environmental changes, but also by specific human activities such as groundwater exploitation, polluting industries, deep and shallow geothermal energy, sand extraction etc. It is clear that a proper impact assessment of these activities and changes necessitates the development of well-calibrated and tested coupled hydro(geo)logical models.
        Here we present the first steps taken into developing an innovative modelling framework to tackle the issue of changes in water cycle under future environmental change in small river catchments draining the Neogene aquifer. The framework includes (i) an integration of different components of the hydrological cycle into a coupled model focusing on unsaturated zone-groundwater-river water interactions at the catchment scale, and, (ii) the use of alternative state variables other than groundwater head, such as hydrochemical and age tracers, temperature, and palaeohydrological proxies.
        In this presentation we will highlight various measurement techniques that we (plan to) use to quantify the water cycle in this particular setting. Results include: (i) groundwater exfiltration patterns in small creeks from infrared thermometry and 222Rn concentrations (smallest spatial and temporal scale), (ii) deep (a few decameter) temperature profiles from piezometers in discharge and recharge zones, (iii) CFC, 14C and 3H/He-based hydrochronological ages for an individual aquifer covering the last couple of decades and (iv) a catchment wide assessment of long-term hydrological variability deduced from historical maps and soil profile information covering the last few millenia. Combining these physico-chemical state variables obtained from various temporal and spatial scales will allow to calibrate and verify (coupled) hydro(geo)logical models in the most rigorous way.

        Speaker: Dr Koen Beerten (Institute of Environment, Health and Safety, Belgian Nuclear Research Centre SCK-CEN)
      • 12:30
        ASSESSING COASTAL AQUIFER VULNERABILITY TO SEAWATER INTRUSION USING GALDIT METHOD: APPLICATION TO THE OULJA COASTAL AQUIFER, SAHEL DOUKKALA, MOROCCO 15m

        The Oulja Coastal Aquifer is part of Sahel Doukkala System Aquifer, is one of the main groundwater coastal aquifers in Morocco. It covers about 160 km2 and has a significant role in satisfying water needs for agriculture and potable water supply in the region. Over years, the need for agricultural water has increased, overexploitation of groundwater resources can put their quality under stress. It could be based on rapid disturbance in groundwater level leading to saltwater intrusion in this coastal aquifer.
        To evaluate extent of the threat of the seawater intrusion. The present study is an attempt to map the vulnerability of the groundwater in Oulja Coastal Aquifer of against this intrusion by means of modeling coupled with GIS. The methodology used in the study consists of assessment of vulnerability using GALDIT method, is based on the most important factors controlling seawater intrusion, that is, four intrinsic hydrogeological parameters, one spatial parameter and one boundary parameter including Groundwater occurrence (aquifer type), Aquifer hydraulic conductivity, depth to groundwater Level above the sea (hydraulic head), Distance from the shore, Impact of seawater intrusion and aquifer’s Thickness.
        Assigning each map an appropriate weightages and ratings, and the overlaid of the six thematic maps has allowed to produce vulnerability map. The result of the study indicates a high vulnerability to seawater intrusion due to excessive groundwater withdrawals, especially in the Oulja coastal zone. This vulnerability is more witnessed in the South near the Oualidia Lagoon than in the North of the studied area. The outcomes of this study provide useful insights on effective groundwater management for the Oulja Coastal Aquifer.

        Speaker: Mr Yassine ECHELFI (University Chouaib Doukkali)
    • 12:45 14:20
      Lunch 1h 35m
    • 14:20 14:50
      Plenary
      • 14:20
        Groundwater Project and eBooks: An Evolving Platform for Groundwater Education and Practice 30m

        Groundwater is the source of drinking water for nearly half of the global population and supplies much of the world's irrigation water. Groundwater is complex, out-of-sight and mostly out-of-mind. The GWP (Groundwater Project) is urgently needed to ensure that society achieves the exceedingly difficult task of scientifically-informed, sustainable management and protection of groundwater. The goals of the (GWP) and its eBooks are to publish educational materials, online and free-of-charge. The first iteration will be in English, followed soon after by other languages. The GWP was initiated 3 years ago to cover nearly all aspects of groundwater relevant to both developed and developing countries. The non-profit GWP will fill large voids in educational publishing to become the global standard for synthesized groundwater science. ‘Publishing’ of the first few dozen chapters on the GWP web site will begin in late 2019. Nearly 400 chapters, organized in ~40 ‘knowledge domains’, are planned for the next few years. Many chapters will be layered to support understanding at both introductory and advanced levels with clickable links to equation derivations, worked problems, public domain educational reports, videos of lab demonstrations, field methods, and lectures. Each domain with its chapters is a book within the series of eBooks. The first is for readers with no science education, followed by a book at the undergraduate to graduate level concerning all of the important physical principles and theory. Then there is a book covering the important chemical and biochemical principles. These two books are the foundation for many others on applied topics and interfaces with other disciplines including ecology, human health and social sciences. Although encyclopedic in scope, the GWP is focused on knowledge synthesis to achieve understanding, underpin classroom teaching and facilitate self-education. The eBook aims to provide explanations from experts who are so advanced in their grasp of complex topics that they can convey ideas in impressively simple form. As of May 2019, more than 120 volunteers from 15 countries on six continents are involved in preparation of eBook chapters while the search for more participants continues. Many contributors are internationally recognized experts. A priority is to capture, while still possible, knowledge and key insights from this senior generation. The GWP will also serve as an electronic archive for old, but still insightful groundwater reports from government and other literature not readily accessible, or in jeopardy of being lost. In addition, the GWP will report on the latest advances in groundwater science and technologies to quickly disseminate new knowledge around the globe, including emphasis on the information needs of developing countries. The electronic format was selected for the GWP because materials will be updated and re-published as improvements are made and as global contributions expand.

        Speaker: Prof. John Cherry (G360 Institute for Groundwater Research - University of Guelph)
    • 15:00 16:00
      Parallel: Monday Afternoon 1: Topic 1 Conference room 2.1 ()

      Conference room 2.1

      • 15:00
        Methods to evaluate aquifer recharge in Spain for water planning 15m

        Aquifer recharge is one of the most difficult water balance terms of a given territory to be accurately evaluated. But its knowledge and variability are essential for water planning to attend the human and ecological needs. Recharge is not an independent value for a given aquifer when water exchange between aquifers and other water bodies are significant as in this case the value depends on other factors such as the estate of water exploitation. Recharge evaluation has a high dependence on spatial and time scale, and the different methods available in a given situation do not yield results that are conceptually equivalent. So, calculations have to be carefully done and compared. In Spain, a relatively large effort has been done at peninsular, hydrographic district, river basin, aquifer and local scales in this regard. This is presented in the report RAEMIA (Aquifer recharge, methods and water isotope support. Application to water planning and knowledge of groundwater in Spain), just finished and under publication as an open-access e-book, produced by the Technical University of Catalonia and sponsored by CETAQUA and SUEZ. This report deals with the different recharge evaluation methods currently available, including those based on hydrodynamic and water balance concepts and on natural tracer studies and mass balance. These methods include the support on satellite data. The supporting examples are worldwide, with special reference to Spanish ones and also the application in Ibero-American areas. The application to water planning and the experience in different peninsular and island areas are summarized and commented. Special consideration deserves the different large spatial scale models and atmospheric chloride ion deposition balance. The report tries to contribute to the open discussion on the validity of the different models, discussion which is lively in water scarce areas, considering that scarcity is mostly an excess of water demand in highly agriculturally productive areas or exposed to increasing pollution

        Speaker: Prof. Emilio Custodio (Departamento de Ingeniería Civil y Ambiental, Universidad Politécnica de Cataluña (UPC). Royal Academy of Sciences of Spain)
      • 15:15
        Reassessing groundwater resources in the southern Iullemmeden Basin: Combining archival data and current monitoring. 15m

        Groundwater resources in Sub-Saharan Africa are promoted by development organisations as reliable alternatives to ensure water supply for human consumption and agricultural use. National efforts to map and monitor groundwater quality and quantity, however, are not adequate to promote sustainable groundwater management. Within a technical cooperation project, the Federal Institute for Geosciences and Natural Resources (BGR) supports the intergovernmental Niger Basin Authority (NBA) and its nine member states to establish groundwater-monitoring networks, map the quality and quantity of the groundwater resources, and elaborate tools for groundwater management.

        The paper presents a reassessment of the groundwater resources of the southern Iullemmeden Basin derived from the combination of archival data and recent measurements within the AGES monitoring network. To improve the limited coverage of national databases, the technical cooperation project strives towards the valorization of so-far neglected grey literature and archival data including, among others, the groundwater appraisals of the mid-20th century as well as available reports of (inter-) national development projects.

        A major challenge for the harmonization process is the differentiation of the multi-layered aquifer system of the Iullemmeden and the assignments of wells to one of the aquifer storeys of the Continental Terminal (Ct1-3) and the Continental Intercalaire/Hamadien. Unreliable lithological and technical profiles together with the usual tapping of multiple aquifer storeys to increase productivity limit the use of both archival and contemporary measurement data for the characterization of defined groundwater levels.
        To create a consistent conceptual (hydro-)geological model, a general reassessment/revision of borehole lithology and stratigraphy became necessary. We explore the geostatistical approaches to discriminate groundwater bodies based on water chemistry, hydraulic head, and isotope data to improve the original lithostratigraphic classification.
        Valorization of archival data – with the respective thorough quality checks – is underestimated provides necessary baseline data for groundwater management.

        Speaker: Mr Matthias Heckmann (Federal Institute for Geosciences and Natural Resources (BGR))
      • 15:30
        ISOTOPIC EVIDENCE OF THE DEEP MAASTRICHTIEN AQUIFER IN THE SENEGAL 15m

        The deep Maastrichtian aquifer belongs to the Senegalese basin and bears considerable groundwater resource. This system outcrops in the Diass horst zone, is composed of sandstone formations with mean thickness of 250-300 m. It is tapped by several hundred boreholes pumping at rates between 50-200 m3/h for human consumption, agriculture, pastoral and industrial needs. It is characterized by a general flow pattern (SE – NW), and the recharge zone is thought in the contact with the basement rock in the SE, in the East with the Senegal River, in the west at the Diass Horst and probably at Bissau Guinea. Since the 70s, the system has been subject to numerous investigations to understand its functioning, recharge processes as well as origin of high Cl and F in the central saline band.
        Computed residence times from the detectable 14C range from 10,000 to more 30,000 yr evidencing palaeorecharge in the hydraulic system. Very low 14C (close to detection limit) and few 36Cl data reveal age of more than 250,000 yr. However high 14C values reveal recharged young water in the Northern part of the basement rock contact. These contents rapidly decay to low values at a short distance evidencing low to non-laminar circulation pattern in this region. Toward the West at the Diass horst zone, detectable 14C between 2-66pmc are mainly due to high abstraction for urban water supply which create an imbalance in terms of water budget in the system and continuous lowering of the water table, which is presently at more than 35 m.
        Radiocarbon data distributed throughout the system and O/H stable isotopes indicate old to very old water which was replenished under different climate conditions. Rapid decayed 14C in the supposed recharge zone and detectable radiocarbon in the horst zone are an indication of dynamic flow patterns which are thought to be convective and/piston type accompanied by dynamic influenced by high pumping in parts of the system. Despite these findings, some scientific issues need to be further investigated in order to build a conceptual model of the system functioning.
        Considering the stable isotopes, distributed statistical values reveal different patterns with high range occurring in the East, saline band and West while lower range characterized the South and the heart of the system. Plotted in the conventional 18O/2H graph, values scatter along the meteoric line with an absence of evaporative effect. The higher range depicted in the eastern part of the aquifer should infer either by different climate recharge period or by circulation pattern which can be through Piston and/or convective flow. In the saline band and the Horst, differentiation in isotopic contents can derive from inflow of high pumping in boreholes operating in these areas.

        Speaker: Prof. SERIGNE FAYE (UCAD/DAKAR, SENEGAL)
      • 15:45
        Geometry and hydrogeological functioning of Ouled Bousbaa aquifer systems: Central Morocco 15m

        The study area is part of the Western High Atlas. The plain of Ouled Bou Sbaâ is located hundred kilometers west of Marrakesh, it is part of the Atlantic trays area. It is a complex basin, with a succession of synclines and anticlines oriented NE-SW between the mountain chain of the High Atlas and the Tensift river.The compilation of geological data, drilling data, geological sections and the analysis of the reconnaissance boreholes logs show that this area is constituted by thick sedimentary series dated from Paleozoic to Quaternary. Hydrogeologically, these series show the superposition of two aquifers; the first one is an unconfined groundwater flow system housed in the Quaternary, Eocene and Turonian; the second one is a deep confined groundwater flow system and located at the heart of the Cenomano-Turonian aged synclines. The feeding of these two reservoirs is ensured by the infiltration of surface waters of the high Atlas's mountains as well as by stoma at the piedmont.By establishing piezometric maps, it has been noticed that on one hand the free groundwater layers have a hydraulic continuity. On the other hand the confined aquifer located at the Sidi Mokhtar's syncline, in the north of the working area has a flow oriented from SSW towards NNE while the one in the syncline of Idouirane situated in the south has a groundwater flow oriented from SW to NE. As there is a separation materialized by the Marmouta anticline, the two aquifers do not have hydraulic continuity.

        Speaker: Ms Rim TIJANI (Phd Student)
    • 15:00 16:00
      Parallel: Monday Afternoon 2: Topic 1 Conference room 2.2 ()

      Conference room 2.2

      • 15:00
        Assessing recharge dynamics by the use of remote sensing and stable isotopes in the arid region of the Nubian Sandstone Aquifer System of Northern Chad 15m

        The Nubian Sandstone Aquifer System (NSAS) is a transboundary aquifer shared between Libya, Egypt, Sudan and Chad. The NSAS is one of the largest aquifers of the world. Groundwater is the only available water resource for most of the population living within its boundaries, given the extreme aridity that characterizes the region. The NSAS of Northern Chad might correspond to the least exploited and to the least investigated part of the system. The region is characterized by two mountainous regions, the Ennedi and Tibesti Mountains, experiencing increased precipitation rates (approx. 100 mmy-1) compared to the mean regional rates (< 5 mmy-1). Albeit small in quantity, recharge occurring in these mountainous regions might constitute an important, renewable resource. Previous authors studying the hydrodynamic properties of the NSAS have also concluded that modern recharge might play a role in maintaining higher hydraulic heads and gradients, thus slowing down the depletion of the NSAS. In view of a likely increase of exploitation of this aquifer in Chad, it is essential to characterize the temporal and spatial dynamics of modern recharge and to assess its influence to the regional aquifer system.
        Key challenges of this project were the remoteness of the region and the lack of ground-based monitoring climatic and meteorological data. In the framework of the ResEau project, several fieldwork campaigns were undertaken between 2013 and 2016, covering approximately an area of 100,000 km2. Hydraulic heads measurements, physico-chemical groundwater characterization and water probe sampling were performed for 185 water points. Water samples were analyzed for their major anions and cations concentrations and stable isotopic ratios (δ18O and δ2H). Remote sensing products (RFE2.0, LandSat8OLI) were employed to visualize the temporal and regional dynamics of precipitation, runoff and evapotranspiration and to quantify the system gains and losses. The period of observation was set between years 2013 and 2016.
        The combined use of remote sensing products, fieldwork and the groundwater chemical and stable isotopic characterization enabled to qualitatively assess the relative importance of diffuse and concentrated recharge within the mountainous regions of Northern Chad. A groundwater flow conceptual model was developed in order to formulate hypothesis on the relationship between the zones experiencing modern recharge and the regional aquifer system. Groundwater’s hydro chemical and stable isotopic compositions shows distinctive characteristics whether if recharged during the current climatic period or corresponding to paleo-groundwater recharged during the previous humid but cooler periods of the late Pleistocene to Holocene. This distinction has important implication for water management.

        Speaker: Dr Marie-Louise Vogt (University of Neuhâtel)
      • 15:15
        COASTAL FLOODINGS AND ITS CONNECTION WITH MOTRIL-SALOBREÑA AQUIFER (SOUTHERN SPAIN) 15m

        Southern Mediterranean has been considered one of the most vulnerable coastal areas in the world due to flooding episodes, especially in low-lying coastal plains and deltaic areas (Nicholls et al., 1999). During de recent decades, coastal areas are experiencing rapid socio-economic development and hence a population increase. Infrastructures and social activities can be particularly affected. Groundwater inundation is poorly recognized and frequently confused with surface water floodings (Hughes et al., 2011). Rotzoll & Fletcher (2013) highlighted the importance of having a detailed understanding of groundwater level spatial distribution and the processes that control changes in water-table height throughout the coastal zone. This research evaluates the response of Motril-Salobreña aquifer to flooding on the deltaic plain of the Guadalfeo river. Periodic floods occur on this area and it causes ecological damage to a wetland nature reserve “La Charca de Suárez” and economic damages to: buildings, crops, and industry and tourism sector.
        From February 2018 to April 2019, continuous water table data had been compared with precipitation, sea level, wind direction and sea wave height records. During the measurements period, several flood episodes took place and they could be related with water level rises registered in the piezometers.
        Our results showed that water table lift plays an important role in the permanence of these floodings. A higher water table reduces the unsaturated zone and hinder surface infiltration, increasing overland runoff. The high water table events can be generated by: i) the lowering of atmospheric pressure that rises sea level. ii) Precipitation. The thin unsaturated zone favours the fast rising of the water table after rain events. iii) Wind speed and direction. East and southwest winds produce large waves which drive seawater inland and producing a local rise of sea level. Therefore, different types of inundation can be detected on the basis of the dominant factor with variable effect depending on the area.

        Speaker: Ms A.M. Blanco-Coronas (University of Granada)
      • 15:30
        Some unsolved aspects on groundwater to be considered in the revision of the European Water Framework Directive 15m

        Groundwater is an essential component of the hydrological cycle, which behaves slowly, thus providing long-term water storage and subjected to slow evolution. In practice results can be largely irreversible in the case of large aquifers and thick unsaturated zones. Through the interaction with surface water it is a key component to many ecological systems of relevant social and economic value, but also an important water resource for humans and their activities. Both aspects have to be combined to get the maximum social benefit in the long-term, which means that they cannot be maximized separately from the others.
        The European Water Framework Directive of 2000 and the so called Groundwater Daughter Directive of 2006 have as a main objective the good ecological status of the Earth’ water bodies and this has to be accomplished in the so defined water bodies. This may be clear for surface water but is more difficult for groundwater, especially because their environmental role is complex, anthropic effects are highly delayed, and the aquifers may and should play the role of natural infrastructures to increase and guarantee the availability of water resources for humans, especially in droughts. The concepts of water heritage, water resource budget in quantity and quality, and loss of them by passive accumulation from human activities has been rarely made explicit with a long-term perspective.
        A revised extension of the Water Framework Directive should consider the role of aquifers as natural manageable infrastructures, whose use may be accompanied by some limited environmental loss when there is a positive social benefit, in the same way that the land can be occupied for urban expansion, transportation or surface water storage in dams. This may be associated with some controlled and managed degree of groundwater level drawdown, wetland reduction, increased cost of groundwater abstraction, water quality changes relative to the natural situation, seawater intrusion in coastal aquifers, land subsidence, water reserves decrease, etc. To consider this, a redefinition of the good status has to be worked out, which is especially needed in the southern areas of Europe.
        Other aspect to be considered more in detail is the delayed effect of water transfers, irrigation or land drainage, which may greatly alter aquifer recharge and consequently the full water system. The water system will evolve slowly, often only perceived with good monitoring and adequate interpretation. Large passives of pollutants may cumulate, making recovery unfeasible. So, aquifers need different qualification of the status and protection according to their human water supply, environmental and security role. In these aquifers should be imposed adequate standards of well construction to prevent the entry of pollutants. Some difficult to recover aquifers should have reduced requirements, but considering externalities and how to compensate them.

        Speaker: Dr Andrés Sahuquillo (Technical University of Valencia)
      • 15:45
        Dealing with seawater intrusion in the Chtouka Aquifer, Morocco 15m

        The joint technical cooperation project CREM (Coopération régionale pour une Gestion Durable des Ressources en Eau au Maghreb) of OSS (Observatoire du Sahara et du Sahel), BGR (Federal Institute for Geosciences and Natural Resources), and GIZ (German Society for International Cooperation) is funded by BMZ (German Federal Ministry for Economic Cooperation and Development) and fosters the exchange of groundwater management strategies between the three countries Morocco, Algeria, and Tunisia. The strategic focus in the pilot area of Souss-Massa, Morocco, by BGR is on saltwater intrusion.

        The Souss-Massa Basin is the country’s most important agricultural area. Groundwater from the coastal Chtouka aquifer is the main source for irrigation. The heavy exploitation of groundwater leads to declining water level in the sub-basin, with the effect of intruding seawater from the ocean. Several measurement campaigns were launched together with the ABHSM (Agence de Bassins Hydrauliques Souss-Massa) and the University of Agadir. Wells and monitoring boreholes along the coast were visited, altitudes and water level data were gathered, and depth specific electrical conductivity profiles were taken.

        Results show an average groundwater depletion of up to 1.5 m per year in several locations. Due to this depletion, a change of the general flow direction in the Chtouka Aquifer was found. The mobilisation of high saline water from the south of the plain and the marine intrusion threaten the irrigated zones. The hydrochemical analyses identified a zone of wells with marine influence. Additional monitoring wells were drilled. A three dimensional density dependent numerical model is used to simulate groundwater flow and the development of salinities in the Chtouka aquifer.

        Countermeasures are already in progress, e.g. the construction of a water desalination plant for agricultural purposes and a so-called aquifer contract. In international workshops, the project’s results, as well as strategies are discussed with the aim to transfer the achievements to other OSS member countries, i.e. Tunesia and Algeria.

        Speaker: Mrs Fatima Abourrig (Agence du Bassin Hydraulique du Souss Massa)
    • 15:00 16:00
      Parallel: Monday Afternoon 3: Topic 2 Multiuse room 2 ()

      Multiuse room 2

      • 15:00
        REGIONAL CLIMATIC FEATURES CONTROLING GROUNDWATER RECHARGE IN SOUTHEASTERN BRAZIL REVEALED BY STABLE ISOTOPES 15m

        Groundwater dependence in the Southeastern region of Brazil has increased during the last 30 years, especially to supply the rising agricultural production and multiple water uses in its growing cities. Knowledge about aquifer recharge is crucial for preventive water resource management, especially under climate change scenarios. Encompassed within the hydrogeological framework of the Parana Sedimentary Basin the Bauru Aquifer System (BAS) and the Guarani Aquifer System (GAS) are responsible for supplying water to more than 10 million inhabitants in the state of São Paulo, and recharge conditions in these aquifers have been poorly studied, despite the importance of groundwater for the state. Isotopologues of water represent a completely conservative tracer of water movement through the hydrological cycle, making possible determine the relation between climatological features and groundwater recharge. Since 2013 groundwater samples from two shallow wells (30 meters depth) and precipitation samples have been collected in two sites located in the recharge area of BAS and GAS aiming to evaluate variations in isotopic composition, and how the isotopic signal of precipitation could be transferred to groundwater through recharge. Seasonal variations in groundwater levels were modulated by local precipitation regimes, and large climatological features, such as the 2014-2016 ENSO event, which was responsible for a continuous lowering of water levels observed until 2016. Isotopic composition of precipitation in both sites presented large variation (variation on d18O up to 16‰) and were marked by strong seasonality with enriched values observed during dry season while depleted values during wet season. During most part of the year d-excess values were higher than 10‰, indicating the influence of moisture recirculation processes during air masses displacement. The calculated weighted average values for d18O in precipitation were -5.70 and -5.10‰, respectively for BAS and GAS sites. Groundwater isotopic composition presented small variations when compared to precipitation (variation on d18O less than 1.5‰). Despite small isotopic variations in groundwater, d-excess values presented large variation, and most samples positioned below the local meteoric water line, indicating the occurrence of strong evaporative processes associated to kinetic fractionation along the unsaturated zone. Average values for d18O in groundwater were -6.93 and -7.25‰, respectively for BAS and GAS sites, which were more depleted than weighted average precipitation. However, such values are similar to isotopic composition of precipitation during the wet season, when the South America Monsoon System is very active, and a large amount of vapor recycled from the Amazonian region is available in the atmosphere and is responsible for the formation of the South Atlantic Convergence Zone. These findings could shed light on past climatic conditions associated to recharge of very old groundwater (up to 500 ky) found in confined portion of GAS.

        Speaker: Didier Gastmans (São Paulo State University)
      • 15:15
        Groundwater runoff in small river basin: retrospective analysis and projections due to climate change 15m

        The analysis of the impact of observed and predicted climate variability on the total and groundwater runoff of the small river basin in humidal boreal conditions is considered on the basis of a physically based precipitation-runoff model. The model consists of two submodels. Surface precipitation transformations within a representative landscape element are simulated using the first SURFBAL submodel. It simulates the processes of snow accumulation on the surface of the earth, its melting during winter thaws and spring, the formation of surface runoff and potential ET, taking into account freezing and melting of soil cover. The results of the calculations are transferred to the second submodel, the groundwater flow model, as upper boundary conditions on the land surface for each landscape zone. The second model is based on MODFLOW2005 using the UZF package. This submodel calculates the flow rate in the unsaturated zone, groundwater recharge and ET, and the formation of surface and groundwater runoff within the basin.
        In the first stage of the study, a retrospective analysis of the runoff in the studied basin was carried out on the basis of data on the dynamics of observed precipitation and temperature over the past 70 years. The results of this analysis have shown the long-term non-stationarity of the processes of total runoff formation, which is well in line with the observations of measured river runoff in the terminal gagging station. This non-stationarity is related to the increase in river flow and groundwater discharge in winter over the last 40-30 years due to the observed increase in winter temperatures.
        At the second stage, the forecast calculations for the next 50 years have been carried out. For predictive simulation of precipitation and temperature series, the climatic generator LARS-WG was used, which generates time series of precipitation and daily temperature resolution based on forecasts of global circulation climate models from the CMIP5 family. For the forecasts 19 CMIP5 models were used.
        The simulation results showed that the predicted groundwater runoff averaged over all climate models turned out to be more stable in the long-term and intra-annual section than the total surface runoff.The estimated intra-annual surface runoff hydrograph has changed in comparison with the retrospective period due to a decrease in the spring peak runoff of the river in the spring and an increase in winter runoff. The results of the forecast for different models from the CMIP5 family differ significantly. This is since all models predict a similar increase in the average annual temperature in the next 50 years. However, the predicted trends in annual precipitation vary greatly, from a 15-20% decrease in some models to a 20% increase in others.
        This work was supported by the Russian Science Foundation via grant 16-17-10187

        Speaker: Dr Elena Filimonova (Lomonosov Moscow State University)
      • 15:30
        GEOMORPHOLOGICAL CHARACTERICS OF THE FLASH FLOOD AFFATED AREA DURING CEMPAKA TROPICAL CYCLONE IN GUNUNGSEWU KARST AREA, INDONESIA 15m

        Cempaka tropical Cyclone occurred on 27 November 2017 in the Indian Ocean, just south of Central Java. The cyclon generated an extrem rainfall and flash floods in Southern part of Central Java, including the Gunungsewu Karst Area. The highest rainfall recorded on November 28, 2017 in area is 369 mm/day. This study aimed at analyzing the geomorphological characteristics of affected areas. The analysis was conducted by mapping the flooded sites, morphological analysis, and morphometry analysis using a topographical map, high-resolution remote sensing image and high-resolution image from unmanned aerial vehicle (UAV). The results show that floods in the study site occured in (1) flash swallet hole, (2) karst window, (3) resurgence and (4) flash flood in doline with small ponor.

        Speaker: Dr Eko Haryono (Universitas Gadjah Mada)
      • 15:45
        Teleconnections between NAO, EA, and SCAND and groundwater levels in Portugal 15m

        This study examines the teleconnections between the North Atlantic Oscillation (NAO), East Atlantic (EA), and Scandinavia (SCAND) climate patterns and groundwater level fluctuations in Portugal. Precipitation and piezometric records (1987–2016) from two aquifer systems, Leirosa- Monte Real in the north and Querenca-Silves in the south, are analyzed using wavelet transform methods and singular spectral analysis. The capacity of wavelet transform methods to analyze processes at various scales exposes not only the impacts of climate modes (NAO, EA and SCAND) but also the existence of complex transitive couplings among modes. Extreme events coinciding with coupled phases mark sharp boundaries in mode interaction patterns or sudden shifts in the time-frequency space. Groundwater levels over the analyzed time interval display consistent relationships with climate indices in distinct period bands and time windows. The strongest covariability occurs in the 6–10 years band for NAO, in the 2–4 years band for EA (especially after 1999) and in the 4–6 years band for SCAND (especially after 2005). Episodes displaying simultaneously multiple coherent relationships are associated with coupled phases among NAO, EA and SCAND. The results indicate that NAO, EA and SCAND patterns together are responsible for most (80%) of the inter-annual variability of groundwater levels in Portugal. NAO is the first leading pattern of variability, accounting for 40% and 60% of the total variance of groundwater levels in the north and south of the country, respectively. The joint contributions of EA and SCAND account for the remaining 40% of variability in the north and 20% of variability in the south, on average. Monthly groundwater levels averaged over years of positive and negative phases of climate indices provide additional insights on the influence of coupled patterns. Combined winter NAO-EA+ phases are associated with maximum groundwater levels while combined NAO+EA− phases are associated with minimum levels. Further understanding on how climate modes influence groundwater storage can improve future projections of groundwater availability and guide integrated water resource management practices not only in Portugal but around the world. This work is supported by FCT- project UID/GEO/50019/2013 – IDL.

        Speaker: Dr Maria da Conceição Neves (Instituto Dom Luiz (IDL), Universidade do Algarve)
    • 15:00 16:00
      Parallel: Monday Afternoon 4: Topic 3 Conference room 1.B ()

      Conference room 1.B

      • 15:00
        Group Water Schemes: Where society’s needs and expectations meet 15m

        In Ireland, a Group Water Scheme (GWS) is a private, community-owned water supply. Group Water Schemes form a significant supply type outside Irish cities and large towns, with many rural communities relying on a GWS for their drinking water. Since 2013, a programme to delineate zones of contribution (ZOC) for approximately 260 groundwater supplied GWSs has been carried out across Ireland. The programme -funded through the Rural Water Programme by the Department of the Environment, Community and Local Government- is a collaboration between Geological Survey Ireland (GSI) and the National Federation of Group Water Schemes (NFGWS). The main output of the pilot project was to delineate ZOCs and highlight groundwater vulnerability within the ZOC. This enables scientifically informed decisions in relation to possible protective measures and future planning. Another fundamental aim of the project was to engage with the GWS personnel so that they would fully understand the concepts and data behind the reports, and why certain data were requested or collected (e.g., hydrochemistry, borehole logs, water levels etc.). The final element of the project was to present the information and discuss the conceptual model, recommendations and any management implications with the GWSs. Evidently an increased understanding has enabled the GWSs to have greater ownership of their supply and the decisions made about it.

        Such understanding and ownership are key since the sustainability and governance of their groundwater supplies are under mounting pressure. On top of the complexities posed by Irish hydrogeological settings (e.g., karst, fractured bedrock aquifers, recharge rejection), water usage and quality are coming under increasing stress from changing population and changing land use practices. Group Water Schemes are affected by: agricultural intensification and the associated impacts from nitrates, pathogens, and pesticides; increased infrastructural development; changing demographic and social dynamics; increased housing and wastewater treatment requirements; climate change in different guises (e.g., drought, groundwater flooding, extreme weather events). The ZOC programme has helped educate GWSs about groundwater and their management options. It has provided communities with a greater understanding of their catchment and established a baseline hydrochemical database from which to operate. The programme has placed GWSs in a better position to advise stakeholders and future proof their water supplies. This paper presents case studies, outlining some of these pressures and demonstrating the benefits of this mutual collaboration.

        Speaker: Dr Sophie O'Connor (Geological Survey Ireland)
      • 15:15
        Technical and economic feasibility of Managed Aquifer Recharge for irrigation development in Northern Australia. 15m

        Irrigation developments in northern Australia have had a checkered history due to many different factors – primarily the highly variable surface water sources and the poor economics of many of the crops grown. With the aim of improving the security of the water sources, the technical and economic feasibility of managed aquifer recharge (MAR) for irrigation development in selected regions in Northern Australia has been assessed. The technical assessment involved matching the MAR method with the varying hydrogeological environments to identify the most cost effective approach. This involved the use of recharge weirs for shallow aquifers and relatively shallow injection bores where deeper confined aquifers were the target. The source water is a small percentage of the wet season surface water flows. Specific characteristics of Northern Australia, namely the cost of transporting water, very high evaporation rates, the variability of wet season rainfall and the need for scalable water resource developments, make MAR an attractive alternative to large dams. So called “mosaic” irrigation, whereby many relatively small scale MAR based irrigation schemes are dispersed across northern Australia is the preferred model for development. Several sites in Western Australia and the Northern Territory were studied in detail to assess their technical and economic potential. Capital and operational costs were determined for various schemes and the levelized cost of the MAR schemes typically varied from A$120 to A$150/ML. The economic return from various crop types was determined and this showed that traditional fodder production for beef cattle production was not economic, whereas a variety of other crops were economic. This work showed that MAR based schemes are technically feasible in many locations, but choosing the most economic method and crop type requires careful judgement.

        Speaker: Dr Richard Evans (Jacobs)
      • 15:30
        Outreach and public education strategies to achieve science based groundwater management policy 15m

        Groundwater governance is a complex process involving the collective influences of opinion on policy and management. Achieving sustainability of water supply from aquifers is major management challenge worldwide that is impacted on the supply-side by changing weather patterns, loss of groundwater inventory because of current and legacy contamination, and because of past over-exploitation. On the water supply demand-side, managers have to balance allocation decisions to satisfy the needs of changing demographics, ecological requirements, water rights and entrenched vested interests.
        Science-based decisions should be the foundation of groundwater sustainability policies and the basis for regulatory frameworks to achieve safe drinking water supply. Groundwater specialists should be in the forefront of helping with scientific awareness and technology transfer endeavors to end-users, citizens, community leaders, regulators and elected officials. The public needs help navigating the minefield of information and misinformation about groundwater resources. This paper examines some current groundwater issues in America and outlines strategies that provide groundwater professionals with an objective platform to influence “opinions”
        Included in the discussion will be the problem of groundwater legacy contamination from PFAS (per- and polyfluorinated alkyl substances). As more evidence emerges about the extent of PFAS contamination, the public in affected areas has growing concerns. With impartial guidance to help frame the issues, outreach strategies can communicate solution-based information to inform opinion by combining private sector-expertise, legal perspectives, regulatory authority, and local community representation in single event platforms.
        An additional focus for the discussion will be the education and outreach approaches that can help achieve policies to solve the impacts of aquifer overdraft. An education route to achieve sustainability is for groundwater professionals to engage with stakeholders and decision-makers who are not professionally in the water sector. The key to achieving science based groundwater management policy is to make groundwater understandable to policy-makers (elected representatives), groundwater end-users (stakeholders), organizations and interest groups, the news media and people active with social media.
        In the traditional top-down approach to managing groundwater the “experts” knew best what was required. The contemporary bottom-up approach requires a broad base of support. Direct involvement in education and outreach by groundwater professionals can help achieve data transparency and jargon-free explanations of the science of groundwater. The presentation considers ways in which effective outreach can assist positive outcomes for sustainability.

        Speaker: Mr Andrew Stone (American Ground Water Trust)
      • 15:45
        Large-Scale Managed Aquifer Recharge in Support of California’s Agriculture: The Salinas and Kings River 15m

        Agriculture is a significant part of California’s economic engine. It accounts for $100 billion in agriculture related business each year. Given California’s Mediterranean climate, large-scale managed aquifer recharge (MAR) is a critical element of sustainably managing water resources in California’s agricultural heartland. Conjunctive management of surface water flows in the Salinas and Kings River drainages, two of the most vital agricultural areas in the State, has been used for many years to augment natural recharge of the important underlying aquifers. Additional projects are being implemented to increase recharge efforts to offset overdraft conditions using excess river flows. Three examples of large scale managed aquifer recharge are examined: 1) an existing and well-studied MAR program in in the Salinas River valley that coordinates reservoir releases to optimize groundwater recharge along the Salinas River in Monterey County; 2) a relatively new water bank along the upper Kings River that recharges seasonal excess flows using an old river channel; and 3) the planned use of agricultural fields to recharge flood flows along the lower Kings River.
        The objectives and operation of each MAR system are evaluated and their overall benefit on underlying groundwater storage conditions is examined. The importance of stakeholder involvement, systematic data collection and analysis, and the potential of climate change are discussed. Benefits and challenges for each example are examined along with key criteria in the selection and design of large-scale MAR programs.

        Speaker: Mr Anthony Daus (GSI Environmental, Inc.)
    • 15:00 16:00
      Parallel: Monday Afternoon 5: Topic 3 Multiuse room 1 ()

      Multiuse room 1

      • 15:00
        Conflicts and resolutions of shared waters in the Americas 15m

        To solve one of the grand challenges facing society today: energy, water, climate and food, natural scientists and social scientists must work together. A new framework is required for bringing together hydrology and social sciences: This way, economics, administration, law, psychology, arts and humanities, are here combined into social sciences.

        From thousands of years (3000 BC)to the latest war conflict in Syria (2015), water has been a source of conflict between countries and even within a country related to water resources, water systems, and national and international security. Solutions to water conflicts have been part of history too, cooperation and good will being the key components of the solutions.

        In this presentation, more than simple solutions to water problems, we try to describe resolutions to water conflicts by means of an explanation of a problem or a puzzle, and a way of looking at, explaining and writing up a water problem that became a conflict in a systematic fashion. Drawing on examples from the American hemisphere, from Chile/Bolivia to Canada/US, we examine surface water, groundwater and wetlands from scientific, socioeconomic and political perspectives, and propose an interdisciplinary socio-hydrology frame for resolving or concluding water disputes or disagreements.

        International organizations play the largest role in mediating water disputes and improving water management. From scientific efforts to quantifying water pollution, to the World Trade Organization’s efforts to resolve trade disputes between nations, the varying types of water disputes can be addressed through the current framework. Yet water conflicts that go unresolved become more dangerous as water becomes more scarce and global population increases.

        We present quick cases of real or apparent situations of water conflicts in the Americas including Bolivia-Chile, Brazil-Argentina-Paraguay-Uruguay; the CGSM in Colombia; Costa Rica-Nicaragua; and Mexico-USA.

        Speaker: Dr Alfonso Rivera (Geological Survey of Canada)
      • 15:15
        Assessment of Climate Change Impacts on Thonon-les-Bains Groundwater Resources: A Requirement for Water Resources Governance and Long-Term Investment Planning 15m

        Thonon-les-Bains is located in the French Alps, on the shores of Lake Geneva. The town has several groundwater resource tapping facilities at elevations ranging from 390 m to about 600 m (with a watershed elevation of up to about 1400 m). These resources differ in terms of their yield, their vulnerability to pollution, their ability to supply by gravity the whole town or only certain districts, and their long-term investment requirements.

        To ensure a sustainable water supply for the town, a master plan has been developed. One of its objectives was to define an optimum groundwater resources operating scheme (defining the resources to be kept, developed or abandoned).

        Within this framework, and as amortization of long-term investments has to be taken into consideration, the impact of climate change on the groundwater resources had to be assessed.

        While significant developments have been made in assessing the impacts of various global economic growth scenarios on climate change, fewer works have examined the impacts of climate change on groundwater resources. This is due notably to the fact that the link between climate and groundwater resources depends on local parameters. Consequently, a long-term decrease in rainfall (depending on the global economic growth scenario considered) cannot be carried over to groundwater resources.

        In the present case, a lumped groundwater model was developed using the Gardenia simulation code (BRGM) for the Blaves catchment supplying Thonon-les-bains. The model was calibrated on groundwater abstraction flow rates measured over a 6-year period using measured rainfall and potential evapotranspiration time series as input parameters. The gap between measured and simulated values was assessed in order to evaluate the reliability of the groundwater model. The IPCC Fifth Assessment Report RCP 8.5 scenario was then considered. Local monthly long-term (2070-2100) rainfall and evapotranspiration values were then used in the groundwater model. While the results showed that long-term rainfall was 21% lower on average compared to the present state, groundwater resources were estimated to be 25% lower on average (annual volume) and up to 45% lower during low-water periods. These two values (long-term average and low-water groundwater flows) were then used to develop an appropriate groundwater resources operating scheme.

        Speaker: Mr Marc Boisson (aih)
      • 15:30
        Analysis of groundwater drought propagation in temperate climates using a water balance model and groundwater model 15m

        Droughts are mainly caused by periods of reduced precipitation and affect both surface and groundwater resources. This drought propagates to the different component of the hydrological cycle. Meteorological drought propagates to surface water and the unsaturated soil zone and to groundwater. This can result in groundwater drought. Groundwater drought can be defined as a temporary decrease in groundwater availability over a significant period of time. Groundwater droughts present a severe risk for water availability but have not received much attention in scientific literature compared to meteorological and hydrological drought.
        This research aims to develop and apply a method for simulating groundwater drought and its propagation in aquifers. The method was developed by combining a water balance model and a groundwater model for simulating groundwater drought. This research is carried out in the Dijle catchment in central Belgium, which overlies the vulnerable Brussels Sands aquifer.
        For groundwater drought analysis, time series of the three main groundwater variables, groundwater recharge (R), groundwater level (H) and groundwater discharge (Q), need to be available with a high spatial and temporal resolution. Although data on the groundwater levels (H) are available with a high temporal resolution, this is usually not the case for groundwater recharge (R) and discharge (Q) data. Therefore, groundwater recharge and discharge time series is simulated using a water balance model (WetSpass) in combination with a groundwater flow model (MODFLOW). Next, groundwater drought was evaluated using a threshold method. Threshold functions of the water table are determined in the context of aquifer sustainability. An aquifer sustainability test is done using recharge-consumption time series in which no systematic trend is detected. The result of this research showed that droughts in the groundwater system are greatly attenuated and delayed.
        Keywords: Groundwater Drought, Drought Propagation, Threshold method

        Speaker: Mr Buruk Kitachew Wossenyeleh (Department of Earth and Environmental Sciences, KU Leuven University, Belgium)
      • 15:45
        GROUNDWATER PUBLIC SUPPLY BASED ON AN ANCESTRAL SYSTEM OF GALLERIES 15m

        Traditionally in North of Portugal, in undifferentiated hydrogeological formations, groundwater has been the main source of small populations. The main sources are natural springs and galleries that intercept fractures in hard rock mountains.
        The subterranean drainage is driven by a fracture network that can be continuous and not largely conditioned by water courses. The recharge occurs through the precipitation that fall directly into the outcropping layers with well-developed and significant fracturing.
        The year 2017 in Portugal was particularly dry. While some cities like Viseu were at risk of running out of water, others like São Pedro do Sul located in same district never lacked water. Why? Because while the former depended on a single source of water, the Fagilde Dam, which was exhausted, the latter was always provided with water supplied by the hundreds of mines located on the slopes of the mountains. Underlying this situation is the fact that groundwater is a much more resilient resource than surface water and therefore more resistant to prolonged drought periods
        Currently, due to the fast technological progress – but not always beneficial to people's lives - many galleries, were abandoned although since the oldest times, the populations have been supplied with water captured in several galleries evenly distributed in the mountains, which never failed. This article describes the use of an ancestral groundwater supply system in small parish of São Pedro do Sul as a paradigmatic example of a sustainable use of a natural resource.
        Consequently, instead of building more dams that cause large economic, social and environmental impacts with high costs for the population, we must consider the use of much less demanding Natural Bases Solutions such as the ancestral systems described here, which proven to be efficient for centuries.

        Speaker: Prof. RIBEIRO LUIS (CERIS - INSTITUTO SUPERIOR TECNICO)
    • 15:00 16:00
      Parallel: Monday Afternoon 6: Topic 5 Auditorium 2 ()

      Auditorium 2

      • 15:00
        A Versatile Multi-Port System for High Resolution Groundwater Monitoring in Rock and Overburden 15m

        Characterization and monitoring of groundwater using boreholes is most effectively and efficiently done when each hole is equipped to measure hydraulic head and water samples can be collected at many depths, with each depth interval sealed off from groundwater above and below to minimize short-circuiting in the natural flow system. Multi depth installations in single boreholes are done using nested wells (several conventional wells: each with a screen) or using assembled multi port systems (MPSs). This presentation concerns a new design of MPS referred to as the G360 MPS, which is a major redesign of that described by Cherry and Johnson, 1982. Although many MPS are reported in the literature, only a few are commercially available beginning with the Westbay system in the late 1970’s, but MPS are generally underused by the groundwater profession. The G360 MPS has versatility in several borehole diameters in both bedrock and overburden. It is modular in design with ports attached to casing lengths of standard Schedule 80 PVC casing (2,2.5,3,4-inch ID). A polytube (e.g. polyethylene, nylon, HDPE, Teflon) attached to each hole port extends to surface to form a standpipe well internal to the PVC casing. The number of ports (wells) depends on the inside diameter of PVC casing and the outside diameter of the tubes. More than 18 G360 MPS have been installed to depths up to 150 m in four different hydrogeologic settings, including bedrock and overburden, with number of ports between 8 and 18 and tubing inside diameters between ⅝ to ¾ inches. The components are standard PVC pipe machined and small off-the-shelf parts for local manufacturing, simple assembly and installation. In overburden holes, sand is emplaced around the ports and bentonite forms the seals. In bedrock, the systems have light-weight rubber packers, either removable or permanent. With its simple manufacturing using readily available materials and installation in many-sized boreholes, the G360 MPS is aimed at global use. During the 6 years since the first installation, much progress has been made in demonstrating the performance of the G360 MLS using various drilling methods,borehole diameters and port configurations. Performance in karst, maximum depth capability (likely 200-300m) and alternative packer seal materials remain to be tested.

        Speaker: Prof. John Cherry (G360 Institute for Groundwater Research - University of Guelph)
      • 15:15
        Combining unsaturated zone modelling with indirect and direct measurements to quantify solute transport during snowmelt 15m

        To improve risk assessment, monitoring, and treatment strategies of contaminated sites in cold climates, we require improved methods for monitoring solute transport and infiltration in the unsaturated zone. Previous studies have documented a highly heterogeneous infiltration during snowmelt this may have a large influence on the risk of contaminating the groundwater in areas where the use of de-icing chemicals is required for winter maintenance of roads and runways. In the last decades the use of geophysical techniques has become more widespread in order to monitor hydrogeological processes. The bulk electrical resistivity of an unsaturated soil profile is a function of soil water content, electrical conductivity of the fluid phase and soil temperature. Time-lapse electrical resistivity tomography (ERT) of a thawing partly frozen unsaturated zone during snowmelt infiltration gives a qualitative impression of how meltwater and salts moves through the unsaturated zone. Here we explore whether the ground truthing methods such as soil water samples from suction cups providing electrical conductivity of the water, tensiometer readings providing information about soil water content and soil temperature can quantify the different contributors to the change in electrical resistivity. The work is based on a combination of a field experiment during the snowmelt of 2010 and unsaturated zone modelling with Sutra_2D3D. The field experiment was conducted at Moreppen experimental lysimeter trench. Which is located next to Oslo airport, Gardermoen, Norway, where large amounts of de-icing chemicals are used to remove snow and ice every winter. During snowmelt these chemicals (Propylene glycol is used for the air planes and Potassium Formate used for the runways) infiltrate into the soil. Bromide, as an inactive tracer, and de-icing chemicals potassium formate and propylene glycol were applied to the snow cover prior to the onset of snowmelt and their percolation through the unsaturated zone was monitored with water sampling from 30 suction cups. At the same time cross-borehole electrical time-lapse measurements (with Syscal Pro, Iris instruments) and automatic measurements of soil tension and temperature were collected. Individual inversions were temperature corrected, to compensate for the change in soil temperature throughout the melting period. To estimate water contents from the ERT values, petro-physical relationships and fitting parameters from soil at Moreppen were used, this gave water contents similar to those estimated from tensiometers. Since petro-phyiscal relationships are required to convert from changes in electrical resistivity to changes in water contents and electrical conductivity of the fluid phase, experimental data was compared with a numerical model. We used the unsaturated zone model SUTRA-2D3D to explore the sensitivity of the parameters in the van Genuchten soil retention curve, and porosity, to the quantitative interpretation of the water and solute behaviour based on the time-lapse electrical resistivity measurements.

        Speaker: Prof. Helen Kristine French (Norwegian University of Life Sciences)
      • 15:30
        Application of hydro-geophysical monitoring method to identify the flow path of CO2 and gas tracers injected in shallow aquifer system at K-COSEM site, Korea 15m

        Artificial CO2-infused groundwater injections into a shallow aquifer system have been performed twice since 2014 by K-COSEM research group at a site in Eumseong, Korea, which was specially constructed to study environmental impacts of CO2 leakage on shallow aquifer system. The first injection was performed for 6 hours (short-term injection) as pulse-type leakage of CO2 under a natural hydraulic gradient (0.02) imitating point leaking situation along vertical preferential pathway such as fracture or crack in an injection pipe. In the second injection, CO2 was continuously injected for 30 days (long-term injection) under a forced hydraulic gradient (0.2) considering CO2 leakage events that can be happened in wide-ranging areas. CO2-infused and tracer gases dissolved groundwater were injected below groundwater table through a well, and various monitoring methods were employed not only for saturated but also for unsaturated zones. As parts of this monitoring, hydro-geophysical monitoring has been applied to identify the flow path of injected CO2 and gas tracers and to trace the temporal and spatial distribution of CO2 plume. CO2 concentration is monitored in real time using a non dispersive infra red (NDIR) sensor and an open loop-air purging (OL-AP) system. Temperature and hydraulic parameters (pH and EC) were also collected while, several gas tracers (He, Ar, Kr, SF6), total inorganic carbon (TIC) and carbon isotope (δ13C) were periodically measured. Further, time-lapse (TL) 3D electrical-resistivity (ER) surveys were also performed at before, during and after the injections. Hydro-geophysical monitoring results for the short-term injection showed that injected CO2 migrated along the preferential pathway identified through hydraulic interference tests. On the other hand, TL 3D ER surveys for the long-term injection test showed that CO2 plume migrated along the direction of the ground water flow, while gas tracer data as well as geochemical data such as pH, EC and pCO2 indicated that the migration of CO2 plume was well controlled by the forced hydraulic gradient. The monitoring results indicated that detection of CO2 leakage into groundwater was more effectively performed by using a hydro-geophysical method in order to capture by-passing plume. With this concept, the direct injection of CO2 gas into a shallow aquifer system was proposed. The injection and monitoring tests at the K-COSEM site indicated that CO2 leakage or by-passing CO2 plume in groundwater can be more effectively detected under a monitoring system based on hydro-geophysical method.
        Financial support was provided by the “R&D Project on Environmental Management of Geologic CO2 storage” from the KEITI (Project number: 2018001810002) and the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (NRF-2018R1C1B6007390).

        Speaker: Mr Seong-Sun Lee (Seoul National University, SEES)
      • 15:45
        Use of 16S rRNA Sequencing Analysis on Bacteria in Well-Water to Identify Groundwater Recharge Sources 15m

        In this study we use a novel approach to evaluate the source(s) of nitrate contamination in a complex coastal environment. Given a low hydraulic gradient, tidal influences, and highly permeable sand and gravel aquifers, a conventional investigation was unable to discern whether a farm was the source of nitrate contamination in surrounding domestic wells. Alternatively, other potential sources of nitrate may be related to local septic fields and household fertilizers. As a novel approach, we evaluated the use of bacteria communities as a groundwater tracer. Bacteria community composition is controlled by measurable environmental factors such as water quality and soil conditions. Additionally, bacteria can be carried by water from source areas into major groundwater flow pathways as a biological colloidal particle. Understanding bacteria transport and biogeography coupled with new rapid techniques for characterizing bacteria populations through 16S rRNA sequencing have made bacteria useful as a practical groundwater tracer tool. In this study, groundwater samples were collected from eight domestic wells and two farm wells. Bacterial DNA was extracted from the well-water samples and underwent 16S rRNA sequencing on an Illumina MiSeq Sequencer. The relative abundances of bacteria groups present in each sample were determined and used to evaluate population similarities and differences. Based on a Bray-Curtis Non-metric Multidimensional Scaling analysis, it was found that the bacteria community structure associated with each well could be divided into three distinct groups. The bacteria communities in the farm wells were found to be distinctly different from the domestic wells which suggests that the farm was not the source of nitrate in the domestic wells. The bacteria communities among the eight domestic wells could be further divided into two distinct groups. It is likely that the bacteria community structure associated with the two domestic well groups is related to the proximity of each well to two surface water bodies; in this case, a brackish river and tidal salt marshes. This study demonstrates the use of bacteria communities as a means to evaluate recharge sources to groundwater. The results of this study also provide a foundation for future work involving this novel method of using bacteria as a groundwater tracer.

        Speaker: Mr Mark Higgins (University of Connecticut Center for Integrative Geosciences)
    • 15:00 16:00
      Parallel: Monday Afternoon 7: Topic 5 Conference room 1.A ()

      Conference room 1.A

      • 15:00
        Monitored Vapor flux and groundwater recharge in 2 hydrological years by a precision meteo-lysimeter 15m

        A high precision meteo-lysimeter was installed 2015 in a coastal dune of the Doñana Natural Reserve SW Spain to quantify water and energy fluxes in dune belts, and to estimate its dependence on regional climate trends. The weighing lysimeter contains an undisturbed soil sample of 1 square meter surface, 1.50 m height with a weighing resolution of 10 g. Furthermore, the site is equipped with 2 automatic meteorological stations, 1 Hellmann pluviometer and six calibrated TDR sensors installed outside the lysimeter at 6 different depths until 3 m below surface. Environmental humidity conditions at the lysimeter bottom were maintained by a peristaltic pump controlled by two tensiometers installed inside and outside of the lysimeter and the volume of the drained water was analysed continuously. A total of 11 meteorological and soil water parameters were recorded in 10 and 1 minuteintervalls,respectively. Intrinsic noise in lysimeter data was reduced by smoothing through the AWAT filter (Peters et al. 2014). Precipitation and drained water from the lysimeter was analysed for mayor ions and stable isotopes of water. Additionally relevant physical and retention curve parameters of the sediment were analysed and the individual fluxes were quantified using lysimeter observations. Monitored data were used to set up a 1D model which was calibrated based on monitored groundwater recharge and TDR time series data. The results of 2 hydrological years with different meteorological conditions and its effect on groundwater recharge and vapor flow are shown.

        Speaker: Dr Kohfahl Claus (IGME)
      • 15:15
        Deep Coastal Aquifers - Case Studies in Tanzania and Somalia 15m

        There is no quick fix to the global water supply situation. Incidentally, an abundance of fresh water may exist right under our eyes, more specifically in deep coastal aquifers and in submarine aquifers extending far out under the salty oceans. The Kimbiji Aquifer in Tanzania, which extends some 65 km under the Indian Ocean, was discovered in 2005 by Ruden AS Geosolutions. This aquifer is presently being developed to sustain some 1.5 million subscribers of the greater Dar es Salaam area, Tanzania. We believe that the exploration methods used in Tanzania may be applied to the coasts of most of the world’s continents. We have developed a search model based on the principle that the presence of deep coastal freshwater aquifers is probable if:

        1. Adequate recharge and relief exists in the coastal hinterland
        2. Transmissive formations with adequate structural control exists between the recharge areas and the coast
        3. Large permeable reservoirs are present along the passive margin on the continental shelf

        We have looked into the water potential of Somalia based on this search model. Virtually all groundwater in Somalia originates from the mountainous Amhar region of eastern Ethiopia. These highlands capture much of the monsoon rains (June to September). The rainwater runoff feeds the Juba and Shebele drainage systems, flowing eastwards through the entire 1000 km of Somalia, towards the Indian Ocean. A proportion of the water infiltrates into underlying aquifers at or near the recharge area. On its way to the coast, the shallow groundwater becomes increasingly separated from the deep underlying aquifers. Meanwhile, a significant portion of the recharged water from the western boundary region is being conveyed along tectonic features such as faults, fractures and karst. The presence of carbonate formations suggests that karst development may be an important feature of groundwater movement in the region. Storage of deep groundwater also occurs in sedimentary basins which serve as reservoirs. There are four principal sedimentary basins in Somalia, and these will be studied in more detail during the next phase of a proposed project.

        With the possible exception of the Mediterranean coastline of North Africa, the coastal areas of the African continent display a geological architecture typical of passive margins. In other words, approximately 20.000 km of the African coastline offer the potential for groundwater resources similar to (or possibly better than-) the Kimbiji reference site.

        Speaker: Ms Sunniva Morris (Ruden AS)
      • 15:30
        Remote Sensing for Monitoring and Mapping Karst Groundwater Flooding in the Republic of Ireland 15m

        Karst related groundwater flooding represents a significant hazard in many rural communities in Ireland. A series of unprecedented flood events in recent years have reinforced the need to improve our ability to quantify the location and likelihood of flood occurrence. Geological Survey Ireland, in collaboration with Trinity College Dublin and Carlow Institute of Technology, has established a collaborative project to investigate groundwater flooding, with particular emphasis on seasonal karst lakes known as turloughs. There are over 400 recorded turloughs across Ireland, the majority of which located on limestone lowlands. Turloughs can completely dry during summer months but extend to hundreds of hectares during the winter flood season. The practical limitations of establishing and maintaining a network of over 400 turloughs supported the use of remote sensing and GIS techniques to delineate flood extents and monitor flood prone areas in near real time using passive satellite imagery such as of the ESA Copernicus programme. Measurements at 50 sites for over 18 months were used to calibrate and validate results from satellite data. With limited recorded groundwater flood data, the use of remote sensing data provides historical archives of images to look at past flood conditions to optimise the detection of groundwater and delineate maximum groundwater flood maps. These new data will improve the fundamental hydrological understanding of groundwater flooding in Ireland, enabling key stakeholders to develop appropriate flood mitigation measures and allow for informed flood assessments to be made in future.

        Speaker: Dr Ted McCormack (Geological Survey Ireland)
      • 15:45
        Exploring the use of Fiber Optic Distributed Temperature Sensing for monitoring seawater intrusion 15m

        As pressure on coastal fresh groundwater resources increases, interest in coastal aquifers monitoring rises. The weakest point of coastal aquifers occurs at the fresh-salt water interface induced by seawater intrusion (SWI), highly sensible to any change in the heads of the fresh and salt water bodies. Therefore, the position, width and dynamics of the interface is one of the main features of a costal aquifer to be monitored and understood, in order to improve coastal groundwater management.
        Traditionally, changes in electric conductivity have been used to identify and monitor the interface in coastal aquifers. Alternatively, natural differences in temperature between fresh and the saline groundwater bodies are also known to provide useful information. Recently, Fibre Optic Distributed Temperature Sensing (FO-DTS) is increasingly being used in the field of hydrogeology because of its high spatial and temporal resolution. To test the FO-DTS technology for the monitoring and quantification of the SWI dynamics, distributed temperature data were collected every 15 minutes in a Mediterranean granular aquifer, matching with the occurrence of an extreme rainfall event. Thermal response to the recharge event is compared to data collected independently in wells with electrical conductivity and temperature probes. A 2D variable density heat and solutes transport model is performed with CodeBright. The numerical model is used to confirm the conceptual model defined from the interpretation of the FO-DTS data, explore possible future scenarios and prove the usability of this technology for coastal aquifers monitoring.
        Distributed temperature data reflect thermal responses to the extreme recharge event. However, smaller displacement of the interface, like those produced by tides, were not detected by FO-DTS. Only hydraulic processes with thermal responses larger than 0.15 ºC could be observed with this technology. Therefore, the high spatial and temporal resolution provided by FO-DTS is limited by its temperature resolution, which depends on many factors, such as the DTS sensor, the number of connections, the calibration baths and the calibration process. In any case, it is a promising technology for monitoring fast responses of the interface to large scale processes like recharge events.

        Acknowledgements: This work was funded by the projects CGL2016-77122-C2-1-R/2-R of the Spanish Government. We would like to thank SIMMAR (Serveis Integrals de Manteniment del Maresme) and the Consell Comarcal del Maresme in the construction of the research site. We would like to acknowledge Sensornet (UK) for their support and collaboration in the acquisition and operation of their Oryx+ system.

        Speaker: Mrs Laura del Val (Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya (UPC) - Associated Unit: Hydrogeology Group (UPC-CSIC))
    • 16:00 19:00
      Meeting: Wikipedia edit-a-thon
    • 16:00 17:00
      Poster with refreshments: Monday Topic 1
      • 16:00
        A cross European project to understand the vulnerability of shallow groundwater resources to deep subsurface energy activities (VoGERA) 1h

        Society is increasingly looking to the subsurface for our energy needs, be that for extracting geothermal energy, shale gas, or buffering heat, gas, or storing by-products of energy production. An increasingly crowded subsurface presents risks to groundwater relied on for water supply, since subsurface activities can introduce or release contaminants and alter subsurface properties. The VoGERA project is investigating the vulnerability of shallow groundwater from a range of subsurface energy technologies across different hydrogeological and geological settings within Europe.

        A suite of conceptual models compare the intrinsic vulnerability for different geological (crystalline, poorly consolidated and well consolidated sedimentary basins) and hydrogeological (basin centre and margins) conditions. They also consider the impacts of different subsurface activity types broadly categorised as those processes including injection, abstraction and a neutral fluid balance.
        Potential contamination pathways are being investigated at four case study sites; the Rauw Fault in Belgium, Panonian Basin in Hungary, The Peel Boundary Fault in the Netherlands and the Vale of Pickering in the UK. Geophysical, hydrological and hydrochemical data from these sites will be assessed in order to improve contamination pathway process understanding in a European setting.
        Findings from the case study sites will be used to evaluate the conceptual models and to develop a tool for decision makers and the public to assess the vulnerability to shallow groundwater from sub-surface energy activities depending on the activity, and geological and hydrogeological conditions at a specific location.

        The VoGERA project is funded as part of the European Union’s Horizon 2020 GeoERA network of projects under the Groundwater theme (Grant agreement number 731166).

        Speaker: John Bloomfield
      • 16:00
        A study on the performance of a groundwater heat pump with doublet system 1h

        Groundwater heat pump (GWHP) with doublet can be used as a highly efficient heat exchanger for air-conditioning according to the hydrogeology of installation site. As an open loop type geothermal heat pump a lot of systems have been installed over the world but it is hardly adapted in South Korea because of the lack of awareness, complex regulation and doubt in technology. We studied on the performance of the system in a pilot test building. In order to characterize the aquifer several tests were carried out in pumping and injection wells having the depth of 150 m. The measured hydraulic conductivities are ranged from 6.26$\times$ 10 $^{-5}$ cm/s to 1.65$\times$ 10 $^{-3}$ cm/s. The groundwater levels were monitored during one heating season with regard of geothermal heat pump operation which demands groundwater pumping, heat exchange and injection to the well. The performance of the system depends on the hydrogeology and the temperature of aquifer, and the installed mechanical equipment. The tested pumping and injection rate was 120 m$^{3}$/day and the groundwater level was increased around 0.5 m at injection well and the level at pumping well was lowered to 22 m below initial water level. The system performance of heating condition during one winter season was monitored. The interpreted performance data would be helpful to design economical GWHP and improve the technical feasibility.
        Acknowledgement: This research was supported by Basic Research Project of Korea Institute of Geoscience and Mineral Resources (KIGAM).

        Speaker: Dr Byoung Ohan Shim (KIGAM)
      • 16:00
        Applicability of managed aquifer recharge (MAR) in a well in an alluvial plain in a semi-arid region: An application on the Upper Litani Basin in Lebanon 1h

        Groundwater resources management has been a growing concern and scheme as the consequences of climate change and other anthropogenic forces have heavily impacted freshwater resources, especially in semi-arid regions. The adoption of managed aquifer recharge (MAR) still remain at its earliest stages of assessment in developing countries, e.g., Lebanon, where only a few studies have been conducted. Groundwater is subject to contamination and depletion due to over-exploitation, poor management, and climate change. Regional conflicts and the current refugee status have amplified the need for accessible uncontaminated freshwater resources in the semi-arid Bekaa region, where water quality is expected to deteriorate further as dry regions become drier. Thus water availability poses a challenge on sustainability. In this present work, a preliminary integrated hydrological model was constructed and calibrated using Mike SHE (DHI, 2016) for the entire Upper Litani Basin catchment at to simulate flow in steady state. Transient flow is simulated and validated based on water level observations while accounting for the different hydrological components; namely climate, river, saturated and unsaturated zone, to assess the degree of groundwater depletion, and the availability of water resources for recharge during high flow periods. It further investigates the feasibility and application of the Aquifer Storage and Recovery scheme devised for a well drilled in the Miocene semi-confined aquifer consisting of coarse alluvial deposits in the Litani Basin, Bekaa (a semi- arid region) in Lebanon, which will store surface run off during the winter, to be utilized for agricultural irrigation purposes in the summer. An experimental borehole has been drilled in the framework of a project “Strengthening Lebanese Water and Agriculture Sector” financed by the Dutch Government. The system was implemented in 2017-2018, in order to maximize well yield efficiency and reduce groundwater depletion and overexploitation. The components of the MAR system consists of a water intake reservoir and pipeline system housed in an operating container securing infiltration to and abstraction from the installed well. The small scale subsurface characterization of aquifer properties was done using grain size analysis of borehole cuttings and several pumping tests to assess transmissivity in the recharged aquifer at the borehole scale. The model will serve as an integrated decision support tool to predict the change in groundwater levels in the future under climate change scenarios and to ensure proper sustainable water management.

        Speaker: Dr Joanna Doummar (American University of Beirut)
      • 16:00
        Application of Airborne Electromagnetics to Characterize Structure and Stratigraphy in the Indian Wells Valley Groundwater Basin, California 1h

        Airborne electromagnetics (AEM) has previously been demonstrated effective at defining stratigraphy (coarse texture versus silts and clays, channels versus linear features), and for delineating water quality (brackish water resources and seawater intrusion), especially when integrated with borehole geophysical logs, lithology from well drilling and construction, and water quality data. Additionally, AEM surveys provide much greater spatial coverage than traditional methods in terms of time and resources, resulting in improved hydrogeologic correlation and interpretation between wells. In this project, approximately 800 linear kilometers of AEM data were collected in the Indian Wells Valley (IWV) groundwater basin to define the nature and extent of brackish groundwater resources, including the local and regional structure and stratigraphy.

        The Indian Wells Valley (IWV) groundwater basin is located at the southeast termination of the
        Sierra Nevada Mountains in a tectonically active area of rifting and crustal thinning associated with differential movement along the North American and Pacific plates. The regional setting has been causal to the IWV basin complexity, having formed a half graben with mountain uplift and IWV basin downdrop along the Sierra Nevada Frontal Fault, with multiple associated faults running through the basin. The IWV basin has been subject to a long series of studies, initially to characterize the geology and hydrology, and later to further delineate geothermal potential of the basin, based primarily upon data from wells, surface soils and geologic mapping, and 11 seismic sections. The AEM survey supplemented the existing data distribution, providing a more continuous spatial coverage of the basin.

        Results of AEM survey of the IWV basin have shown the utility of the technology for mapping subsurface structure and stratigraphy, with multiple faults visible in the AEM data, showing evidence that internal basin structure controlled the depositional environments. A number of buried channels, alluvial fans and coarse delta deposits as well as fault controlled barriers to groundwater flow were mapped. The AEM data also provided detailed information on the extent of brackish groundwater as well as potential locations for groundwater recharge.

        Speaker: Timothy K Parker (Parker Groundwater)
      • 16:00
        Assessment of groundwater resources in Beijing based on numerical simulation technology 1h

        Groundwater numerical modeling is the essential technique of groundwater movement research and groundwater resource assessments. By modeling the groundwater movement of Beijing, By the first joint modeling of Beijing groundwater in mountain and plain areas in this paper, the hierarchical evaluation of groundwater resources has been realized, and the impact of groundwater level variation on urban buildings is analyzed that based on the water distribution plan of the South-to-North water diversion project. These achievements can be used to optimize the water distribution plan and provide data support for reasonable conservation of groundwater.
        Firstly, the Beijing hydro-geologic condition is generalized, the aquifer of the study area is divided vertically into five layers. The groundwater model is built by GMS and the study area is divided into 190 rows, 190 columns, 1 km * 1 km regular grids. Secondly, by using the monitoring data from 2013 to 2015, the model is identified and validated, the five aquifers are equilibrium analyzed, the groundwater recharge and excretion are calculated, the Beijing groundwater resources are evaluated that the recharge resources are 27.97 108m3/a, the exploitable resources are 24.8 108m3/a. In the end, by predicting, in 2025 the phreatic water level would not exceed the limited water level for groundwater recoverable that the restrictions are the floors of underground engineering and landfill, therefore, it would not harm the urban architecture and environment when the South-to-North water diversion project lasts ten years.

        Speaker: Mrs Yin Liu (Beijing Institute of Hydrogeology and Engineering Geology)
      • 16:00
        Assessment groundwater (springs) in Baumberge and Schöppinger Berg for hydrogeology and ecology purposes 1h

        This study deals with the spring waters flow in münsterland in west of Germany in the area extended between Baumberge and Schöppinger berg, which represented closed groundwater system and fractured pore system. Eight springs, four in Baumberge (Arning ost, Aring west, Stever a, Stever new), and four in Schöppinger berg (Schwarthof, Wearning, Leerbach and Kirche ). The springs have been addressed for the purpose of water evaluation for hydrogeology and ecology. In order to meet the objectives of this research, all springs were sampled and analyzed three time in November 2018, January and April 2019 for field parameters (the electrical conductivity, pH value , temperature, dissolved oxygen concentration, While for two time November 2018, and April 2019 for major cations (Mg2+, Ca2+, K+, Na+, Al +, Sr2+), major anions (SO42-, Cl-, HCO3- ) minor anions (PO43-and NO3-) as well as the heavy elements that included (Pb, Zn, Cd, Ni, Fe, Mn, Cu, Cr) and total organic carbon. In addition to isotopes δ34S and biological analysis such as biomass, activity, furthermore faunal measurements for example body size (macrofauna and meiofauna), the ratio of stygobiont to stygoxene fauna and the number of stygofauna per groundwater filled aquifer volume.The organisms were separated from sediments, counted and pre-sorted into taxonomic groups (crustaceans, oligochaets, water mites, nematodes, turballarians). All crustacean groups, which constitute the major part of the animals in groundwater samples, and oligochaets were determined to species level, whilst the remaining taxonomic groups were identified to order or higher level. The results revealed that the springs belong to the classified as Ca-HCO3, which show that most the same hydrochemical properties and only slight variations were observed. Compared to priveous study , there are no major changes in hydrochemistry. However, the evolution of nitrate concentrations in groundwater, which has been described shows a tendency to increase NO3 Concentration. In contract the ecological result refer to determination of the groundwater animals, more from 7 groups of individuals were identified and a total of 642 Copepoda Cyclopoida, 14 Copepoda Harpacticoida, 23 Ostracoda, 17 Nematoda and estimated 162 Nauplius larvae could be detected over the sampling period. The determination show the Arning west and Leerbach largest biodiversity, which is probably due to the high food supply. At the sources. At Kirche no more species were detected. The reason for this could be an influence on the settlement or lack of detritus as a food source from the development in addition to defecult fauna sampling in this spring.

        Speaker: Mrs Sura Alqargholi (münster university)
      • 16:00
        Assessment of groundwater contamination vulnerability in a predominant fractured rock-aquifer area 1h

        This study was carried out in the Miryang City, Korea where had the characteristics of urban and rural functions. The study area is surrounded by high mountains except the southern part which forms the flat area around the large Nakdong River. The city area is about 800km2 and about 5,200 wells are developed there. 325 wells were investigated for the sustainable development and effective management. 230 wells located in the fractured rock, and 95 wells were in the unconsolidated deposits such as alluvium, colluvium and highly to completely weathered rock. Advanced DRASTIC Model (ADM) adding 2 more factors of land use and lineament density to Original DRASTIC Model (ODM) of 7 factors were applied for the assessment of groundwater contamination vulnerability in the study area. In case of all monitoring wells, ADM produced a more accurate contamination vulnerability map and a larger correlation coefficient between contamination vulnerability index and NO3-N concentration comparing to ODM. The correlation coefficients of ADM and ODM were 0.35 and 0.24, respectively. In two cases of all monitoring wells and unconsolidated aquifer wells, ADM of unconsolidated aquifer wells produced a more reasonable contamination vulnerability map and a larger correlation coefficient between contamination vulnerability index and NO3-N concentration,comparing to ADM of all monitoring wells. The correlation coefficients of all monitoring wells and unconsolidated aquifer wells were 0.35 and 0.74, respectively. Thus, the assessment of groundwater contamination vulnerability was more effective for the unconsolidated aquifer than the whole aquifer of unconsolidated material and rock because DRASTIC evaluation basically assumed that groundwater contamination was conducted through the surface ground. Artificial Neural Networks (ANN) technique was also applied for the vulnerability assessment of unconsolidated aquifer. ANN model (ANNM) rendered a more accurate contamination vulnerability map and a larger correlation coefficient between contamination vulnerability index and NO3-N concentration, when compared to the application of simple ODM. The correlation coefficients of ANNM and ODM were 0.81 and 0.74, respectively. It was concluded that the assessment of groundwater contamination vulnerability in a predominant fractured rock-aquifer could draw the better result in conducting the evaluation only of the unconsolidated aquifer except the fractured rock aquifer, and that ANNM was very effective for the evaluation of groundwater contamination vulnerability.

        Speaker: Sang Yong Chung (Pukyong National University)
      • 16:00
        Assessment of groundwater natural recharge in difficult environments: A case study at the Lake Chad Basin 1h

        Reliable recharge assessment for sound hydrogeological analysis in arid and semi-arid area is a challenge due to the complex process requiring of intensive data mining and especially in face of limited access to data sets or only short data periods available. This has forced researchers to improve the available data using remote sensing products for input data (e.g., TRMM, CMORPH, TMPA). Recharge estimation through a water-soil-plant distributed model based on satellite products appears to be an interesting solution being adopted at the Lake Chad Basin for the Maiduguri area (Southwest of Lake Chad basin). Natural recharge is performed with a water-soil-plant distributed model (Visual Balan) based in meteorological data obtained from a ground station (Miduguri, 532 mm) and from satellite products (MSWEP, 673 mm) for the same geographic location of ground station and satellite for the 2009-2010 period. Satellite products generally overestimate precipitation with regard to ground station; this fact is attributed to no raining cirrus with cold cloud-top temperatures. As a result, groundwater recharge estimation in the area by field stations and satellite products is 80 and 100 mm per year respectively, a 20% of difference in the final value. Considering the non-linearity of aquifer recharge process and dependence on precipitation values, comparison between ground-based and satellite data sets is the initial step for recharge estimation assessment.

        Speaker: Mrs Nafiseh Salehi Siavashani (PhD student, Technical University of Catalonia (UPC), Civil and Environmental Engineering, Spain)
      • 16:00
        Assessments of surface water-groundwater interactions in the arid zone — case study in the Yanqi basin, northwestern China 1h

        Groundwater is a critical water resource for human survival and social-economic development in arid and semi-arid areas. With the development of economy and the continuous increase of population, and especially to meet irrigation demands, aquifers are subject to intensive exploitation in the Yanqi Basin, in the central region of Xinjiang, China. The decreasing groundwater table changes the interactions between groundwater and surface water. To quantitatively evaluate the exchange capacity between river and groundwater, a flow model based on MODFLOW was built to simulate the interactions of river and groundwater in Yanqi Basin in a 10 years period. Results show that the water exchange capacity between surface water and groundwater increased obviously with the increasing groundwater exploitation. The exchange capacity increased from 1.18 hundred million m3 in 2004 to 2.2 hundred million m3 in 2013, when the groundwater exploitation increased from 1.19 to 3.8 hundred million m3 in the same period. The groundwater exploitation was close to the value of available exploitation quantity in this area. The increasing river seepage due to excessive groundwater exploitation also plays an important role in the water level decline in the Kaidu River and in Bosten Lake. This implies the current utilization of groundwater resources in the Yanqi Basin is unsustainable and a strong groundwater resources management is needed in this extreme arid area.

        Speaker: Dr Jiangbo Han (Nanjing Hydraulic Rsearch Institute)
      • 16:00
        Bauru Aquifer System, State of Sao Paulo, Brazil: Conditioning factors of water level variations 1h

        The Bauru Aquifer System is characterized as a sedimentary aquifer, of predominantly free condition, whose recharge is associated with the direct infiltration of precipitation. This aquifer is the main source of public and private water supply in the western portion of São Paulo state, a Brazilian industrial and agricultural pole. The Bauru aquifer has been monitored as part of the Groundwater Monitoring Network, maintained and operated by the Geological Survey of Brazil. In this context, the present study contemplates the investigation and multi-thematic analysis of the intervening factors of the correlation between groundwater level response, rainfall events and anthropogenic alterations, with the purpose of increasing the knowledge of the potentiality of the Bauru aquifer system. Time series of groundwater and rainfall data were also analyzed and evaluated in order to identify the factors that could influence this relationship, such as: composition of the lithological profile above the filter in each well, thickness of the unsaturated zone, specific capacity of the well, number of production wells installed within a 5km radius, soil types and cover in the region. The time series analysis was conducted by using simple correlation between the groundwater level series to verify their similarities, and cross correlations to determine precipitation influence on the wells static level, in order to estimate the necessary time for water to infiltrate and recharge the aquifer, increasing the static level. Subsequently, the data was spatialized using ArcGIS and a multicriteria analysis was performed, assigning weights to the different variables in order to explain the time series correlations. Based on the identification of the interactions and influences of the aforementioned factors, a correlation between groundwater level and the rainfall was identified. This correlation is mainly affected by the lithological profile above the filter, the specific capacity of the wells and the number of production wells located within a radius of 5 km. Series with rapid responses to rainfall events were generally associated with essentially sandy lithographic sequences, specific capacities above 0.29 m3/h/m or with the number of production wells below 10. On the other hand, the absence of correlation or very slow response to rainfall was associated with wells whose lithographic profile had clay layers that could lead to confinement, or had a specific capacity lower than 0.29m3/h/m associated with a large number of production wells in the surroundings. Additionally, there was a significant water level decrease during a severe drought between 2013 and 2015, corresponding to the same period of the water crisis in the State of São Paulo.

        Speaker: Ms Marcela Barcelos Barbosa
      • 16:00
        Comparative Analysis of impacts of groundwater droughts in a European context 1h

        Groundwater is of crucial importance for society, as it can uphold provision of hydrological services when there is a lack of water during drought. However, when droughts extend over longer periods of time and groundwater abstraction is increased, longer-lasting groundwater droughts can develop, aggravating existing water shortages and impacting groundwater-dependent environmental systems. This complex interaction means that groundwater contributes to mitigate droughts, but may also during longer droughts exacerbate drought hazards impacting society. In theory, it is understood that this interaction exists. However, to date no study used empirical data on how and when groundwater is factually reported as a mitigation agent or as an impact agent. In this study, we build on previous efforts to synthesize text-based reports on drought impacts in the European Drought Impact Inventory (EDII). We extended the EDII with additional, groundwater-related reports. We then analysed the EDII data to find out: a) how is society impacted by groundwater drought?, b) how is groundwater used during drought?, c) is the role of groundwater during drought different in different climatic or legislative settings?, and d) did the role of groundwater during drought change over time? To answer these questions, we isolated the EDII reports that directly relate to groundwater, and mapped them onto new groundwater-related impact categories. We qualitatively summarized the way groundwater is reported as an impact, or as a mitigation agent, and provide statistics on the frequency of each occurrence. We further present the temporal development of the reporting, and compare the type and number of occurrence of groundwater-related reports between the UK, the Iberian Peninsula (Spain and Portugal) and the DACH region (Germany, Austria, Switzerland). The study provides the first systematic documentation of groundwater impacts and use during drought. It will thus provide guidance for researchers and water resource professionals considering whether groundwater can be used sustainably as an alternative resource during drought under different circumstances.

        Speaker: John Bloomfield (British Geological Survey)
      • 16:00
        Contribution of Hydrochemistry and environnemental isotopes to the study of seawater intrusion in the coastal aquifer of the Eastern Mitidja Plain (Algeria) 1h

        The Mitidja Plain is situated in the north of Algeria, the Eastern part (575km2) lies by the sea in the north and is limited by the Atlas Monntains in the south. the region has two main aquifers separated in some places by the El-Harrach Formation (Calabrian) , The Plaisancian marls (lower Pliocene) are the substratum of the whole area , the second and most important aquifer , Mitidja formation , is alluvial , coastal. The Eastern Mitidja plain constitutes a subterranean water reservoir essential for the agricultural, urban and industrial development of the capital Algiers. Recently, industrial activities, the spreading of exhaustive agricultural practices and the urbanization of the plain have lowered the quality of water. As many of the Mediterranean countries, Algeria has known a severe dryness during the last two decades. Unfavourable climatic conditions causing long period droughts have predictably led to a contamination of coastal groundwaters along the Mediterranean by ingressive seawater. Intensive pumping practices in use for the sake of securing water allocation for both populations and agriculture have drastically affected the groundwater reserves through overexploitation of the resource creating a consequent drawdown in the water table. During the dry season, the mobile fresh/sea water interface moves forward farther inland contaminating wells and boreholes. Two approaches making use of both hydrochemical and isotopic tools were applied to assess the extent of seawater intrusion. The Br vs. Cl plot showed that the points align in a parallel way to seawater dilution line confirming thus a marine origin for those elements. Na/Cl ratio vs. Cl plot brings to the fore two poles of points: one composed of shallow unaffected groundwater and a second one composed of deeper boreholes and wells in which seawater is present to different extents. This is further confirmed by isotopes which exhibited a wide range of values mirroring the affected and unaffected areas as well as those points submitted to intermingling between different endmembers.

        Keywords: Seawater, Groundwater, Saline Intrusion, Environnemental isotopes, Hydrochemistry, Algeria.

        Speaker: Dr Dalale KHOUS (Algiers nuclear research center)
      • 16:00
        Development and Application of Approaches for Geosphere Modelling in Support of Adaptive Phased Management: An Overview 1h

        The Nuclear Waste Management Organization (NWMO) was established in 2002 by Canada’s nuclear electricity producers in accordance with the Nuclear Fuel Waste Act (NFWA). The NWMO is responsible for implementing Adaptive Phased Management (APM), Canada’s plan for the long-term management of used nuclear fuel. The technical end point of APM is the centralized containment and isolation of the used fuel in a deep geological repository (DGR) located in a stable crystalline shield or sedimentary bedrock formation. The DGR concept comprises multiple barriers to contain and isolate the used nuclear fuel for time frames of 1 Ma. A key component in the DGR concept is the surrounding geosphere, which acts to protect the engineered barrier systems, to preserve a stable environment in which radionuclide migration is minimized, and to create a barrier to inadvertent intrusion. At a depth of approximately 500 m, the ability of the geosphere to act as a natural barrier is governed by site-specific features and attributes.

        The NWMO is pursuing an active geoscience program into the long-term evolution of crystalline and sedimentary geospheres, which includes collaboration with Canadian and international experts, focused on a wide range of topics related to the development of DGRs for the safe containment of used fuel. The primary objectives in developing geosphere models are to: 1) support site selection and future site characterization activities; 2) advance the understanding of the geosphere in terms of stability, predictability, and resilience to long-term perturbations; 3) substantiate the role of geoscience in establishing support for a DGR safety case; and 4) maintain a high level of competency and a credible Canadian-based technical program. This is achieved through the development of approaches for evaluating and interpreting geosphere properties, groundwater system behaviour and predictions of long-term geosphere and DGR performance. The evolution of deep-seated groundwater systems in fractured crystalline rock is illustrated in part through the integrated application of fracture network, groundwater, and glacial system modelling.

        Speaker: Mr Eric Sykes (Nuclear Waste Management Organization)
      • 16:00
        Development of an integrated groundwater information system and its application to the Geum river basin, Korea 1h

        An integrated groundwater information system, which is a web-based platform, was developed to utilize and manage groundwater efficiently in Korea. The system was designed to input and modify data interactively by various users such as managers, well developers, and scientists. Groundwater database is coupled with a web-based modeling tool based on Analytic Element Method(AEM)(Visual AEM by James R. Craig in University of Waterloo) to assess groundwater resource and impacts from various factors such as climate change, hydrologic environment changes, and contaminant loading. The groundwater database contain the well locations and the related facilities, hydrogeological units and characteristics, geothermal data, water quality, various geo-spatial data including land use, soil type, geology etc. The groundwater modeling can be possible on the platform straightforward due to the information access in the same time. There’s a limit to what you can implement using the adopted AEM model, but it is powerful in that it can well reflect the characteristics of a large scale area flow system. The integrated system is called as GEE system, and it means Groundwater-(Geothermal) Energy-Ecosystem, which is the three components that make up the Groundwater Dependent Ecosystem(GDE). Through the development of the system, we intend to secure sustainable groundwater-geothermal resources and to maintain GDE according to climate change. Database were constructed for each of the three factors (groundwater, geothermal, ecosystem) as the components of the GEE system in the Geum river basin which is one of 4 largest basins. Furthermore, the database and groundwater modeling module on the platform in the Geum-river basin was tested and has been confirmed to be effective for a good groundwater management tool.

        Speaker: Dr Kyoochul Ha (Korea Institute of Geoscience and Mineral Resources)
      • 16:00
        Dynamic storage and volumetric filling levels indicating regional groundwater availability 1h

        Groundwater shortage during drought periods will become more important in future and of relevance even in water-rich regions. Switzerland as considered Europe’s water tower disposes of large groundwater resources in the range of 150 km3, but some problems may arise under extreme conditions, such as in 2018 with dramatic precipitation deficit over more than 6 months. Therefore, additional tools going beyond classical monitoring are needed to better characterize such situations and to improve the knowledge on the state and evolution of groundwater quantity on regional and national scales.

        Fluctuations in regional groundwater volume can be used as indicator for actual groundwater availability. An approach was developed accordingly for assessing groundwater volumes, and dynamic storage respectively, for Swiss unconsolidated porous aquifers, corresponding to areas of high water demand. Actual volumetric quantification is deduced from water level records in the framework of the national groundwater monitoring. Those are representative for typical hydrogeological settings, i.e. groundwater regimes, and were linked to static groundwater volume estimates. Upscaling of normalized level amplitudes with respect to long-term mean values thereby allowed for the regionalization of the measurements. This provides complementary online information on the groundwater filling level, i.e. the ratio of volume variation and total volume, which in turn indicates sensitivity to drought.

        The spatial pattern of the filling level is of particular interest in low-level situations, and identifies actual and potential areas at risk. The example of 2018 illustrates the decrease and recovery of groundwater volumes in the different regions of the country, many of which are provided with sufficient reserves despite very low groundwater levels reached. The groundwater volume indicator in this context gives useful information for characterizing the impact of drought conditions for the different groundwater regimes. It represents a tool for administrations and water managers to define critical low-level values and to adapt regional groundwater planning. This also implies infrastructural measures, such as the interconnection of differing water resources, in order to ensure water supply today and related to expected climate change scenarios.

        Speaker: Michael Sinreich (Swiss Federal Office for the Environment FOEN)
      • 16:00
        Economical development and Tubarão Aquifer System relationship: an example in the State of São Paulo, Brazil 1h

        The Tubarão Aquifer System - TAS is a permo-carboniferous sedimentary aquifer, deposited in a glacial continental and shallow marine environment (DAEE/IG/IPT/ CPRM, 2005). The productivity is relatively low, presenting transmissivity between 1E-6 to 3E-4 m2/s (Iritani et al, 2009) and hydraulic conductivity between 1E-8 to 1E-5 m/s (DAEE, 1981; 1982).
        Municipalities in the outcropped TAS are experiencing economic and population growth, driven by development policy implemented in the late 1980s. They are inserted in the water resources management units denominated UGRHIs 5 and 10 where the water availability has been strongly reduced during the last decades.
        In 7 years, the availability per capita reduced over 7%, reaching, in 2017, 981 m3/hab.year in the UGRHI 5 and 1686 m3/hab.year in the UGRHI 10. According to published information, the regular extracted volume of groundwater, authorized by management agency, is less than 30% of the surface water (CBH-SMT, 2016, 2018; CBH-PCJ, 2016, 2018).
        Studying the TAS in 12 municipalities, it was observed that groundwater plays an important role in the economic development of the region.
        The TAS thickens to west and the well depth in the study area range from 50 to 455 meters. Due to its heterogeneity which imposes a semi-confinement condition, the well productivity is low, with average specific capacity and flow rate of 0.13 m3/h/m and 7.2 m3/h, respectively. In the southern portion of the study area the productivity is higher, where flow rates can be above 30 m3/h per well, allowing its use for public water supply in some municipalities as Tietê, Capivari, Rafard, Porto Feliz and Elias Fausto. The estimated rate in 2015 of 132 public water supply wells was around 0.61 m3/s.
        However, the largest number of wells belongs to private users (929 wells) whose pumped volume was estimated at 1.05 m3/s. The industrial sector, with 564 registered wells, is the main user of groundwater. According to SEADE (2019), this sector accounts for 30% of jobs in these municipalities, playing an example of the groundwater importance for the economic development in São Paulo State.
        According to TrataBrasil (2019) the total number of wells may be much higher due to the irregular wells not registered by the management agency (about 60% in the São Paulo Metropolitan Region). Besides that, in Capivari and Tietê, where intensive pumping occurs, locally water level drawdown is observed (Iritani et al., 2009; Ferreira et al., 2005).
        In addition, radiocarbon isotope analyzes of TAS provided a range of pmc between 0.39 and 79.96, indicating high residence times, greater than 15,000 years BP, demonstrating the use of old groundwater.
        These facts demonstrate that the improvement of knowledge of the TAS, especially about recharge processes, is necessary to subsidize a sustainable use of the aquifer.

        Speaker: Dr Didier Gastmans (Sao Paulo State University - Environmental Study Center (UNESP-CEA))
      • 16:00
        Empirical model as tool for a correct management of groundwater: an experience on a carbonate aquifer in Tuscany (Italy) 1h

        Most of the available freshwaters on Earth are stored in the underground, consequently groundwater represents the main resource in term of water supply. The exploitation of groundwater bodies will increase to face the significant increasing of the global water demand, which has been predicted as a consequence of the future economic expansion, population growth, and urbanization (Rosegrant et al., 2002). Furthermore, the reliance on this resource is continuously growing given the key role that groundwater plays for mitigating the climate change/variability. The estimation of the entity of these effects is mandatory for a reliable management of this crucial resource, which must be protected by suitable actions in order to guarantee safe water supplying for the next generations (Doveri et al., 2016). This work is focused on the water resources destined to the drinkable water distribution, by studying possible empirical relationship between meteorological parameter and groundwater quantity indices. This activity is in the wider context of a research for the development of support tools for the management of the resources under specific climate scenarios. Furthermore, for what regards carbonate aquifer, the impact of climate change can be very significant, given the high sensitivity caused by their karst features. In this work, flowrate of the Cartaro spring (draining a karst aquifer of the Apuan Alps, northwestern Tuscany) and meteorological timeseries (both historical and synthetic scenarios) in the relevant hydrogeological basin were used. Flowrate measurement were provided by the Tuscan Water Authority (AIT) and GAIA ApA (Integrated Water Service), while synthetic meteorological scenarios were provided by Consorzio LaMMA. This work describes the data-driven approach experimented with the collected time series, essentially based on multi-variate analysis techniques and on a simplified machine learning scheme based on neural networks. In fact, a preliminary test of a data-driven approach based on Multi Layer Perceptron Neural Networks (MLP-NN) is described here. Dedicated techniques for data pre-processing, training and validation have been experimented. In particular, a strong hypothesis of linearity and time-invariance of the system under observation was done, and MLP-NNs were essentially used as non-linear approximators. A further activity regarded the assessment of a performance metric for the evaluation of multiple MLP-NNs with respect to independent test sets, based on either historical or synthetic data. Results are shown in terms of predicted flowrates in a given time window (up to 90 days in our case study), and are organized according to different scenarios of total rainfall quantity.

        ACKNOWLEDGEMENTS
        This research has been supported in part by the Project of National Interest NextData of the MIUR (Italian Ministry for Education, University and Research) and in part by the AIT (Tuscan Water Authority).

        Speaker: Matia Menichini (Institute of Geosciences and Earth Resources, National Research Council of Italy, Pisa, Italy)
      • 16:00
        Enhancement on the hydrogeological data management and analysis 1h

        The conceptualisation of a groundwater system involves continuous monitoring and evaluation of a large number of parameters. All these datasets collected and generated to perform a groundwater conceptual model are often stored in different scales and formats (e.g., maps, spreadsheets or databases) from different entities. This continuous growing volume of data entails further improving on how it is stored.

        One of the pillars of effective data governance is data management. Data management is successful when data are: harmonised collected, structured stored, error checked, available, understandable and reusable ensuring maintenance of the data model. There are several developments to stewardship information and they can be implemented in industry, government and academia reducing times and resources to perform environmental analyses. These kinds of data infrastructures and their governance are becoming more mature worldwide because of their importance in ensuring sustainable resources. Data infrastructures, such as spatial data infrastructures, and their governance are continuously being used and developed because of their impact on groundwater management. In addition, these kinds of data infrastructures currently require information communication technology (ICT) tools for improving geodata governance by delivering quality information to users and helping them perform further analyses on a unique platform. To implement these data infrastructures or to connect it to ICT tools is essential an optimal data migration and integration (DMI). DMI also is useful for decision-making with clean high-quality data, which produces a more confident and stringent groundwater governance. To ensure an optimal DMI, it is valuable to provide frameworks with which to assist and facilitate processes to connect and transform multiple systems from different sources and formats to the required destination formats of new systems. Facilitation of how the connections among system structures and the organisation of a DMI model in terms of its application and maintenance should be as intuitive as possible.

        We present a methodology to facilitate and optimise DMI to improve data governance. The implementation of this DMI methodology facilitates merging multiple sources of information, installing new systems to exploit stored information while using the original systems of information storage, and upgrading databases, formats or standards that may not be supported in the future to one that is supported or most appropriate, among other processes. The outcomes of its application by the Barcelona City Council (Spain) are used to optimise the groundwater management in the city. DMI models performed in this application can be easily adapted to other external datasets, increasing the volume of quality data to improve the understanding of the groundwater system behaviour and the monitoring network in the city. The proposed methodology can be widely implemented in any kind of DMI project to develop data infrastructures or to implement ICT tools for further analyses.

        Speaker: Rotman Criollo (Institute of Environmental Assessment and Water Research (IDAEA) - CSIC)
      • 16:00
        Estimating of Surface and Groundwater Availability and Demand from Lower Chambo River Basin (Ecuador), as a tool for Water Management. 1h

        This work proposes a zoning method as a tool for water management and it is applied to lower Chambo River Basin, located at Chimborazo Province (Ecuador). In order to achieve this goal, it was necessary to estimate the availability of surface water as well as of groundwater in the basin. The amount of exploitable groundwater was computed using standard water balance methods and Darcy mass balance relation, estimating thus the aquifer recharge. The conceptual model for the groundwater circulation is based on physiochemical, chemical and isotopic analysis applied on samples collected from spring and wells. The potential surface water supply was estimated from a hydrological analysis using the reported flow rate of rivers in the basin, which shows consistency with the measured values of local precipitation. The water demand in the basin was estimated using the rate of urban water consummation in the two biggest cities in the basin (Riobamba and Guano), the reports of the concession agreements from the National Water Secretary (SENAGUA) and the minimum water necessary for farming the products that are grown in the basin from the FAO report (1991).
        It was possible to identify three multilayer aquifers, with an origin volcano-sedimentary (Llío-Guano, Riobamba and Yaruquíes) composed by volcanic deposits from Chimborazo, Igualata, and El Altar. These aquifers are fed mainly by two mountain ranges; from the west (Chimborazo and Igualata) and from the east (El Altar). The recharge has also a secondary contribution from local precipitation. The Chambo river becomes the main discharge of the surface flow and groundwater. Hydrogeochemical and isotopic data ($\delta^{18}$O and $\delta^{2}$H) evidence the possibility of two sources for groundwater. Llío and Riobamba aquifers are composed of calcium-magnesium bicarbonate waters, from slightly acidic to neutral as well as with enriched $\delta^{18}$O and $\delta^{18}$H. The Yaruquíes aquifer is constituted by waters from sodium-bicarbonate to calcium-magnesium. While the springs located in Cubijíes are constituted by sulfate waters with more depleted of $\delta^{18}$O and $\delta^{2}$H values, indicating that there is influence of the volcanic activities from El Altar. From those results and from morphological and water availability characteristics, the study area was divided into eight zones. Our results show there exists an unequal relationship between management and water usage in the eight defined zones, prioritizing water usage for farming and cement industry to the detriment of urban and rural supply. In this sense, we propose a water management for the basin to short (one year), medium (five years) and long term (twenty years).

        Speaker: Sandra Procel (Escuela Politecnica Nacional)
      • 16:00
        Evaluation and Optimal Management of Groundwater Resources (Bakhtegan-Maharloo basin) 1h

        Due to the lack of surface water resources in Bakhtgan- Maharloo basin, the amount of water withdrawn from groundwater resources has been more than the allowed limit. This amount has significantly affected surface water resources which led to some phenomena such as drying up of the Kor river, creating subsidence in 70% of basin plains, economic damages caused by reduction in the area under cultivation in downstream of kor river and drying up of Bakhtegan lake. In order to obtain a general view of this basin and optimal management of its groundwater resources, the situation of groundwater resources has been considered. In this regard, the unit hydrograph of basin plains and annual variations of the groundwater levels were studied. For preventing from further decline in the groundwater level some scenarios such as reducing the area under cultivation, changing cropping patterns, changing irrigation system and combination of these scenarios were presented. 19 out of 28 case studies which had 14 years (2002-2016) of groundwater level data were considered. The results illustrated that among 19 studied plains, all plains except Kherameh and Shiraz have the annual decline of more than 25 cm, also 68% of the plains have the annual decline of more than 50 cm, 47% of the plains have the annual decline of more than 75 cm and 26% of the plains have the annual decline are more than one meter. In this research, the plains more than 1 meter‘s annual decline including Arsanjan, Kavar- Maharloo, Sa'adat abad, Sydan- Faroogh and Marvdasht with decline values of 2.43, 1.75, 1.44, 1.09, 1.02 meter respectively, were regarded as critical plains. At the next step, by taking into account the cultivation information, crop patterns, irrigation systems, and the volume of water-supply into the farm in pumping wells, four scenarios were performed and the annual decline under new conditions were calculated and compared with the prior annual decline. From the results, it can be expressed that only the use of modern irrigation systems instead of traditional systems in all or part of the dominant crops of the area under cultivation is not alone sufficient to reduce the available decline and will not compensate the major part of aquifer ‘s annual decline of these fields. Therefore, it is necessary to change the major crop pattern into products with low water needs to be considered. The investigations showed that the second scenario (changing irrigation method for the available crop pattern) is operationally more appropriate among other scenarios but the third scenario (case b) (changing irrigation method and crop pattern Simultaneously) has a highest impact on compensating aquifer‘s decline among all scenarios. In conclusion, according to the critical conditions of this basin the third scenario is suggested.

        Speaker: Dr Heidar Zarei (Association Professor in Hydrology)
      • 16:00
        Evolution Characteristics and Driving Mechanism of the Land Subsidence for Typical Regions of the North China Plain 1h

        The North China Plain (NCP) is one of the biggest groundwater systems in the world, and the development and utilization of groundwater has led to severe land subsidence. The NCP has more than 80% of the total area of severe subsidence in China, so the situation of prevention and control of land subsidence is severe. Due to diverse sedimental environment, different geological conditions, and intensive groundwater abstraction, the mechanism of land subsidence is complex. With the help of earth observing technique and traditional monitoring tools, the disaster process of land subsidence was monitored, and the developing history and current situation were analyzed. Also, the difference features of land subsidence and the mechanism of hysteretic deformation were analyzed with the help of strain-stress diagrams and soil mechanics tests. The results show that the subsidence areas are mainly located in the areas of the Quaternary sedimentary depressions, having characteristics of west-east sub-zone and north-south subsection. The major contribution layers to the land subsidence have varied with the change of groundwater abstraction layers. The drought is an important and indirect factor enlarging the scale of land subsidence by reducing natural recharge and leading to the increase of groundwater abstraction for emergency water supply. The hysteresis of land subsidence is obvious, and the time of hysteresis can last for twenty-five years. Besides the consolidation, the creep is another important reason for the hysteresis which can reach 28.3% of the total deformation for the Late Pleistocene strata in the Cangxian uplift. The deformation characteristics of the soil layer bear strong relationship to the physical characteristics and variation pattern of groundwater levels. The strata at different depths have distinct deformation characteristics such as elastic, visco-elastic, and visco-elastic-plastic deformations, and shallow aquifer groups indicate typical elastic deformation.

        Speaker: Dr Haipeng Guo (China Institute of Geo-Environment Monitoring)
      • 16:00
        Extending the knowledge about the Tikuna Aquifer - Western Amazon 1h

        The transboundary Amazonian Aquifer System extends over a vast territory of around 2.7x106 km2 in the western Amazon. Its major portion is located in Brazil, although comprising areas in Peru, Ecuador and Colombia.
        The Amazon Aquifer System is composed of three major hidrogeologic subunits: the outcropping Alter do Chão and Solimões aquifers, and Tikuna Aquifer, a confined extension of Alter do Chão aquifer. From these subunits, the Tikuna Aquifer was the last one to be defined. The other two subunits have historically been used as water supply sources in the Amazon plain. Tikuna Aquifer has a limited water use, both due to its location, involving the great depths and remoteness of the western Amazon region, and its quality, that is predominantly composed by brackish water, saltwater or even brines, sometimes with a high temperature, except near recharge areas or in the farthest discharging areas.
        Sampling campaigns were focused on aquifer recharge and discharge areas with relatively easy access, due to high field trip costs in the region as a consequence of remoteness and lack of transport means. Study areas comprised Ecuadorian provinces of Napo and Sucumbios, Peruvian Contamana city in Ucayali province, Serra do Divisor highlands in Acre State, Brazil, and the Eastern border of the aquifer system, in Iranduba, Manacapurú, Careiro, Manaquiri and Codajás cities, in Amazonas State, Brazil. The integration of hydrochemical data, groundwater head measurements, and other geological data, such as geophysics and stratigraphic data, obtained both during field campaigns, cooperation with research groups in Brazil, Ecuador and Peru and literature review, allowed developing the Tikuna Aquifer flow conceptual model and a regional 3D mathematical flow model considering a variable density water flow, using a modified version of the finite-element CODE_BRIGHT (COupledDEformation, BRIne, Gas and Heat Transport) code, originally developed by the Geotechnical Engineering Department at Politechnical University of Cataluña, Spain.
        From the field work, some new Tikuna Aquifer discharging areas have been identified. These discharging areas have peculiarities, such as the discharge of very hot water, forming cascades and high temperature rivers in the Peruvian territory. Hydrochemical facies comprise HCO3(Cl)-Na-Ca waters with Cl-Na waters in salty water bodies. Isotopically, 14C age dating and 18O-2H results showed a well-behaved aquifer system in agreement with the conceptual model initially proposed by Rosário et al. (2016). One regional numerical flow model helped to identify the groundwater connection between Ecuadorian and Peruvian aquifer basins with the Brazilian Amazonian aquifers and its influence over the groundwater quality and flow pattern.

        Speaker: Prof. Gerson Silva Jr. (UFRJ)
      • 16:00
        Geology and hydrogeochemistry as groundwater assessment and management tools in Douala sedimentary basin/Cameroon 1h

        Douala city, located in the littoral province of Cameroon, receives abundant rainfall quantities due to its geographical position in the gulf of Guinea and bears considerable surface water and groundwater resources. Due to socio-economic development and rapid demographic growth and its consequences of unplanned urbanization and improper sanitation system, these water resources are poorly protected and managed. Streams occurring the Wouri watersheds are mostly used as waste water discharge and hundreds boreholes have been drilled to the aquifer system without any management plan. A detailed geological, hydrodynamic and hydrogeochemistry study in Douala town and vicinity was conducted to get a better insight of the groundwater system functioning. Three field campaigns were carried out with 225 samples collected and analyzed for major ions and silica, stable isotopes (δ18O, δ2H, δ13C), tritium (3H) and 14C.
        The system have been reconfigurated through petroleum and hydraulic lithologic boreholes data for a thickness of 200 m and two main geological and hydrogeological formations have been defined such as the superficial system namely Mio-Pliocene/Quaternary aquifer (0 to 70 m of depth) and the intermediate system namely Upper Eocene/Oligocene aquifer (70 to 200 m of depth). The general hydrochemistry is characterized by the chloride water type as the dominant one, mixed water type are also represented and to a lesser extend bicarbonate water type. The Q-mode HCA for both of systems deciphers 4 main clusters C1 to C4 according to the major ions and silica and the hydrogeological conditions. Then, the R-mode FA stand out the mineralization processes. These latters coupled to the isotopical results confirm the general hydrodynamic schema where modern groundwater types indicate silicate minerals weathering as the main geochemical process, allitization and monosiallitization as the principal pedogenetical processes and calcite dissolution (C1 and C2). Whereas sub modern groundwater type mostly show silica deposition, ion exchange and to a lesser extend other carbonate minerals dissolution (C3 and C4) and bisiallitization as the main pedogenetical process occuring. Furthermore, the spatial distribution of stable isotopes exhibit a groundwater enrichment gradient from the recharge areas (NE) to the main catchment (Wouri River). Depleted isotopic contents of superficial aquifers are closed to rainfall signature contents, attesting of direct infiltration. Mixing water characterize vertical flow acting in both systems precisely in the lower part/semi-confined aquifer of the Mio-Pliocene/Quaternary and in the upper part/semi-confined aquifer of the Upper Eocene/Oligocene. Radiocarbon reveal ages from few hundreds to thousands for the Upper Eocene/Oligocene aquifer system. These results refine understanding of the aquifer system functioning which is essential to provide a reasonable basis for effective groundwater control measures and sustainable water management in the study area and the entire sedimentary basin of Douala.
        Key words : hydrogeochemistry, groundwater ressources, management, Douala basin, Cameroon

        Speaker: Dr HUGUETTE CHRISTIANE EMVOUTOU (UNIVERSITY OF DOUALA/CAMEROON)
      • 16:00
        GEOPHYSICAL EVALUATION OF GROUNDWATER RESOURCES VULNERABILITY: CASE STUDY OF PART OF AKURE, SOUTH WESTERN NIGERIA. 1h

        Anthropogenic activities constitute a major threat to groundwater resources if not monitored and controlled and thus may hamper the optimum harness and utilization of the scarce resources. Most groundwater resources evaluation focuses on delineation of the water bearing unit and less attention is centered on the quality and vulnerability of the resources. It is on the latter that the focus of this paper is based.
        Field measurements using electrical geophysical methods was adopted for the study and sixty five vertical electrical sounding (VES) data using schlumberger array method were acquired . The computer assisted VES data interpretation enables the delineation of the subsurface into three to four geoelectric layers; the topsoil, the lateritic or weathered layer, the fractured basement and the resistive bedrock. In the topsoil, resistivity values range from 20 ohm meters – 580 ohm meters with the layer thickness varying from 0.4 m – 2.0m. The second layer which is presumably the weathered zone, has resistivity in the range 21 – 648 ohm meters with the thickness ranging from 0.3 m to 36.6 m. The fractured bedrock has resistivity in the range 36 ohm- m – 796 ohm meters. Geoelctric layers with relatively low resistivity values are considered zone of saturation which are the potential target for groundwater resources.
        Assessment of the vulnerability potential of the aquifer especially the topmost aquifer was based on the geo-electric parameter evaluated from the resistivity data. Aquifer overlain by topmost layer with low resistivity (< 100 ohm-m) has been interpreted to imply clayey formations with good protective capability and less vulnerable. This occupies most of the central part and the southwestern part and constitutes about 65% of the study area. Aquifers within the zones overlain by geoelectrically pervious materials (resistivity of 101 to 300 ohm meters) interpreted to be sand around the northern part and some portions of the southern part of the study area is about 35%. This is considered vulnerable to infiltrating surface contaminants.
        The study has made possible the characterization of the vulnerability potential of the aquifer in the study area. The area is mostly covered by materials of thin protective capacity top layer with pockets of weak protective topsoil (sandy). This makes the groundwater resources in the area vulnerable to surface anthropogenic source pollution. However precautionary measures to protecting the resources must be put in place by the local municipal authority for adequate monitoring of waste disposal by individuals and factories in the area.

        Key words: Groundwater, Electrical sounding, Resistivity, Aquifer, vulnerability.

        Speaker: Mr Akinniyi Akinsunmade
      • 16:00
        GROUNDWATER CHEMICAL AND ISOTOPIC CHARACTERIZATION OF AN AQUIFER IN BRAZILIAN CEARA STATE. 1h

        This work is being developed in the district of Pecém (Brazil) in a region included in the so called Polygon of Droughts, which presents a pluviometric regime marked by extreme irregularity of rains, in time and space. In this scenario, water constitutes a natural asset with a high limitation on the socioeconomic development of the region and even on the subsistence of the population. The objective of this work is to identify the quality of the groundwater, the salinization processes and the efficiency recharge of the aquifer, using isotope measurements of Oxygen-18 and Deuterium, physical and chemical analysis and measurements of concentration of the major ions, in a set of samples collected in 33 tubular wells, belonging to the Ceará Water Resources Management Company (COGERH) sampled in two collections. The pH measurements reveal acid waters with values of up to 6.0 and most of the hydrochemical data show waters chemically suitable for human consumption. The results of the electrical conductivity measurements show values lower than 800 μS/cm in 31 of the 33 wells sampled; the highest values were 826 and 1125 μS/cm, characteristic of waters with high salinity. The concentrations of the cations and anions of the largest elements present in the water, in the two collections, indicated waters of the sodium chlorite type in most of them. The average values of electrical conductivity in the first collection 434 μS/cm and in the second collection 260 μS/cm show dilution process in the groundwater caused by the recharge with rainwater also indicated by the pH values. The relations δ18O - δD evidence evaporation processes.

        Speaker: Ms Luisa González (UFC)
      • 16:00
        Groundwater flow modelling: A decision-making tool for water resource management in coastal areas - Case study of the Oussouye plateau (South Senegal) 1h

        The Continental Terminal (CT) aquifer in Casamance (Southern Senegal) is one of the main sources of fresh water for usual activities. This shallow aquifer especially in the Oussouye plateau, bounded largely by salt brackish water (locally called bolongs) and the Casamance River is very vulnerable to intensive abstractions that could influence saline intrusion advance. The increase in water demand and the lack of boreholes there are leading the authorities to set up a rational management system for this aquifer. The aim of this study is to set up a management and decision-making tool through a groundwater modelling for an efficient and sustainable exploitation of this vulnerable aquifer.
        The methodological approach particularly geophysical, hydrogeological and hydrochemical investigations aim to develop a conceptual model of the CT aquifer functioning. Two field campaigns were carried out (June and October 2017) to measure physicochemical parameters and groundwater sampling. All the sampling points were then surveyed by differential GPS to define the piezometric map and thus the groundwater flow. The geometry and hydrodynamic parameters (conductivity and transmissivity) of the CT were approached using geophysical technics (electrical methods) but also the drilling logs from previous studies carried out in Oussouye region. These investigations made it possible to define the conceptual model of the aquifer and to build the mathematical model under the Visual modflow interface with the Modflow-2000 code developed by USGS. This model takes into account the abstractions of current boreholes and dug wells where pumping rates were investigated by statistical survey.
        The results show a general groundwater flow towards the bolongs and the Casamance River from two domes located in the Nord and in the center of the plateau which represent the recharge zones. Electrical conductivity varies from 28 to 1314 µs/cm with high variance and standard deviation values reflecting variable sources, geochemical and dilution processes occurring in the plateau. Despite physiochemical data, the analysis of water samples show an excellent groundwater quality. Major elements contents meet WHO standards except the Iron contents (Fe) which are relatively high in some wells due to the nature of the aquifer formation. The mathematical model was calibrated in steady state. The average difference between simulated and observed head is 0.08 m, while the average absolute difference is 0.24 m. Simulations under transient conditions showed that the groundwater is vulnerable to high pumping rate due to the drawdowns at the catchment wells, which can reach 7m for 75 m3/h. This significant drawdown should be avoided for this type of piezometric configuration where the maximum hydraulic head is 6m. However, the model revealed a sustainable groundwater potential for the needs of local and neighboring populations by transfer at 50m3/h with a steady state regime system reached after 10 years.

        Speaker: Prof. SERIGNE FAYE (UCAD/DAKAR, SENEGAL)
      • 16:00
        GROUNDWATER IN ALICANTE PROVINCE (SPAIN) 1h

        Alicante Province, with an area of 5,817 km2, is located in the SE of Spain. It ranks as the 4th most populous province of the fifty into which Spain is divided. From the middle of the last century, it has experienced an important economic development due to the transformation from rainfed to irrigated agriculture, as well as to the increase of tourism and industry. The scarcity of superficial resources in the region has made groundwater to have been a basic resource to supply water for these activities.

        Regarding hydrogeological features in the province most of the aquifers are carbonated. There are mainly Cretaceous limestones and dolomites, but also Tertiary calcarenites, sandstones and limestones and Jurassic limestones and dolomites. There are also some detritic aquifers but not only their extension is smaller but also have worse hydraulic characteristics and in some cases poor quality water. Broadly speaking, the North-East and the South-West areas of the province are two differentiated domains. The first one has larger carbonatic aquifer systems under more humid climatic conditions, with average annual rainfall ranging between 500 and 900 mm. Thus aquifers have significant recharge rates and greater resources. On the other hand, in the South-West, where the carbonate aquifers are smaller due to the high tectonic compartmentalization and with rainfall annual averages ranging between 250 and 400 mm, recharge rates and so resources are scarce. Therefore, these areas concentrate the main overexploitation problems, specifically the basin of river Vinalopó.

        In general, the quality of groundwater for current uses vary from good to excellent, with a predominance of bicarbonated calcium-magnesium facies related to the numerous carbonate aquifers. However, in the southern half of the province and in some aquifers in connection with the sea the quality is insufficient for practically all use, due to mineralization problems.

        Provincial total input is currently estimated to be about 445 hm3year-1, with a difference between inputs and outputs of 28.5 hm3year-1 in average. This latter figure is considered the overall groundwater overexploitation in the province, which is nearly half than ten years ago. This reduction is the result of a series of factors such as the arrival of external flows, the improvement of the efficiency of irrigation and supply networks, as well as infradotation to irrigation, or even abandonment, of some uses due to insufficient supply in quantity or quality. However, the natural scarcity exposed causes that the moderate to small recharge rates are incapable of balancing the intensive extractions that have taken place for decades.

        Speaker: Jose Miguel Andreu (University of Alicante)
      • 16:00
        Groundwater recharge sources in the Gandak alluvial aquifer, NE India: how important is leakage from irrigation canals? 1h

        There is ongoing debate around the status of groundwater in the Indo-Gangetic Basin (IGB) alluvial aquifer, which as a whole is the world’s most heavily exploited aquifer. There is clear evidence for over-abstraction and/or contamination in some parts of the aquifer, but other areas do not show the same intensity of human impact. The hydrogeology and external influences on groundwater across the IGB aquifer are complex and diverse. Influences include increasing groundwater abstraction, changes in land use and other economic behaviour, and the impact of the network of engineered irrigation canals that distribute river water across many catchments. The role of leakage from irrigation canals is now a fundamental part of groundwater dynamics in the IGB aquifer. Recharge to some areas of the aquifer contains a high proportion of canal leakage (Joshi et al. 2018), but to others it is much less (Lapworth et al. 2015).

        The Gandak catchment, in the northern part of Bihar state in NE India, provides an excellent laboratory for studying the evolution of groundwater-river-canal dynamics in the centre of the Ganges basin. Evidence shows no overall long term declining groundwater level trend in the Gandak alluvial aquifer (MacDonald et al. 2016, CGWB 2016), such as is seen in some other parts of the IGB aquifer. Our study, carried out as part of the joint UK-India funded CHANSE project, is the first detailed investigation of the Gandak aquifer.

        We used isotopic, residence time and geochemical tracers to quantify the contribution of recharge from canal leakage, the Gandak River and local monsoon rainfall; and to characterise groundwater flow and mixing behaviour. We show that canal leakage has been a significant source of aquifer recharge since at least the 1960s, but that this is restricted to shallow depths, above ~30 m. Deeper groundwater, below 30 m, shows no evidence of canal or river leakage, but is consistent with long term active recharge from local monsoon rainfall. Groundwater in the shallow zone shows more chemical and isotopic variability than in the deeper zone. This is different from other studied parts of the IGB aquifer, where deep groundwater has been shown to be significantly impacted by over-abstraction and groundwater pollution. These differences are partly linked to hydrogeological conditions and partly to abstraction behaviour, including borehole depth and typical borehole pumping rates by farmers. Most groundwater abstraction is from <30m, and although abstraction has increased significantly over past decades, it does not currently exceed long term recharge rates, as evidenced by available groundwater level data.

        References:
        CGWB. 2016. http://cgwb.gov.in/Regions/GW-year-Books/GWYB-2015-16/GWYB%20MER%20(Bihar)%202015-16.pdf
        Joshi et al. 2018. https://doi.org/10.1016/j.jhydrol.2018.02.056
        Lapworth et al. 2015. https://doi.org/10.1002/2015GL065798
        MacDonald et al. 2016. https://doi.org/10.1038/ngeo2791

        Speaker: Brighid O Dochartaigh (British Geological Survey)
      • 16:00
        Groundwater resources of the Pyrenees in the global change context – The PIRAGUA Project 1h

        The Pyrenees range is a transboundary region shared by Spain, France and Andorre whose water resources are diverse (snowmelt and rainfall runoff in a topographically variable context, groundwater in complex and heterogeneous aquifers) and poorly known. As many other mountain regions, this territory is particularly vulnerable to the impacts of climate change. The PIRAGUA project, funded by FEDER through the EU POCTEFA Program, addresses the assessment of the hydrological cycle of the Pyrenees in the context of climate change. The goals of the project are to unify and homogenize the existing information, prospect for future scenarios, develop indicators of change, and propose adaptation strategies in relation with the territory, with the ultimate goal of supporting investment aimed at adapting to climate change in relation to water resources.

        In the PIRAGUA framework, the groundwater component of the hydrological cycle of the Pyrenees range is being assessed with focuses on: 1) the design of an homogenous hydrogeological database at the Pyrenean scale, 2) the groundwater recharge from precipitation estimation over the last 30 years (including comparison with different modelling methods) and 3) future recharge evolution according to climate projections downscaled on the Pyrenean scale.

        Speaker: Yvan Caballero (BRGM)
      • 16:00
        Hard-rock groundwater potential assessment in the Aji-Chay basin, West of Iran’s drying Lake Urmia 1h

        Lake Urmia, the largest in the Middle-East, is located in the northwest of Iran. The lake has been dramatically desiccating during the last two decades, mainly as a result of human-induced agricultural development, which remarkably accounted for diminishing of surface and subsurface inflows to the lake. This research focused on the mountainous area of Aji-Chay river basin, the largest basin supplying the lake, determining different groundwater potential zones, GWPZ, over the area. In order to indicate the zones, Multi Criteria Decision Making, MCDM, techniques in the frame of Geographical Information System, GIS, were utilized. Accordingly, GIS thematic layers of precipitation, lithology, landform, density of lineaments and faults, slope, land curvature, and stream density were quantified based on the direct field observations, geological maps and Remote Sensing. Among available MCDM techniques, Entropy, Analytical Hierarchy Process, and Fuzzy techniques were comparatively employed, utilizing spring and exploitation wells as validation tools. Results showed that, Entropy based MCDM techniques was slightly more accurate than the rests. Since impermeable intrusive and extrusive igneous rocks of low fracturing are abundantly cropped out over the area, the high and very high GWPZ were estimably negligible. The resultant map of GWPZ can be adopted to site any new exploitation water wells in the region, indeed. However, the prospective karst and hard-rock groundwater has to be considered as substitution of current drinking water supply of low quality in the villages and rural areas. Because, any further exploitation cannot be amenable for such a basin, feeding one of the most precious UNESCO Biosphere Reserve.
        Keywords: karst and hard-rock groundwater potential zone, Entropy, Analytical Hierarchy Process, Fuzzy, Lake Urmia

        Speaker: Dr Alireza Kavousi (Water Research Dept., Water Research Institute)
      • 16:00
        Hydrochemical characterization of a nitrates polluted aquifer to test a treatment with biological-base to produce drinking water (LIFE ECOGRANULARWATER project) 1h

        The objective of LIFE ECOGRANULARWATER project is to demonstrate a new treatment system, low-cost and environmentally friendly, based on biological methods and powered by solar energy, for the purification of groundwater, polluted by nitrates, intended for human consumption. With this aim, the installation of a full-scale plant in Torre-Cardela (760 inhabitants; Granada, Spain) has been carried out, where high nitrates contents have been reported from the 1990s. It is expected that the new plant will achieve the same results (water suitable for human consumption) but with an improved cost-effectiveness ratio in the production process than the current treatment (reverse osmosis).
        The study of groundwater characteristics is essential, in order to improve the efficiency of the new treatment proposed. For this reason, a comprehensive characterization of the aquifer (Calcarenitas de Torrecardela, ES050MSBT000054106) that supply the municipality has been carried out, through reliable groundwater sampling campaigns.
        Main lithologies present on the studied groundwater body are calcarenites, bioclasts sandstones and marls, Eocene-Oligocene, affected by faulting and bending. The resulting aquifer is fissured-karstic, classified as moderate productivity and with a good global status (Hydrological Basin Plan of the Guadalquivir river basin).
        Sampling campaigns were carried out from February to December (2018). Water samples were collected from springs, supply wells and boreholes, on which pesticides, predominant cations and anions, and nitrates have been analysed.
        Interpretation of the hydrochemical data results indicated that the main hydrochemical facies was calcium-bicarbonate and nitrates concentration varied on those months between 0.4-105 mg/L, although on samples from the main supply well ranged between 23-84 mg/L. Regarding the content of pesticides, only two substances were detected above 0.100 μg/L (diphenylamine and fluazifop) at two different sampling points (springs). In general, the load of organic pollutants was low (from 0.072 to 0.474 μg/L).
        Higher nitrates contents have been detected after rainfall events that took place after olive trees crops fertilization periods (main economic activity of area inhabitants). Therefore, fluctuations were consequence of the combination of crops fertilization cycles and rainfall events, that allowed the percolation of the nitrogen excess accumulated in the soil to the water table.
        In conclusion, it is essential to anticipate these nitrates concentration variations in order to adapt the operational tasks of the full-scale plant to improve the bioreactor working and produce water suitable for human. For this reason, nitrate contents in raw water will be monitored in the facility itself, in order to adjust the cycles/turnover time of treatment depending on nitrates contents. These biological analyses are in progress. At the end of this part, the project purpose will be reached, a replicable and low-cost drinking water treatment, affordable for small communities, and with easy operating and maintenance tasks.

        Speaker: Dr Virginia María Robles Arenas (University of Granada)
      • 16:00
        Hydroelectric use of the water supply system to the city of Oviedo (NW Spain) 1h

        The demand for drinking water of the city of Oviedo is satisfied in normal conditions with the contribution of the springs of the Aramo Mountains (Namurian limestones), whose surplus is regulated in the Los Alfilorios Reservoir, and water from the Asturian Consortium for water supply and sanitation (CADASA), coming from another council (Sobrescobio). In times of shortage (summer months) it is necessary to pump water from the Quaternary connected to the Nalón River (the main river in the region) between the reservoir and the city. The annual flow needed to supply Oviedo (220,000 inhabitants) distributes approximately in: 63% from the Aramo springs, 17% from the Alfilorios reservoir, 5% from the Nalón River and the rest is bought from CADASA. With the exception of the latter, the remaining waters are treated in the Cabornio Drinking Water Treatment Station (DWTS), located near the reservoir, before being supplied to Oviedo. This work presents the possibility of installing a multiple system of renewable hydroelectric use: i) between the Aramo springs and the Cabornio DWTS; ii) between this DWTS and the supply tanks of Oviedo, in both cases taking advantage of the difference in elevation, by means of turbogenerators; iii) between the Los Alfilorios reservoir and the Nalón River, by means of a pumped-storage hydroelectricity system which turbines during periods of high electrical demand (using turbogenerators) and pumps in off-peak hours. This design would allow to increase the flow extracted from the river when necessary, reducing dependence on external water. The proposed systems are economically viable and interesting from the financial point of view, obtaining positive values of VAN, IRR between 7 and 20% and amortization periods between 5 and 12 years. This resource could be used for sale or self-consumption, and its use should be enhanced, especially in an energy-dependent country. Additionally, the use of renewable energies has environmental advantages, such as saving CO2 emissions. These systems are framed within the concept of "sustainable city”, and can be extrapolated to the water supply hydraulic infrastructures operating in other cities.

        Speaker: Dr Almudena Ordóñez (University of Oviedo)
      • 16:00
        HYDROGEOLOGICAL FEATURES OF THE WESTERN PO PLAIN (PIEDMONT, ITALY) 1h

        Piedmont Region, in North-Western Italy, extends for approximately 25,400 square kilometres and represents the more western part of the Po Plain. About 43% of its territory is constituted by mountains, 30% by hills while the plain covers 27% of the whole territory. The Piedmont plain is the most important water reservoir of the Region because of its size, the features of its deposits and the possibility to recharge.
        A hydrogeological map of Piedmont plain (scale 1:300,000) is presented, which summarises about twenty years of research in the area. The main hydrogeological units are shown with an indication of their type and degree of permeability. The piezometric map of the shallow aquifer in plain, referred to summer 2016, is reported, highlighting the main groundwater flow directions. Other information are also presented, namely the map of depth to water table, the map of permable deposits (0-50 m from the ground surface) and litostratigraphic cross- sections.
        Moreover, time plot of piezometric level fluctuations in representative monitoring wells are provided. More specifically, monthly average piezometric level in the period 2002-2017 was analysed, describing different hydrodynamic behaviour of the groundwater table in the Piedmont Plain.
        This map wants to represent an overview of the hydrogeology in Piedmont, not only for researchers but also to provide support to local authorities and professionals working on groundwater management.

        Speaker: MANUELA LASAGNA (Turin University, Earth Sciences Department)
      • 16:00
        Hydrogeology of the Sands, Sandstones and Gravels of the Litoral Alentejo (Portugal) 1h

        In the past, the hydrogeology of the sands, sandstones and gravels of the Alentejo Litoral were studied only in areas where they occur as one of the hydrostratigraphic units of the Sines and Bacia de Alvalade multilayer aquifer systems, in which they play an important role. We present the hydrogeologic characterisation of these rocks in the coastal area extending from the proximity of Morgavel Dam in the north, to about 5km south of the Cabo Sardão. Porto Covo, Almograve, Cabo Sardão and other smaller towns, are located in this area characterised by the existence of both traditional and intensive agriculture and seasonal tourism, which are the main economic activities in the studied area. As far the authors know, the hydrogeologic studies described in this communication are the first contribution in this field in this extensive area of about 196 km2.

        In stratigraphic terms the studied lithologies correspond to formations in the Tertiary to Quaternary transition (Plio-Pleistocene) and are deposited at the top of the widespread carboniferous flysh (schists and greywac) formations present on the west coast of the Alentejo Region. As the Paleozoic metamorphic rocks present considerably lower permeability and porosity than the observed values for these parameters in the Plio-Pleistocene sediments, the recharge occurring in the shallow detritic phreatic aquifer cannot be absorbed by the underlying hard rocks. Therefore most of the regional flow generated from recharge at the top of the system is discharged in the sub-aerial and horizontal contact between the detritic shallow aquifer and the carboniferous rocks. These boundary conditions are responsible for the existence of several springs along this contact and, together with the hydraulic connection between the stream network in this area, define the general flow pattern from East to West. The estimated long term average recharge in the studied area is in the order of 26 hm3 (corresponding to 20% of precipitation).

        The groundwater flow system was studied through traditional large diameter wells and newly drilled piezometers. Piezometric in situ measurements were complemented with the continuous monitoring of electrical conductivity, depth and temperature (using CTD probes). Hydrochemistry was characterised by in situ measurements of physio-chemical variables (pH and temperature) and water samples for laboratory analysis of major ions and other chemical species. The first contribution to characterise the chemical composition of groundwater in the studied area shows that most of the sampled waters are circum-neutral with very low mineralisation (TDS < 1000 mg/L) and are mostly of sodium-chloride type. Moreover, the results of the hydrochemical characterisation of the studied area shows that the respective typology is clearly distinguishable from groundwater in neighbour formations.

        Speaker: Prof. José Paulo Monteiro (UALG/ CTA/ CERIS)
      • 16:00
        Hydrogeotoxicity assessment in aquifer systems of Malaga province (S Spain): a preliminary approach to evaluate the potential risk of groundwater consumption for human health 1h

        The increasingly water quality impairment due to anthropogenic pressures and environmental factors is one of the major public concerns and its control and management remain still challenging. Groundwater is highly vulnerable to human-induced pollution effects and, therefore, appropriate monitoring programs and representative groundwater quality stations are crucial to control pollutant levels for evaluating the qualitative status of aquifer systems as recommended by the EU Water Framework Directive. In Málaga province, 33 groundwater bodies hosted in two main river catchments (mostly Guadalhorce river draining to the Mediterranean Sea) partial or totally supply almost 1.5 million of inhabitants. Thus, the principal natural and induced factors such as the wide diversity of geological exposures -including those containing high solubility minerals-, the relatively high extension of cultivated areas, as well as the very often insufficient treatment of waste waters in urban and rural settlements, are demonstrated to endanger the groundwater quality in aquifers across the Málaga province.
        In this study, the regional assessment of toxicity levels in groundwater (understood as a potential risk for the human health), have been performed focused on selected inorganic (SO4-2, Cl-, F- and trace metals) and organic pollutants (N-compounds and plaguicides). To that, the statistical treatment of public water quality databases has been performed and single hydrogeotoxicity indices has been applied to evaluate the exposure levels for drinkable groundwater, according to national water regulations and international recommendations.
        The groups of selected chemicals were categorized by means of the resulting toxicity levels (extremely toxic, highly toxic, moderately toxic and little toxic), but also based on the adverse effects potentially caused over the functional groups of human body (i.e. genotoxic, neurotoxic, hormonal disruptor, etc.). A hydrogeotoxicity (HGT) threshold equal to 1 was set up, according to precedent studies conducted in Spain, from which groundwater from aquifers are potentially considered toxic for human health in case of prolonged consumption. The first results obtained in this work suggest that HGT values for the evaluation of individual chemicals range between 0 (for total sum of plaguicides) and 2.1 (for SO4-2). Accordingly, 12% of total aquifer systems studied show HGT values >1 for inorganic and organic-derived pollutant such as iron, manganese, nitrate, sulphate and glyphosate, which reflects deficient qualitative status and significant groundwater quality impairment in the main cultivated areas of the province. The evaluation of groundwater toxicity must be included in the groundwater quality control programs performed by health authorities from the quantification of the susceptibility to health risk for citizens. Additionally, this type of human health-oriented hydrogeological research should be linked to epidemiological studies in medical centres to predict potential mid/long-term consequences of polluted groundwater intake in the human population.

        Speaker: Mr Adrian Palomino-Gómez (University of Malaga)
      • 16:00
        IFLUX AS A VALUABLE TOOL IN AQUIFER STORAGE & RECOVERY 1h

        The monitoring and management of groundwater is a challenge. In times of water scarcity and in area with freshwater shortage, injecting or pumping water into an aquifer for storage and use at a later time, known as Aquifer Storage and Recovery, or ASR, is gaining importance. ASR can be an efficient technique to store freshwater surpluses for times of demand. During times of plentiful water, extra water can be withdrawn from a river (or other source) and then injected and stored within an aquifer. When the original water source runs low due to drought, low rainfall or other causes, this water can then be pulled from the aquifer and used.

        Some ASR facilities inject treated wastewater rather than surface water into an aquifer, while other facilities inject groundwater from a different aquifer. However, the geochemical changes during the injection/retrieval as well as the hydrological changes and influences need to be assessed thoroughly. The formation of deposits and complexes can clog the systems and reduce the quality of the water. Also, in brackish-saline aquifers for instance can the density-driven flow result in limited recoverability of freshwater.

        The recently developed iFLUX technology uses a modular passive flux sampler that provides simultaneous in situ point determinations of a time-averaged target compound mass flux and water flux. The sampler is typically installed in a monitoring well where it intercepts the groundwater flow and captures the compounds of interest. The sampler consists of permeable cartridges which are each packed with a specific sorbent matrix. The sorbent matrix of the water flux cartridge is impregnated with known amounts of water soluble resident tracers. These tracers are leached from the matrix at rates proportional to the groundwater flux. The measurements of the contaminants and the remaining resident tracer are used to determine groundwater and target compound fluxes.

        The iFLUX sampler technology is being applied in two ASR field projects and has proven its operation and benefit. The modular design enables to determine several parameters at the same time. Currently, 6 cartridge types are validated and available: 1 groundwater flux cartridge to monitor speed and direction of flow and 5 compound cartridges to monitor different compounds – nutrients, VOC’s, metals & heavy metals, free cyanides and 1,4-dioxane. Cartridges for PFAS and pesticides are currently being developed.

        The two ASR cases will be presented, together with the iFLUX technology application.

        Speaker: Dr Goedele Verreydt (iFLUX)
      • 16:00
        Improving Freshwater Security in the Caribbean using Managed Aquifer Recharge 1h

        Climate change poses a major threat to the freshwater supply in the Caribbean region due to a variety of factors including the small size of the countries, an overwhelming dependence on rainfall for the supply, the potential devastating impact of hurricanes on the water supply, and the proximity of groundwater aquifers to the Caribbean Sea and Atlantic Ocean. As part of an effort to improve the freshwater security and sustainability in the Caribbean region, a study was undertaken on behalf of the Interamerican Development Bank to identify suitable managed aquifer recharge strategies (MAR) for the region. This study focused on the technical and socio-economic dimensions of MAR, subsurface considerations and constraints when employing MAR technologies and methodologies, MAR management and governance, costs to implement and operate MAR programs, and case studies where MAR has been employed in or near the region. A decision tool was developed to assist in assessing potential implementation of MAR schemes.

        Speaker: Mr Anthony Daus (GSI Environmental, Inc.)
      • 16:00
        Interaction and connectivity of stream water with groundwater in Wangjeon-ri WCC(water curtain cultivation) area, Nonsan, Korea 1h

        Since 1984, Korean WCC area has been spread rapidly. Annual groundwater use in WCC area has been estimated to be 5.4~5.7 m3/y, which is equivalent to 32~35% of agricultural groundwater use in Korea. The WCC usually begins at November and ends at March every year. Therefore, every year starting from November, groundwater level in WCC area gradually declines and reaches to its lowest level at March. Thus one of problems related to WCC in Korea includes severe shortage of groundwater resources during the peak season. Because nearby stream water is definitely introduced into the aquifer system due to much lower level of groundwater compared to stream water during WCC peak time, it is likely that the problem can be resolved efficiently if the connection characteristics between groundwater aquifer and stream water are well understood. In order to understand the connection between stream and ground water, and the influence of stream water on the nearby aquifer, this study examined temperature, and oxygen/hydrogen stable isotopic compositions for both stream and ground water extracted from wells. This study was performed at Wangjeon-ri of Nonsan City, which is one of well-known strawberry WCC areas in Korea. The study area covers about 1.2 km2 in which about 74% of 291 vinyl house used to be applied for WCC. Water sampling was done during February 2010 through June 2011. Groundwater temperatures for 51 wells were measured to be ranged from 9.8 to 16.3 ℃, and mostly 14.6 ℃. Inflection point for water temperatures was identified at the zone of 140 m to 160 m distance from the stream, which might be inferred to be range of intensive intrusion of stream water into aquifer. Overall temperature distribution pattern indicates that Noseongcheon stream water widely intruded into the surrounding aquifer and affected groundwater temperature obviously in the southern right part of WCC area. However, in the southern left part, the influence of stream water into aquifer seems to occur in very narrow restricted range near the stream. This phenomenon can be similarly found by the oxygen and hydrogen isotopic data. There are two possible end members affecting water quality in aquifers beneath WCC area; groundwater in the northern rolling hill part (δ18O = - 7.71 ~ -7.59 ‰ (- 7.62 ‰ in average), δD = - 54.1~ - 53.7 ‰ (- 54.9 ‰ in average)) and Noseongcheon stream water in the southern area (δ18O = - 6.86 ~ - 6.66 ‰ (-6.74 ‰ in average), δD = - 49.7 ~ - 47.8 ‰ (- 48.1 ‰ in average)). The average values can be used for estimation of mixing ratios in each point of WCC area between stream water and groundwater recharging from northern rolling hills.

        Speaker: Sang-Ho Moon (KIGAM (Korea Institute of Geoscience and Mineral Resources))
      • 16:00
        Inverse modelling of hydrogeochemical processes analysed along a flowpath within the Doñana National Park (Southern Spain) 1h

        The Santa Olalla pond is the only permanent pond located in the Doñana National Park (Southern Spain). Hydrochemistry of both surface and groundwater samples was analyzed during 2017 and 2018. Those samples were representative of the wet and dry seasons, respectively. In total, 22 samples were analyzed. Samples were taken in alignment with the general flow path from the dunes to the pond. Sampling points were: one medium-depth piezometer (21 m depth), three shallow piezometers (3 m) and surface water. Groundwater samples were taken using a pump and conserved for subsequent analysis. Physical-chemical parameters and iron analysis were measured in situ. Salinity values ranged from 45 mg/l at the beginning of the flow path, close to the dunes, to 8,850 mg/l in the pond itself. Facies varied from calcium-bicarbonate to sodium-chloride facies depending both on seasonality and location. The three inverse model scenarios performed with Phreeqc 3.0 and the database Wateq4f reveal sulfate reduction, redox reactions (Fe-S), mineral dissolution-precipitation, evaporation and mixing with deep water. These processes change seasonally, in accordance with hydrodynamic modifications in the flux directions in this pond. Minerals that were found to play a role in the pond hydrodynamics were calcite, gypsum, halite and pyrite. Evaporation was also found to be one of the main driving factors controlling the ionic composition in the surface water.

        Speaker: Mrs Ana Fernández-Ayuso (Pablo de Olavide University)
      • 16:00
        Investigation of industrial waste heat storage in porous media 1h

        The preferable geothermal conditions of Hungary give good opportunities to produce geothermal energy. Besides this well-known fact, Hungary also concentrates on the investigation of industrial waste heat underground storage possibilities. In Northern-Hungary there are many industrial areas with high amount of waste heat emission. Nowadays, most of the unused heat is released into surface waters, and there is no reutilization activity. On the other hand, several heat storage technologies are known, which use geologic formations as a storage volume. During our investigations, we outlined different heat storage possibilities of shallow porous formations using real data. We decided that one of our test sites could be in Tiszaújváros, because this is an industrial area, which produce a high amount of waste heat, and on the other hand, we have detailed geological information about this test site.
        The presented research analyses the use of hot wastewater coming from the cooling systems of huge enterprises. The industrial waste heat can be stored in sedimentary aquifer thermal storage systems (ATES), and later it can be used as a heat source in heating systems during wintertime. The aim of the conducted research is to assess the heat storage capacity of the underground sediment formations at Tiszaújváros industrial town through three-dimensional groundwater flow and heat transport simulations, as well as to identify the ideal parameters of storage using different scenarios. The simulations have been developed using MT3DS as heat transport simulator. We developed a basic simplified model, with 700 m total thickness, and a 100 m thick ATES layer in it. In this simplified model four different types of well locations were investigated. In the models we used injection wells which inject hot water in the sedimentary target formation, and we used production a well or wells to pump the stored hot water to the surface. We calculated energetic efficiencies for each basic situation. Based on the obtained results, it is possible to realize a well-working and reliable underground heat strorage system.
        Acknowledgments
        The research was carried out in the framework of the GINOP-2.3.2-15-2016-00010 ‘Development of enhanced engineering methods with the aim at utilization of subterranean energy resources’ project of the Research Institute of Applied Earth Sciences of the University of Miskolc in the framework of the Széchenyi 2020 Plan, funded by the European Union, co-financed by the European Structural and Investment Funds.

        Speaker: Dr Balázs Zákányi (University of Miskolc, Institute of Environmental Management)
      • 16:00
        Making the unseen groundwater levels a drought indicator 1h

        South Africa is known for droughts and its effect on groundwater. Water levels drop, and some boreholes run dry during low recharge periods. However, how different groundwater levels indicate a drought?
        The department monitors the water levels of just over a 2000 geosites of which some monitored on a monthly, bi-monthly, quarterly and some bi-yearly base. The data is analysed from a national perspective to assess the groundwater level trends made. The analyses indicate the decline or rise in groundwater levels for the last ten years. The analysis was extended to provide a “Groundwater level Status” per each geosite. 2 boreholes with different geological settings, water levels, characters, etc. can be compared with each other for the first time. The current groundwater level is given as the status then the shallowest and deepest groundwater levels ever measured at the geosites are compared against the current groundwater level. The “Status” can now be used to indicate the severity of the drought and thus a possible groundwater restriction level indicator. SDG Goal 6.6.1 on the change of the groundwater level calculation is base on the groundwater level status methodology.
        The paper will present a detail methodology description and limitations of the methodology. The applicability to use the methodology from a national to a municipal level will be showcase through practical examples of the recent drought.

        Speaker: Fanus Fourie (Department of Water and Sanitation)
      • 16:00
        Multiscale impact of widespread managed aquifer recharge (MAR) implementation in the state of Gujarat, India 1h

        The state of Gujarat is located in an arid to semi-arid area in western India. Throughout history, the state has witnessed several famines and droughts. At the present time, the region continues to be subjected to water stress due to high inter and intra annual rainfall variability, further exacerbated by climate change and population growth. As a result, groundwater represents a vital resource for drinking, domestic and especially irrigation supply. In fact, it accounts for almost 80% of the total irrigation demand in the state.
        Due to the rapid agricultural development over the last decades, the region has been subjected to groundwater overexploitation. In order to cope with the unsustainable use of groundwater, the government implemented new energy policies to rationalise abstractions and promoted decentralised water harvesting structures to recharge the aquifers.
        Many studies have reported a significant rejuvenation of the water levels with a reversal in the declining trends of groundwater storage in the last decade. However, there is still a lack of scientific evidence regarding the cause of this rejuvenation. Multiple possible drivers have been proposed, including: the change in rainfall patterns, the introduction of new energy policies by the government, the import of surface water from the Sardar Sarovar dam and the widespread implementation of rainwater harvesting structures for MAR.

        The aim of this study is therefore to thoroughly assess the impact of widespread MAR on groundwater resources. This was done by combining local and catchment scale assessments of MAR impacts through a multi-scale analysis. The study area chosen for this analysis is the Bhadar basin (6 500 km2), located in the southwestern part of the Saurashtra peninsula in Gujarat. This area is characterised by hard rock aquifers and has witnessed the strongest development of MAR structure among the state, with more than 4 000 check dams only in Bhadar basin. Because of the fore-mentioned discussion over Gujarat aquifers' replenishment, and the scale and intensity of MAR implementation, this region offers a unique opportunity to assess the large-scale impact of this technique.

        In this part of the study, the focus is on the local scale MAR structure impacts. This entails the systematic analysis of 3 representative MAR structures in terms of recharge capacity, availability of water recharged underground for its subsequent use, water balance of structures, and dynamics of water demand, in terms of irrigation practices, crop patterns and calendars. A MAR typology is then used to upscale to the basin scale applying local findings.

        Speaker: Ms Gloria Mozzi (Technische Universität Dresden, Gruondwater and Global Change – Impacts and Adaptation)
      • 16:00
        NUMERICAL MODELING AS A TOOL FOR THE GROUNDWATERMANAGEMENT 1h

        In large brazilian urban centers, where there is a complexity of land-use planning, water supply becomes worrying due to factors such as population concentration, increased demand, diversity in the types of uses, unrestrained tubular well drilling, climatic changes, besides watercontamination. These factors, associated to the greater accessibility to well drilling technologies and inadequate groundwater management, hydrogeological studies was encouraged in certain regions that present high demands and evidence of an intense drawdown, such as in the Baquirivu-Guaçu River Basin - Guarulhos (Sedimentary Aquifer System), Bauru (Guarani Aquifer System), São José do Rio Preto (Bauru Aquifer System), São José dos CamposCaçapava-Jacareí (Taubaté Aquifer System), all in the Sao Paulo State. These areas are extremely dependent of groundwater, justifying the high number of existing wells. However, it was observed that about 70% of the registered wells do not have a concession, which could upset the adequate management of water resources. In this context of importance, and with the purpose of avoiding water collapses, the use of groundwater numerical modeling was highlighted as an important aid in the management of water resources, as it allows the understanding by the dynamics of complex hydrogeology systems, simulating future exploitation scenarios, and thereby enable important planning decisions to be made based on a well-defined technique. Fromtheresultsof the numerical model, well based on a conceptual model, it was possible to identify critical or potentially critical areas, which may require drilling restriction and indicate other areas more suitable for drilling new wells; or allow drilling in the critical area as long as the grant of the new well is conditional on monitoring and detailed studies. This requirement causes more data to be collected by improving the numerical modeling and knowledge of the aquifer, in addition to avoiding possible inadequate exploitation. The management decisions aim to minimize the cost of extraction and increase the benefits of groundwater, and these decisions may be related to the definition of pumping regime and well flow; the most appropriate location for the drilling of new wells; of incentive programs for use or restriction; of programs of benefits or financial compensation, control of land use, among others.

        Speaker: Mrs Ana Carvalho (Maciel)
      • 16:00
        Overview of the hydrogeological investigations of recently discovered world class deposits in Serbia 1h

        Europe industry has growing concerns on availability of the raw materials. To address this challenge, the European Commission has created a list of critical raw materials for the EU, launched EIT Raw Materials initiative, and continuously support research projects (like INTRAW, UNEXMIN etc.) with the aim of reducing the dependency and meeting growing demands. In the last 15 years Serbia is experiencing new bust in geological exploration of mineral deposits. Currently 167 exploration licenses are active, covering approximately 6000 km2 or close to 7 % of the territory. The most significant results of these efforts are discoveries of “Jadar” Li-B and “Čukaru Peki” Cu-Au world class deposits. It is estimated that from “Jadarite” mineral deposit 10 % of worlds demand for lithium can be met. Among extensive geological exploration works, significant efforts were made on hydrogeological characterization of the ore body and surrounding rocks. Presented methodology of the hydrogeological explorations included application of water inflated packer systems for in-situ determination of hydraulic properties of deep hydrogeological units, installation of monitoring wells, pumping wells and aquifer testing, installation of deep (up to 2000 m) fully grouted multilevel vibrating-wire piezometers, deep groundwater sampling and levels monitoring. Based on collected data conceptualization of hydrogeological system was performed, which was followed with development of numerical groundwater flow models. Exploration works which are subject of this paper are related to prefeasibility and feasibility stage of the projects development and were conducted with the aim to estimate dewatering requirements, support mine and tailings design and assess the possible impacts on water resources and the environment. Specific challenges, which were identified during the project development, are related to frequent changes in mine infrastructure plans and interaction and continuous update between different project teams and elements. Since projects for opening of the new mines are long lasting and very complex, hydrogeology is present throughout the life of the project in different scales, starting from wider deposit area characterization to resolving site specific engineering issues. Experience from Serbia, along with the need for application of the industry best practice, emphasize the importance of improving the position of hydrogeology in local legislation and permitting procedures, in order to ensure proper groundwater resources characterization and protection.

        Speaker: Dr Nebojša Atanacković (University of Belgrade, Faculty of Mining and Geology)
      • 16:00
        Planning of Groundwater Resources Protection in Shuangyashan City 1h

        Shuangyashan City, located in the northeast of China, is the largest coalfield in Heilongjiang Province and one of the ten largest coalfields in China. In this study, hydrogeology, hydrogeochemistry, environmental hydrogeology and other comprehensive research methods were used to find out the groundwater environment of Shuangyashan City based on the specific conditions of Shuangyashan City and the previous achievements of water resources development and utilization evaluation. The groundwater resources in the planning area were calculated in detail by equilibrium method, and the internationally advanced three-dimensional visualization underground was used. Water simulation software Visual Modflow is used to simulate groundwater regime, establish groundwater flow field prediction model by numerical method, and evaluate groundwater vulnerability in planning area by DRASTIC index system method. The results show that the groundwater resources in Shuangyashan City are 13504.24m3/a, the groundwater quality is good as a whole, the vulnerability of groundwater is high as a whole, and groundwater is vulnerable to pollution. Finally, the groundwater protection area and groundwater protection target are determined synthetically. The overall scheme of groundwater protection in Shuangyashan City is put forward, and the engineering and non-engineering measures of groundwater protection are proposed.

        Speaker: Prof. XIN XIN
      • 16:00
        Pollution vulnerability assessment of Coastal Plain Sand Aquifer based on standard and modified DRASTIC approaches, southeastern Nigeria 1h

        Two vulnerability index approaches: Standard and a modified DRASTIC, were applied to assess the pollution vulnerability of a coastal plain sand aquifer in parts of southeastern Nigeria. These methods were used to produce vulnerability maps and a groundwater risk map. The results suggest that the aquifer is of moderate vulnerability, while the risk of pollution is high. These maps also identified three vulnerability categories: low, moderate and high. Agreements in the categories of the two methods is found for about 80% of the aquifer area. Generally for this study, 23% of the southern parts of the study area is highly vulnerable and urgent pollution prevention method is necessary. This is due to the high human activity related to oil and gas activities. Comparison of the vulnerability indices with nitrate concentration showed some discrepancies. The study is expected to guide the future development, pollution and management of the aquifer.

        Speaker: Prof. Aniekan Edet (University of Calabar)
      • 16:00
        Recharge processes and groundwater age along the hyperarid western edge of the Andes (Atacama Desert): fossil groundwater recirculation 1h

        The assessment of groundwater recharge processes is mandatory for the sustainable use of aquifers, especially in arid environments. In the literature, natural recharge processes (i.e. direct or indirect addition of water to the saturated zone of an aquifer from the ground-surface) are exclusively related to the contemporary (or coexisting) hydroclimatic context. Along the hyperarid western edge of the Andes, in the Atacama Desert (Northern Chile), recent findings in the Andean Piedmont have revealed a hydraulic correlation between aquifer recharge areas and perennial river losses areas. In this hyperarid area, where mean annual precipitation below 2000 m a.s.l are less than 10 mm.yr-1, the perennial base flow originates from springs in the bedrock of the Precordillera. In studies performed during the 1980s and 1990s, carbon and water isotope analyses of base-flows revealed that groundwater stored in the bedrock of the Andes is old and related to another hydroclimatic context than the current one.
        This work addresses the role of fossil groundwater recirculation in the renewal of groundwater of the regional scale Pampa del Tamarugal Aquifer. This study analyses 14C, δ13C, δ18O and δ2H isotopes of surface and groundwater in the Quebrada de Tarapaca catchment (19.8°S). In the Precordillera and the regional aquifer, groundwater recharge occurred during the late Pleistocene wet phases related to the Bolivian Altiplano paleolakes (Tauca and Coipasa). Depleted δ18O and δ2H isotopes, disconnected from modern precipitation, agree with the cooler and wetter climate of the late-Pleistocene. In the bedrock of Precordillera, the observed constancy of water isotopes for 50 years highlights both the disconnection of groundwater from modern precipitation and the fossil nature of groundwater. In the area of perennial river infiltration, ~80 % of groundwater isotope content match with the water isotope content of these perennial rivers base-flow. Numerical modeling of vadose zone processes shows that and 90% of this base flow recharge the aquifer (~ 180 l.s-1 for Quebrada de Tarapaca) while only 10 % goes to evaporation.
        Fossil groundwater recirculation appears to be a significant process in the renewal of groundwater of the Pampa del Tamarugal Aquifer. It implies to reconsider the real proportion of modern precipitation in the current recharge of the Atacama Desert aquifers, but also to reconsider the basis-concept of recharge usually assumed for such aquifers.

        Speaker: Prof. Hervé Jourde (HydroSciences Montpellier UMR5569, Univ. Montpellier, Montpellier, France)
      • 16:00
        Risk assessment of not achieving good chemical status of groundwater bodies in Slovakia 1h

        Directive 2000/60/EC of the European Parliament and of the Council (WFD) defines in Article 4 "environmental objectives" for surface waters, groundwater and protected areas. In order to achieve the "environmental objectives" for groundwater (GW) (Article 4.1b), the WFD requires the adoption of specific measures to prevent and limit GW pollution. The basis for many of the WFD risk references is the concept that underlies the environmental impact of human activities, especially those that threaten our ability to meet the WFD's objectives (5 main objectives for GW).
        In accordance with the WFD, Groundwater Directive (2006/118/EC) and CIS Guidance Documents no. 26 (Guidance on risk assessment and the use of conceptual models for groundwater), the risk analysis of not achieving good chemical status was developed and performed for each of the pre-quaternary and quaternary groundwater body (GWB) in the SR considering conceptual model. Risk assessment includes the following factors:
        1. previous risk and chemical status assessment in the previous cycle,
        2. trends in pollutant concentrations in monitoring point,
        3. GW vulnerability,
        4. significant point sources of pollution (environmental burdens),
        5. use of plant protection products (pesticide active substances) and fertilizers on agricultural land,
        6. sewer system for settlements,
        7. the extent and degree of protection in safeguard zones and drinking water protected areas, including protected terrestrial ecosystems,
        8. predicted climate, population and land use changes,
        9. GW interaction with surface waters (aquatic ecosystems).
        Based on the detailed risk assessment, the 6 quaternary GWBs and 1 pre-quaternary GWB (from total of 75 GWBs) were classified “in risk” of not achieving environmental objectives in the GWB by 2021. GW vulnerability was identified as an important risk factor. This factor is less time-changing and has little to do with human activity. From the view of anthropogenic impacts, the environmental burdens and the use of pesticides were assessed as significant factors. Less important factor was fertilization. The re-evaluation of all factors (except of factors 3 and 8) within developed risk assessment methodology is being performed for assessment of not achieving environmental objectives in the GWB by 2027. These results of the risk analysis are taken into consideration when making proposals for program of measures.

        Speaker: Mária Bubeníková (Slovak Water Research Institute)
      • 16:00
        Risk assessment of water erosion by RUSLE - Lahmer watershed in the Setat plateau in Morroco 1h

        In Morocco, this erosion is linked to the combined action; the nature and condition of the soil material; relief; vegetation cover; anthropogenic factors (deforestation of landforms, overgrazing, poor agricultural practices and exploitation of clay and limestone quarries) as well as the torrential nature of rainfall which is accentuated by climate change.
        The objective of this study is to map the areas vulnerable to water erosion in the Lahmer basin. The approach followed is based on the exploitation of available data in order to map the major factors involved in the erosive process such as precipitation, vegetation cover, soil erodibility and topography as well as their integration into the revised universal loss equation. in soils "RUSLE". using the geographic information system "GIS". and remote sensing based on monthly and annual climate data, terrrain missions, Landsat multidate satellite images and the digital terrain model.
        The final results of the water erosion maps show that the year with the highest rate is 2015, which has experienced a significant rainfall compared to previous years, on the one hand, and the zone has become embroiled in a new one. development path that converts it into an industrial zone and has several units for the exploitation of natural resources that abound in the region, such as quarries made of clay and limestone.
        Keywords: water erosion, RUSLE, SIG and remote sensing, spatial aproach, high plateau de Settat.

        Speaker: Dr NAIMA EL ASSAOUI (FACULTY OF SCIENCES RABAT AGDAL OF UNIVERSITY MOHAMMED V MOROCCO)
      • 16:00
        Seasonal Catchment Water Balance Using Storage-Discharge Relationships 1h

        Mountainous areas provide important sources of fresh water for adjacent lowlands. However, hydrogeological and hydrometeorological complexities of mountainous catchments, make reliable seasonally estimation of catchment water balance components challenging, such as the evapotranspiration (ET), subsurface lateral flow (L) in the dry season and catchment water storage change of the wet season. In this study, an improved method based on storage-discharge relationship (SQL) is proposed to estimate seasonal catchment water balance for mountainous catchments. In comparison to the previous approach, the improved SQL method has incorporated the subsurface lateral flow.
        The improved SQL method was applied over six catchments with various sizes, climatic and hydrogeological conditions in the Mount Lofty Ranges (MLR) of South Australia. ET estimate for the six catchments agrees well with that from the method based on surface reflectance from MODIS-Terra and interpolated climate data, suggesting that the improved SQL method can be an alternative approach for catchment water balance quantification in mountainous regions. The improved SQL method, only based on continuous streamflow data, provides estimation of inter-annual variation of ET and subsurface lateral flow in the dry season, and catchment water storage change of the wet season. For the dry season, it is critical to understand the contribution of the subsurface lateral flow to the region, which may be the main water sources to the adjacent catchments. For the wet season, it is of importance to know that how much water has been left in the catchment for sustainable water sources management.

        Speaker: Xiang Xu (Lanzhou University)
      • 16:00
        Study of the quality of irrigation water in the plain of Sidi-Bel-Abbes 1h

        In the plain of Sidi-Bel-Abbès (Northwest of Algeria), in a semi-arid climate, the use of irrigation is inevitable for most crops. Groundwater are increasingly sought.
        The aim of this work is the determination of the chemical composition, facies and class of water quality for irrigation of the plain of Sidi-Bel-Abbes. This is more precisely determining the constraints and opportunities of using this water for irrigation of agricultural land in the area of Sidi-Bel-Abbes. A hydrochemical study was carried out which focused on the major elements of the water aquifer. Samples were taken over a period of two months (June and July). The 17 wells are controlled spread across the plain. Analyzes reveal a variety of chemical compositions, samples split between two facies: the sodium chloride and calcium sulfate. Mineralization of water, which is generally high, poses a risk of soil salinization.

        Speaker: Dr zouaoui rabah mustapha (university)
      • 16:00
        Surface water and groundwater interaction in crystalline aquifer: an example from Itu (São Paulo, Brazil) 1h

        In São Paulo State the crystalline aquifer system occupies an area of approximately 62,000 km² (~25% of the state area). Despite of low productivity and highly heterogeneous aquifer, the increasing water demand in the metropolitan areas has intensified crystalline aquifer exploitation. Typically, high productivity wells are related to thicker weathered profile and occurrence of expressive discontinuities, concentrating wellbore perforation along the lineaments as well as valley positions. However, many studies recognize poor relationship between well productivity and its geomorphological position suggesting other constraints control well productivity. Aiming to better understand the constraints and groundwater dynamics in crystalline aquifers, this work developed a numerical groundwater flow model to evaluate a conceptual model of a production well based on geological survey, structural data, electrical resistivity imaging, pumping test and stable isotope analysis. The study area encompasses a well field catchment located in the municipality of Itu (São Paulo, Brazil). The crystalline aquifer system is composed of phyllite and quartzite of the Neoproterozoic São Roque Group. The conceptual model assumes a set of subvertical discontinuities, responsible for a hydraulic connection between surface water and well, and four layers representing the weathered profile described in the study area. Constant head boundary conditions were associated to the rivers and reservoirs, which are connected to the well by a discrete feature representing the fracture sets. The model was calibrated by pumping test drawdown data providing hydraulic conductivity values from 1x10-9 m/s to 3.24x10-4 m/s. The numerical simulation estimated a production of 12.6% surface water after 1440 minutes of continuous pumping, corroborating the water mixture inferred from isotope analysis. The results show that recharge and well productivity are related to connectivity of crystalline aquifer with surface water, as well as the extent of the weathered zone. The constant renewal of groundwater and its interaction with surface water ensure the sustainable groundwater usage for the municipal water supply.

        Speaker: Mr Juan Navarro (UNESP - Universidade Estadual Paulista "Júlio de Mesquita Filho")
      • 16:00
        Taking a deeper look - revisiting our understanding of deep (>200 m) groundwater systems 1h

        Recent interest in use of the deep subsurface for energy and storage has highlighted a lack of knowledge about groundwater at depths greater than about 200 m – the maximum usual depth for groundwater abstraction in the UK. Questions are being asked about the quality and availability and therefore future resource potential of deep groundwater, and its role in linking the deep subsurface and shallow groundwater resources. However, a lack of data and understanding of fluid properties in the deep subsurface, often resulting from difficulties accessing, measuring and/or retrieving information from such depths, means that deep groundwater systems are still relatively poorly understood.

        Here we describe initial results from a project bringing together information from a range of sources to produce a UK-wide resource that can be used to improve the knowledge and understanding of the deeper subsurface including groundwater processes and environmental response. The initial phase of work has focussed on collating Total Dissolved Solids (TDS) data in order to understand the distribution of water quality with depth, and in particular the base of freshwater aquifers. Analysis of this data indicates that freshwater may be present to a depth of about 500 m, with brackish water present to a depth of about 1 km. An understanding of basin history, geology, past and present hydrogeological systems and past climates are key to understanding this distribution. Results from preliminary work on collation and analysis of UK-wide groundwater chemistry (TDS/Specific Electrical Conductivity, major, minor and trace ions and environmental tracers such as stable isotopes and noble gases), deep groundwater pressure/head and hydrogeological property distributions (e.g. permeability/hydraulic conductivity, porosity, storativity, transmissivity) is providing insights into regional deep groundwater flow systems.

        Speaker: John Bloomfield (British Geological Survey)
      • 16:00
        The environmental impact assessment of intensive groundwater abstraction on the groundwater flow and salinity of the Nadhour Saouaf Sisseb El Alem Aquifer System (Central Tunisia) 1h

        ABSTRACT
        The Nadhour Saouaf Sisseb El Alem (NSSA) multilayer aquifer system is one of the most intensively used water sources in central Tunisia. Since the 1970’s, the growth in economic productivity linked to intensive agriculture in this semiarid region has been sustained by increasing groundwater abstraction. The use of this aquifer system has augmented rapidly, ultimately causing depletion and salinization; to better understand its behavior and, to predict the groundwater flow and chemical evolution, the finite difference Groundwater Modeling System (GMS) software was applied. Groundwater levels observed in 1970 were used for steady-state calibration; levels from 1971 to 2015 served to calibrate the transient state. The impact of abstraction on the evolution of groundwater flow and salinity was studied through three hypothetical scenarios. The increase in abstraction rate of 30% and 50% in the first and second scenarios examine the tolerable extraction threshold. The results of increase in abstraction show a drawdown in the hydraulic head elevation of ≈17 m and ≈23 m; salinity was increased in 2.71 g/l. The center of the NSSA aquifer system is mostly affected. Abstraction was stopped in a third scenario, resulting in increasing groundwater reserves by ≈7 Mm3/year and a salinity response of 1,47 g/l. NSSA groundwater qualitu and reserves could improved considerably if government abstraction rules were given serious consideration by the users.
        KEYWORDS: Groundwater Abstraction, Depletion, Salinization, Groundwater Modeling System, hypothetical scenarios, Semiarid Region.

        Speaker: Dr Emna BAHRI (Dr)
      • 16:00
        The impact of land use cover change (1988-2018) on aquifer recharge capacity across Bogota river basin, Colombia 1h

        Groundwater represents an important natural resource that must be managed in an adequate manner for its sustainable continuous use. The Teusacá River, tributary of the Bogotá River, is located in an area with aquifers of primary and secondary porosity. They represent an important water supply for municipalities of La Calera, Guasca, Sopó and Bogotá, the Colombian capital. The recharges of these reservoirs are vital for the preservation of their service, and the land use and cover change (LUCC) could be the most impacting factor to infiltration and runoff. This study has the objective of quantifying the impact of the LUCC between 1988 and 2018 in the groundwater recharge of the Teusacá catchment, heavily impacted by urbanization, deforestation and proliferation of weekend leisure ranches. To accomplish the abovementioned, we estimate the loss of recharge volume through a GIS based model that integrates physical variables that influence the runoff rate and a 30 year time series of river flow, precipitation and air temperature to obtain a groundwater recharge map. Additionally, a statistical analysis of the time series of the flow water and precipitation was performed to detect any inset trends on the river flow throughout the 30 year period. First, a land use map is obtained for 1988 and for 2018. Subsequently, the maps of soil permeability, infiltration capacity and slope of the land are combined in order to produce a final potential percolation map corresponding to each year. Next, a water balance calculated using the 30 year time series to find the approximate percolation annual volumes, and finally, these values are associated with their respective spatial locations using the potential percolation map. The statistical analysis includes Mann-Kendall nonparametric test to detect trends in the historical data and analysis of hydrographs. The results show a significant loss of Paramo ecosystem and an increase of the urban/bare soil, crops and greenhouses area. The loss of covers with high infiltration rate lead to an annual decrease of approximately 8.5% of total the volume infiltrated in 1988. The statistical analysis of the shows a positive trend (p-value < 0.0001) of the surface runoff across the 30 year period, whereas the hydrographs, for similar volumes of precipitation, also shows drastic increases in the river flow volume for each precipitation event.

        Speaker: Dr Fabio Iwashita (Los Andes University)
      • 16:00
        THE PROTECTION OF SPRINGS USED FOR HUMAN WATER SUPPLIES. A CASE STUDY BASED ON MULTI-CRITERIA EVALUATION 1h

        The problematic that commonly arises when protecting springs that supply water for human consumption requires a methodological method to prioritize springs that are used for this purpose according to the greatest need for protection from contamination and exploitation processes. The present study proposed the application of a method to prioritize springs in order to facilitate the sustainable management of springs that urgently need protection.
        The stages included in the method were: a) regionalization of the study area considering physical variables, which included precipitation, hydrogeological functioning, and slope of the terrain; b) selection of the springs used for human supply that have the greatest exploitation flows and c) prioritization of springs to be protected based on a multi-criteria evaluation (MCE), considering criteria such as exploitation flow, land use, population to be supplied, conservation of spring water collection systems, existence of alternative supply sources, and marginalization index of nearby populations. Using MCE (through the AHP), it was possible to analyze the different criteria based on the opinion of experts, thereby considering different points of view when assigning a weight to each criterion. The methodological process was performed with the help of geographic information systems (GIS). The study case was the State de Mexico. The National Water Commission (CONAGUA, 2015), a government agency responsible for managing water resources, has 2,937 water use permits registered for the use and exploitation of springs. Of the total springs, 1,997 (67%) are used for human consumption, with an exploitation volume of 94,869,976 m3/year (34.5% of the total allocated volume). These springs are used particularly by rural and semi-urban communities.
        Regionalization enabled identifying regions that were homogeneous in terms of the characteristics of the springs and their physical environment. Six of those regions with the largest territorial areas were selected, where 88% of the springs used for human consumption were located. Within each selected region, the springs that were representative of exploitation flow were identified, and a total of 23 were included. Lastly, MCE was applied to identify six springs (one in each region) that were priorities for protection. The prioritization of the springs to be protected in each of the six regions selected will facilitate the future application of protection methods based on the physical characteristics of the springs and their physical and socioeconomic environments.

        Speaker: Maria Vicenta Esteller (Instituto Interamericano de Tecnología y Ciencias del Agua)
      • 16:00
        Vulnerability assessment and actual groundwater quality data - a case of study in Mozambique 1h

        The Nhartanda Valley is located in Southern Africa, center of Mozambique, in the southern part of the City of Tete. It occupies an area of 6.8 km2. City of Tete faces a set of serious structural issues of access to water such as a precarious public water supply system - large losses, pressure drawdown, and lack of investment in the network management, water rationing and a poor sewerage system. Historically, the public water supply in the area relies mainly on surface water reservoirs and groundwater. Nevertheless, repeated droughts have caused groundwater abstraction increase in the last few decades, and it was identified as a risk for the groundwater quality and quantity. Furthermore, the presence of potential contaminant activities along the valley and adjacent areas associated with Zambezi river pollution contribute to the degradation of water quality. The analysis of hydrology, hydrogeology and land uses of the study area has been carried out. Groundwater vulnerability was determined through the calculation of the GOD index and DRASTIC index for wells and boreholes of the Nhartanda Valley. The vulnerability to water pollution of Nhartanda Valley, through the application of the GOD methodology, varies from medium to high. The 9.1% of the study area is considered of medium vulnerability, while 90.9% is of high vulnerability. Of the latter, 80 % of the area has a moderately high vulnerability. The vulnerability of the aquifer, through the application of the DRASTIC methodology, varies from high to very high, corresponding to 40% and 60% of the area, respectively. The two methodologies have shown a similar vulnerability response of the aquifer, which is characterized by a high to very high vulnerability. On the other hand, the actual physico-chemical and microbiological water quality of the aquifer has been evaluated from the results of water samples analyses from the wells and boreholes of the valley. A specific set of actions and measures are necessary and urgent for the protection of Nhartanda Valley aquifer; which main function is to provide drinking water to City of Tete population. The identification of the most vulnerable areas has generated basic information to water use planning and designing of measures for aquifer protection and remediation.
        Acknowledgments: This work is co-funded by the European Union through the European Regional Development Fund, based on COMPETE 2020 (Programa Operacional da Competitividade e Internacionalização), project ICT (UID/GEO/04683/2013) with reference POCI-01-0145-FEDER-007690 and national funds provided by Fundação para a Ciência e Tecnologia (Portugal).

        Speaker: Dr ACACIA NAVES (UNIVERSIDAD A CORUÑA)
    • 16:00 17:00
      Poster with refreshments: Monday Topic 2
      • 16:00
        A regional-scale assessment of soil moisture changes in Golmud River Basin, China 1h

        A regional approach was presented in this paper for the spatiotemporally distributed assessment of soil moisture changes in an arid area where ecosystems are highly groundwater dependent. To achieve this, the recent trends (from year 2002 to 2016) of soil moisture in Golmud River Basin were assessed using a combination of remote sensing and CLDAS data.
        The Golmud River Basin is located in middle part of southern Qaidam Basin which covers a surface area about 4,566 km2. With average elevation of 2780 m above sea level, the area is a plateau basin and has a typical arid climate. The annual precipitation is only 40 mm and most precipitation is concentrated in summer season from June to August. The annual air temperature is 4.7°C and the winters are cold and windy. The pattern of land cover is as follows: 7% water bodies (mainly salt ponds), 12% shrub and grassland, 1% farmlands, 80% desert and salty areas.
        MOD09A1 data of summer (June to September) from 2002 to 2016 formed the core datasets and the Apparent Thermal Inertia (ATI) was employed as the main method for mapping spatial distribution of soil moisture in Golmud River Basin. The Mann-Kendall non-parametric test was used to discuss the time series trends of soil moisture in this research.
        The results revealed that the highest ATI is observed in the salt pond areas and it can reach up more than 0.08. Higher ATI areas are mainly occurred in farmlands, followed by grasslands and shrubs. On the other hand, the small ATI areas are mostly clustered in desert areas and ATI can be reduced to 0.02. When we look at the time series change of the annual ATI in the Gulmud River Basin, it generally increases during the period of 2002-2016 and the annual average ATI is varied between 0.02 and 0.03. According to the spatial distribution of the trends, the ATI of most areas has increasing trend and the decreasing trend is only happened in small parts of salty areas in the middle-east river basin. The ATI estimated from remote sensing data are in good agreement with the corresponding CLDAS soil moisture data in all four layers (0-10 cm, 10-40 cm, 40-100 cm, 100-200 cm) and the R-squares between their correlations are 0.80, 0.85, 0.84, 0.76, respectively. The soil moisture is increased with the depth to land surface and the value of layer 0-10 cm is obviously smaller than that of the other three layers. The vegetation cover is an important impact factor for soil moisture and the climate has no big effect on soil moisture due to the small precipitation in the Golmud River Basin.

        Speaker: Prof. Xiaomei jin (China University of Geosciences (Beijing))
      • 16:00
        Advancing Groundwater Sustainability within the Water-Energy-Food-Climate Nexus: Transferring Knowledge between Developed and Developing Countries 1h

        Water, energy, and food are the most critically important resources for society, particularly in meeting Sustainable Development Goals (SDGs). The demand for these resources will increase in future decades because of climate change, population growth, and socioeconomic forces. This growing demand is creating more trade-offs and conflicts, particularly among groundwater resources and stakeholders in both developed and developing countries. These conflicts have exacerbated the challenges of managing sustainable groundwater and coupled food and energy resources. This complex relationship between water, energy, and food resources and climate change is called the water-energy-food (WEF) Nexus. There is a research need to quantify the impacts and feedbacks of the WEF Nexus and identify how those concepts may help scientists and resource managers design optimal groundwater sustainability (WEF-GW Nexus) plans to best meet diverse stakeholder interests. Our WEF-GW Nexus project uses a transdisciplinary approach that integrates different knowledge systems from developed and developing countries; including those from academic researchers, early-career scientist and students, farmers, and other groundwater users and practitioners from rural and urban communities, local resource agencies, and other stakeholders. We will also hold training and knowledge transfer workshops, creating a dialogue about science and research to advance management, policy, and stakeholder engagement that leads to sustainable groundwater within the WEF-GW Nexus. To address the identified lack of WEF-GW studies, the WEF-GW Nexus project has established a global collaboration in 2019 of dozens of participants from three continents, and is supported by the International Geoscience Programme and UNESCO-GRAPHIC. The WEF-GW Nexus collaboration targets groundwater basins on three continents —Africa, America, and Europe — containing vast groundwater resources with an estimated dependence of tens of millions of people. We will present the WEF-GW Nexus project, show examples from groundwater basins, and discuss collaboration possibilities to integrate groundwater information from these regions.

        Speaker: Viviana Re (Department of Earth Sciences, University of Pisa)
      • 16:00
        ALPINE SPRING WATER AND GLOBAL CHANGE : EVIDENCE FROM TEMPERATURE, CHEMISTRY AND OXYGEN-18 MEASUREMENTS 1h

        Global air-temperature changes over the last 150 years and in particular during the last 30 – 40 years are well documented world-wide. In alpine areas in Europe the increase in air-temperature is even higher in the range of 2° C. Very few studies exist about groundwater temperature changes due to global warming. The increase or decrease in temperature at the point of discharge depends besides the air temperature at the time of infiltration on the amount of precipitation, the local meteorological conditions, the mean residence time, the land use, and the natural and anthropogenic heat flow during the passage underground.
        Nearly no papers exist about the water quality changes due to global change impacts. This is very difficult to evaluate due to missing long-term quality measurements and strong impacts by anthropogenic activities and land use changes. To avoid the complication by anthropogenic land use changes and activities the authors investigated the on-line discharge, temperature, and electric conductivity measurements as well as quarterly hydro-chemical analyses of 38 Alpine springs from a monitoring network all over the Austrian Alps (approx. 60,000 km2). All the selected springs have a recharge area with no or minimal anthropogenic impacts during the last 30 – 40 years. About 235,000 on-line measurements and 11,000 chemical analyses were evaluated for trends and compared to daily measurements at meteorological and surface water stations close to the recharge areas of the springs. To show the connection to the paleoclimatology changes of existing δ18O measurements on precipitation and spring water was evaluated as well indicating altitudes of recharge areas in range of 500 – 2400m.
        Thirty-eight springs with a minimum record of 16 years have been selected for trend analysis over a period of 20 years (1993 – 2013). 28 (74%) of the selected spring show a significant mean increase in water temperature of 0.34 °C in the range of 0.06 to 1.03 °C. This increase is half of the air- and water temperature increase in meteorological stations and surface waters close to the recharge areas of the investigated springs. The electric conductivity linearly increased in 21 (55%) of the investigated springs at about 4%. The discharge stayed the same in most springs. In 23 (72%) springs the content of dissolved oxygen decreased over these 20 years at about 9% percent.
        The reasons of the changes in water-temperature, dissolved load and the oxygen content as well as potential water quality changes will be discussed and interpreted.

        Speaker: Dr Martin Kralik (University of Vienna, Department of Environmental Geosciences, Vienna, Austria)
      • 16:00
        Analyses and Tools to Assess the Landscape Potential for Enhanced Groundwater Recharge and Land Restoration in Darfur - Sudan 1h

        Darfur landscape is characterized mostly by semi-arid climate and intensively used land: rainfall is concentrated in few months of the year; vegetation coverage is low and erosion rates are high. Conflicts, population growth and poverty also lead to increasing competition on the usage of natural resources. Planning and developing natural resources requires thus an integrated approach which analyses the physical and social contexts (geology, hydrogeology, geographical distribution of people, other social-political aspects) and seek for matching the different users’ demand versus availability.

        Taadoud partnership works towards improved Natural Resources Management (NRM) in the five states of Darfur – North, South, East, West and Central. Acacia Water is supporting Taadoud II in identifying and assessing opportunities to implement small-scale infrastructure and increase water availability throughout the year. In cooperation with the implementing partners (NGO’s: CRS, NCA, Oxfam, UMCOR and World Vision), five hydrological catchment areas have been selected as pilot for implementation of 3R-interventions (Retain, Recharge, Reuse).

        A series of analyses and tools have been used to better understand the geological conditions and categorise the potential for 3R-interventions. Remote sensing analyses have been carried out to identify geological features and distinguish the different soil coverage in the catchment areas. Satellite imagery and Google Earth imagery were also combined with existing geological and hydrogeological maps to give better insights in the potential and limitations of the project areas.
        As a result, a 3R potential map has been produced distinguishing the potential for water storage in the landscape and for in-stream interventions. A SWAT model (Soil & Water Assessment Tool) was also set up for four out of the five catchment areas for a better understanding of the run-off processes and to estimate the expected groundwater recharge.

        Based on the results obtained in the desk study and observations made during the field visit, a comprehensive set of measures have been proposed to increase (ground)water availability and reduce soil erosion. The most promising strategy is to promote reforestation to slow down run-off coupled with infrastructure to maximise retention; enhance recharge of shallow aquifers and develop artificial groundwater storage in the wadis bed, by infrastructure such as sand dams and subsurface dams. Such interventions will benefit livelihood activities and create opportunity for land and soil restoration. With the landscape approach we were able to make local stakeholders and implementation partners aware of the opportunities that the landscape offers for enhancing groundwater recharge and availability. Ideally, an IWRM approach (Integrated Water Resources Management) should be implemented in the area to ensure the long-term sustainability of the interventions and maximise stakeholder’s engagement.

        Speaker: Mrs Daniela Benedicto van Dalen (Acacia Water)
      • 16:00
        Application of the climatic water balance method for recharge evaluation and extreme climate indices analysis in the northern region of Rio de Janeiro state - BR at the present climate 1h

        The increasing use of groundwater as an alternative source to meet the water demand leads to the necessity of availability studies and the influence of climate variations to aquifer recharge. Assessment of aquifer behavior in face of climate change scenarios may provide invaluable information and can assist in the planning and management of these resources. The objective of this work is to use climate data (precipitation and temperature) to estimate recharge using Thornthwaite-Mather (1955) method through simulations with groundwater budget software and extreme climate indices analysis using the software RClimDex elaborated by the Meteorological Service of Canada.
        The climatological analysis of Campos dos Goytacazes municipality, located in the northern region of Rio de Janeiro state - Brazil to the period of 1961-1990 indicates an annual rainfall relatively low (1055 mm) with 64% of the total (672 mm) concentrated in the rainy period that goes from October to January. The number of rainy days (days which total rainfall exceeds 1 mm) fluctuates between 4 and 12 in June and December, respectively. With respect to consecutive dry days, the average is around 30 and 35 days/year, which probably occurs in the winter period. The compensated temperature oscillates between 20.7 ° C in July and 26.6 ° C in February.

        The recharge estimate was elaborated through the Hydrometeorological Balance using temperature and precipitation data obtained from the meteorological station of the Brazilian Institute of Meteorology (INMET) located in the city of Campos dos Goytacazes - RJ for the period of 1961/01/01 to 2016/12/31 using as tool the software Easybal 4.0 (Vazquéz-Suñe and Castro, 2002), provided average annual precipitation results of 958.2 mm and average annual recharge of 232.32 mm, so approximately 22% of the water that precipitates in the form of rain percolates and arrives at the aquifer recharging it. The obtained results show a high correlation (0.93) between the recharge and precipitation values in the study area, so that the precipitation variations are directly related to the variations of the recharge to the aquifer.

        Results also indicate an increase trend in temperature and a decrease in rainfall in the study area, which is becoming hotter and dryer through time. As rainfall and recharge trends are strong related, it is possible to conclude that a decrease in rainfall leads to a decrease in the recharge. This process is certainly accelerated by climate change and affects the water availability in the aquifer, reducing its water potential.

        Speaker: Dr Gerson Cardoso Silva Junior (Universidade Federal do Rio de Janeiro)
      • 16:00
        Assessing the water balace in the high mountain mediterranean karst aquifer of Ordesa and Monte Perdido (Central Pyrenees) 1h

        High mountain karst aquifers generate important natural water resources that are used in the low zones to satisfy the demand of both the users depending on this resource and the existing downstream ecosystems. These hydrological systems are highly vulnerable, especially those located in the drought-prone Mediterranean area, where climate change is expected to have a significant negative effect on water availability. Despite of their importance, most of these hydrogeological systems are still vaguely characterized.

        The Ordesa and Monte Perdido National Park (PNOMP) is located in the Southern Pyrenees and it constitutes the highest karst system in Western Europe. It is formed by upper Cretaceous and lower Paleocene–Eocene fissured and karstified limestones. The recharge zones are mainly located between 2500 m and 3200 m a.s.l., where snow accumulates and remains almost half of the year. During the spring, snow-melt water infiltrates though the well-developed karst system and recharges the aquifer. Groundwater discharges through a large number of springs that naturally drain the aquifer. This work is twofold: (1) to estimate the terms of a first water mass balance of the Ordesa and Monte Perdido hydrogeological system, highlighting the uncertainties and weaknesses of the estimated terms of the mass balance, and (2) to delineate the conceptual model of the aquifer system behavior.

        Speaker: Dr Jorge Jódar (Instituto Geológico y Minero de España, Unidad de Zaragoza)
      • 16:00
        Global assessment of the impacts of climate variability on total water storage: implications for groundwater resources management. 1h

        Due to global trends in climate and human activity, groundwater is becoming increasingly more important as a water source. Alongside the effects of climate change and anthropogenic factors, natural climate cycles have considerable impacts on the hydrologic cycle. In particular, they can affect groundwater recharge. However, to date only a small number of studies have sought to gauge these impacts at the global scale and to consider their implications in terms of management and policy decisions. In this paper we look at how global climatic oscillations cycles, like El Niño–Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO) and the Atlantic Multi-decadal Oscillation (AMO), affect total water storage and groundwater storage in several large aquifers (area > 100 000 km²) located in varying climatic regions of the world. To evaluate the impact of inter-annual and multi-decadal climate variability on groundwater resources, we look at time series of oceanic indices and compare them to total water storage estimates made from two approaches. The first one is made through the analysis of data from the Gravity Recovery and Climate Experiment (GRACE), which provides information from 2002 to 2017. The second is through a climate-driven model which comprises of two-variables, precipitation and evapotranspiration, that reconstructs past water storage changes from 1980 to 2017. Observed groundwater levels are used to validate these estimates and adapt the methods where possible. Results are expected to show that rainfall patterns connected with the ENSO are the main driver of changes in inter-annual groundwater storage, whereas decadal to multi-decadal variability is believed to be significantly affected by AMO. The combined effect of ENSO and AMO could trigger significant changes in recharge to the aquifers and groundwater storage. These results are aimed at helping to address the threat of water scarcity and the effects of climate variability and change, indicating where more detailed local studies are necessary, and further supply scientific information to support the development of long-term groundwater management strategies of large (in some cases transboundary) aquifers. This study is a contribution to the UNESCO-IHP Groundwater and Climate Change programme (GRAPHIC).

        Speaker: Mr Michael Allen (IHE Delft Institute for Water Education)
      • 16:00
        Groundwater resources in Chile: the required revision of conceptual models to cope with anthropogenic and climate pressure changes 1h

        Along the western edge of the Andes, from the semiarid and mediterranean areas of Central Chile to the hyperarid Atacama Desert to the North, climate changes together with a significant increase of water demand has led to strong pressures on the water resources. In Chile, since the late 1980s, the growth of exports (minerals, agricultural products) increased the water demand. As a consequence, severe withdrawals have been registered in surface-water (river, lake, dams) and alluvial aquifers. These hydrological reservoirs being highly sensitive to precipitation changes and water extractions, negative water balances are common along the northern half of Chile even if there are restrictions for new private water rights. This results in a decline of the water levels of rivers, dams or shallow alluvial aquifers sometimes submitted to severe depletion.
        Today, water scarcity is impacting all aspects of the Chilean society (landscape, water supply, irrigation, industry, etc.) and water-resources issues become more and more a matter of concern.
        Surely, the general poorly knowledge of aquifers functioning (geometry, boundary conditions, recharge processes, water ages), leading to unsuitable local management plans to cope with actual water challenges.
        Recent studies have highlighted that Chilean traditional approach of aquifer conceptual models need to be reviewed. An example, that supports the need to have conceptual models more in line with the complex hydrogeological reality of Chile, is the new insight about the role of Andean Piedmont and Western Front in recharge processes of the sedimentary basins aquifers. Reservoirs so far neglected by management plans (e.g. fractured medium, complex architecture aquifers) may provide different perspectives for the groundwater resource exploration in Chile.
        Effort have to be done in academia, water authorities and whole society to provide trained professionals, rules and knowledge that will face properly and in time with water resources issues due to the increasing anthropogenic and climate changes.

        This work is funded by FONDECYT Projects 1170569 and is a contribution to the Andean Geothermal Center of Excellence (CEGA) FONDAP/CONICYT Project 15090013 and to ECOS 180055. Taucare’s PhD studies are funded by CONICYT-Beca Doctorado Nacional 21160325.

        Speaker: Linda Daniele (Geology department/ UNIVERSIDAD DE CHILE)
      • 16:00
        Groundwater response to meteo-climate variation: example from the foothill aquifer system of the Piedmont Alpine zone (NW Italy) 1h

        Many foothill zones in Italy contain aquifer systems of strategic interest for water supplying, especially for drinking purposes (Doveri et al., 2016). The hydrogeological features in these environments generally promote the infiltration of both local rainfall and seepage from stream water originating in mountain catchments. On the other hand, because of their linkage with mountain areas, these systems are characterized by significant sensitivity towards the meteo-climatic variations and changes. To cope with climate change, a high level of knowledge of this type of aquifer should be reached in order to address the water management issues. This work focus on the aquifer system extending in the foothill plain located in the Piedmont region (NW Italy), between the Western Alps and the Torino Hill (Piana et al., 2017). Taking into account previous studies (De Luca et al., 2014 and references therein) and datasets from monitoring activities institutionally performed by the Environmental Protection Agency of Piedmont Region (ARPA Piemonte), the study examined the geological, hydrogeological and hydraulic-hydrodynamic features of the aquifer, as well as the chemistry of groundwater. This comprehensive approach steered the definition of the aquifer system conceptual model as well as the evolution of groundwater quantity and the chemical quality of groundwater. The statistical analysis performed on datasets highlighted some trends over the lasts two decades, both for groundwater quantity and quality. In particular, a significant sensitivity to meteo-climate conditions was pointed out by high confidence trends of piezometric level decrease occurred over both the periods 2004-2008 and 2010-2017, because of the respective rainfall decrease patterns. The rainy year 2009, which interposed itself between the two relatively dry periods, promoted sharp increases in terms of piezometric levels and concentrations of some chemical compounds in groundwater, thus pointing out as the hydrologic extremes can lead to the accumulation of nutrients and salinity in the unsaturated zone of the aquifer and their successive concentrate release in groundwater.
        Acknowledgements: This research was supported by the Project of National Interest NextData of the MIUR (Italian Ministry for Education, University and Research) and by the SMAT-Torino (Società Metropolitana Acque).

        References
        Doveri M., Menichini M., Scozzari A. 2016. Protection of groundwater resources: worldwide regulations, scientific approaches and case study. In: Scozzari A, Dotsika E (edited by): “Threats to the quality of groundwater resources: prevention and control" - The handbook of envir. chem, Springer-Verlag Berlin Heidelberg 2016, 40,13-30.
        Piana, F., Fioraso, G., et al, 2017. Geology of Piemonte region (NW Italy, Alps-Apennines interference zone). J. Maps 13 (2), 395–405.
        De Luca, D. A., Destefanis, E., Forno M. G., Lasagna, M., Masciocco, L., (2014) The genesis and the hydrogeological features of the Turin Po Plain fontanili, typical lowland springs in Northern Italy. Bull Eng Geol Environ 73:409–427.

        Speaker: Matia Menichini (IGG-CNR)
      • 16:00
        Groundwater storage assessment and flow path identification in a large-scale fractured bedrock aquifer system 1h

        Fractured bedrock aquifers account for 20% of the world’s aquifer systems, yet significant questions of how to characterize and quantify the magnitude of subsurface storage in the context of water supply development remain to be understood. These aquifer types are the only water source for many regions of the world, and it is imperative to understand their hydrologic sustainability under the threat of changing climate. In this work we describe the results of an on-going study to understand the magnitude of groundwater storage and water supply sustainability of one such aquifer system on the the island of Tobago. The island is predominately composed of highly fractured Mesozoic igneous and metamorphic rocks with well-developed saprolite soil cover. Prior work has established a robust hydrologic budget of the entire aquifer system, with the major conclusion that the fractured bedrock receives recharge of ~400 mm of the ~1900 mm total annual precipitation. This study aims to use geochemical and environmental tracers to further confirm, constrain, and refine this conceptual framework.
        We evaluate the distribution and abundance of solutes provided by both weathered rocks (e.g. saprolites) and non-weathered fractured crystalline rocks during the storage and transport of groundwater. Preliminary results suggest that fractures have provided flow paths and enabled groundwater mixing due to increases of major elements, compounds and stable isotopes from the central northeast region of the island towards the south-southeastern region, across significant topographic watershed divides. This is supported by the observations that groundwater production exceeds calculated recharge inputs in these sub-catchments. Strontium concentration also increases by an order of magnitude towards the southeast creating three distinct water groups: fresh water (87Sr/86Sr ratio range 0.70400 to 0.070750 and 0.05 to 0.50 mg/Kg), fresh water (87Sr/86Sr ratio 0.70450 to 0.70650 and 0.5 to 2.0 mg/Kg) and brackish water (0.70550 to 0.70650 and 2.0 to 5.0 mg/Kg). Stable isotopic measurements of ground and surface water suggest a well-mixed large-subsurface storage reservoir. On-going measurements of tritium, CFCs, and SF6 will establish mean transit times of groundwater that can assist in estimating the groundwater response time of the aquifer under different climate scenarios. Together, this study will established the magnitude of groundwater storage in the complex fractured bedrock aquifer system, which is essential for management of this freshwater finite resource.

        Speaker: Ms Allen Marsha (UMass-Amherst)
      • 16:00
        INFLUENCE OF SNOW MELTING RECHARGE AND RIVER MANAGEMENT AT MEDITERRANEAN RIVER BASSINS: ALTO TAJO CASE OF STUDY. 1h

        The influence of snow storage and melting processes on the infiltration and recharge of aquifers has been little studied. In cooperation with some Spanish Confederaciones Hidrográficas, major governance organism within Spanish river basins, the UPM Department of Morphology and Terrain Engineering has designed a first experience on improving River Management related to recharge through melting processes. Results indicate that, under certain conditions, the formation of the snow mantle on high permeability lands and its subsequent liquefaction, increase the percentage of infiltrated water and the volume of water underground finally recharged. The peculiar hydrological characteristics of most of the Iberian Peninsule mean that the flow of low water at a certain point of the river network, is primarily due to the underground runoff from the depletion of the Masses of Groundwater (MASb) that drain upstream. These are sensitive to changes in the amount and distribution of snow in the headwaters of rivers. On this basis, the work proposes a methodological study of the influence of snow on the recharge within the ASTER model. At the same time, it carries out a study of the regional piezometric level of the Alto Tajo region and its relationship with the natural discharge of water bodies, which are largely natural, and the contribution to the Entrepeñas and Buendía reservoirs in the months of low water. The objective is twofold: 1)To be able to establish a quantification of the recharge caused by snow melting and 2) To relate the level of the piezometers with the dynamic reserves in the aquifer.
        Thus, the work addresses a systematic collection and study of the readings of piezometers currently installed, the contributions to the aforementioned reservoirs and the calculation of the balances for different situations of snow and precipitation modeled with ASTER. From these data and relationships, interesting conclusions will be obtained for the exploitation of mentioned basin.

        Speaker: Dr Justo Mora Alonso-Muñoyerro (Centro de Estudios Hidrográficos CEDEX)
      • 16:00
        Sustainable development of groundwater resources under salinity and climate change impacts in Great Maputo, Mozambique 1h

        The area of Great Maputo in Mozambique, located on the south-eastern coast of Africa is facing a severe water crisis. Due to growing demand and a problem of groundwater salinity, freshwater resources are under extreme pressure. The ongoing drought has further worsened the water supply situation, and in future, the climate variability is imposing an additional threat. Therefore, a study is carried out to understand the impact of seasonal and inter-annual fluctuations in the rainfall on the groundwater resources. The main focus is to address the potential consequence of future climatic variations on groundwater development, with a possibility of enhancing aquifer recharge.

        To address the objectives, a transient groundwater flow and chloride transport models are developed for a baseline period of 2010-2018. Transient groundwater recharge is computed by soil-water balance method to analyse the seasonal fluctuations. The baseline models are tested for three scenarios 1) climate change for a period of 2019-2100 by incorporating Regional Climate Model (RCM) projected data; 2) groundwater development by modelling an optimized distribution of abstraction wells; 3) managed aquifer recharge (MAR) by changing vegetation cover in the study area.

        Results of the baseline model indicated a rapid depletion of groundwater storage after the start of severe drought in 2015, with a drop in water levels that is more pronounced in the urban areas. The results highlight that western and northern regions contain brackish to saline groundwater, due to seepage of entrapped fossil saline water from the semi-permeable aquitard units, also discharging as baseflow into brackish surface waters and wetlands. The eastern part of Maputo City also presents a high groundwater salinity associated with the mixing with seawater in the coastal zone. Climate change is foreseen to affect the groundwater levels and storage in a negative manner in the long-term, but it becomes more threatening when an enhanced groundwater development scenario is coupled with it. The groundwater levels show a drop in all the zones but more noticeably below the Maputo City due to high well density and pumping rates. The integration of newly planned wells by the Water Utility showed a continuous decline in the water levels and increasing salinity over the coming decades. Application of both optimized well distribution and MAR strategies resulted in the inversion of the falling water levels and storage improved significantly.

        The importance of these strategies becomes more critical for the sustainability of the groundwater resources in the coming decades due to longer periods of drought. To continue groundwater abstraction and avoid excessive drawdown and groundwater salinization, both optimized well distribution and MAR need to be discussed with the local water resource users, planners and authorities.

        Speaker: Tibor Stigter (IHE Delft Institute for Water Education)
      • 16:00
        Why Managed Aquifer Recharge is a successful tool to Climate Change adverse effects adaptation? Examples and indicators 1h

        Managed Aquifer Recharge (MAR) has been considered for a long time as an important technology to combat the adverse effects of Climate Change (CC). This is not a gratuitous claim. In this article, the authors will support this statement on the basis of real sites, indicators and international cases. Examples from five continents together with figures and trends will demonstrate that MAR, in combination with other measures of Integrated Water Resources Management (IWRM) are able to conduct adaptation and even mitigation activities against climate change challenges.

        The main effects of climate change are raising the average atmospheric temperature, decreasing average annual precipitation, causing extreme weather and inducing sea level rise. These result in a series of negative impacts reflected in an increase in certain parameters or events, such as evaporation, evapotranspiration, water demand, fire risk, floods, droughts and saltwater intrusion; and a decrease of others, such as in water resources availability, run-off, modified wetland areas and hydro electrical power production.

        MAR is a flexible tool with a wide array of techniques that can address not only different objectives, but also a mix of goals. Examples taken from different MAR systems all around the world have been selected to show their effectiveness to mitigate the problems previously mentioned. Solutions include underground storage, temperature decrease, soil humidity increase, reclaimed water infiltration, punctual and directed infiltration, self-purification, off-river storage, wetland restoration and/or establishment, gravity flow water distribution, power saving, eventual recharge of extreme flows, multi-annual management and intrusion barrier wells, as most remarkable activities and effects.

        As success must be measured, some indicators have been adopted or designed so as to calculate and quantify the actual influence of these solutions, their trends and even some benchmarking actions have been applied to compare the general evolution from different places. These have been expressed in the form of volumes, lengths, areas, percentages, grades, euros, CO2 emissions or years. Therefore, MAR demonstrably supports its usefulness in battling climate change impacts in a variety of environments and circumstances.

        Speaker: Dr Enrique Fernandez (Tragsa Group)
    • 16:00 17:00
      Poster with refreshments: Monday Topic 3
      • 16:00
        AgriMAR Bangladesh – Managed Aquifer Recharge to provide irrigation water for saline agriculture in the Bagerhat District 1h

        Agriculture in the coastal plain of Bangladesh faces a number of serious challenges, among which the issue of seawater intrusion that is exacerbated by the effects of climate change. During the dry season most of the surface water bodies of the vast delta area become saline or brackish, making the water unsuitable for irrigation. Farmers are therefore limited to one or two harvests of rainfed crops (usually rice) per year. This project aims at improving livelihoods and climate-resilient agriculture by making irrigation water available during the dry season, which allows farmers to grow an off-season harvest of high-value crops, such as water melon or bitter gourd.

        In 2018, a managed aquifer recharge (MAR) system for the irrigation of crops was implemented in the district of Bagerhat, in the coastal plain south of Khulna, Bangladesh. Constructed as an aquifer storage and recovery (ASR) system, it provides a low-cost solution for storing freshwater in a saline environment to be used for irrigation during the dry season. The abundant monsoon rains provide large amounts of freshwater and applying ASR has proven to be a suitable solution for bridging the water availability-demand gap between rainy season and dry season.

        In the project area, rainwater is collected in shallow ponds that can also be filled with river water. The developed AgriMAR scheme features a horizontal drain that is installed parallel to a pond. To reduce the turbidity, water flows from the pond to the horizontal drain through a jute-lined chamber with filter sand. Using a motor pump, a 5 m3 reservoir is filled with water from the drain. The water then infiltrates under gravity in the shallow and deep 4” filters of the well. The infiltration capacity is around 9 m3/h with an overhead pressure of 1.5 to 3.0 m, depending on the water level in the reservoir. The infiltrated freshwater displaces the brackish groundwater and forms a lens at the top of the aquifer. As a considerable amount of infiltrated freshwater is lost to mixing at the boundary of the lens, only the shallow filter is used for recovery.

        The simple, low-cost AgriMAR system was constructed with locally available materials and unskilled labor. The annual infiltration volume is estimated to be at least 5,400 m3. Assuming a recovery efficiency of 50% this allows for the irrigation of at least 0.3 ha of high-value crops. A detailed economic assessment showed that there is a positive business case for growing bitter gourd or water melon using the AgriMAR system.

        By providing a low-cost source for irrigation water throughout the year the AgriMAR system can greatly improve the climate resilience of farmers in the delta of Bangladesh, one of the most vulnerable regions regarding climate change impacts.

        Speaker: Mrs Daniela Benedicto van Dalen (Acacia Water)
      • 16:00
        Application of Na-Ca-Cl-Br Systematic in the Evaluation of Sources of Salinity in the Saline Groundwater Systems of the Benue Trough, Nigeria 1h

        Over the years, research community has been in search for a valid phenomenon to explain the occurrences of saline groundwater and brines within the evaporate-deficit but shale rich sedimentary units of the Benue Trough, Nigeria (BTN). Thus, this study is an attempt at unraveling the origin and possible diagenetic reworking of the primary saline source as precursor of saline groundwater occurrences in the BTN, using Na-Ca-Cl and Na-Cl-Br systematics.
        Due to the prominent surface occurrences in the Lower and Middle Benue Trough, thirty-eight (38) saline groundwaters and brines samples were collected alongside in-situ determination of physical parameters using a portable hand-held multi-parameter meter while laboratory analyses of major cations and anions were undertaken using Inductively Couple Plasma Atomic Emission Spectrometry (ICP-AES) and Ion Chromatography (IC) methods respectively at the ACME Laboratories, Vancouver, Canada.
        The average electrical conductivity (EC) values are 55,929μS/cm and 31,965μS/cm and total dissolved solids (TDS) values are 36,354mg/l and 20,777mg/l in the Lower and Middle regions respectively. These variations in EC and TDS indicate variable dilution or mixing event in the two regions as laboratory analyses and interpretation revealed Na-Cl dominated type of fluids. Hydrochemical evaluation of the chemical elements indicates significant enrichment in Ca2+, Sr2+, and Cl- and depletion of Na+, Mg2+, K+, HCO-3, and SO42- relative to seawater values, attributed to subsurface intereactions with geological materials. Furthermore, rCl/Br and rNa/Br inferred two origin to the salinity as; halite precipitation and halite dissolution sources. However, the excess-deficit plot (Na-Ca-Cl) revealed seawater origin and modification in the original chemistry of the fluids in the order of 2 Na for 1 Ca exchange reaction, responsible for the enrichment in Ca2+ with a corresponding observed depletions of Na+; this enrichment-depletion patterns accompanying the salinity increases were mostly attributed to albitization of plagioclase feldspars as the major diagenetic reaction rather than dolomitization.
        In summary, these saline groundwater and brines in the Benue Trough were actually seawater and dissolved halite originated; however, possible reworking / modification abound via interaction with the geologic materials and environments as a result of compaction of compressible sediments in the Trough during the tectonic episodes that affected the Trough.

        Speaker: Prof. Moshood TIJANI (University of Ibadan, Ibadan, Nigeria)
      • 16:00
        Chalk AquifeR Management (CHARM): Groundwater modelling of a complex aquifer for the sustainable management of strategic drinking water reserves in Flanders (Belgium) 1h

        Groundwater is an important source of drinking water in Belgium. In some regions, locally produced groundwater is the source of 100% of the drinking water supply. One of the most important aquifers in the eastern part of Belgium is the Chalk Aquifer. This aquifer is phreatic in the northern part of Wallonia, but dips down towards the north, in Flanders, where it quickly reaches large depths. This largely confined aquifer is of strategic societal importance because it is well protected against negative influences from the surface (nitrates, pesticides) on the water quality.

        However, geological and hydrogeological information is scarce, leading to important uncertainties regarding sustainable yields. Due to the large depth of the aquifer in its confined part, relatively little borehole information is available. Furthermore, the Chalk Aquifer is characterized by a double porosity system which results in a strong heterogeneity and spatial variability of the hydrogeological properties. The goal of the CHARM project is to analyse the capacity of the Chalk Aquifer on a regional scale, and to deliver a management instrument that can be used for decision-making with regards to the quantitative use of this strategic aquifer for drinking water purposes. Special attention will be given to the characterization of all sources of uncertainty and its incorporation in a groundwater flow model.

        In a first step, the geology and hydrogeological parameters of the Chalk aquifer are characterized in detail. Based on gamma-ray logs, flow measurements, pumping tests and literature data, the horizontal and vertical variability of the hydrogeological parameters are identified. Exploitation results are linked to geological and hydrogeological data providing insights why some exploitations have a higher yield than others. Next, a regional groundwater model (MODFLOW) is set-up. The integrated Bayesian multi-model approach of Mustafa et al. (2018) is adapted, so that input, parameter and conceptual model uncertainty can be quantified. This is done by coupling the MODFLOW model with the DiffeRential Evolution Adaptive Metropolis (DREAM) algorithm (Vrugt, 2016) and by applying Bayesian Model Averaging (BMA). Based on the results of this approach, well-founded decisions can be made regarding the quantitative use of this aquifer considering all different sources of uncertainty, which is of strategic importance for long-term drinking water purposes.

        Speaker: Mr Gert Ghysels (Vrije Universiteit Brussel)
      • 16:00
        Comparison of groundwater recharge under conservation agriculture and conventional practice 1h

        Up to 70% of the populations in the sub-Saharan countries of Malawi, Zambia and Zimbabwe rely on groundwater resources. Under the pressure of demand for agricultural production in already water scarce regions, and further threatened by drought events, it is important to effectively select agricultural practices that minimize negative effects on groundwater recharge and availability. Over the last two decades, conservation agriculture has been promoted by many sub-Saharan governments and NGOs as a tool to obtain reliable crop yields while increasing soil fertility. Key principles of conservation agriculture comprise minimum tillage and mulching, and previous studies indicate positive effects of these practices on soil moisture balance. However, only limited studies have been undertaken on the effects on groundwater recharge in general, and none of these in the sub-Saharan context.

        In this study, we introduce a plot-scale approach with a combination of different measurement techniques to identify differences in recharge patterns between sites under conventional and conservation agricultural practice. By combining these different methods, we want to answer the question if increased infiltration of water into the soil promotes recharge, or if improved water retention in the root zone of the soil increases losses in groundwater recharge in the sub-Saharan environment. The presented setup comprises three experimental sites in Zambia, Zimbabwe and Malawi on which both conventional and conservation agriculture is practiced. Each site is instrumented with soil moisture monitoring probes, automated pressure transducers to log groundwater level fluctuations over time, and time-lapse electrical-resistivity tomography equipment to track soil moisture changes. Environmental isotopes, residence time tracers (such as CFCs and SF6) and water chemistry will be analysed to estimate groundwater age and chemical signatures at different depths.

        Speaker: Bentje Brauns (British Geological Survey)
      • 16:00
        Developing a model for a transboundary aquifer in the water-scarce region of Central Asia 1h

        Due to climate change and increased human impact, water use and its protection have become one of the major regional issues in Central Asia. As the availability of surface water is decreasing and becoming erratic, the reliance and pressure on groundwater resources are constantly growing. That is also a case with the Pretashkent Transboundary Aquifer (PTBA), located between the Republic of Kazakhstan and Uzbekistan. Groundwater withdrawal from the aquifer is increasing, responding to the high demand for water supply and irrigation. Aquifer-sharing countries have started a dialog about water policy and management tools for the PTBA, including the development of an operational numerical model. This model is required for better understanding of the aquifer dynamics and for development of scenarios for utilization of this hardly renewable aquifer.
        The aim of this research is to develop a conceptual hydrogeological and a numerical model of the PTBA in a framework of transboundary cooperation.
        The model is developed using the Groundwater Modeling System software (GMS). The model input preparation, including challenging transboundary harmonization (differences in language, classification, reference system, etc.) is conducted through a process of intensive discussion and collaboration among all international stakeholders. That was the main novelty of the conducted research. The conceptual model is the first major step in the development of the PTBA model and the first visible result of joint efforts to improve management of precious groundwater resources in the region. The following modelling steps are already stipulated by geological surveys of aquifer-shared countries and will be conducted with the continuous support of UNESCO-IHP and the Swiss Development Cooperation.

        Speaker: Ms Ainur Kokimova (IGRAC; IHE Delft Institute for Water Education)
      • 16:00
        Drivers of rainfall isotope composition in the northern Chilean Central Andes 1h

        The Central Andes is a geographical barrier that exceeds the elevation of 5000 m a.s.l. The Central Andes is constituted by two mountain ranges: the Eastern Cordillera and the Western Cordillera. Between them, the Central Andres plateau is well known for its fresh and salty lakes and its salt flats. During the austral summer, the strong easterly winds bring moisture from the Atlantic Ocean to the Central Andes. In the Eastern Cordillera (i.e. Bolivia) the strong continental and altitude effect component on the rainfall isotopic composition suggests the high influence of moisture sources from the Atlantic Ocean in the Eastern Cordillera during the austral summer.
        The Pacific Ocean is considered a secondary and limited source of moisture to the Western Cordillera. During the austral winter, the Western Cordillera and the high plateau receives from the Pacific Ocean a precipitation less than 20% of annual precipitation. The limited rainfall isotope data and isotope mapping studies from northern Chilean translates into difficulties in the interpretation of changes in moisture sources. Despite this, we hypothesise that the northern Chilean Central Andes (latitudes 18° S to 24,6° S; elevation >3000 m a.s.l.) rainfall is enriched in heavy isotopes towards higher latitudes.

        Speaker: Ms Sonia Valdivielso (Institute of Environmental Assessment and Water Research (IDEA/CSIC))
      • 16:00
        Educational dissemination of geoscientific knowledge for geoconservation of the Brazilian groundwater: the Guarani Aquifer System case 1h

        Considered the fourth largest freshwater reservoir in the world, the Guarani Aquifer System (GAS) extends for about 1.2 million km² in South America. Its area of occurrence has a greater volume and extension in Brazil, but comprises also territories of Paraguay, Uruguay and Argentina. The GAS waters are contained in sandstone rocks formed in the Mesozoic Era, when much of the supercontinent Gondwana harbored a vast desert environment. During that period, the landscape was mostly sediments, accumulated in large sandy dune fields. In the transition from Upper Jurassic to Lower Cretaceous, a gigantic volcanic activity covered the dunes, originating thick lava flows that solidified on the desert sands and gave rise to the Serra Geral Formation. This unit constitutes, in most of its area of occurrence, a protection cover for the GAS waters. The waters are widely used in Brazil, both for agricultural production and for public supply. It is known that currently more than 1,500 Brazilian municipalities can supply themselves with the GAS waters. and may be compromised by industrial activities, agricultural activities, urban use, land subdivision, and land occupation without previous studies. Thus, studies that promote public policies aimed at its preservation are extremely important. The research is based on the concerns and goals of the Geo-School project – which proposes that any educator of the XXI century has the responsibility to raise awareness for the next generation, aiming to solve environmental problems accumulated over the years. The project seeks to reflect on new modes of production which do not imply the exhaustion of natural resources. The objective of this study is to identify ways to develop strategies towards disseminating geoscientific knowledge and to support the geoconservation of groundwater, promoting a continuous recognition and acknowledgement of the areas of occurrence of GAS. These strategies should enable people to understand the environmental aspects inherent to the local reality of the places where they live. By highlighting the importance of the geological heritage and the imperative need to preserve groundwater, the authors hope to contribute to the formation of a more conscious society and individuals more critical and sensitive to environmental issues. The diffusion actions of Geosciences involve initiatives of formal and non-formal education. The result is the elaboration of a geology-based website that will support the training of teachers and contribute to deepening conceptual actions. As long as new forms of dissemination are identified, such as social networks – with online pages and videos – the authors will expand their use as tools for the dissemination of geological and environmental contents.

        Speaker: Mrs Isabella Barbosa (Bittar de Castilho )
      • 16:00
        GROUNDWATER INFORMATION MANAGEMENT AT CANAL DE ISABEL II 1h

        Canal de Isabel II (CYII) is the main water and wastewater service provider in Madrid Region, supplying services to more than six million consumers. Water supply is accomplished through 14 dams which storage 946 hm3. In extended periods
        of drought and/or disruptions in the water supply system, CYII is able to produce up to 70 hm3 per year from 68 wells located in the Tertiary Detrital Aquifer of Madrid (ATDM). Over the last 25 years, CYII has produced 300 hm3 from the
        ATDM during five significant pumping periods, each of them ranging from 12 to 18 months.

        Data management on complex environment mean a challenge itself. Adding all related issues of any industry, as maintenance, construction, QA/QC, to the more classic task of hydrogeoly as modelling, groundwater sampling..., trigger the problem to a next level. In order to tackle this problem, Canal de Isabel II is handling a powerful package of tools, focus on keeping data available and stable along the time in its well network.

        From database to calculus software are provided from solid international tech companies which guarantee a long term usable framework.

        This poster shows appliance of each software, interactions and main capabilities that any user can get from them. Each of these softwares are feed with data either manually or taking raw data from sensor, gauges or digital signals.

        Eventually this set of software and information work as a decision aid software which let us to analyze, schedule and react to any new event or information by simplifying and reducing time consuming task.

        Our groundwater database provides a quick update to our Modflow model to conduct groundwater supply scenarios and aquifer response for short and long term pumping periods

        Speaker: Mr Raúl Nogueras Martínez (Canal de Isabel II)
      • 16:00
        Health risk assessment of groundwater nitrogen pollution and its uncertainty analysis in Songnen Plain. 1h

        Affected by human activities and agricultural development, the nitrogen content of groundwater in the Songnen Plain seriously exceeded the standard. To explore the status of nitrogen pollution and its effect on human health, this study employed shallow groundwater sampling test data, geostatistical analysis and conducted the triangular random model to assess the risk of nitrogen exposure in children and adults, and performed the uncertainty analysis. The results showed that: 1) The main nitrogen pollutants was nitrate nitrogen, and the sample exceeded the standard rate of 44.35%, and the maximum value reached 566.2 mg/l, and the region with a concentration of nitrate nitrogen greater than 20 mg/l accounts for about 60% of the total area in the region, mainly distributed in the high plain area of the eastern and central parts, and the western front slope plain is less polluted; 2) Based on the triangular fuzzy coupled stochastic model on the Isight5.9-2 platform, considering the impact of human activities and agricultural development, the study area is divided into different units. The analysis shows that the non-carcinogenic risk ranking is: evaluation unit III> evaluation unit II>evaluation unit I, and the contaminants in Unit III are mainly derived from agricultural activities, and the risks in Units III and II are much higher than the safety threshold value of 1, which may cause potential harm to children and adults, and threaten children more; 3) The uncertainty of pollutant concentration and parameters has a large fluctuation range for the risk value, and the triangular random model is more sensitive to data changes, which can reduce the uncertainty of the triangular fuzzy method. The unit I risk interval value crosses the safety threshold 1 ,and it may mislead pollution prevention and control decisions; the contribution rate of nitrate nitrogen concentration to risk is above 90%, which clarifies the necessity of random sampling, at the same time, the test error of nitrate nitrogen should be minimized and relevant data should be collected to improve the reliability of the evaluation results.
        Key words:groundwater; nitrogen pollution; health risk assessment; uncertainty.

        Speaker: Ms juanjuan wu (College of New Energy and Environment Institute, Jilin University)
      • 16:00
        Hydrological characterization of Maullín river basin 1h

        The knowledge of the hydraulics and the intrinsic properties of the hydrogeologic units is fundamental for the sustainable use of the hydric resource in a basin. The objective of this study is to accomplish an integrated analysis of the hydrologic system of the Maullín river basin (a lacustrine basin covering approximately 4.300 km2), focused on determining the dynamics of groundwater and the properties of the materials where the water flows. It was developed on the basis of geology, geophysical prospecting and water well information (referring to its stratigraphy and pumping tests), which define the hydrogeologic units and the piezometry, from which groundwater flow is deduced. From the integration of the information it was established that the hydrogeologic units of high potential for water extraction are of granular type and are found, mainly, in sedimentary deposits of the Pleistocene-Holocene of glacial and glaciofluvial origin, harboring confined and unconfined aquifers. These units are connected to each other, so they can be considered as a large aquifer system. The very low hydraulic conductivity units are associated to the metamorphic rocks of the Paleozoic-Triassic and to intrusive rocks with granitic composition of Oligocene -Miocene, which constitute the impermeable basement. Based on the information from the water wells, an analysis was carried out on 233 pumping tests, obtaining estimates of their transmissivity. The results showed a maximum of 9.480 m2/day and a minimum of 0,8 m2/day. The statistic analysis of the transmissivity allowed to compare the water extraction capacity of the different units and to define the characteristic ranges of the most important ones. The storage coefficient could be estimated from a single pumping test that had record levels in an observation well, which resulted in a value of 0,002.
        The basin piezometry is closely related to the surface morphology, where the topographic highs coincide with the areas with the highest elevation in the piezometric surface. This condition indicates that the main source of recharge of the aquifer system has its origin in rainfall and that the relationship between the Maullín river and its main tributaries, with the aquifer system is of the effluent river type. In addition to this, the piezometry shows a lateral outlet at the south of the basin
        With the information given by the piezometry and the hydraulics properties of the hydrogeologic units we can conclude that the water received by the soil and the vegetation cover, is divided into a evapotranspiration, surface runoff and a third component that infiltrates to join the aquifer system. The main outlet of groundwater is the discharge to the bodies of surface water, to which are added: the water extractions by pumping wells and the lateral outlet of the basin.

        Speaker: Mr Felipe Avilés (SERNAGEOMIN)
      • 16:00
        Is current groundwater development in Ergene River Basin (North-western Turkey) sustainable? 1h

        Ergene River Basin is a part of the Thracian Basin with its drainage area of 11300 km2. The Pliocene aged Sandy Complex aquifer (SCA), environing about half of the Ergene River basin, is a regional aquifer. It is tapped by several thousand wells, mainly for irrigation use. The eastern and western parts of the SCA is unconfined while the central part is confined. The saturated thickness of this spoon-shaped aquifer reaches the maximum value (350 m) in the central part. The Çorlu-Lüleburgaz fault interrupts the continuity of the SCA by acting as a barrier in the artesian area. SCA has experienced extreme declines in groundwater levels since the 1970s (70 m in the last 46 years). The persistent declines in groundwater levels in the SCA drew the attention of many researchers and a groundwater flow model was constructed to determine the safe and sustainable yields and the limits of utilization for the SCA (Ökten and Yazıcıgil, 2005). This model was first calibrated under steady-state and transient conditions and, eventually, tested a total of eight alternative groundwater pumping scenarios (from 2001 to 2030) to predict both groundwater level and reserve changes in the aquifer system along with the average base flow to streams. In one of these scenarios (A), Ökten and Yazıcıgil (2005) continued the pumpage conditions of the year 2000, for the rest of the scenarios, they decreased the annual pumping rates to be equal to 100%, 90%, 80%, 70%, 60% and 45% of the annual recharge rates, respectively. Eventually, they found out that the average decline in groundwater levels is between 28 m (Scenario A) and -3.9 m (Scenario G). This study is carried out to examine the current groundwater levels in the SCA by using five selected observation wells with limnigraphs. Accordingly, the groundwater levels obtained through 8 different scenarios are compared with the actual groundwater levels from January 2001 to September 2018. The results showed that the current pumping rates are greater than both the sustainable and safe yields of the system. In fact, in two wells, the groundwater levels are even below the levels estimated by Scenario A and in two of them, the levels are similar to the ones obtained as a result of Scenario B. These comparison efforts suggest that, sustainable groundwater management policies and plans have not been adopted in the area. The pumping rates over the past 18 years were significantly greater than the sustainable yield (168 hm3/year) and traditionally defined safe-yield in Turkey (about 70% of the annual recharge, 261 hm3/year), causing significant declines in groundwater levels and base flow of the streams.
        References: Okten, S. & Yazicigil, H., 2005, Turkish Journal of Earth Sciences, Vol: 14, 209-226 p.

        Speaker: Sebnem Arslan (Ankara University)
      • 16:00
        Isotopic tracing and numerical modelling of saline groundwater discharge into the Matola Wetlands, Mozambique 1h

        Population pressure, recent droughts and sea-level rise associated with climate change projections increase pressure on secure water resources, notably on groundwater of the coastal areas like Maputo, Mozambique. The Matola River, located in the west of Maputo, is a perennial river that consists of mostly brackish/salt water originating from groundwater seepage and salinity makes the river water unusable. The main source of the saline groundwater is assumed to be fossil seawater, entrapped in the silty marl and clay dominated aquitard. However, detailed studies about the salinity problem of coastal Maputo city, particularly of Matola River is very limited. This research focuses on the integration of regional hydrogeochemistry, isotopic analysis, and groundwater flow models to trace the source of saltwater and to improve the management of water resources in Matola wetlands. The hydrogeochemical analyses of major ions will reveal the prominent hydrochemical processes responsible for the evolution of groundwater. Water stable isotopes (δ2H, δ18O) results will validate the sources of salinity and mixing processes. Using the result of 13C/14C (DIC) and 36Cl/Cl isotopes, the study aims to calibrate the residence time and flow paths of the already existing groundwater flow and salt transport models for testing the mentioned hypothesis. Based on the overall findings, some adaptation measures will be proposed to cope with the saline groundwater. Investigating the origin of salinity and proposing measures are expected to help in the domestic supply and crop productivity sectors of Matola River adjacent areas. It can also assist the policymakers to take feasible solutions to sustainable groundwater management.

        Speaker: Ms Rezwana Binte Delwar (IHE-Delft Institute for Water Education )
      • 16:00
        Key Policy Changes Required to Reduce Environmental Degradation in the United States and Beyond 1h

        Climate change is just one of many examples of how humans have negatively impacted Earth through the introduction of pollution in its many forms into the natural environment. Other impacts caused by pollution that may not be in the public eye as often but that are also significant include impacts to the land, oceans, surface water, groundwater, and the biosphere. Each are related and affects the others in a complex web that involves the interaction and physical and chemical dynamics of human interaction with the natural world.
        Quantifying anthropogenic impacts on a global scale has only recently been available through new technologies and research but the data clearly demonstrates that anthropogenic impacts are substantial and are getting worse. However, now that the many aspects that have caused much of the environmental degradation have been identified, we can now move to action to reduce those impacts.
        To reduce further environmental degradation, action must be undertaken at the global level, national level, state and municipal level, and the individual level. The actions must include many aspects of how humans behave and treat the Earth and involve changing our lifestyle through modifications of transportation, energy needs, shelter, and agriculture. Modifications at the global level may be the most difficult but are the most important because pollution does not respect political boundaries. Pollution from one country often migrates and affects all environmental media of other countries and sometimes the entire planet.
        In order to support a human population on Earth we must not consume and pollute at current levels. In order to achieve a sustainable living, vibrant, and diverse world instead of a world without humans, we need to diligently work cooperatively towards living in productive harmony with nature instead of trying to change nature.

        Speaker: Mr Daniel Rogers (Amsted Industries Incorporated)
      • 16:00
        Spanish Careos and Peruvian Amunas. Comparative analyses for pioneer managed aquifer recharge systems 1h

        The most ancient written references for MAR Recharge are the Careos, in the South of Spain, and the Peruvian Amunas. Both high mountain systems are complex and present extraordinary analogies and differences, despite being chronologically Pre-Columbian structures in the case of Amunas. From both there are written chronicles since the XII Century and both evolved in parallel, although disconnected, with amazing similarity.

        After studying in detail 10 Careos and 6 Amunas from a construction techniques perspective, they have been decomposed in 24 different components. All these units have been compared, studying their analogies and differences according to the employed materials, hydraulic masonry, mortar types, carved stones, layout, profiles, relationships between the different elements, water origin and treatment and water recharge. Units’ pathology and recovery measures have also being studied by means of polygonal, linear or punctual structures.

        Some common points are the low rainfall conditions, temporal water availability from snow smelt and runoff, induced recharge by means of infiltration fields, canals, ditches and simas, subsurface and deep groundwater transit and recovery from springs or irrigation ponds.

        Some of the differences are based on the form of carving the stone and masonry, maximum flowrate capacity from 200 l/s to 800 l/s, distance between consecutive canals, time of transit (15 days to 7 months), recovery flow rate from 1 to 5 l/s (respectively for Amunas and Careos), etc.

        In both MAR cases, ancient structures work as a hydrogeological and socio-cultural complex system, with values, norms and traditions scarcely evolved in 8 centuries. Water management is accompanied by land and crops management too, to the extent that both can be considered a cultural met in the distance or “cosmovision of water”, as there are certain evidence of synchrony in their temporary development.

        Both systems fit the definition for Adaptive Complex System (Murray, 2010) as a articulated group of subsystems with self-similarity, complexity, and self-organization, rather than a Multi-Agent or system, defined as a composed system with multiple agent in permanent interaction (Wooldridge, 2002, for artificial intelligence).

        Finally, the article recommends some improvement advices, based on their cross-comparison. It also studies the possibilities of replicability for other ridges of mountains in the world and suitability to face climate change adverse impacts.

        Speaker: Dr Enrique Fernandez (Tragsa Group)
      • 16:00
        Spatial controls on groundwater quality in Sierra Leone: moving towards a national data management framework? 1h

        West Sub-Saharan Africa is one of the regions most affected by global change, with predictions of rainfall deficit over the next 50 years (World Bank Data). Post-civil war demographic boom, combined with increasing water demand to boost the agricultural and mining sectors have highly challenged the current capacity of post-colonial infrastructures to supply the needs in drinking water. Moreover, the assessment of groundwater as an alternative source across the country is still very limited to local and regional studies. Well data from over 475 well locations from around Sierra Leone was compiled from third-party sources including NGOs, drilling companies and government agencies. Relevant chemical data from 86 of those well locations were discovered and analyzed in order to find relevant spatial correlations between groundwater quality, demographics, population density and land-use patterns. Preliminary results suggests that 1) biological contamination shows a positive spatial correlation with predominantly agricultural land-uses and a low dependency on human density, 2) physicochemical parameters (TDS, turbidity) are likely associated to proximity of major transportation lines, and 3) trace metals (copper, iron, manganese) contamination suggest a natural (geologic) signature. A danger scale for chemical contamination was computed and will be useful to target the most vulnerable regions. A major obstacle to the development of this project is the lack of a national groundwater data framework. The development of a national groundwater database is crucial to analyze the sustainability of current groundwater uses and will be useful to inform future sustainable management of the resource.

        Speaker: Dr Gilles Tagne (Wheaton College)
      • 16:00
        Spring Development for a Small Village Water Supply: The Story of Ginda B Village, Nigeria 1h

        Ginda B is a village in Nasarawa State, Central Nigeria which is one of the small villages that benefited from the Conditional Grant Scheme of the MDG’s in 2008. The benefits included the establishment of a Primary Healthcare Centre as well as a solar powered borehole scheme to provide water for the center as well as the village. The village is situated on a hilltop (elevation = 450m above mean sea level) has a population of about 300 people. Due to a challenging terrain (geology and topography) and the remote location of the village it was impossible to provide the solar powered borehole scheme originally proposed. The hill upon which the village is situated is made up of the Nigerian Basement Complex terrain specifically gneisses, but is characterized by a series of fracture springs along the slopes and at the foot of the hill. The most productive of these springs are situated at the foot of the hill. Spring development was proposed as an alternative to provide water to the primary healthcare center as well as the immediate village. In the past, the village had faced a lot of socio-economic challenges associated with lack of sustainable water supply. Women and children old enough spend most of the day in search of water which requires downhill trips to the network of springs, some of which are seasonal. This has negatively impacted on level of education and also economic well being of the villagers. The scheme thus proposed and constructed consisted of a collection point, and infiltration gallery, reservoir/ground tank, a pump house and finally an over head tank adjacent the Healthcare Center. Water from the springs is filtered in the gallery and then stored in the ground reservoir from which a 3hp submersible pump powered by a diesel generator pumps the water to the overhead thank adjacent the Healthcare Center. A reticulation network from the overhead tank was also set up to provide water to the households in the village. Once the reservoir is filled up, it takes 2 hours of pumping to fill up the over head tank which has a capacity of 20,000litres. Pumping is done thrice a week which consumes about 32 litres of diesel (N8, 000 ~22USD). Basic training on routine maintenance of the scheme (such as servicing of the generator) was provided after which the project was handed over to the village. Ten years on, the scheme is a still functioning major challenge faced is breakdown and subsequent repair of the diesel engine that powers the pumps.

        Speaker: Dr Aisha Kana (Nasarawa State University, Keffi)
      • 16:00
        The effect of La Niña 2016-2017 and the current abstraction regime on diverse water-reliant companies in Kwale groundwater resources (Coastal Kenya) 1h

        In Kenya, as in much of Africa, there is significant growth in water-reliant industry. In 2016-17 much of East Africa was affected by a severe drought. During such events, groundwater resources can act as a buffered resource, but may themselves be stressed by reduced recharge and increased abstraction, posing significant challenges to water resource management. Despite the importance of groundwater use in the continent, there is a lack of knowledge of the groundwater hydrodynamics of many African aquifers. The aim of this study is to characterise the groundwater system in Kwale County in south-eastern Kenya, examining the possible influence of increased abstraction by new industry and agriculture and determine the effects of the 2016-17 La Niña drought. This area has been selected as an aquifer representative of much of coastal East Africa, where new water-reliant activities (mining and irrigated sugar) were established in 2012-2013; these coexist with the long-standing tourism industry and local communities.
        Diverse hydrochemical, isotopic, geophysics and groundwater level measurements were carried out to study the groundwater hydrodynamics and characterise the aquifer system before and during the drought period. The recharge in the study area was estimated using the soil mass balance. Due to the difficulties in obtaining good abstraction data, different information sources were used to determine the groundwater abstraction of the different water-reliant industries. These included direct information from the companies and using Google Earth, Trip Advisor and interviews to define hotel abstractions.
        The results show that the current level of groundwater abstraction does not significantly affect aquifer water levels. However, during la Niña there was a 69% reduction in recharge compared with an ‘average’ climate year. Furthermore, there was a concurrent increase in seawater intrusion even during the wet season. The main impact occurred to community handpumps, prone to drying up during drought periods, as they exploit a shallow aquifer that is less resilient to drought. On the contrary, groundwater abstraction by irrigated agriculture and mining is from the deep aquifer, which is more resilient to the drought periods common in the area.
        Acknowledgements
        The authors gratefully acknowledge the support of Kenya's Water Resource Authority (formerly WRA), the Kwale Country Government, Base Titanium Ltd., Kwale International Sugar Company Ltd. and Rural Focus Ltd. This research was funded by the UK Government via NERC, ESRC and DFID as part of the Gro for GooD project (UPGro Consortium Grant: NE/M008894/1).

        Speaker: Núria Ferrer Ramos (Universitat Politècnica de Catalunya)
      • 16:00
        The sustainability of non-renewable groundwater from Guarani Aquifer System – A case study in a city at São Paulo State, Brazil 1h

        The Guarani Aquifer (SAG) in South America is a huge hydrogeological system that underlies an area of about 1,100,000 km2, mainly distributed in Brazil (62%), Paraguay, Uruguay and Argentina, is composed by a sequence of sandstone beds, mainly weakly-cemented, of Triassic-Jurassic age, formed by the processes of continental deposition (aeolic, fluvial and lacustrine). The average thickness is about 250 m, varying from < 50m to > 600m, and reaches depths of over 1,000 m (Foster et al., 2009).
        The west of São Paulo State - Brazil, where is localized the study area, has a huge dependency on groundwater resources, since the surface water resources are distant from the urban centers. Around the Marilia municipality, within an area of approximately 800 km2, there are nine pumping wells in the SAG. The Marilia municipality, the biggest city at the study area, is supplied by SAG with 1,300 m3/h (33,3% of the total water resources), with five pumping wells.
        In this region, the average thickness of SAG is about 218 m, with minimum of 180 m and maximum of 254 m, and the thickness of basalt varies between 564 and 785 m. This portion of SAG belongs to the IV resource management zone classified by Foster et al. (2009) as “Deep Confined Zone”, where pumped groundwater is being ‘mined’ from aquifer storage with continuously (but very gradually) falling potentiometric surface. Prandi et al. (2013) identified residual drawdown varying between 48 a 59.5 m in three of the SAG pumping wells located at Marilia since 1990.
        Within this scenario, five SAG’s pumping wells were monitored for two years with the objective to measure the variation of the groundwater level with the pumping schemes. The activities developed consisted by the preparation of a database, well selection and installation of the monitoring equipments, download the monitoring data, consolidation and interpretation of data, and management recommendations were given.
        Besides of many problems during the two years monitoring, some results could be described. The SAG drawdown is happening at the region and still in course. In approximately twenty years, the potenctiometric surface decline at maximum 60 m. The hydraulic gradient between the pumping wells is lower in comparison with at the beginning of the pumping, and bigger between these pumping wells and other closest confined SAG wells.
        Considering that the SAG is a transboundary aquifer and the west of São Paulo State is very dependent of groundwater resources, this region demands a consistent and constant monitoring program. The aquifer system characterization (quantification of aquifer storage reserves – specific yields, assessment of contemporary recharge rates and appraisal of depletion trends) to provide adequate predictions is essential (Lloyd,1999) to define restriction areas and control of abstraction and use of groundwater.

        Speaker: Dr Emilio Prandi (DAEE)
      • 16:00
        To what extent does community management ensure good functionality of groundwater supplies in rural Africa? 1h

        Within rural Africa, communal boreholes fitted with handpumps (HPBs) are likely to remain the main source of improved water supplies for decades to come. Understanding how the performance of these supplies can be improved will be central to achieving improved water security. The functionality of community HPBs relies on a range of elements which include not only groundwater resource availability, correct siting and construction of the borehole and handpump mechanism, but also equitable and enabling management arrangements.

        Since the 1980s – the first UN ‘Water Decade’ – Community Based Management (CBM) has been the policy prescription par excellence for operationalising participatory development in the rural water supply sector. The cornerstone of the CBM model is the creation of a local water point committee or similar community organisation, which is charged with the operation and maintenance of the borehole. Despite its popularity and endurance, there is a relative lack of evidence on how the management capacity of communities relates to the functionality of their boreholes, and a growing recognition among development practitioners and academics that CBM of rural water supply has struggled to deliver on many of its promises.

        Here we present the findings from a survey of six hundred communities across rural Ethiopia, Uganda and Malawi to examine the extent to which community water management capacity is related to borehole functionality. The capacity of water management arrangements (WMA) was assessed according to four dimensions: finance system; affordable maintenance and repair; decision making, rules, and leadership; and external support. HPB performance was assessed using on a nuanced definition of borehole functionality, which captures different tiers of functionality from a simple binary ‘yes/no’ working, to capturing the level of functionality performance and reliability.

        The findings reveal that whilst over two thirds of WMA are of medium to high capacity in communities, there is no strong relationship between the WMA capacity and the functionality of the borehole. Of the four management dimensions, affordable maintenance and repair was the best predictor of borehole functionality. However, the capacity of this dimension was seen to be lowest overall, with nearly two thirds of sites having weak or non-existent capacity in this respect. These findings provide evidence to support the growing claim that, in many instances, CBM by itself does not ensure improved functionality performance.

        Speaker: Helen Fallas
    • 16:00 17:00
      Poster with refreshments: Monday Topic 5.3
      • 16:00
        A new inverse modelling algorithm for hydraulic tomography based on a mixture model 1h

        Hydraulic Tomography (HT) has become one of the most robust methods to characterize the heterogeneity in hydraulic parameters such as hydraulic conductivity and specific storage. However, in order to obtain high resolution hydraulic parameter estimates, several pumping/injection tests with sufficient monitoring densities are necessary. In highly heterogeneous media, even with large numbers of measurements, the resolution may not be sufficient for predicting contaminant transport behavior. In addition, during inverse modeling, the groundwater flow equation is solved numerous times, thus the computational burden could be large, especially for a large, three-dimensional, transient model.

        In this work we present a new approach to model aquifer heterogeneity, based on a Gaussian Mixture Model (GMM) to parameterize the K field, which significantly reduces the number of parameters to be estimated during the inversion process. In addition, a new objective function based on the spatial derivatives of hydraulic heads is introduced. This objective function increases the sensitivity of the parameters and eliminates the skin effect.

        The developed approach is tested with synthetic data and data from a previously conducted sandbox experiments. Results indicate that the new approach improves the accuracy of the K distribution produced through HT and reduces the computational effort. It also addresses the problems involved in the inverse problem due to including noisy data, the need for many pumping/injection tests and the lack of resolution when the K distribution does not have a Gaussian distribution. For two-dimensional synthetic experiments, this approach was able to achieve a significant reduction in the error for K field estimation as well as computational time compared to a geostatistical inversion approach. Similar results were also achieved when the approach was tested using pumping test data conducted in a synthetic aquifer constructed in the laboratory.

        Speaker: Prof. Walter Illman (University of Waterloo)
      • 16:00
        Analysis of hydrographs from a karst aquifer in a former mining area, Hungary 1h

        The Transdanubian Range is a complex, thick karst aquifer, which can be characterized by hydraulic interrelationships. Because of mining, a large amount of groundwater was extracted from this area in the second part of the 20th century for a preventive purpose. At the end of the 90's, the mining was stopped, and the rising of karst water has begun, which led to serious economic and technical-engineering problems as well. The examination of hydrographs of observation wells, showing the recovery process, helps to understand the hydraulic behaviour of the karst aquifer and to prepare for problems related to the phenomenon.
        The aim was to understand this special hydrogeological situation by applying stochastic approaches. 127 long-term time series could be analysed from the area of the depression having affected by water recovery. The time series (from 1995 to 2015) located in the study area have been grouped into three clusters with hierarchical cluster analysis based on their pattern. The individual groups were separated prior to their spatial positions related to the depression centre. The water levels of the first group showed significant (30-40 meters) and continuous rising. The water levels in these wells are characterized by less fluctuation and the effect of the recovery is crucial. These wells are located in the NE part of the study area. In the wells of the second group the water levels increased tens of meters as well, moreover, a definite fluctuation pattern has also occurred. These wells are located in the area represented by high water level of topographic heights. The wells of the third group are situated in the SW part of the study area where the rising of the water level is also typically tens of meters (some places more than 70 meters) but without a fluctuation pattern. As a next step, the forecast of the water levels in each individual well took place with the estimation of a well-fitting trend and their extrapolation until January 2030. Thus, the so-called growth curves, which has an upper limit, have been fitted to the time series describing appropriately the recovery process. A significant part (82.68%) of the studied hydrographs showed an excellent fitting (where R$^{2}$>0.9). In most cases, out of the 10 examined functions, the process can be modelled most accurately by the so called "Richards" and "63%" functions. Important result of the research is, that using the growth curve models can expand the number of methods which may be used in forecasting groundwater levels.
        This research is part of a project that has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 810980.

        Speaker: Kamilla Modrovits (Department of Geology, Eötvös Loránd University, Budapest, Hungary)
      • 16:00
        Application of machine learning technique and network selection for prediction of the groundwater level 1h

        Prediction of the groundwater level is needed for management of groundwater resources or monitoring in specific site such as pollution area. Neural network of machine learning technique is one of the fancy and powerful tool to estimate or predict the groundwater level in hydrology. There are various kinds of architecture in neural networks such as Artificial Neural Network (ANN), Deep Neural Network (DNN), Long Short Term Memory (LSTM), and Stacked Long Short Term Memory (S-LSTM). These models were applied to predict the groundwater levels in riverside area where much of groundwater is consumed. Model performances from each neural network model were obtained to be compared with each other. While ANN model which is the most basic neural network had a range of RMSE errors from 0.0331 m to 0.0562 m, LSTM showed the best model performances among the four neural network models. Additionally, deeper networks like DNN and S-LSTM did not always show better performances than simple networks, which can imply that the most complex model is not necessarily the best network. Because various neural network models give their efficiency differently according to type of data or system, determination of proper network would be important when machine learning technique is applied for prediction of the groundwater level.

        Acknowledgement: This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIP) (No. 2017R1A2B3002119)

        Speaker: Sanghoon Lee (Seoul National University SEES)
      • 16:00
        Assessing the potential of denitrification through Managed Aquifer Recharge (MAR) 1h

        Nitrate (NO3) is a common contaminant in groundwater and surface water worldwide. Denitrification is a microbial respiratory process in which dissolved NO3 is reduced to nitrogen gas (N2). Research has shown that MAR can enhance natural attenuation of nitrates by accelerating denitrification that occurs during groundwater recharge and groundwater flow. However, very few MAR sites aim primarily at denitrification and the physical and biochemical processes controlling denitrification through MAR are not well-documented. This study aims at assessing the potential for denitrification through MAR, taking into consideration factors such as redox conditions, availability of organic matter, aquifer hydraulics and nitrate concentration. Based on a literature review, a conceptual model was developed which incorporates the most significant factors for enhanced biological denitrification. This conceptual model can provide the basis for a numerical model to obtain the optimal range of dissolved oxygen, redox potential and easily biodegradable organic matter which will lead to a maximum denitrification rate within a MAR setting. Using spatial distribution of soil parameters and other site characteristics, the potential for denitrification through MAR was mapped over Europe. This map can serve to select pilot areas for further experimental research in the field. Characterization of optimal conditions for denitrification through MAR and their spatial distribution can provide a focus for future field studies and ultimately assist practitioners and policy-makers to reduce nitrate contamination in aquifers.

        Speaker: Mr Muhammad Muqeet Iqbal (IGRAC and TU Dresden)
      • 16:00
        Comparative hydrogeology – application of quantitative descriptors to groundwater time series with spatial proximity 1h

        High frequency as well as long-term fluctuations of groundwater levels are the consequence of a large number of different processes within the aquifer system. Groundwater levels are generally influenced both by natural processes (e.g. groundwater recharge, interaction with river systems) and anthropogenic influences (e.g. water abstraction, artificial recharge and piling). Spatial and temporal superposition of these processes cause fluctuations of groundwater levels, referred to as groundwater dynamics, at the position of the well’s screen. Due to superposition, the differentiation between multiple driving forces (input signals) is difficult and requires knowledge of hydro(geo)logical properties of the system. This includes characteristics of the surface, vadose and phreatic zone on different scales. The exploration of all those characteristics is complex as well as time-consuming and, therefore, information are generally only available on a point scale. In contrast to the limited availability of system characteristics, high-resolution data records of groundwater hydrographs are more generally available. Analysis of high-resolution hydrographs is a frequently applied tool for the prediction of ungauged basins (PUB, e.g. Blöschl et al., 2013; Hrachowitz et al., 2013). The PUB community introduced a number of different quantitative indices to characterize different parts of river flow dynamics. Based on similarities of these indices, river catchments are clustered in groups of similar dynamics and can, subsequently, linked to system characteristics. Due to the various differences between surface and sub-surface systems, the transferability of streamflow indices on groundwater time series might be limited. This study is focused on the question of how transferable these river flow indices are to groundwater time series measured in alluvial aquifers in Bavaria (Southern Germany). More than 50 indices are calculated from sub-monthly groundwater level time series from different regions, with the purpose of covering various hydro(geo)logical settings. The result of hierarchical clustering (Ward Linkage algorithm) of these 50 groundwater hydrographs serves as a baseline. The ability of each index to express hydrograph similarity is quantified. Additionally, the study also analyses the ability of different indices to express similarities of groundwater hydrographs from different regions but with similar hydro(geo)logical settings.

        References:
        Blöschl G, Sivapalan M, Wagener T, Viglione A, Savenije H. (2013): Runoff Prediction in Ungauged Basins:Synthesis across Processes, Places and Scales, Cambridge University Press.
        Hrachowitz, M. et al. (2013): A decade of Predictions in Ungauged Basins (PUB) - a review, Hydrol. Sci. J. 58 (6), 1198–1255, doi:10.1080/02626667.2013.803183.

        Speaker: Markus Giese
      • 16:00
        Devise strategies and modelling tools to target the objectives of the EU Nitrates Directive and to enhance agricultural water management 1h

        During the last decades, severe qualitative and quantitative imbalance is being detected for many important aquifer systems worldwide, even beyond the limits of sustainability, due to overexploitation and climate change. Among the most challenging topic, the increase of nitrate concentration in groundwater, especially in rural areas, is a matter of concern. More than 20 years after the issue of the EU Nitrates Directive, the spatial/temporal trend of nitrates in groundwater is still poorly understood. As argued within EU water-related Directives, ICT (Information and Communication Technology) may provide proper tools (e.g., numerical models and GIS (Geographic Information Systems)) to address integrated water resource management.
        Efforts have been spent in this direction within the framework of the HORIZON 2020 FREEWAT project, whose main result is a composite QGIS plugin, the FREEWAT platform, which couples the power of GIS geo-processing tools for spatial data analysis with that of free and open source process-based simulation models (e.g., MODFLOW and other codes developed by the USGS) for the simulation of the hydrological cycle. Taking step from FREEWAT results, the general objective of the SMAQua project (SMArt ICT tools per l’utilizzo efficiente dell’AcQua - smart ICT tools for efficient water use) is to deal with water quality issues by means of smart software applications aimed, among the others, at reducing the impact of irrigated agriculture.
        In order to fulfill the objectives of the Nitrates Directive, a tool for the simulation of the nitrogen cycle in the unsaturated zone has been integrated within the FREEWAT platform. The integration strategy consists in coupling vertical flow through the unsaturated zone and surface runoff, as simulated by MODFLOW, and all the processes involved in the nitrogen cycle, as simulated by the ANIMO (Agricultural Nutrient Model) model. The latter is a lumped code which simulates nutrients leaching to the water table, taking into account agricultural strategies, soil properties, land use and the hydrological conditions. The coupling approach consists in downscaling at the grid cell scale, all the processes simulated by ANIMO at the basin scale. As a result of the coupling methodology, the amount of nitrate which reaches the water table by percolation is estimated and treated by solute transport models (e.g., MT3DMS) for the simulation of advection-dispersion processes in groundwater.
        The proposed solution is thought to provide innovative and digital tools for companies and water authority to evaluate the impacts of agricultural practices on water quality and to enhance agricultural water management.

        Acknowledgements
        The SMAQua project has been co-financed by Regione Toscana, ASA S.p.A. and ERM Italia S.p.A.
        This paper provides exploitation of the H2020 FREEWAT project results. The FREEWAT project received funding from the European Union’s HORIZON 2020 research and innovation programme under Grant Agreement n. 642224.

        Speaker: Giovanna De Filippis (Scuola Superiore Sant'Anna)
      • 16:00
        ESTIMATION OF RECHARGE AND EVAPORATION IN THE NORTH-WESTERN SAHARA AQUIFER SYSTEM (NORTH AFRICA) USING STABLE ISOTOPE AND CHLORIDE PROFILES IN SOIL WATER 1h

        Due to constant demographic growth and agricultural growing demand for irrigation water, the inescapable use of groundwater has continuously increased during the last forty years in North African arid and semi-arid regions. Some of these areas are known to comprise worldwide and in many locations huge underground water reserves. This is the case of the large confined aquifers of well-known sedimentary basins such as those of the Sahara desert (North Africa) and Australia (Great artesian basin).
        For the sake of integrated groundwater resource management, hydrogeologists and water managers have constantly been worried by the same question that is: what are the evaporative losses and the recharge rates of those huge aquifers?
        In addition to the technical and the logistic constraints related to the nature of these regions, they are also characterised by extreme climatic conditions. Whereas conventional techniques often failed, it is surprisingly in such precipitation-poor environments that isotopic tools have proven their efficiency in tackling groundwater issues. Arid zone isotope hydrology has gained more and more importance during the last three or four decades.
        The present paper review the contribution of this methodology as applied to the groundwaters occurring in the north western part of the Sahara sedimentary basin (North Africa). Water transfers through the unsaturated zone were investigated in order to compute steady-state groundwater recharge rates and evaporative losses.
        Many sites have been investigated during the last twenty years: Béni-Abbès, Chott Chergui, Ouargla, El-Oued in Algeria and Tozeur, Dissa in Tunisia within the framework of separate studies. These investigations aimed at estimating evaporation rates based on unsaturated zone stable isotopes and chloride profiles. This was implemented making use of the deterministic model developed by Barnes and Allison (1982). The evaporation and recharge rates obtained for a 10 m unsaturated soil profile varied between 1 and 40 mm/y. The main objective of the present study, is to gather all these data and to examine how they may be interpreted in terms of recharge rate, evaporation losses can help the water managers of the involved countries to develop or refine appropriate models. This should facilitate the implementation of a trans-boundary integrated management of the shared resources.

        Keywords: stable isotopes, chloride, aquifer, modelling, Evaporation, Recharge, Sahara

        Speaker: Prof. ABDELHAMID GUENDOUZ (Blida1 university, water sciences departemeent)
      • 16:00
        Falaj Modelling by Aquifer – Pipe Flow Coupling 1h

        The Falaj system is an ancient water supply and distribution system used in several countries ranging from Morocco in the West to China in the East. While they are also discussed under the Persian name ‘quanat’, we are using the Arabic term, as our study site lies in Oman. The so called Daoudi Falaj collect groundwater, which is then channelled to places of consumption, mostly for irrigation within oases and plantations. There are more than 3000 Falaj still in operation alone in Oman, which are understood as a technique for sustainable use of water under semi-arid or arid conditions. Nowadays Falaj are under decline not only to the advent of additional sources (desalination), but also due to decline of groundwater discharge and of contamination.
        Falaj Daris near the city of Nizwa, located inland Oman, belongs to one of five Omani Falaj that were inscribed by UNESCO on the World Heritage list in 2009. The total length of three channels amounts to about 8 km, delivering a discharge of up to 2000 l/s. The channels are connected to a clastic aquifer, located between the Hajar mountains in the North and ophiolite rocks in the South. The clastic aquifer has an extension of 6.5 km2.
        For modelling of the Falaj we couple a 2D horizontal groundwater flow model with flow simulation of the network of 1D pipes. To our knowledge this is the first hydraulic model of an Falaj and its connected aquifer. It is set up by the COMSOL Multiphysics software and calibrated for aquifer transmissivities and inflow rates from the adjacent mountainous regions. We utilize groundwater and Falaj discharge measurements obtained from the Ministry of Regional Municipalities and Water Resources (MRMWR).
        We present the model and its results. It is intended to include further data from observation campaigns. In a further step it is planned to extend the flow model by a transport simulation, which can be a useful tool to predict the spreading of contaminations.

        Speaker: Dr Ahmed Hadidi (German University of Technology in Oman)
      • 16:00
        MODELING A HEAT TRACER TEST IN ALLUVIAL SEDIMENTS USING MONTE CARLO: ON THE IMPORTANCE OF THE PRIOR 1h

        In hydrogeology, deterministic model calibrations are useful to understand the influence of parameters on the considered variables or to image large-scale spatial parameter distribution. Oftentimes, deterministic solutions bias the problem with too smoothed parameter distributions leading to unrealistic transport predictions with underestimated uncertainties. Instead of predictions using an optimum parameterization in conjunction with reference data confirming the model, a realistic heterogeneity consideration is crucial for robust transport simulations and managing aquifer systems sustainable. Thus, using random generated models as multiple hypotheses (e.g. with Monte Carlo), then a hypothesis may be rejected, when the model does not confirm reference data (falsification step).

        For that, the reference data set in this study is a heat tracer experiment in alluvial sediments (Belgium). Between an injection well and a pumping well 20 m apart, three observation panels are located at distances of 3, 8 and 15 m downgradient from the injection well. Each panel consists of 3 wells with screened intervals in the upper and lower aquifer parts. A deterministic calibration of the experiment on temperature data, using jointly HydroGeoSphere and PEST, hardly describes the experimental observations. The resulting spatial hydraulic conductivity distribution (K) is probably too smooth. Instead, 250 realizations using Monte Carlo in combination with sequential gaussian simulation for the K-distributions define the prior (hypotheses). For the K-distribution two scenarios are used: (1) a random K-distribution with unknown mean, variance and spatial correlation and (2) the same approach but with a downwards increasing vertical trend for the K-distribution, to mimic the observed increasing grain sizes of the sediment with depth.

        With Scenario 1, the prior range (250 simulations) surrounds the reference data (i.e. heat breakthrough curves) for most of the experiment, but not for the tailing. The prior generated using Scenario 2 (with the vertical K-trend) improves the simulation of the breakthrough tailings for panel 1 and 2. In panel 3 (15 m downgradient), simulations for the lower aquifer part show significant lower peaks than measured.
        Scenario 1 is falsified (rejected), because the prior (250 models) do not confirm the reference data, while scenario 2 is not-falsified till panel 2 (8 m downgradient). Scenario 2 addresses the heterogeneity of the test site more realistically than all previous unsatisfying deterministic attempts. A global sensitivity analysis at panel 1 and 2 identifies then the spatial K-distribution and its variance as the most sensitive parameters. This confirms, that future efforts needed for panel 3, should focus on identification of heterogeneous patterns in the aquifer and their subsequent introduction in the model.

        As a perspective, the use of a direct predictive framework (e.g. Bayesian Evidential Learning), avoiding the commonly used calibration procedure, promises robust decisions made by more realistic quantifications of the uncertainty caused by heterogeneity.

        Speaker: Mr Richard Hoffmann (Liege and Mons University)
      • 16:00
        Multi-method approaches to quantify groundwater and river exchange in lowland floodplains of Belgium 1h

        Floodplains play an important role in the hydrological cycle. They serve as buffer zones where water and solute exchange and heat transfer take place between the shallow groundwater (GW) and surface water (SW). Presented research focuses on quantifying the water flux between the shallow aquifer and river, which is often characterized by a high temporal and spatial variability.

        A multi-method approach is used to measure the fluxes in three distinctive Belgian catchments (Zwarte Beek, Mombeek and Dijle). As GW head observations do not directly allow for quantifying the exchange flux, other state variable observations such as heat, hydrochemistry and isotopic tracers, are monitored to quantify the fluxes. Multiple temperature lances are installed in the catchments, which measure riverbed temperatures at multiple depths every 15 minutes. Point-in-time riverbed temperature measurements were carried out along the river channel to capture the spatial differences of the exchange flux. Based on these temperature data, the calculated fluxes have an order of magnitude varying from 10-7 to 10-6 m/s during observation period. The flux direction, representing either losing or gaining river, changes not only within the time of year but also along the longitudinal river profile. Besides the heat, a number of other tracers have been deployed, including major ion concentrations, electrical conductivity, stable isotopes (2H and 18O), and radon (222Rn). In total, 74 GW and river water samples have been collected during seasonal field campaigns. Major ion concentrations show that both river water and shallow GW belong to the calcium-dominated water type in all catchments. Nevertheless, the dominant anions vary from catchment to catchment and display a seasonal shift, e.g. from CaHCO3 type in summer/autumn to CaMIX type in winter in the Mombeek and Dijle catchments. Stable isotopic values of the autumn campaign show a narrow range: δ2H between −49.5‰ and -42.9‰ and δ18O between –7.4‰ and -6.4‰. Nearly all samples are isotopically depleted since they fall below the global and local meteoric water lines, suggesting a meteoric origin and evaporation effect for both GW and SW. Radon surveys indicate that its activities, especially in shallow GW, show large seasonal variations (from autumn to winter) in the Dijle catchment. A couple of SW samples from all three catchments show elevated radon activities which is most likely the result of GW exfiltration into the river. A quantitative analysis of these field approaches and preliminary interpretations will be presented and discussed during the conference.

        Speaker: Ms Min Lu (KU Leuven, SCKCEN)
      • 16:00
        Numerical analysis of periodic transient contaminant-leaching episodes in the unsaturated zone 1h

        The concentration of contaminants in groundwater underneath landfills and mine tailing piles and treatment facilities increases when the water table rises sharply due recharge events or the rise of the level rising a negihboor rivers connected to the aquifer.
        Reactive contaminants may persist for long periods of time due to mineral precipitation and sorption reactions. Here, we present a numerical 2-D flow and solute transport model in a vertical plane to study the leaching of uranium from the unsaturated zone underneath a uranium tailings pile. Model results show that the uranium concentration increases linearly when the leachate flux increases and the upstream flux and the upstream flow of unpolluted groundwater decreases. The concentration of uranium increases in response to the rise of the water table. The peak of uranium concentration takes place about 40 days after the maximum water level in a point located 30 m downstream the uranium source.

        Speaker: Javier Samper (Universidad de A Coruña)
      • 16:00
        Permanently operating mathematical model of a group of groundwater well-fields in Kazakhstan as the basis for groundwater's monitoring and management 1h

        Seven deposits of groundwater, which are located in the slope side of the Caspian depression in the Lower Cretaceous Albian aquifer complex, were investigated and put into operation to provide drinking and industrial water supply for oil and gas production facilities. The well-fields are located within the plateau, which was dissected by valleys of rivers and streams. The aquifer complex is composed of different-grain sands with interlayers of clay with a total thickness of about 200 m. It is confined or unconfined on different areas. Its groundwaters are interconnected with river waters in some places. The groundwaters of the aquifer complex are fresh or brackish with mineralization of 0.2 ÷ 3.2 g/l. The estimated volume of the exploitable groundwater resources of seven well-fields reaches 1.03 m3/s.

        Groundwater intakes are operating under conditions of their mutual influence. In addition, the abstraction of the brackish groundwater for production and technical purposes can attract the fresh groundwaters to these industrial water intakes. But the use of fresh drinking water for production and technical water supply is prohibited by the legislation of Kazakhstan.

        Thus, a rational exploitation of these groundwater well-fields, taking into account environmental limitations, is an actual problem.

        An observational network of groundwater monitoring has been created in all groundwater well-fields. To assess and predict the state of the well-fields and the aquifer complex as a whole, in 2014, in the ModFLOW Flax software, a permanently operating mathematical model (POM) of seven groundwater fields was built and put into operation. POM is operated to ensure promptly reliable assessment and predictive information on changes in the hydrogeodynamic and hydrogeochemical state of water intakes and of the Albian aquifer complex as a whole.

        The result of solving the geofiltration and geomigration tasks on the POM allow anticipating the development of undesirable hydrogeodynamic and hydrochemical processes, to develop recommendations for optimizing the monitoring network and the regime of groundwater well-field's abstraction to eliminate the risks of special hydrochemical situations for the industrial groundwater supply on the oil and gas production facilities. This can significantly reduce the risks of inadvertent use of fresh groundwater for production and technical purposes and provide the sustainable development of the oil production sector.

        Speaker: Dr Oleg Podolny (Hydrogeoecological research and design company "KazHYDEC" Ltd. )
      • 16:00
        Radionuclide content of groundwater in hydrogeological approach - Case study in the adjacent area of a granitic complex 1h

        Groundwater is a very common drinking water source. In Hungary, 88% of the water supply is sourced from groundwater. Radioactivity of groundwater, as a possible threat and its hydrogeological background, had not been widely investigated until recently. Following the Euratom Drinking Water Directive the radioactivity of drinking water is screened in Hungary in the last three years by gross alpha and gross beta activity measurements. Whenever the measured concentrations surpass the limit values the long-term consumption of the water can lead to health issues.
        Based on data provided by the National Public Health Institute high values of gross alpha activity can be found in the southern foreland of Lake Velence. Previous studies already showed high uranium concentration values (compared to average crust values) related to the Velence Granite Formation in Velence Hills and to the carbonatic and organic-rich beds of the Ujfalu Formation in the southern foreland of Lake Velence. Until recently no observations and measurements were made regarding the radioactivity of the groundwater. Therefore, uranium, radium and radon concentration measurements were carried out in the adjacent area and interpreted in flow system context. A total of 53 samples were taken from surface water (springs and lakes) as well as from groundwater. Alpha spectrometry applied on Nucfilm discs was used to measure the uranium (234U+238U) and radium (226Ra) activity while radon (222Rn) activity was determined by TriCarb 1000 TR liquid scintillation detection. Pressure-elevation profiles, hydraulic cross sections, tomographic potential maps and potential difference maps were compiled to understand the groundwater flow directions and regime characteristics in the wider area. The areal distribution of the activity concentration values was interpreted regarding the groundwater flow system, physicochemical parameters measured onsite and in the laboratory. Those areas can be delineated where according to the flow conditions and the related geochemical environment the mobility of the uranium or radium and thus elevated activity concentration can be expected in groundwater. This novel approach may facilitate safe water management of drinking water supply systems.

        This study was supported by the ÚNKP-17-4 and ÚNKP-18-3 New National Excellence Program of the Ministry of Human Capacities. This topic is part of a project that has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 810980.

        Speaker: Ms Petra Baják (Eötvös Loránd University, Department of Geology, József and Erzsébet Tóth Endowed Hydrogeology Chair )
      • 16:00
        Rare Earth Elements in thermal and mineral waters from Mesozoic aquifers of the Polish Lowlands 1h

        Chemical composition including rare earth elements (REEs) was determined in thermal and mineral water samples collected from 33 spa and geothermal wells located in the Polish Lowlands (northern and central Poland). REE examinations have not been performed for this kind of thermal and medicinal mineral waters in Poland so far.
        Observation covered the Mesozoic aquifers, built mainly of Jurassic and less often Triassic or Cretaceous sandstone series, which occur at the depth ranging from 20 to 2,500 m below land surface.
        Selected elements in filtered (0,45 µm) and acidified (HNO3) water samples were determined by inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS) methods with the use of Sea-Fast preconcentration tool.
        The examined waters, characterized by TDS value ranging from several to 114 g/L, represent mainly Na-Cl type and much less common HCO3 or SO4 types. The Cl ion concentration changes from 16,5 mg/l to 71,100 mg/l. The highest water temperature value 89 oC was measured at the well head in the Stargard geothermal plant, NW Poland.
        Total rare earth elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) concentration in groundwater samples changes from 0,06 to 59,9 ng/L, with the average being value 13,3 ng/L. Yttrium content ranges from 0,84 to 54,5 ng/L with the average being value 14,9 ng/L. In most of the water samples the ∑REE value is lower than 10 ng/L. Within the presented data population, ∑REE concentration as well as concentrations of individual REEs values display no clear correlation with basic physical and chemical parameters of the examined waters, such as pH, TDS, temperature and depth of occurrence.
        The obtained REE results normalized to European Shale allowed for describing 6 general types of REE fractionation patterns, expressing relation between 3 groups of the REEs: light (LREE: La-Nd), middle (MREE: Sm-Dy) and heavy (HREE: Ho-Lu). The following REE patterns were distinguished: 1)LREE < MREE < HREE -described for waters from most of the examined wells; 2)LREE < MREE > HREE -frequent; 3)LREE = MREE < HREE, 4)LREE > MREE > HREE; 5)LREE < MREE = HREE; 6)LREE = MREE > HREE. REE patterns of 3-6 types are less frequent.
        When we apply the division into two groups: (HREE: La-Eu) and LREE (Gd-Lu), we can notice a distinct quantitative advantage of HREE over LREE in the examined water samples. This is usually explained by the fact that LREE display a stronger tendency than HREE to be absorbed by sediment particles. The development of this process is favored by a long residence time typical of waters in deep seated aquifers.

        Acknowledgements: This work was supported by the National Science Centre, Poland, under Project no.UMO-2015/17/B/ST10/03295

        Speaker: Dr Dorota Kaczor-Kurzawa (Polish Geological Institute - National Research Institute)
      • 16:00
        The use of inflation in ensemble Kalman filter for the joint identification of contaminant source parameters and hydraulic conductivities in a sandbox experiment 1h

        Identifying contaminant source information from limited concentration measurements downstream from the source is a crucial step in groundwater pollution investigation for accountability and remediation purposes. However, in reality, the partially known but influential hydraulic conductivity field is always a significant obstacle in this inverse problem. In this work, we apply the restart normal-score Ensemble Kalman filter (NS-EnKF) method to identify the contaminant source and a non-Gaussian conductivity field jointly in a sandbox experiment by only using concentration measurements at a few observation points. As a preliminary step, we verify the restart NS-EnKF in a synthetic case mimicking the sandbox experiment. Some simple tries demonstrate that with a small ensemble size, measurement affected by observation errors and a complex sandbox conductivity lead to filter inbreeding. Consequently, a larger ensemble size, and several inflation methods are analyzed to solve this problem. We found that using a large ensemble size or Bauser's inflation method avoids filter inbreeding. These conclusions are used to analyse the sandbox results to identify the contaminant source and the conductivities using the restart NS-EnKF. The results show that the restart Ns-EnKF with a proper ensemble size or a suitable inflation method is capable to identify the contaminant source and the non-Gaussian conductivities in the sandbox experiment.

        Speaker: Jaime Gomez-Hernandez (UPV)
      • 16:00
        Thermal springs as „outcrops” of geofluid systems and provenance of biogeochemical accumulations and environmental impacts 1h

        Buda Thermal Karst is an exceptional natural laboratory to study the interaction of geofluid systems influenced by different driving forces such as water table differences and heat convection; and by fluids from meteoric infiltration and saline water of geological formations. Due to the elevated heat flux of the area (up to 100 mW/m2), the temperature of the fluids is influenced by advection and heat convection (Havril et al. 2016; Szijártó et al. 2019). The evolution of geofluid systems is ongoing since the late Miocene, consequently fluid systems have an outstanding effect on mobilization and accumulation of matter and heat. Thermal springs arise at the boundary of confined and unconfined part of the BTK can be handled as “outcrops” of interacting geofluid systems (Mádl-Szőnyi and Tóth 2015), since they reveal the complex physical and geochemical processes of the system. At the same time, they accumulate the mobilized and transported matter at the surface in the form of carbonate and biogeochemical precipitates (Dobosy et al. 2016; Kovács-Bodor et al. 2018; Kovács-Bodor et al. 2019). The long term scientific researches of the area revealed the necessity of the approach, to handle fluids of thermal springs and their precipitates, and discharging water and its heat content; radioactivity and trace elements of precipitates and CO2 and 222Rn exhalation from thermal water, in a comprehensive way. This result is part of a project that has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 810980”.
        References:
        Dobosy, Z Sávoly, M Óvári, J Mádl-Szőnyi, G Záray (2016): Microchemical characterization of biogeochemical samples collected from the Buda Thermal Karst System, Hungary. Microchemical Journal 124, 116-120.
        Havril, T., Molson, J.W. and Mádl-Szőnyi, J., (2016): Evolution of fluid flow and heat distribution over geological time scales at the margin of unconfined and confined carbonate sequences - A numerical investigation based on the Buda Thermal Karst analogue. Marine and Petroleum Geology, 78, pp. 738-749.
        Kovács-Bodor P, Anda D, Jurecska L, Óvári M, Horváth Á, Makk J, Post V, (2018): Integration of In Situ Experiments and Numerical Simulations to Reveal the Physicochemical Circumstances of Organic and Inorganic Precipitation at a Thermal Spring. Aquatic geochemistry 24 (3), 231-255
        Kovács-Bodor P, Csondor K, Erőss A, Szieberth D, Freiler-Nagy Á, (2019): Natural radioactivity of thermal springs and related precipitates in Gellért Hill area, Buda Thermal Karst, Hungary. Journal of Environmental Radioactivity 201, 32-42.
        Mádl-Szőnyi J and Tóth Á (2015): Basin-scale conceptual groundwater flow model for an unconfined and confined thick carbonate region. Hydrogeology Journal 23 (7), 1359-1380
        Szijártó, M., Galsa, A., Tóth, Á. and Mádl-Szőnyi, J. (2019): Numerical investigation of the combined effect of forced and free thermal convection in synthetic groundwater basins.

        Speaker: Judit Mádl-Szőnyi (Associate Professor)
    • 17:00 18:30
      Parallel: Monday Afternoon 10: Topic 2 Multiuses room 2 ()

      Multiuses room 2

      • 17:00
        Climate Change and Groundwater in Low Islands, a surprising resilience 15m

        The impact of climate change, and particularly rising sea levels on shallow fresh groundwater lenses, is widely regarded as a major challenge to the sustainability of ow-lying island countries. Recent research, however, has shown that over 88% of atoll islands in the Pacific and Indian Ocean are counter-intuitively either stable or increasing in land area. During major ENSO events, sea level changes of up to 0.4m above and below normal levels have been observed. Whether atoll reef systems will continue to cope with increasing temperatures and ocean acidification is a critical question. Climate model projections of changes in drought severity and frequency are of generally low confidence because, ENSO events, key drivers of drought in the Pacific, are not well described by climate models. This work reviews both climate change projections and observed impacts on groundwater hydrology in atoll countries in the Pacific. Changes in evaporation requires further work. Greatest vulnerability is to changes in recharge rates, groundwater extraction and island overtopping. Increasing population densities, growing water demands, inadequate sanitation and poor water and sanitation governance are more immediate threats. The best adaptation strategy appears to be overcoming the current challenges by building on the recognised strengths and resilience of island communities, strengthening institutional structures and human resources while maintaining and enhancing the integrity of island ecosystems, as Barnett has concluded, and investing in education and training at all levels.

        Speaker: Ian White (Australian National University)
      • 17:15
        Present and future potential groundwater recharge from precipitations over France 15m

        Quantifying the future renewable groundwater resource is a key point for water managers in the context of climate change. A method to estimate potential groundwater recharge from precipitation has been developed and applied over France for that purpose.

        A gridded water budget model was developed to compute the effective rainfall with a spatial resolution of 8x8 km, at a daily time step. Three different water budget methods were included to assess uncertainties associated to the model design. We then elaborated a method to split the effective rainfall between runoff and infiltration, relying on a GIS built parameter called IDPR. This distributed parameter relates to the drainage density and hydrological network. We calculated the river baseflow index (BFI) using the Wallingford method over more than 350 French monitored river basins. Assuming that BFI represents the groundwater contribution to surface flow in a river basin, it can be used to estimate the mean infiltration coefficient over the considered basin. A relationship between the calculated BFI and IDPR spatial average calculated over the 350 river basins was established. It thus allowed estimating a spatially distributed infiltration ratio. The potential annual recharge was defined as the product of this ratio with the effective rainfall previously calculated. Hence, present and future recharge maps for France were generated to assess the impact of different climate change scenarios.

        Speaker: Yvan Caballero (BRGM, Univ. Montpellier)
      • 17:30
        DEEP AQUIFERS IN SPAIN: A NECESSARY RESEARCH TO ADAPT TO CLIMATE CHANGE 15m

        The future scenario of global climate change brings a major challenge for the groundwater resources sustainability. The evolution of groundwater in the coming years forecasts a progressive decline of the water table and a decrease in the streamflow, which implies a reduction of the water reservoir storage. This will have negative consequences not only on the associated natural ecosystems, but also on the resources focusing on water supply, among others.

        Underground hydrological resources considered in river basin management plans include those belonging to aquifers that have a link with natural ecosystems, and those associated with aquifers that support the main supplies. The resources under the usual withdrawal depths are not taken into account because they are considered as non-renewable resources, in addition to the pumping cost or its assumed high salinity. In the case of surface aquifers with several hundred meters thickness, the use of groundwater resources is usually limited to the upper part of the saturated zone for the same reasons.

        Therefore, under of this non stablished depth –variable according to the hydrogeological structure and the climatic and economic local factors– there exists an amount of unexploited groundwater resources, mostly unknown or not yet evaluated. Investigation of deep aquifers is extremely complex and has a high economic cost. Aspects like deep aquifer geometry, hydrogeological and hydrochemical characterization and resources estimation, need complex and specific techniques different from those used in the study of shallow aquifers.

        There is a growing interest in the knowledge of deep aquifers because of the climate change context. In the present study, deep aquifers have been considered as deep groundwater reservoirs, regardless the quality or the hydraulic aquifer properties. The main goal is to define some aquifers –or geologic formations– like strategic reservoirs for human use. An adequate characterization of a deep aquifer could be integrated in the groundwater resources management and help to reduce the scarcity in extreme situations.

        The Geological Survey of Spain –IGME– has performed the work of improving the knowledge and characterization of deep aquifers in this project. As a starting point, an inventory of deep aquifers has been carried out in the main river basins of Spain –Iberian Peninsula area– under specific selected criteria. The main characteristics have allowed a classification of Spanish deep aquifers. Some examples, representative from different typologies, have been selected for a detailed study as a “deep aquifer” with a proper methodology.

        Speaker: Mr Jesús del Pozo (Geological Survey of Spain IGME)
      • 17:45
        Climate change impact on groundwater recharge in Slovenia in the period 2011-2100 15m

        Slovenia is a water rich country. More than 90% of its drinking water supply is covered from groundwater resources. Due to the geographical positon of Slovenia on the junction of the Alps, Mediterranean, Dinaric Alps and Pannonian Basin, big inter- and intra- annual variations occur in both, time and space. For the determination of country-wide actual groundwater recharge quantities in high spatial resolution (100m grids), the water balance model mGROWA (Herrmann et al., 2014) has been implemented in Slovenia in 2017.
        mGROWA is a deterministic water balance model, calculating runoff generation and runoff components including net groundwater recharge in daily time steps. . On one hand mGROWA model results are used for water resources management issues. For this purpose runoff quantities determined in daily time-steps are aggregated to mean long-term averages, e.g. mean long-term groundwater recharge levels for hydrological periods or decades.
        For assessing the impact of climate change on Slovenian groundwater resources the high temporal resolution of mGROWA is used in order to represent inner-annual shifts of groundwater recharge appropriately. Projections of groundwater recharge under climatic change conditions were analysed by running the mGROWA model with EUROCORDEX scenario data as climate input. For this purpose three scenarios were used: RCP2.6, RCP4.5 and RCP8.5. For each climatic scenario the combinations of regional and global climate models for Slovenia were selected based on the best fit of the climate scenario results to observed climate data in the past. For the RCP2.6 scenario two regional model combinations were used and for the RCP4.5 and RCP8.5 scenarios six regional model combinations. Arried out for the
        Model calculations have been carried out for the period 1980-2100 using the model period 1981-2010 set as the reference period. For assessing the the climate change impact, the periods 2011-2040, 2041-2070 and 2071-2100 have been selected. For these periods (and the 3 scenarios) geographical and geostatistical analysis were carried out, e.g. with regard to the absolute change and relative deviation of groundwater recharge for minimum, maximum and median. All that was analysed on annual and seasonal (spring, summer, autumn, winter) timescale along with a confidence analysis. The results indicate impacts of climate change on groundwater resources with distinctive periodical and regional patterns that will be presented at the IAH conference.

        Speaker: Dr Peter Frantar
      • 18:00
        Evidence for changes in groundwater drought in temperate environments associated with climate change 15m

        There is currently a significant gap in our understanding of the effect of anthropogenic warming on groundwater drought. This is due to a number of factors including the limited availability of long groundwater level time series suitable for analysis, the low signal-to-noise ratios characteristic of many hydrological systems, and the infrequent nature of episodes of groundwater drought in temperate systems. Formal attribution of groundwater droughts due to anthropogenic warming is also challenging because of the potentially confounding influences of land use change and groundwater abstraction on groundwater drought. In the present study, we have not attempted to formally attribute groundwater droughts to climate change. Instead, we investigate how known centennial-scale anthropogenic warming may be modifying the nature of groundwater droughts when other factors are discounted, and address the following question: how has the occurrence, duration, magnitude and intensity of groundwater drought, as expressed by changes in monthly Standardised Groundwater level Index (SGI) and in episodes of groundwater drought changed since 1891 under anthropogenic warming?
        Standardised indices of monthly groundwater levels (SGI), precipitation (SPI) and temperature (STI) are analysed, using two long, continuous monthly groundwater level data sets from the UK, for the period 1891 to 2015. Precipitation deficits are the main control on groundwater drought formation and propagation. However, long-term changes in groundwater drought include increases in the frequency and intensity of individual groundwater drought months, and increases in the frequency, magnitude and intensity of episodes of groundwater drought, are shown to be associated with anthropogenic warming over the study period. These is a transition from coincidence of episodes of groundwater and precipitation droughts at the end of the 19th century, to an increasing coincidence groundwater droughts with both precipitation droughts and with hot periods in the early 21st century. In the absence of long-term changes in precipitation deficits, it is inferred that the changing nature of groundwater droughts is due to changes in evapotranspiration (ET) associated with anthropogenic warming. Given the extent of shallow groundwater globally, anthropogenic warming may widely effect changes to groundwater drought characteristics in temperate environments.

        Speaker: Dr John Bloomfield (British Geological Survey)
      • 18:15
        Impact of sea level rise and Sustainable groundwater management in in Kalpitiya Peninsula, Sri Lanka 15m

        Sri Lanka is an island which is vulnerable to sea level rise. Therefore, sea level rise and its impact directly face to coastal region and their population. It is evident that most of the future settlements will be located along the Coastal Belt of Sri Lanka while the global warming tempted Sea Level rise in the Indian Ocean could have a number of physical impacts on the country as an island. One of the major consequences is the depletion of coastal ground water resources due to salt water intrusion leading to potential shocking impacts on Coastal Population. In the contemporary context, ground water has become a diminishing resource in the dry zone coastal areas of the island due to the vast utilization and over exploitation. The study was conducted to identify the sea level rise and its impacts on coastal water in Kalpitiya Peninsula, west coast of the Sri Lanka, using geographical Information System and Remote Sensing. Both natural and human factors apply to sea level rise and its impact evaluation, which includes sea level, tide, land use, ground water and several physical and human factors were analyzed by spatial analysis methods in ArcGIS 10.1 and suitable statistical analysis methods on several statistical software. The significance of ground water usage in the context of demographic and economic conditions of the case study area was reviewed using secondary data. The results of the analysis indicate that, the Dry Zone Coastal Ground Water table facing de-facto deprivation under the threat of Sea Level Rise. Accordingly the sustainability of dry zone coastal settlements is in a critical need of due attention since the growing population of the area do not possess the capacity to sustain without the water they need for the daily life.

        Speaker: Prof. Ranjana Ranjana Piyadasa (University of Colombo)
    • 17:00 18:30
      Parallel: Monday Afternoon 11: Topic 3.1 Multiuses room 1 ()

      Multiuses room 1

      • 17:00
        Governance and Management of high arsenic Ground water based Drinking water supply in India 15m

        Governance and Management of high arsenic Ground water based Drinking water supply in India

        Dr. S.P. Sinha Ray
        (Retd.) Member, Central Ground Water Board
        Emeritus President, Centre for Ground Water Studies, Kolkata
        Member, International Association of Hydrogeologists

        Abstract
        The high concentration of arsenic in ground water of the alluvial plains of Ganga Basin comprising the states of Uttar Pradesh, Bihar, Jharkhand and west Bengal as also in neighboring country, Bangladesh has emerged as a major drinking water issue, since ground water provides the main sources of drinking water in these areas. Significant researches are being carried out to understand the areal extent of contamination, causes of arsenic mobilization in ground water, impact of human health hazards, remedial interventions etc. The impact of excess arsenic in ground water (more than 10 ppb) has caused considerable concerns, both for drinking water and food chain. It has, therefore, become imperative to evolve a policy framework to address such arsenic menace so that sustainable remedial measures can be developed and to provide relief by supplying safe water to the suffering millions. High arsenic in ground water has been detected in the state of West Bengal in India restricted mainly in the lower gangetic valley since 1983. The maximum number of arsenic affected population due to ingestion of contaminated groundwater has been reported from the state. A concerted and well conceived plan to mitigate the arsenic menace is being practiced here by the Government of West Bengal who is primarily responsible for safe drinking water supply in the rural areas. Arsenic Task Force for the state of West Bengal has been set up in the year 1994 whose task is to plan and overview the progress and monitoring of the mitigation measures being under taken. Apart from short term mitigation measures, long term solutions to provide sustainable drinking water supply to the arsenic affected areas have been executed which have been discussed in the paper. In addition to utilization of treated surface water sources a number of treatment techniques of contaminated ground water are in use for dearsenification of water. Awareness generation and behavior change communication are proving to be quite useful. People’s participation in execution and maintenance of the community drinking water supply projects are being encouraged. Other Arsenic affected states in India are also taking suitable measures based on their research findings and successful implementation of projects in west Bengal. Government of India is also taking keen interest in coordinating the efforts among the various arsenic affected states.

        Keywords: Arsenic Mitigation, Technological options, Sustainable mitigation measures, Behavior Change.

        Speaker: Dr Syamaprasad Sinha Ray (Emeritus President, Centre for Groundwater Studies)
      • 17:15
        MAPPING OF SUITABLE ZONES FOR MANUAL DRILLING IN RDC AND SETTING UP A NATIONAL GROUNDWATER DATABASE 15m

        Introduction
        Despite continued efforts, in the Democratic Republic of Congo (DRC) only 52% of its population having access to a water point in 2015, and even less in rural areas.
        To find low-cost solutions, UNICEF has implemented in 2012 a programme in order to professionalize the manual drilling sector. But an effective strategy for development of manual drilling requires the identification of areas with favourable hydrogeological conditions.

        Methodology
        The methodology used in this work derives from UNICEF experience in 16 other African countries and a research project in Guinea Conakry and Senegal managed by the University Milano Bicocca . It is based on the integration of existing data, together with field experiences of local technicians.

        The aptitude to manual drilling derives from the combination of:

        1. The feasibility : possibility of drilling using manual techniques
          and of reaching an aquifer. It has been estimated from the depth of
          rock and the depth of water
        2. The potential for exploitation : semi-quantitative assessment of potential yield estimated indirectly from the thickness of coarse layers in the exploitable aquifer
        3. The presence of partially hard layers that increase time and cost for
          drilling

        The procedure for the estimation of the aptitude for manual drilling at national level has been carried out through these steps: 1) collection of available data and stratigraphic logs; 2) organization and standardization of data in a specifically designed database; 3) estimation of hardness and permeability for regular intervals of 1 m, using a semiautomatic method; 4) extraction of a set of hydrogeological parameters; 5) estimation of the class of feasibility, potential and difficulty of perforation for each drill; 6) extrapolation of feasibility and potential to the whole country on the basis of geological map and morphology; 7) comparison with the direct expertise of drillers and water technicians.

        Results
        The majority of the territory is located in areas favourable to manual drilling (42% classified with high or very high aptitude, 24% moderate), especially in the western part of the country, covered by thick loose layers. On the other hand, in the east of the country there is a strong presence of cristalline rocks that form favourable discontinuous alteration layers.
        One of the main contributions of this project is the creation of a database at a national level in which the information used and generated is collected and organized.

        Conclusions
        Manual drilling currently exists in several areas of the country, but is also non-existent in some provinces despite their favourable or moderately favourable conditions for manual drilling. The dissemination of this technique can improve the access to water.

        Indeed, the database is designed as a dynamic tool that, regularly updated, is an important support for groundwater resource management.

        Speaker: Dr Fabio Fussi (University of Milano Bicocca)
      • 17:30
        Governance Status in Water Management Institutions in Barind Tract, Northwest Bangladesh - An Assessment based on Stakeholder’s Perception 15m

        Water situation in the drought-prone Barind Tract in the north-western part of Bangladesh is deteriorating day by day due to increasing demand of food production, urbanisation and industrialisation. Here balance situation between food and water security is a serious challenge to the policy makers. This study is undertaken in the southern part of the Tract to assess the existing status of water governance and to identify challenges of sustainable development. Both quantitative and qualitative methods were used to assess governance status in five water management institutes (WMIs) like Barind Multipurpose Development Authority (BMDA); Bangladesh Water Development Board (BWDB); Department of Public Health and Engineering (DPHE); Local Government and Engineering Department (LGED); and DASCOH Foundation - a non-government organization) selected purposively based on their activities in the area. Eight indicators like institutions, transparency, accountability, participation, social equity, environmental integrity, efficiency and effectiveness are taken into consideration and each indicator includes five sub-indicators. The overall governance situation of WMIs fall under ‘moderate’ category while DASCOH Foundation performs ‘good’, BMDA and LGED ‘moderate’, while BWDB and DPHE perform ‘bad’. Moreover BWDB and DPHE should look into the governance issue seriously and take a rigorous action plan for scaling up of governance status. On the other hand, BMDA and LGED apparently perform satisfactorily in governance issues but lag far behind in indicators like transparency, accountability, participation and social equity. In strategic plan, the DASCOH Foundation is trying to introduce noble concepts to institutionalise the Integrated Water Resource Management (IWRM) under BWA (2013) and disseminating models not only to the community and local government but also to the government sector. Moreover, there are significant gaps in coordination, technical capacity, transparency in project selection, implementation and citizen’s participation in WMIs. Finally actions to meet challenges such as implementation of IWRM in managing water resource; role rationalisation of water institutions and actors; updating and harmonising water laws to cope with existing challenges; enforcement and compliance of laws; establishing independent regulatory body and Water Resource Management Organization (WRMO) etc. will help managing water resources in sustainable manner.

        Speaker: Dr Chowdhury Sarwar Jahan (Professor )
      • 17:45
        The use of mixing cell modelling to determine transboundary groundwater flow between Malawi and Mozambique: 15m

        Groundwater has often been described as an invisible resource, yet it is important to recognise that almost 98% of the world’s available freshwater resources are in the form of groundwater. Integrated water resources management (IWMI) acknowledges the important role of groundwater within frameworks that can sometimes be unduly surface water focused. The importance of IWRM is recognised in Sustainable Development Goal 6 ‘to ensure availability and sustainable management of water and sanitation for all’ (United Nations, 2017). Groundwater development is central to meeting this goal. A pressing need though IWRM is to recognise that many aquifers identified for resource use may cross national borders (i.e. through transboundary aquifers). It is then critical that transboundary cooperation comes into play to allow sustainable groundwater of use of these aquifers by those involved.

        The current challenge faced by many countries is to accurately define the movement of groundwater through transboundary aquifers and translate this knowledge into management policies (Fraser et al, 2018). Mixing cell modelling can be used to determine groundwater flow through an aquifer system. Based on mass balance between cells, mixing cell modelling is a concept that is easy to understand and communicate. Until now, mixing cell models have not been applied to a transboundary aquifer context however it is believed that they could bridge the gap between science and policy as they can translate hydrogeological science in an accessible format to inform policy.

        Malawi is a low-income developing country bordered by Mozambique, Tanzania and Zambia where transboundary aquifer knowledge is limited. The Shire River Basin is shared between Malawi and Mozambique. The Shire River within this Basin is transboundary however to date there is no scientific data to support the conceptual assumption that groundwater also flows across the international border shared between the two countries. This limits management of the resource and thus sustainable use of the aquifers within the Basin.

        A transboundary aquifer within the Shire River Basin has been analysed using geochemical and stable isotope data through a mixing cell model. Results indicate that there is indeed transboundary groundwater flow from Malawi to Mozambique and that groundwater interact directly with surface water within the region. Verification of transboundary groundwater flow across the international border will now allow both counties to move forward to cooperatively manage the aquifer and ensure its sustainable development.

        Speaker: Ms Christina Fraser (University of Strathclyde)
      • 18:00
        The upper aquifer in Lake Chad basin: a tremendous opportunity to supply good quality water to people and cattle in an extremely arid region 15m

        Lake Chad is located in the center of an extremely large sedimentary basin (2 million km2), which is filled with neogenous sandy-clay sediments and contains several huge aquifers of regional importance. This study covers the northern part of this basin, an area of 200,000 km2 located in Chad.
        Although this is a very arid area (50 to 400mm of rainfall a year), it is inhabited by different population groups (2,500,000 inhabitants), whose main source of income is predominantly pastoral livestock farming (the livestock population includes more than 30 million ruminants).
        The only surface water resource is Lake Chad and most of the population therefore depends on groundwater for both drinking water and water for their livestock.
        Rapid population growth (2%/year) and the rise in sedentary lifestyles are increasing the demand for drinking water. In addition, growing insecurity in the Lake Chad area (Boko Haram) has led part of the Lake Province population to migrate further to the North, where there is no surface water resource.
        The plio-quaternary aquifer offers a tremendous opportunity for meeting the growing water demand, as it is shallow, extensive and highly productive (the drilling success rate exceeds 95%). The relatively easy access to this resource makes it vulnerable to overexploitation in adverse conditions: climate change models anticipate a decrease in precipitation and, therefore, in groundwater recharge.
        To assess this risk and map this resource, we have used the results of the 1,000 boreholes drilled over the past ten years. We have built hydrogeological maps (piezometry, aquifer productivity, drilling success rates and water quality), and produced economic maps (production costs, operating costs) as these constitute important decision-making criteria in poor regions such as this.
        On a regional scale, groundwater flows from south to north, where the aquifer is exhausted when it reaches the wide Bodole depression. The piezometric surface is marked by a series of domes and depressions whose origin, based on their chemical tracers, is discussed in this paper.
        For the time being, aquifer recharge by rainfall far exceeds the abstraction rate. However, an increase in aridity and the progressive concentration of people in urban centers, which leads to local aquifer depletion and groundwater pollution, could upset this balance.
        The chemical quality of the groundwater varies greatly from one area to another. The south-north salinity gradient has long been recognized and is connected to aridity. Consolidation of the drilling data highlights two other areas with excessive salinity: the western part of Lake Province and the eastern part of Hadjer Lamis Province.

        Speaker: Mr Clément Masse (Université d’Avignon – Département Hydro-Géologie )
      • 18:15
        Meeting the challenges of sustainable groundwater development and management in emergency response: a joint initiative by Groundwater Relief and Médecins Sans Frontières Holland (MSF-OCA) to build understanding about the Tipam Sandstone Aquifer whilst meeting immediate needs of refugees in the Mega camp of Cox’s Bazaar, Bangladesh 15m

        The Cox’s Bazaar District in Bangladesh is hosting a massive rapid, influx of over 700,000 Rohingya Refugees from Myanmar, placing huge strain on local resources including water resources. The largest camp, known as the Mega Camp, is spread across a 13km2 block of land between Kutupalong and Balukhali. Water supply for this camp is sourced from the underlying Tipam Sandstone Aquifer. The aquifer comprises over 400m of loosely compacted and structurally deformed Miocene aged sandstone. To date, the Tipam Sandstone Formation has received little study but is being pumped at an unprecedented rate. A sustainable water supply for all residents of the Mega Camp and surrounding areas depends on a sound conceptual understanding and carefully managed development of the underlying groundwater resource. With this aim in mind, Groundwater Relief in collaboration with Médecins Sans Frontières Holland, have been engaged in collecting groundwater data since January 2018 across a 7km2 area. New boreholes drilled have been logged and pumping tests carried out. A monitoring programme was established including the installation of 10 water level data loggers across a network of monitoring and abstraction boreholes; the set up of three rain gauges; and a monthly water quality monitoring programme across 12 boreholes measuring basic field parameters. Hydrographs comparing rainfall with groundwater levels relative to sea level showed groundwater levels quickly increased on the onset of the rainy season with a 1.5m increase over one month in July 2018. Groundwater levels increased almost simultaneously to peak rainfall events, suggesting rapid infiltration and recharge. Elevated ferrous iron concentrations were encountered in the top 120m of the aquifer with lower concentrations found at greater depths. Electrical Conductivity values in the groundwater are significantly below the Bangladesh Standard of 1500 μS/cm at present.
        Over the course of 2019 Groundwater Relief is working with Dhaka University and the International Organisation for Migration to expand the monitoring programme across the entire Tipam Sandstone Outcrop in Cox’s Bazaar. As part of this programme a groundwater model and management tools will be developed to support the Bangladesh Authorities with the planning of new water supplies for the camp and the host population.

        Speaker: Mr Geraint Burrows (Groundwater Relief)
    • 17:00 18:30
      Parallel: Monday Afternoon 12: Topic 5 Auditorium 2 ()

      Auditorium 2

      • 17:00
        Numerical modelling to assess head losses and flow characteristics through water well screens 15m

        In this communication we develop a methodology to simulate head loss and flow characteristics through water well screens, comparing different screen types and well construction parameters (e.g. well diameter, pumping rate, screen slot aperture, screen open area, hydraulic conductivity of the filter/gravel pack, etc.). We use COMSOL Multiphysics to perform coupled simulations of turbulent fluid flow (across the screen slots and within the well) and Darcy flow (in the porous media such as the filter/gravel pack and adjacent aquifer). Solving Randomly Average Navier-Stokes (RANS) equations for turbulent flow requires implementing the theory of Computational Fluid Dynamics (CFD) for an appropriate turbulence model.
        Our objective is to set up a methodology to understand how the different elements of a pumping well interact and determine the overall head loss, among other flow characteristics, observed in real pumping wells. At this stage of development, we focus on the hydrodynamic processes taking place at the scale of the screen slot (sub-mm). We formally define the screen head loss as the difference between average hydraulic head of inner- and outer- screen surfaces. We compare the behavior of 4 different screen types available in the market: Louver screen, Wire Wrap screen, Bridge screen and vertical slotted screen. For solving the flow efficiently, we build a cylindrical sector from the well bore to the rock formation that includes a defined “unit cell” for each screen type having appropriate symmetry and/or periodic boundary conditions. The simulations indicate that the screen head loss depends on the screen geometry and slot opening but also depends on the hydraulic conductivity of the filter/gravel pack.
        The traditional approach to quantify well head loss consists in fitting an equation of the form BQ+CQ^2 to step drawdown tests. Commonly applied methodologies associate the “screen head loss” with the term CQ^2 through the “orifice law” (as governing equation for flow through the screen slots) while the term BQ is considered a separate entity, subject to Darcy’s law and the hydraulic parameters of the filter/gravel pack and overall aquifer. Our simulations indicate that the screen head losses are intimately related to properties of the filter/gravel pack, and the “orifice law” underestimates the screen head loss more than one order of magnitude.

        Acknowledgements: The authors thank Roscoe Moss Company for funding this R&D project and giving permission for publication.

        Speaker: Marti Bayer-Raich (Amphos21)
      • 17:15
        The mapping and characterisation of sand and gravel aquifers across Ireland; recently completed and proposed future work 15m

        The first phase of the ‘Groundwater 3D’ (GW3D) project was a government funded, multi-annual endeavour, focussed on assisting Geological Survey Ireland meet its policy goals in the areas of characterisation of and research into groundwater resources, within a number of specific themes. The investigation of the geometry of sand and gravel deposits throughout Ireland, as both a water resource and a flow pathway, was one of the priority themes identified for pursuance. The output of a previously collated national sand and gravel aquifer map, comprising 93 sand and gravel aquifer bodies, was variable, due to the inconsistent amounts of information available to delineate each aquifer body. ‘Full’ Quaternary stratigraphic mapping, showing the three-dimensional extent of these sand and gravel deposits, had not been completed for the majority of these areas across the country. Such mapping and subsequent characterisation was undertaken in phase I of GW3D to provide field evidence on the true nature of these deposits (i.e. thickness, saturated thickness, depth to bedrock, depth to water table, degree of grading and bedding, lateral extent and variability), in the third dimension. Thus, as well as mapping the extent and depth of the deposits, the investigations considered their hydraulic properties. A consistent, systematic approach was developed which led to the investigation of 420 discrete deposits of sand and gravels nationwide; of these approximately 200 aquifers were delineated or further characterised. Dissemination of the work is achieved through online publishing of the revised aquifer maps on the Geological Survey Ireland website with an accompanying bespoke report for each aquifer.
        Geological Survey Ireland is currently moving in the direction of providing three-dimensional subsurface models, focusing on applying sound geological science to meet the requirements of end users. Phase 2 of ‘GW3D’ will be a direct progression of phase 1, focussing on further investigating of the hydraulic properties of the aquifers and developing sand and gravel aquifer models. It is envisaged these models will help to undertake and facilitate the management of resources (such as wholesome drinking water supplies) and the environment (such as applied data provision for integrated catchment management). At the commencement of phase 2 a systematic approach to the investigations has recently been developed, using geographically-distributed case studies. The detailed hydrogeological investigation of the Robertstown Sand and Gravel Aquifer in Co. Kildare is one such case study. This project will use groundwater modelling software (MODFLOW) in order to better understand the geometry of the aquifer, the water resources it holds, and the effect of groundwater abstraction on the stability of a nearby canal.

        Speaker: Natalie Duncan (Geological Survey Ireland)
      • 17:30
        Groundwater flooding – assessment of different engineered flood relief schemes using semi-distributed modelling of karst system 15m

        A characteristic of much of the karst in Ireland is its low-lying nature, with many springs discharging at or below sea level. The low hydraulic gradient for such karst networks also promotes a lot of groundwater-surface water interactions with many ephemeral lakes, known as turloughs, appearing over periods of high recharge (normally in the winter) in topographic depressions. These turloughs are designated as groundwater dependent terrestrial ecosystems (GWDTEs) by the Water Framework Directive and are also designated as Priority Habitats in Annex 1 of the European Habitats Directive due to their unique ecology created by the intermittent hydrological environment.
        However, extreme rainfall conditions can lead to high levels of groundwater flooding which is disruptive to the local population, flooding road and rail networks, houses and large areas of agricultural land which, unlike fluvial flooding events, normally takes much longer to recede. This paper documents the history of different studies and attempts to understand the hydrogeology and impact of groundwater flooding for an area of lowland karst in south Galway, centred on the town of Gort. This area has experienced several extreme groundwater flood events over the past 25 years (particularly in 1989/90, 1991, 1994, 2009 and 2015/6) which have created much disruption. There have been two major studies on the catchment which have aimed to design flood relief infrastructure for the area, with the latest one currently nearing conclusion.
        This paper documents all of the groundwater hydrological studies carried out over the years used to generate insights into the karst plumbing of the area, including anthropogenic and geogenic tracer studies, cave diving, borehole and turlough level monitoring, meteorology and allogenic river flows. These field data have been used to develop a series of conceptual and numerical models ending up with an extensive semi-distributed model based on a pipe network approach (including diffuse recharge) currently being used to design high level flood relief overflow channels. In addition, a new methodology by which specific groundwater flood frequency design events have been defined is detailed. Such statistical analyses of groundwater flooding requires a different approach to design storms typically used for fluvial flooding, as they are more a function of antecedent cumulative rainfall events and surface water levels than just single rainfall events. This process by which climate change forecasts have been incorporated into the target design events is also outlined.
        Finally, the process by which different flood relief options were selected to bring down extreme flood levels whilst not interfering with the more natural ecohydrological wetland function of the turloughs is described. In addition, the socio-economic tensions between the pressure from local NGOs who want the scheme built against the central government’s financial responsibility to the wider population is considered.

        Speaker: Dr Laurence Gill (Trinity College Dublin)
      • 17:45
        Depth-discrete groundwater flow quantification in poorly cemented sandstone using active distributed temperature sensing to optimize remediation strategy 15m

        Characterization of preferential flow paths is important for assessing the delivery of treatment amendments to contaminated portions of an aquifer. Field investigation methods with high spatial resolution are required to capture the flow variability in unconsolidated or discretely fractured aquifers, and to identify the nature of flow pathways (i.e. fracture vs matrix flow) relative to the contaminant distribution. The active distributed temperature sensing (A-DTS) method, originally developed for fractured rock boreholes, was adapted for application in a poorly cemented sandstone aquifer contaminated with chlorinated solvents in southern France.

        The composite fiber optic cable was attached to a PVC pipe and grouted in the borehole to avoid cross-connected flow and to recreate natural-gradient flow conditions in the aquifer representative of flow conditions over the past decades of plume transport at this aged contaminated site. The A-DTS tests consist of heating the cable for up to 24 hours with constant heat input and recording temperature along the cable continuously using a DTS unit. Active groundwater flow in preferential flow paths causes an enhancement of heat transfer from the cable creating a cooler thermal response than zones with lower or no flow. The geometry of the test was recreated in a numerical heat transport model and a relationship was developed between the thermal responses measured with the A-DTS, and the volume of water flowing through the preferential flow paths.

        The results show variable flow rates along the borehole indicating the presence of preferential flow zones. A fluorescein tracer injection experiment followed by detailed core logging and sampling, with visual inspection of fluorescein tracer distributions under UV light to guide high frequency, depth-discrete rock core sampling, provided additional evidence for the presence and distribution of preferential flow paths, also indicating flow anisotropy and tracer transport retardation. The results from these two methods, combined with detailed profiles of contaminant concentration distribution from rock core and groundwater sampling, inform and optimize the design for in-situ remediation.

        Speaker: Dr Carlos Maldaner (G360 Institute for Groundwater Research, College of Engineering & Physical Sciences, University of Guelph)
      • 18:00
        Hydrogeological conceptual model of andesitic stratovolcanoes. The Bromo-Tengger case-study (Indonesia) 15m

        Andesitic volcanic aquifers are an important source for water supply in many countries of the world, particularly in subduction zones, such as Indonesia. Their sustainable management requires a thorough understanding of their hydrogeology. Given their complexity, multidisciplinary approaches are required and were implemented on the northern flank of the Bromo-Tengger volcano, Java Island, a 2700 m high strato-volcano, 40 km in diameter, comprising geological, hydrometeorological, hydrodynamical, hydrochemical, temperature and isotopic measurements.
        Two main hydrogeological units are unveiled:
        (I) An upstream volcanic unit mostly composed of a more than 1500 m thick lava flows series, Quaternary in age, topped by more recent pyroclastites up to several hundred meters thick. Despite the geological complexity of these formations in the detail, it hydrogeologically appears as homogeneous and permeable at the scale of the whole northern flank of the volcano. It hosts an unconfined aquifer, similar to a “basal aquifer” described in shield volcanoes. Some local perched aquifers (on ash layers and cooked paleo-soils) feed a few low discharge springs (few L/s).
        Quantitative isotopic modeling, confirmed by thermal modeling to account for the “cold anomalies” observed downstream in the aquifer, demonstrates that aquifer recharge occurs on the whole Northern flank of the volcano. Recharge spatial distribution is mostly driven by the rainfall pattern, peaking around 4000 mm/y at about 1200 m amsl, and the area of the volcano’s flank that decreases with elevation.
        (II) A more than 300 m thick downstream multilayer volcano-sedimentary unit, which roof extends up to about 50 m amsl, composed of coarse to fine volcanic sands, with a transmissivity ranging between 10-2 and 10-4 m2/s, interstratified with ashfalls, lahars and tuffs. It is confined by superficial decametric thick clayey layers and bounded to the North by distal clayey deposits. No geological limits were found West and East, as this aquifer gathers with the ones of neighbor volcanoes; then, for modelling purpose its hydrogeological limits were set-up based on groundwater flow lines. This geological unit hosts a confined aquifer, artesian in most places, exclusively fed by the upstream unit. Groundwater outflows correspond to (i) high discharge artesian springs (total discharge of about 4000 l/s and 3500 L/s for the Umbulan spring alone), (ii) more than 600 artesian wells (total discharge of about 2400 L/s), and (iii) vertical leakage estimated to about 600 l/s.
        Hydrochemistry and water dating demonstrate a South-North groundwater aging, accentuated in the downstream distal part of the confined aquifer due to artesian wells development during the last few decades.This research unveiled the conceptual model of this aquifer and, more largely, of such type of andesitic volcanic and volcano-sedimentary aquifers. It also enabled its hydrogeological modeling, and the building-up of sustainable groundwater management scenarios.

        Speaker: Patrick Lachassagne (Danone Waters)
      • 18:15
        The effect of multi-step adsorption isotherms on the solute transport in porous media 15m

        Retardation due to adsorption may be an important factor in the fate and transport of contaminants in porous media. Reversible adsorption is generally described by isotherm functions giving the relationship between the concentrations in dissolved and in adsorbed phases. Several authors defined such parametric functions, the most widely used being the linear, the Freundlich and the Langmuir isotherms, which are also implemented in many solute transport simulation software. Some substances however exhibit a multi-step adsorption isotherm, mostly for organic compounds or organic adsorbents, as indicated by a few papers.

        The isotherm function defined by Czinkota et al. (2002) introduces a limit concentration above which new adsorption mechanism starts to takes place. By summing up simple nonlinear isotherms in which the limit concentrations are set, isotherms including several steps may be described. One important feature of these multi-step isotherm is that their first derivative is not a monotonic function, hence the retardation factor may have several peaks if plotted against the solute concentration.

        The effect of multi-step isotherm have been studied numerically with a modified version of the MT3DMS software. For this reason a general sorption isotherm (GSI) package have been developed which extends the functionality of the reaction (RCT) package with the ability to define arbitrary isotherms.

        Adsorption described by multi-step isotherm may develop a specific concentration distribution during advective transport. As the retardation factor may have several peaks, the position of which is determined by the limit concentrations, several solute concentration fronts may develop, forming a step-wise concentration distribution.

        The most evident parameters affecting the concentration distribution are the limit concentrations as they determine the “height” of the plateaus. Concentrations higher than the limit are characterized by sharply increased retardation which will delay their propagation. Other relations may be described depending on the type of isotherm function being used to describe the multi-step isotherm. When using Langmuir parameters, the propagation of concentration fronts seems to be determined by the adsorption capacity and the Langmuir constant.

        The concentration distribution developed by multi-step isotherm may be altered by other transport processes like dispersion/diffusion or reactions. Their effect is to be expected as usual. The diffusion may be increased by the high concentration gradient along the concentration fronts.

        The research was carried out within the GINOP-2.3.2-15-2016- 00031 “Innovative solutions for sustainable groundwater resource management” project of the Faculty of Earth Science and Engineering of the University of Miskolc in the framework of the Széchenyi 2020 Plan, funded by the European Union, co-financed by the European Structural and Investment Funds.

        Czinkota, I., Földényi, R., Lengyel, Zs., Marton, A. (2002): Adsorption of propisochlor of soils and components equation for multi-step isotherms. Chemosphere, 48, 725-731

        Speaker: ZSOMBOR FEKETE (University of Miskolc)
    • 17:00 18:30
      Parallel: Monday Afternoon 13: Topic 5.3 Multiuses room 3 ()

      Multiuses room 3

      • 17:00
        A quantitative appraisal of groundwater head time-series measurement: How well are we doing? 15m

        Accurate determination of subsurface water levels is essential for the reliable quantification of hydraulic head gradients from which groundwater flow is inferred. Head measurements also underpin the quantification of hydrogeological properties based on aquifer pumping tests or tidal propagation analysis. While measuring a water level seems an easy task, the collection of water level time-series data is by no means trivial and there is a high potential for errors and misinterpretation. In this contribution we comprehensively analyse the individual measurements required to determine hydraulic heads and gradients: (1) geo-spatial positioning, (2) manual water depth, (3) automated pressure, and (4) spatial reference point for the head. For each component we determine the systematic and random errors based on our own data sets and field experience, as well as data from the literature. We assessed the effects of instrument and clock drift, variable density inside the piezometer, borehole inclination, well aging and instrument performance. By propagating the minimum achievable random measurement errors for horizontal and vertical hydraulic gradient calculations we evaluated the accuracy with which groundwater flow processes can be quantified using current best practice. The largest errors contributing to hydraulic head and gradient uncertainty originate from borehole inclination and manual water depth measurement, respectively. Our analysis demonstrates that resolving head gradients, which are smaller than 0.01 for boreholes that are closer than 10 m, requires extraordinary effort.

        Speaker: Dr Vincent Post (Federal Institute for Geosciences and Natural Resources (BGR), Hannover, Germany)
      • 17:15
        Numerical Modelling of Groundwater Flow in Medipalli open cast mine area, Telangana, India. 15m

        Sustainable groundwater management is a worldwide challenge. Numerical modelling is one such tool which addresses this challenge. Regional-scale modelling of groundwater flow is necessary for planning and management of groundwater resources. The aim of the study is to numerically model the groundwater flow in Medapalli Open cast block area. Medapalli Open Cast Block is a coal mine operating under Singareni Collieries Company Limited SCCL in Telangana, India. It is spread across and lies near river Godavari. The observation well locations and depth to water level data are collected from SCCL. A finite-difference based groundwater flow model is developed in Visual MODFLOW using MODFLOW-2005 code with forty conceptual layers and with a total thickness of 240 m. The model is constructed based on the geological and spatial data of the study area. The model calibration is performed at steady state conditions through trial and error method. In addition to this, a solute transport model is developed using MT3DMS code at steady state conditions. The results indicate that the computed water table values fairly match the observed water table values and the simulated flow direction is towards the river Godavari, in accordance with the field conditions and following the general topography of the region. The solute, i.e. (TDS) migration extends up to a maximum distance of 168 m along the periphery of Medapalli open cast block towards the river. The study shows that the impact of fly ash deposition in Medapalli Open cast mine on the groundwater quality in the vicinity of the open pit will be very less and no harmful effects will be observed as the contaminant levels decrease steeply along the periphery of the mine and concentration of the plume is reduced sharply.
        Keywords: Groundwater flow Model, Visual MODFLOW, Medapalli Open Cast block, solute transport, Numerical Modelling

        Speaker: Mr Santhosh Madhav Chandra Parsa (Research Scholar)
      • 17:30
        Quantifying the contributions of silicates weathering and calcite dissolution to hydrochemistry of groundwater in sandstone using Sr isotopes 15m

        In a flow system from the recharge to the corresponding discharge area, there are usually systematic changes in the hydrochemistry of groundwater. Although it is well known that silicates are the main minerals in sandstones, silicates and minor carbonates in sandstones both consume CO2 and control of hydrochemistry of groundwater. However, it is difficult to differentiate the contribution of each type of minerals. Considering that 87Sr/86Sr ratios of water is mainly controlled by different sources, Sr isotopes of groundwater could be used to evaluate the contents of Sr derived from silicates and carbonates with different Sr isotopic compositions. In this study, it is assumed that due to the relatively abundant CO2 in the shallow part of the aquifer, the contents and isotopes of Sr in shallow groundwater are determined by rainwater influenced by silicates weathering and carbonate dissolution. From recharge to discharge area, due to the decreased dissolved CO2 in a closed system, the isotopes of Sr in deep groundwater are determined by shallow groundwater influenced by carbonate dissolution. The contribution of carbonates to Sr isotopes is found to be less than that of silicates in the recharge area, but outweigh that of silicates in the discharge area. The different ratios of carbonate to silicates partly explain the difference of Mg isotopes in shallow and deep groundwater in the same study area (Zhang et al., 2018).

        Zhang H., Jiang X.W., Wan L., Ke S., Liu S.A., Han G.L., Guo H.M. and Dong A.G. (2018) Fractionation of Mg isotopes by clay formation and calcite precipitation in groundwater with long residence times in a sandstone aquifer, Ordos Basin, China. Geochimica et Cosmochimica Acta. 237, 261-274.

        Speaker: Prof. Xiao-Wei Jiang (China University of Geosciences)
      • 17:45
        Are 253 samples better than 65 samples? Urban groundwater monitoring in developing countries – Lessons learnt in N’Djamena, Chad 15m

        In the frame of a technical cooperation project between the Lake Chad Basin Commission and the German Federal Institute for Geosciences and Natural Resources, four groundwater sampling campaigns were conducted in the Chadian capital N’Djamena in 2013, 2016, 2017, 2018. 253 samples were taken from 67 private bore wells equipped with handpumps and 16 large-capacity production wells of the public water supplier. The first campaign was designed to get an overview of the chemical and bacteriological groundwater quality and included samples from 52 private wells from across the entire city area and 13 production wells within the city. The subsequent sampling campaigns were conducted for monitoring purposes. Many 2013 sampling points were broken or inaccessible in the following campaigns and were replaced by wells in the vicinity. Only 32 private and nine production wells were sampled in all four campaigns.
        The 2013 campaign identified bacteriological contamination, elevated nitrogen, and fluoride concentrations as the main areas of concern. While 40 % of the private and 23 % of the production wells contained fecal bacteria, nitrogen species and fluoride were found (with one exception) to be below the WHO guideline values. Although the subsequent sampling campaigns confirmed this general picture, the overall benefit of the additional 188 samples was limited to the finding that nitrogen concentrations were increasing in some points. In 2016, 2017, 2018 two, five, and four samples, respectively exceeded the WHO guideline value of 50 mg NO3/L. However, the distribution of the nitrate hot spots were somewhat random and it was not possible to draw more than general recommendations (e.g. protection zones around wells) from these findings.
        In 2019, a survey was started to measure the total depths of all sampled wells and to make an inventory of possible sources of contamination. Re-evaluating the collected data in the light of this additional information leads to some insights on contaminant pathways, but most importantly, clearly shows that the monitoring network needs to be optimized. (1) Before choosing a sampling location, the well depth must be known and the future accessibility ensured: Replacing a broken well by any random well in the proximity does not help, unless both wells are filtered in the same depth and additional sources of pollution can be out ruled. (2) The construction of new observation wells is inevitable, as our data proves that random wells close to production wells cannot be used for monitoring purposes. (3) An additional focus on mapping of the sewerage system (design and construction years) is necessary to make predictions about the future development of nitrogen concentrations. In technical cooperation projects, baseline samplings are an important tool to identify problems, but groundwater monitoring needs more careful planning to be cost effective

        Speaker: Ms Mélanie Ronelngar Ndedje-Allah (BGR Chad)
      • 18:00
        Assessing the feasibility of managed aquifer recharge through unsaturated zone modeling with VS2DTI in a multilayer system 15m

        Managed Aquifer Recharge (MAR) can play an important role as a measure to control over-abstraction and to restore the groundwater balance under climate change scenarios. MAR may also be applied to sustain or improve the functioning of ecosystems. One of the major difficulties in evaluating the applicability of MAR is to model the infiltration process through variably saturated media with the presence of perched aquifers in alluvial systems. This is the case of the Medina del Campo groundwater basin within the Duero River basin.
        In this study, we apply the unsaturated finite difference flow code VS2DTI to simulate MAR to the deep aquifer system used for groundwater exploitation. We estimated average natural recharge for a typical 10-year distribution of wet, medium and dry years based on the data of the period 1940-2010. Eight textural layers with their corresponding hydraulic parameters (saturated hydraulic conductivity, specific storage, porosity, residual moisture content, and alpha and beta van Genuchten parameters) were defined according to reference values in a 2000 m x 55.5 m axisymmetric rectangular domain. A variable grid with increasing cell size from the top left corner (MAR point) was specified. In the top boundary, artificial recharge was simulated as a constant specified flow condition through a 4 m riverbed in the top left corner and natural recharge was evenly distributed along the 2000 m of this boundary. A constant pressure head (p=0) was used to define the deep groundwater level in the bottom boundary. We used flow source points as a Neumann type boundary condition inside the domain to simulate the top aquifer located between 2 m and 11 m deep. The amount of flow in these points as well as the initial moisture conditions were derived from the steady flow model.
        The average volume of available water for MAR as estimated by the Duero basin Water Authority was set to 0.3 m/d and distributed proportionally as a function of average annual precipitation for each type of year. For wet years, MAR equaled 0.4 m/d, 0.3 m/d for medium years, and 0 during dry years. A sensitivity analysis of the hydraulic parameters was also carried out.
        The results show low water balance errors in the simulations (< 2%) and that the MAR is inefficient to recharge the deeper aquifer due to the low transmissivity and water retention capacity of the aquitard underneath the top aquifer. The main interest of the proposed approach is that it provides a basis for simple assessment of MAR feasibility through unsaturated flow modeling. This is an important contribution since multilayer aquifer systems where there are perched aquifers are difficult to tackle with standard saturated groundwater flow programs.

        Speaker: Dr Héctor Aguilera (igme)
    • 17:00 18:30
      Parallel: Monday Afternoon 14: Topic 8 Conference room 1.A ()

      Conference room 1.A

      • 17:00
        Flow path and velocity by 3-D groundwater flow simulation based on detailed facies analysis of Fukushima Daiichi Nuclear Power Station in Japan 15m

        Since 2011, groundwater contaminated by radionuclides from Fukushima Daiichi Nuclear Power Station (FDNPS) in Japan, flows into the adjacent sea. Despite several countermeasures to prevent outflow of contaminated groundwater into the sea, this issue has not been solved. Contaminated groundwater primarily flows through the unconsolidated sand layer of the upper Pliocene (the Dainenji Formation), which the nuclear reactor was built in. However, results of field survey in areas surrounding FDNPS and boring logs analysis, show that the sand layer is not distributed uniformly and has irregular intercalations of several muddy layers. Such results are needed to reveal heterogeneous facies considering flow path and velocity of contaminated groundwater. In this study, 3-D groundwater flow simulation based on detailed facies to reproduce heterogeneity in the formation was carried out using MODFLOW. Groundwater flow was analyzed by transient simulation. Flow path and velocity of groundwater through the sand layer were controlled by non-uniformly distributed muddy layers. Land and sea side impermeable walls which are countermeasures at FDNPS, reduced outflow of groundwater through the unconsolidated sand layer to the sea. Assuming the impermeable walls do not exist on the simulation model, groundwater outflow to the sea is within the harbor. Potential upward groundwater flow appeared under reactor and turbine buildings. Groundwater flows from a lower aquifer to the upper aquifer through the sandy mud layers below these buildings. In the next step, mass transport simulation of contaminated groundwater will be performed based on results of groundwater flow simulation.

        Speaker: Ms Hikaru Sato (Graduate School of Symbiotic Systems Science and Technology, Fukushima University)
      • 17:15
        Diffusion and weathering of oil spill in Daya Bay, the South China Sea 15m

        With the development of marine resources and marine transportation, oil spill accidents occur frequently which threaten the marine ecological environment and human life. In this paper, an oil spill model was established. With discretizing two-dimensional shallow equation by finite element method, the oil spill hydrodynamic-numerical model was established. As the water boundary condition was defined by harmonic analysis method, the model was verified by measure tidal level data. The boundary treatment method of multiple islands and complex shoreline was proposed. Monte Carlo Method is used to simulate the diffusion and drift of oil spill, Euler-Lagrange method is used to track the film centroid and oil film boundary, and a random number was added to indicate the randomness of oil film expansion. The diffusion drift of oil film was verified by flume test. At the same time, this model considered the weathering process of evaporation, emulsification and entrainment of oil spills, and calculated the onshore adsorption of oil spills. The model is applied to Daya Bay, South China Sea, the oil spill behavior and destination under different residual currents were simulated and calculated, which provides a theoretical basis for the prevention and emergency treatment of oil spill accidents.

        Speaker: Dr Zhen Zhu
      • 17:30
        Effect of microbially mediated sulfate reduction on arsenic mobilization in the Pleistocene aquifers of the central Yangtze River Basin 15m

        Understanding the mechanism of geogenic arsenic mobilization from sediments to groundwater is important for safe and sustainable drinking water supply and water quality management in floodplain aquifers. Laboratory-scale microcosm incubation experiments and seasonal biogeochemical monitoring were conducted to elaborate the effects of microbial sulfate reduction on As mobilization in the shallow aquifer systems from the Jianghan Plain, central Yangtze River Basin. Dissolved As species (including thio-As), Fe(II), dsrB/arrA functional gene abundance, 16S rRNA gene sequences and iron mineral phase transformation (by sequential extraction) were analyzed during the incubation and field monitoring study.

        Sulfate reduction promoted arsenic mobilization at the initial stage of microcosm incubation with the increase of dsrB gene and arrA gene abundance, since sulfidogenesis significantly contributed to the mobilization of As via sulfide-induced reduction of both As-bearing Fe(III) oxide minerals and As(V), while a part of the arsenic was converted to soluble thio-arsenates (H2AsS4-). 16S rRNA gene sequences identified as Desulfomicrobium could be responsible for the microbially mediated sulfate reduction process. A decrease of dissolved As and Fe(II) was observed at 14th day after incubation, the results of sequential extraction of sediments indicated the increase of Fe(II) sulfide mineral phases, suggesting the precipitation of Fe(II) sulfides can restrict the build-up of dissolved Fe(II) and sequester As from the solution. Then after transient arsenic removal, As re-released into the solution without corresponding increase of dissolved Fe(II), probably due to the competitive adsorption for the surface sites of iron-sulfide minerals between As and other ions (Fe(II), bicarbonate,etc) and newly formed crystalline iron (hydro)oxides.

        Our lab-scale microcosm observation was consistent with the results from our long-term field monitoring. Microbially mediated sulfate reduction could promote seasonal increase of As and Fe(II) through abiotic reduction of iron (hydro)oxides minerals in aquifer sediments by bacterially generated HS-, which was evidenced by corresponding increase between Fe(II) and δ34SSO4 in groundwater. Moreover, Fe(II) sulfide formation could scavenge the dissolved Fe(II), which leads to the decoupled seasonal variation of As and Fe(II) under sulfidogenesis conditions. While sulfate reduction process only resulted in transient and incomplete arsenic immobilization due to competitive adsorption between As and phosphate in groundwater. Our results provide new insights into the coupled As-Fe-S biogeochemical processes accounting for arsenic mobilization and seasonal variation in alluvial aquifer systems.

        Speaker: Prof. Yamin Deng (School of Environmental Studies, China University of Geosciences)
      • 17:45
        Assessing emergent contaminants as anthropogenic markers and its fate in aquatic ecosystems at Yucatan Peninsula 15m

        The Northeast of Yucatan Peninsula; Mexico; due to its natural resources: beaches, jungles, sinkholes, reef is one of the main Mexican touristic poles. Presenting one of the most accelerated growth is recreational activities and in consequence the rise of development on the coast and inland. Moreover, this region underlies a vulnerable karstic coastal aquifer at the Yucatan Peninsula, high permeability fractured limestone, which allows rapid transport of contamination resulting in a significant potential increase of pollution affecting the ecosystems.
        Several studies indicate the importance of chemical markers to track pollution by domestic and industrial activities. Potential candidates are endogenous metabolites released by the human body and components of pharmaceutical products, personal care products and food. Regular and constant consumption is a prerequisite for the selection of a good marker, which implies that consumer habits do not change or change gradually in the coming years. Caffeine has been used as a chemical marker of the water quality to improve the accuracy with which are detected polluting sources of domestic origin. Caffeine occurs mainly in beverages such as coffee, tea, some bottled drinks (sodas) and some drugs for human consumption.
        This work summarize three evaluations of caffeine along with bacteriological quality and the toxicity to the ecosystem. Caffeine was used as an emerging contaminant as a marker to identify the sources of pollution and its impact on groundwater (wells, sinkholes and lagoon). The detection of caffeine to points of high presence of bacteria E. coli, can confirm that the alteration of the water quality in some of these sites has a direct connection with the tourist type anthropogenic activities. While the presence in the area of extraction wells is due to infiltration of untreated or semitreated wastewater water, moreover presence of caffeine was also detected at the lagoon where only rural and domestic activities characterize the area, the toxicity evaluation by zooplankton indicated an impact in the aquatic biota.
        The importance of these results indicated that presence of contaminants might not be related to the increase or the size of the human developments but the lack of wastewater service that represent a potential impact to the aquatic ecosystems.

        Speaker: Dr Rosa Leal-Bautista (CICY-UCIA)
      • 18:00
        Groundwater/surface-water interactions and their effect on nitrate pollution in the Oglio River basin (N Italy) 15m

        In the Po Plain of northern Italy, one of the larger alluvial basin in Europe, groundwater quality is threatened by nitrate pollution. The main aim of this work is to assess the origin of this pollution and understand how groundwater/surface-water interactions affect nitrate concentrations in the region.
        The study area is part of the Oglio River basin and covers around 1,900 km$^{2}$ between the outflow from Lake Iseo and the confluence with Mella River. The northern part of the area (i.e. higher plain) hosts a sandy mono-layer aquifer that passes southwards into a multi-layer aquifer (lower plain) with increasing silt and clay contents. The transition between higher and lower plain is marked by a series of semi-natural springs, the so called “springs belt". The Oglio River is losing in its first ~30 km crossing the higher plain, then becomes gaining. The area is crossed by hundreds of irrigation channels fed by Oglio River water.
        Six field surveys (November 2015, February, June, September 2016, March and July 2017) were carried out and up to 58 groundwaters, 20 Oglio River and tributaries waters, 7 spring waters and 1 Lake Iseo water were sampled in each survey. Analyses were performed for major ions, trace elements and stable isotopes (δ$^{18}$O/ δ$^{2}$H in water, δ$^{18}$O/ δ$^{15}$N in nitrates and δ$^{11}$B).
        Concentrations of NO$_{3}$ were higher in groundwater from the higher plain and spring water (median of 39.8 and 40.6 mg/L, respectively) than in groundwater from the lower plain, where NO$_{3}$ was generally below the detection limit. The losing reach of the Oglio River had low concentrations of NO$_{3}$ that nevertheless increased downstream from a median concentration of 2.5 mg/L at Lake Iseo to 20.6 mg/L in its lower gaining reaches. This is due to the gaining of groundwater from the higher plain that is higher in NO$_{3}$.
        Isotope data showed that NO$_{3}$ originated from different anthropogenic sources, such as animal manure, septic tanks and, to a lesser extent, synthetic fertilizers. Beneath intensively-irrigated areas, the isotopic composition is shifted through the compositional range of synthetic fertilizers. This could be due to an increased dissolution of fertilizers related to the intensive irrigation. Irrigation also plays an important role in controlling groundwater NO$_{3}$: concentrations are lower (mean 38.4 mg/L) where irrigation water is sourced from the channels and higher (mean 56.4 mg/L) where irrigation is performed using groundwater. The difference arises because irrigation channels carry Oglio River water, that has low NO$_{3}$ concentrations (mean 8.5 mg/L). Therefore, in this case, irrigation water contributes to diluting the high anthropogenic NO$_{3}$ contents in groundwater. This finding is supported by water isotopes since the Oglio River is more depleted than local precipitation.
        This work was supported by Fondazione Cariplo, grant 2014-1282.

        Speaker: Marco Rotiroti (University of Milano-Bicocca)
      • 18:15
        Study on the groundwater quality management in unconfined aquifers of rural areas, South Korea 15m

        The purpose of this study is to investigate the cause of groundwater contamination in the selected study areas and to propose the appropriate management plans for the drinking shallow groundwater in agricultural areas. The study areas were selected in 2014 and 2015 with consideration of the groundwater quality, field survey and hydro(geo)logical factors. For five years(2014-2018), we have been monitoring the groundwater quality, analyzing the hydrogeological characteristics, and investigating on-site contaminant sources in the study areas.
        In the study area 1, the organic fertilizer used in the field was investigated as the main source of groundwater contaminants. We have managed the use of organic fertilizer since 2016 and installed the new groundwater wells in the weathered vadose zones and weathered rock layers to improve the groundwater quality and supply the safe groundwater. The result showed that high NO3-N (>20 mg/L) concentrations in some wells have decreased with time. However, the contaminant concentrations of the newly installed groundwater wells showed no significant variations during the study period. It implies that the shallow aquifers have been heavily contaminated by the non-ponit contaminant sources mainly located in the vadose zones.
        In the study area 2, the groundwater deterioration was investigated by the excessive use of organic fertilizer and livestock manure accumulated throughout the field. Relatively deep-groundwater wells (approximately 100 m drilled from the ground surface) and direct groundwater supply system were proposed and applied to provide the safe and drinkable groundwater in 2016. In order to analyze the characteristics of groundwater quality changes after removing the point contaminant source of livestock manure in October 2017, the monitoring wells were installed in the downstream direction of groundwater flow from the point sources. Despite of removing the point sources, the NO3-N concentration of monitiong wells showed no significant variations. The contaminant concentrations, however, increased when the groundwater level rose in the study area. Therefore, more time to monitor is needed to evaluate the test bed for the point source control.
        As the result of this study, various action plans such as (non) point contaminant source controls and so on, are needed for improving groundwater quality. This whole process should be performed by the comprehensive management plans, which are based on evaluating and estimating groundwter quality status and characterizing the detailed hydrogeological setting in the agricultural study area, and so forth.

        Speaker: MoonSu Kim
    • 17:00 18:30
      Parallel: Monday Afternoon 15: Topic 10 Conference room 1.B ()

      Conference room 1.B

      • 17:00
        Smart management of unconfined aquifers in urban areas 15m

        The water supply of cities presents great challenges since the demand is concentrated in areas where human activities threaten water resources. Where available, deep confined aquifers are protected from contamination. But they often suffer from a lack of recharge and long term withdrawals shall be limited to protect the stock. In contrast, unconfined aquifers usually present greater recharge rates and may be of interest for drinking water supply. Though vulnerable to anthropogenic contamination, such aquifers often present a better quality than surface waters. This study discusses the relevance of using unconfined aquifers in urban areas and investigates the solutions to mitigate their vulnerability to contaminants. The approach is illustrated with a case study in the city of Bordeaux (France). Deep aquifers were subject to overpumping so that unconfined aquifers were considered as an alternative. A flow and transport groundwater model was implemented in a well field vulnerable to a contaminated stream. An adaptive, multi-objective optimization approach was proposed. The objective was to maximize the water production at the well field while minimizing stream water intrusion. The well-field operator can adjust production settings to optimum conditions in function of the observed stream water level and desired production rate. Such a smart use of unconfined aquifers may be advantageous in many cities around the world.

        Speaker: Dr Alexandre Pryet (Georessources and Environment, Bordeaux INP and Univ. Bordeaux Montaigne.)
      • 17:15
        Hidden figures: What the JMP data do not tell us about groundwater use in urban Sub-Saharan Africa 15m

        Sub-Saharan Africa (SSA) is undergoing rapid urbanization and dependence on groundwater is expected to increase, especially for the urban poor. Accurate quantification of groundwater use is necessary to develop measures to protect and enhance the resource. The current scheme of global water access monitoring, done by the Joint-Monitoring Programme (JMP), neglects groundwater use when offered as piped water and also neglects self-supply of groundwater when in use as a secondary source. The present study aims to quantify urban groundwater use for Uganda and compare it with JMP national data. A method will be developed to estimate urban groundwater use through Geographic Information Systems by coupling the spatially distributed urban water cycle, urban structure analysis, and high resolution population density. The calculated groundwater use is expected to show that current JMP data underestimates the proportion of population using groundwater. The method developed in this research will be applicable to other cities in the SSA region, and provides a tool for further understanding groundwater dependence and supports evidence-based groundwater management measures.

        Speaker: Mr Rafael Chavez
      • 17:30
        Managing the Response to Clean Air and Carbon Reduction Targets from Open Loop Ground Source Heat Pump Systems on Urban Groundwater Resources; Two Case Studies 15m

        In September 2018, the Greater London Assembly published; Low Carbon Heat: Heat Pumps in London. This report states that, to meet carbon reduction and air quality targets there needs to be a significant uptake in heat pumps in the next 10-15 years. Based on estimates of market share (Abesser, 2010), around 1,000 of the 1 million heat pumps sold in the EU in 2016 were Open Loop Ground Source Heat Pumps (GSHP). In 2017 heat pump sales grew 13%, the third consecutive year of growth (EPHA, 2017). Subsequent pressure on urban groundwater resources is expected to continue to rise with the proliferation of Open Loop GSHP systems.

        In England the Environment Agency (EA) regulates Open Loop GSHP by Abstraction Licence and Environmental (discharge) Permits. Since the first Open Loop GSHP in 2000, London has 44 licensed systems. In this time, the EA have noted raised groundwater temperatures potentially reducing GSHP efficiency (EA, 2018). Stakeholder’s agreed that thermal impacts of GSHP systems should be increasingly considered by the EA, particularly thermal interference. The EA responded with a Legislation and Policy document (EA, 2008) and an Environmental Good Practice Guide (undated) advocating a risk-based approach. Based on experience, the author considers this to be broadly successful in managing groundwater levels in the Chalk Aquifer of the London Basin, corroborated by the Annual Groundwater Status Report (EA). However, regulatory focus on protecting groundwater levels do not guarantee abstraction volumes or temperatures. In that sense, it is the applicant’s responsibility to assess if the proposed GSHP will be sustainable or impact other systems (Fry, 2009). Local best practice for hydrogeological input into the design Open Loop GSHP systems is discussed in this context; undertaking Environmental Impact Assessment using numerical coupled groundwater flow and heat transport modelling.

        In Christchurch, New Zealand the rapid uptake of Open Loop GSHP occurred in response to the 2011 earthquakes and with incentives including streamlined planning and funding grants (Seward et. al. 2017). Up to 20 systems are operational or planned in Central Christchurch, the majority being installed since 2012 (Rekker, 2017). The local regulator (Environment Canterbury) commissioned a groundwater model to investigate anecdotal reports of water table mounding in the city (Rekker, 2017). Groundwater modelling results and anecdotal evidence of groundwater flooding, reactivation of historical springs and problematic recharge pressures will be reviewed in the context of the local regulatory requirements. Christchurch’s layered confined aquifer system mitigates the potential for thermal interference, however, lessons learnt from the regulatory and design perspective will be discussed and presented in this context; demonstrating the absence of regulatory mechanisms to assess individual and cumulative hydraulic impacts of open loop GSHP systems may have led to undesirable outcomes for the City of Christchurch.

        Speaker: Mr Huw Williams (Agua Enodo Ltd)
      • 17:45
        Informal and formal groundwater use in peri-urban areas of Jaipur, India, and implications for its management 15m

        Jaipur, the capital of the Indian state Rajasthan, is a fast growing city in the semi-arid region of northwestern India. In its expanding peri-urban areas, a huge share of the population has to rely on an informal water supply system which is often based on groundwater sources. To understand the influence of groundwater availability on the official and the informal water supply system, and the impact of the water demand and the fast changing land use on groundwater quality and quantity, a detailed research was conducted in two study areas in the northeast of Jaipur.
        Interviews with the population, the official water supplier, and informal water suppliers revealed that the water supply system in the two study areas is characterized by a high diversity related to water sources, service providers, pricing, quality, and transport systems. This, together with a general lack of reliable data makes an analysis of the current system challenging. Hydrogeological studies showed that in both study areas the main aquifer, the Quaternary alluvium and the weathered and fractured parts of Proterozoic quartzite, respectively, is significantly influenced by the unsustainable and un-managed use of the groundwater resources. Declining water tables indicate groundwater over-abstraction, while elevated electrical conductivities up to 7 mS/cm point towards an influence by agricultural practices as well as long-term effects due to high evaporation rates.
        It is necessary to understand the close relationship between groundwater and humans, especially in fast changing environments like peri-urban areas, to be able to develop sustainable and fair management strategies for the future. For example, the current situation is highly unfair, with the quantity and quality of domestic water supply depending on the location of the house, on the economic status of the residents and on their social position within the community. Furthermore, the land-use change from agricultural to residential can even lead to a higher water demand due to the change in societal water consumption pattern coming with a changing lifestyle.
        We will present our data on the water supply system, the socio-economic realities and impacts related to it and on the hydrogeology and, based on this, examine the above mentioned challenges on data availability and reliability. Furthermore, we will discuss the possibilities and constraints to model the current water demand and supply with the software WEAP (Water Evaluation And Planning) in which we included agricultural irrigation needs, domestic and industrial demand and the simulation of groundwater recharge.

        Speaker: Theresa Frommen (Freie Universitaet Berlin, Germany)
      • 18:00
        Thermal Impact and Performance of High-Temperature ATES (HT-ATES) systems: a strong dependence on hydrogeological and storage conditions 15m

        Particularly in urban areas, heating and cooling is responsible for a large fraction of total energy demand. Due to the seasonal and diurnal variation in heat demand and for example that of solar heat supply, the storage of heat is critical for the development of sustainable heating.

        Aquifer thermal energy storage (ATES) systems allow the storage of heat cost-efficiently and at a scale that is sufficiently large to allow seasonal heat storage from office buildings to regional district heating networks (DHN). Critical for the performance of ATES systems is the heat recovery efficiency. While for low-temperature (LT, <25°C) ATES systems, recovery efficiency mainly depends on conduction losses from and displacement of the stored volume, at higher storage temperatures density differences between the stored hot water and the lower native groundwater temperatures (e.g. ~10°C in NL), result in losses by buoyancy driven flow. Particularly for HT-ATES systems, also the effects of heat loss on the thermal, chemical and microbial quality of the surrounding groundwater and that in over- and underlying aquifers still need to be understood.

        We therefore focused in this study, on the controlling factors for the heat recovery efficiency and thermal impact through integrated density-dependent, heat transport and groundwater flow modelling of ATES systems for a wide range of representative storage (e.g. T:15–90°C, storage volume: 10,000–1 Mm3) and hydrogeological conditions. Results showed that for storage temperatures up to 30°C, under all conditions tested, conduction losses were dominant in controlling recovery efficiencies (55–85%), as evidenced by its observed strong linear correlation with the thermal area over volume ratio (A/V) with an optimum ~2 for the aquifer thickness over thermal radius ratio (L/Rth) for a particular storage volume. For storage temperatures of 45 and up, the negative impact of density driven flow was significant and became the dominant control for lowering of the observed recovery efficiencies (18–75%) at 90°C. From 45 to 90°C, the recovery efficiency was progressively more negatively and non-linearly correlated with L/Rth, with the highest recovery efficiencies at the lowest tested L/Rth (0.1). In addition to storage temperature and volume, the thermal impact on the simulated overlying aquifer depended strongly on the thickness of the confining aquitard. For the heating of the aquifer overlying and surrounding the HT-ATES system, an analytical 1-D conduction and 2-D radial conduction expression was found to give a good first approximation, respectively, but deviated at higher temperatures due to the occurrence of buoyancy flow at higher storage temperatures.

        Overall, it is shown that both the performance and impact of a particular HT-ATES system strongly depends on a range of site-specific storage and hydrogeological conditions. These need to be considered carefully for system optimization and assessment of business cases and potential thermal environmental impact.

        Speaker: Dr Niels Hartog (Utrecht University)
    • 17:00 18:30
      Parallel: Monday Afternoon 8: Topic 1 Conference room 2.1 ()

      Conference room 2.1

      • 17:00
        The Groundwater Drought Initiative (GDI): Analysis of European groundwater drought 15m

        With an estimated share of about 65 percent, groundwater is one of the major drinking water sources in Europe, and is often essential for irrigated agriculture. Groundwater availability can also be especially important in times of surface water scarcity when groundwater abstraction may increase to alleviate negative effects to the livelihood of people. Drought events such as in 2011-12, 2015 and 2017-18 showed spatial coherence across several European regions in surface water deficits, and are likely to affect groundwater levels in a similar pattern. However, groundwater droughts may also show distinct spatial coherence based on their hydrogeological settings and recharge patterns as much as on the driving meteorology and available recharge. To assess whether the patterns in groundwater drought propagation are similar to the observed extent of major surface water droughts, a pan-European analysis of historic groundwater level data is required. However, no such study has been undertaken to date.

        To address this gap, and to evaluate spatial patterns of groundwater drought response on a continental scale from the late 1900s to present, a pan-European Groundwater Drought Initiative (GDI) was formed. Within GDI, groundwater data from numerous supporting institutions was gathered and jointly analysed, covering a spatial extent from the Iberian Peninsula to Eastern Europe (Ukraine). Thus we produced the first comprehensive overview of historic groundwater droughts across Europe. The spatio-temporal analysis is based on the Standardised Groundwater Index (SGI), which allows for comparison of sites from disparate regions in a consistent manner. Spatial patterns in the drought response across the continental scale were analysed. First insights from the study highlight differences in groundwater system responses to the driving meteorology, such as fast and slowly responding sites and their spatial coherence. Delayed responses to major surface water droughts, like the 1975-1976 or 1996-1997 events, are observed at many of the analysed sites, though impacts differ based on the specific site setting. The further processing of this data will allow for more detailed comparison of the historic groundwater droughts with major surface water drought events, and the analysis of driving factors will increase our understanding of how catchment and local characteristics impact on groundwater responses. Additionally, areas particularly vulnerable to groundwater droughts will be identified, thus allowing for improved groundwater management.

        Speaker: Bentje Brauns (British Geological Survey)
      • 17:15
        Fusing geological information with hydraulic tomography: Lessons from unconsolidated deposits 15m

        The accurate assessment of groundwater and its management requires obtaining reliable estimates of hydraulic conductivity (K) and specific storage (Ss). A large number of empirical, laboratory and field techniques have been developed over the last several decades. However, research suggests that Hydraulic Tomography (HT) yields the most accurate hydraulic parameter estimates that can then be used to build robust groundwater flow models. The majority of algorithms used for HT analysis has relied on geostatistics, however, a number of studies have shown that smooth K and Ss estimates are obtained when the inversion begins with homogeneous hydraulic parameter estimates and when data densities are not high. These smooth estimates are not visually appealing from a geological standpoint. One could overcome this by integrating geological data that are typically available through outcrops and borehole logs.

        Here, we examine the usefulness of geological data for HT analysis in unconsolidated deposits by: (1) comparing “traditionally” calibrated geological models to highly parameterized geostatistical inverse models and (2) using geological models as prior information for the geostatistical inversion approach. The investigation has been conducted with laboratory sandbox experiments, at a small-scale field site on the University of Waterloo campus consisting of highly heterogeneous glaciofluvial deposits and using data obtained from a municipal well field.

        Results reveal that the calibration of groundwater models built primarily with geological data, yields mixed results in terms of model performance, perhaps reflecting the uncertainties in geological structures along the vertical direction and between boreholes. The geostatistical inversion approach without the explicit reliance of geological data yields improved model performance over traditional geological models when data densities are high, although the resulting K and Ss distributions may not be geologically appealing. On the other hand, when geological data are fused with the geostatistical inversion approach, the resulting K and Ss estimates are more visually appealing from a geological standpoint, and that model performance is most robust. Overall, our results suggest the joint use of both geological and pumping test data for HT analysis when accurate geological data are available.

        Speaker: Prof. Walter Illman (Department of Earth & Environmental Sciences, University of Waterloo)
      • 17:30
        Permeability of the crystalline basement in Uganda - evidence from approximately 600 pumping tests and implications for solar pumping 15m

        Crystalline basement rocks of Precambrian age underlie nearly three quarters of Uganda, providing groundwater supplies to meet ever increasing demand from rural areas and urban growth centres. Development of groundwater sources is commonly based on several factors including physical and socio-economic considerations that have a bearing on their functionality and long term reliability. Here we present new transmissivity data from >600 boreholes across basement aquifers in Uganda calculated from previously unanalyzed pumping test data. Other data are available to help interpret the transmissivity values, including borehole lithological logs, weathering thickness, well design and depth to groundwater. Spatial and depth comparisons are made to relate aquifer permeability to lithology and weathering, and also to relate borehole yields to well design. The data provide an improved understanding of the physical permeability of weathered crystalline basement rock aquifers across Uganda, complimenting earlier studies of vertical permeability profiles in focused areas. The analysis helps inform the physical capacity of the aquifer to supply the borehole yields to meet increasing demands, and application potential for higher abstraction technologies, such as solar pumps.

        Speaker: Dr Michael Owor (Makerere University, Kampala, Uganda)
      • 17:45
        An Intelligent Framework for Groundwater Overexploitation Management (based on hydrogeological modeling) 15m

        Hydrogeological modeling is an indispensable decision support tool for sustainable groundwater resources management. However, one of the major issues in Groundwater numerical modeling is related to the basic data preparation required for running this open sources or commercial packages models. The experienced user or a newcomer of various existing powerful models such as MODFLOW, FEFLOW, etc, is often lost during the data preparation phase. Hence, one of the main motivations for this work is to develop an expert system able to reproduce heuristics mechanisms of hydrogeologists/experts in order to assist engineers/researchers in the main stages (essentially prior) of hydrogeological modeling (to analyze and study in depth the aquifer system).
        A rule based expert system, called ALAES (ALae Aquifer Expert System), dedicated to this purpose, was built adopting object oriented approach, and using an Expert System Shell. It includes: 114 class, 1136 instances, 179 functions, 192 rules and two types of interfaces. This work describes the main steps of ALAES development, its top level object hierarchy, and corresponding heuristics rules. Most of the advice given by ALAES working system was evaluated and validated in the Moroccan Rhis-Nekor aquifer case study. ALAES allows to: i) select the appropriate hydrogeological model depending on the aquifer problem studied and judge its modeling feasibility, ii) prepare the necessary inputs data for Hydrodynamic model, iii) guide the user during the modeling process, and determinate the optimal future water management scenario of groundwater resources.

        Speaker: Ms Meriyam MHAMMDI ALAOUI (Université Mohammed V / Faculté des Sciences de Rabat)
      • 18:00
        Evaluation of sustainable groundwater of the Mexico Basin aquifer after a century of intense pumping 15m

        The Mexico Basin (MB) includes the nation’s capital Mexico City, and is one of the most important metropolitan areas in the country representing the largest urban area in North America and the fifth largest in the world. A population currently reaching 22 million with constantly increasing water demands has resulted in the overexploitation of groundwater resources in the basin with changes in hydrological conditions over centuries. The urban, agriculture and industry practices on this area heavily rely on the basin’s aquifer groundwater resources to meet water demands; forecasts of expanding the metropolitan area will result in continued groundwater use with additional overexploitation. Historic and recent groundwater pumping has caused decrease in groundwater storage, significant declining groundwater levels, accelerating aquitard compaction translated in land subsidence, which is by now mostly permanent. The subsidence of the land has caused operational, maintenance, and construction-design problems for water delivery and flood control. Additional problems, which must be considered and monitored, are the changes in groundwater quality. Management and evaluation of this precious resource requires a detailed understanding of the aquifer dynamics along and within its natural boundaries. An integrated conceptual model of the Mexico Basin Aquifer (MBA) was developed for the first time based on literature, three-dimensional geologic and hydrogeological models, processes of hydro-mechanical behavior and geochemistry. This conceptual model updates and improves an existing numerical model, which is used as a guide to assessing the current and historical aquifer behavior and to provide aquifer sustainable evaluation through indicators. The model proposed in this study could be use in the evaluation of management plans designed to mitigate adverse impacts due to regional subsidence while also optimizing groundwater demands. This knowledge is critical to understanding the long-term sustainability of this resource under future land use and population growth in the MB. This work attempts to address the following issues and questions: What is the state of groundwater conditions in Mexico City after 100 years of increased pumping? What is the status of ground deformation (subsidence)? Is current groundwater use sustainable? What are the lessons learned and what is next?

        Speaker: Adriana Palma Nava (Universidad Nacional Autonoma de Mexico)
      • 18:15
        Combination of hydrogeological and geophysical techniques to characterize the origin of salinity in a porous multilayer aquifer (Estepona, southern Spain) 15m

        Hidralia is the company responsible for the supply of drinking water to the population of Estepona, a 65,000 inhabitant’s city located in the western Costa del Sol (Málaga province, southern Spain). Water resources come from both surface (reservoirs) and ground (aquifers) sources. One of the most strategic groundwater extraction zones corresponds to Padrón sector, where Hidralia has got two pumping wells 114 and 146 m deep, respectively. Despite the fact that the two wells are situated close by (350 m) and go through the same deposits, the quality of water is quite different. The easternmost well produces water of very good quality with values of electrical conductivity (EC) around 700-800 µS/cm, whereas the westernmost one regularly suffers from salinization problems leading to significant increases of EC values up to 4,000 µS/cm. Besides, the latter eventually becomes an artesian well -usually during or immediately after the recharge period- and the salinity of water does not remain stable along the year. In consequence, the current pumping strategy in this sector depends entirely on the easternmost well and in case it would become inoperative, there would not be any operational alternative. The objective of this contribution is to clarify the origin of the salinization and characterize the factors explaining its spatial and temporal variability, making use of a combination of hydrochemical, hydrodynamic and isotopic techniques. Methodology included monthly field campaigns for in situ EC, temperature (T), pH and oxidation-reduction potential (ORP) measurements, groundwater sampling and laboratory analyses of water samples for determination of major components concentrations and water isotopic signature (d18O-d2H). CTD-Diver devices were deployed in two monitoring points for continuous EC, T and groundwater depth recording. Vertical EC profiles in selected wells were periodically carried out. Finally, electrical resistivity tomography and induced polarization was used to characterize the freshwater-saltwater interface and provide information about the subsurface geometry of the aquifer. Results show the existence of, at least, three independent permeable layers in the study area made up of Quaternary and Pliocene sands, gravels and conglomerates. Water stored in the deepest layers shows low-to-intermediate EC values (<850 µS/cm) all throughout the year, whereas the shallower levels can become salinized because of their hydrogeological connection with seawater and extensive pumping, especially during the summer season. Changes of the piezometric pressure in the various permeable layers generate longitudinal flows inside the wells which modify the vertical distribution of EC. The different salinity of water from the two wells is attributed to the configuration of the filtering screen, in such a way that the non-salinized -easternmost- well would be disconnected from the upper levels and would only pump water from the deeper aquifer. This aspect remains to be validated through borehole video inspection.

        Speaker: Dr Damián Sánchez-García (Cetaqua Andalucía)
    • 17:00 18:30
      Parallel: Monday Afternoon 9: Topic 1 Conference room 2.2 ()

      Conference room 2.2

      • 17:00
        Hydrogeochemical and Environmental isotope characteristics of deep and shallow circulating groundwaters along a regional fault, Eastern Cape, South Africa 15m

        Natural CO2-rich springs emanate along an 80 km long North-South trending Fault in Eastern, South Africa. The geological units that outcrops along the Fault are the Dwyka Group rocks that are made up of mainly tillites and subordinate sandstone, shales and conglomerates. Hydrogeological, hydrochemical and environmental isotopes (δ2H, δ18O, 3H, δ13C and 14C) were used to characterise deep and shallow circulating groundwater along the fault. Groundwater and surface water samples at both CO2 emission and CO2 free streams, springs and boreholes around the Fault zone were collected and analyzed. Onsite physicochemical parameters including electrical conductivity (EC), total dissolved solids (TDS), pH, Temperature, DO, Eh, ORP, total alkalinity, CO32-, HCO3- at various surface and groundwater points were measured onsite. The results indicate that all deep circulating travertine cone springs along the fault zone are characterized by high salinity (EC > 6000 µS/cm), Na-Ca-Mg-HCO3 water type, depleted heavy stable isotopic signal with > 30‰ d-excess values, detectable tritium and dead 14C values. The δ18O versus δ2H stable isotope plot of the travertine cone springs shows a major negative shift from the meteoric water lines with δ18O and δ2H values ranging from -7.78 to -6.52 ‰ and -21.5 to -17.9 ‰, respectively. While, the shallow circulating groundwater and river samples show freshwater, Ca-Na-Mg-HCO3 water type, stable isotopic composition that reflect local and modern precipitation and < 18 d-excess values. These observations indicate that the reservoir and source of recharge for the deep circulating groundwater are different from the shallow groundwater and surface water.
        A conceptual hydrogeological including inverse hydrogeochemical model is proposed to explain the deep circulation of groundwater and generation of CO2 along the fault zone and formation of travertine springs. The hydrogeochemical inverse model indicates that the major geochemical processes that are responsible for the observed hydrochemistry are the dissolution of calcite, dolomite, Pyrite, Goethite, K-feldspars, fluorite, albite and sylvite and the formation of calcite, amorphous silica, iron hydroxide, iron carbonates, kaolinite and CO2 gas. The inverse modelling results are supported by calculation of saturation indices (SI) for various mineral phases. The precipitation of calcite, amorphous silica and iron carbonates were validated by XRF, XRD and thin section analyses results of samples taken from the travertine cones.

        Key Words/Phrases: CO2-rich springs, deep and shallow groundwater, Environmental isotopes, Hydrogeochemical characterization, eastern South Africa.

        Speaker: Prof. Molla Demlie (University of KwaZulu-Natal)
      • 17:15
        Managing Groundwater Resources: Case Studies from British Columbia, Canada 15m

        Groundwater is an essential resource for many rural communities in British Columbia, however also municipal water systems rely on groundwater (albeit often in conjunction with surface water). In British Columbia, after the Water Sustainability Act (WSA) came into effect (February 29, 2016), the need and requirement of (better) groundwater management has increased not only from a water allocation point of view but also from a water system planning point of view to ensure that future water demand can be met with the available water resource.

        Three years into the WSA implementation, some challenges have been identified regarding groundwater licensing and managing groundwater resources. Stock is being made of what are the lessons learned and how to move forward.

        Clearbrook Waterworks District (CWD) is a water utility located in southwestern British Columbia and serves a population of about ten thousand people (regionally and internationally known for its award winning drinking water). CWD solely relies on groundwater for water supply and extracts water from the Abbotsford-Sumas Aquifer, a transboundary unconfined aquifer composed of glacial outwash deposits.

        Supervisory Control and Data Acquisition (SCADA) has become an integral tool for CWD for managing groundwater and their well systems. Over the years, CWD has developed a comprehensive natural asset monitoring and management program (with the aquifer being the natural asset). With the help of SCADA a methodology has been developed for analyzing and interpreting groundwater levels and groundwater discharge and recharge trending over the years as observed at CWD’s production and monitoring wells.

        By using SCADA for groundwater monitoring, aspects such as well interference from third party wells is better understood as well as the possible effect of winter snowfall (or lack thereof) on aquifer recharge. The analysis of SCADA data has also provided insight in the possible effect of increased annual groundwater withdrawal volumes and changes in pumping regimes on groundwater levels and groundwater balance, information of which is relevant for determining the overall effectiveness of groundwater management strategies that are in place.

        Speaker: Dr Ineke Kalwij (Kalwij Water Dynamics Inc.)
      • 17:30
        Understanding the potential of Nature Based Solutions to recover the natural ecosystem services of the Medina del Campo Groundwater Body in the NAIAD EU project 15m

        The area covered by the Medina del Campo Groundwater Body (Duero River Basin, Spain) is an important agricultural production region. The area is prone to climatic and geomorphological hazards such as floods, dry spells and landslides. Climate projections indicate that these hazards might become more frequent in the future. The main economic activity of the area is agriculture, which is also the main water user almost entirely relying on groundwater. Currently there are more than 5000 wells pumping groundwater to supply the agricultural water demand. Measurements show that groundwater levels have declined up to 20 m in some areas in the last 40 years. In the framework of the NAIAD H2020 project we developed a 3D numerical groundwater flow model with the objective to understand the dynamics of the groundwater, to evaluate the impact of climate change, and to assess the potential of some Nature Based Solutions (NBS) for recovering the original ecosystem services of the groundwater body. The model was built to simulate a pristine system without abstractions, and a system under anthropic pressure with the current abstractions. The NBS simulated include the artificial recharge of the aquifer, the change of crops, and the modification of abstraction rates and distribution. The preliminary results indicate that under a scenario of climate change with reduced precipitation, although the assessed NBS solutions can be beneficial, they are not able to totally reverse the impact caused by the abstractions, and therefore do not succeed to completely restore the original ecosystem services of the groundwater body.

        Speaker: Marisol Manzano (Universidad Politécnica de Cartagena, Spain)
      • 17:45
        GROUNDWATER MANAGEMENT: AN EXAMPLE OF A PROJECT RELTED TO REHABILITATION OF THE SOUTHERN COASTAL AQUIFER AS PART OF THE NATIONAL WATER SYSTEM IN ISRAEL 15m

        The coastal aquifer of Israel serves as one of the main water resources. It extends from Mount Carmel in the north to the Gaza Strip in the south, bounded in the west by the Mediterranean sea and in the east by mountainous formations. The average natural recharge to the aquifer is around 270 MCM/Y. It consists basically of alterations of calcareos sandstones and eolinites with clay and loam intercalations which subdivide the aquifer to four subaquifers. The aquifer is subjected to salination by seawater encroacment from the west while salination occurs also in its eastern margins through lateral flow of brackish water from eastern aquitards. In addition, the aquifer is contaminated by downward flowing pollutants related to anthropogenic domestic, industrial and agricultural activity.
        Due to the contineous deterioration of the water quality and the resultant onging shortage of high quality water for domesic use and agriculture, a new operational and water management policy was determined. It includes a reduce of seawater encroachment from the west, and active prevention of the flow from the aquitards in the east.
        The southern part of the coastal aquifer is defined as the major operative storage for the national water system as well as for local consumers. As such, maintaining its quality is especially important. However, this part is threatened by over-exploitation, and successive drought years , resulting in reduction of the storage and depletion of groundwater levels. In addition, inflow of brakish water from an aquitard along its eastern boundary, as well intensive irrigation with treated sewage water affect its quality.
        In order to minimize the salination processes and allow replenishment of the storage, a rehabilitation program has been established, introducing the concept of brackish water desalination as the basic outline for rehabilitation. The two main components of this plan are:
        1. "The Eastern Interceptor", a battery of 33 production wells located along the eastern zone of the aquifer pumping 35 MCM/Y of water with salinities of 500 to 800 mg Cl/L, as raw water for desalination. This prevents the entrance of 30,000-35,000 tons of chloride per year into the western part of the southern coastal aquifer. The 30 MCM/Y of desalinated fresh water are delivered to the supply system, and the residual brine of 5 MCM/Y, are delivered to the Mediterranean Sea.
        2. A balanced pumping in the western part of the aquifer, based on the annual recharge rate. This is intended to prevent the seawater from advancing to the east and salination of the aquifer.

        Speaker: Israel Gev (Water Authority of Israel)
      • 18:00
        BOREHOLE YIELD ESTIMATION FROM ELECTRICAL RESISTIVITY MEASUREMENTS – A CASE STUDY OF GARU TEMPANE AND BAWKU WEST DISTRICTS, UPPER EAST REGION, GHANA 15m

        Electrical resistivity survey has proven to be an effective tool for groundwater exploration and has been widely embraced to help reduce the drilling of unsuccessful wells. Currently, information from electrical resistivity survey is often used in locating points for drilling, but it does not give indication of the yield of the borehole. The lack of this information therefore sometimes results in the drilling of dry and marginal wells. This study therefore looks at the possibility of using resistivity data, which is readily available from electrical resistivity surveys for groundwater exploration, for estimating the yield of yet to be drilled borehole. The study was limited to the Garu Tempane and Bawku West Districts. Secondary data on Vertical Electrical Sounding (VES) and drill logs for 49 boreholes in the selected districts were used. The thicknesses, apparent resistivities, longitudinal conductance and transverse resistance of the various subsurface layers of the boreholes were determined from drill logs and VES data. Correlations between borehole yields and the third layer apparent resistivity, longitudinal conductance and transverse resistance were then investigated to develop regression models for estimation of the borehole yields. The results showed that the third layer is fractured and contributes significantly to borehole yields in the area; hence the fractured subsurface layer is of primary interest to be considered in groundwater exploration and estimating potential borehole yield from VES data. The results obtained further indicated that apparent resistivity, longitudinal conductance and transverse resistance had good exponential and positive linear relationships with borehole yield.

        Speaker: Mr ALBERT ACHEAMPONG (WORLD VISION INTERNATIONAL)
    • 18:30 19:30
      Meeting: IAH Early Career Hydrogeologists Network (ECHN) meeting
    • 09:00 10:30
      Plenary
      • 09:00
        Transboundary Aquifers: Groundwater Management and Governance in a Water Scarce World 30m

        With the exception of most island nations, every country on the globe is hydrologically connected to its neighbors. This is especially evident in the more than 600 cross-border aquifers that have been identified world-wide and that are being exploited to varying degrees. Surprisingly, and in contrast to the more than 3,600 treaties and agreements governing transboundary rivers and lakes, there are currently only five treaties and a small handful of informal arrangements in place for transboundary groundwater resources. This presentation will provide an overview of the governance of groundwater resources in an international context. It will also address the role that science and policy have in supporting the further development of such regimes, and the role that the International Water Resources Association has taken in bridging the science-policy interface.

        Speaker: Prof. Gabriel Eckstein (Texas A&M University)
      • 09:30
        Groundwater, water-security and sustainable livelihoods 30m

        For many parts of the world, the development of groundwater increases water security and can lead to more sustainable livelihoods and a reduction in poverty. This is particularly the case for Africa and South Asia where water insecurity is endemic. This talk will explore: (1) water security in rural Africa particularly throughout drought condition and the interlinking factors influencing the functionality and reliability of groundwater supplies; (2) the benefits of having a reliable groundwater supply; (3) the potential across Africa for higher yielding supplies both for urban supply and irrigation; and (4) water security in South Asia given high abstraction for agricultural and urban use. The discussions will be framed by the high pace of global environmental change and the challenges of governing groundwater development.

        Drawing on 25 years of research funded mainly by the UK Department for International Development the talk will be illustrated by recent results from the ongoing UK/Africa research programme, UPGro (unlocking the potential of groundwater for the poor), and various South Asian / UK research partnerships on the Indo-Gangetic Basin and Peninsular India.

        Speaker: Prof. Alan MacDonald (British Geological Survey)
      • 10:00
        Climate Change Effects on Groundwater: Expectations and Observations 30m

        Groundwater storage fluctuates more slowly than the near-surface, non-frozen components of terrestrial water storage (soil moisture and surface waters), but because of its larger range of variability it is often more indicative of long period climate changes. Hindering groundwater’s use as an indicator of water cycle and climate variability is the paucity of long term, continuous measurement records that are publicly available. Further, it is challenging to distinguish climate change impacts on groundwater levels from natural variability and direct anthropogenic effects. In this presentation we will review the current state of understanding of how climate change is influencing or could potentially influence groundwater recharge and storage. We will also quantify and attribute apparent trends in terrestrial water storage observed worldwide by the NASA/German Gravity Recovery and Climate Experiment (GRACE) satellite mission during 2002-2016. Many of the apparent trends were dominated by groundwater storage variations, and climate change appears to be a factor in some cases. In particular, water storage increases in northern Eurasia and Canada and decreases in northern Africa and southern Asia are consistent with climate model predictions.

        Speaker: Matthew Rodell (NASA Goddard Space Flight Center)
    • 10:30 11:15
      Coffee break 45m
    • 11:15 12:45
      Parallel: Tuesday Morning 1: Topic 1 Conference room 2.1 ()

      Conference room 2.1

      • 11:15
        Natural radioactivity of groundwater, the new challenge in drinking water quality: how can flow system approach help? 15m

        Uranium, radium and radon are usually found in groundwater, as moving groundwater interacts with its environment, it can mobilise, transport and accumulate these isotopes similarly to other chemical substances. As groundwater represents the main source of public drinking water supplies in many regions (EU 75%, Hungary 88%), presence of natural radioisotopes in groundwater may pose a hazard factor to the public. However, in accordance with Council Directive 96/29/EURATOM, the risk from ionising radiation must be kept as low as reasonably achievable. The Council Directive 2013/51/EURATOM, therefore, lays down requirements for the protection of the health of the general public with regard to radioactive substances in water intended for human consumption. This was implemented in Hungary in 2015. Thus, nation-wide overview of the radioactivity of drinking water in Hungary became available only recently, since waterworks and authorities are measuring and generating data only in the last three years. Based on the results 11% of the measured gross-alpha and 3% of gross-beta values are above the threshold values. This indicates that in areas where elevated gross values are found natural radionuclides may pose a health risk to the public.
        In general, however, there is no apparent relationship between the type of rock constituting the water-bearing formation and the observed activity concentration levels of the radionuclides, since wide ranges of activity concentrations of the radioisotopes are observed within the same aquifer. The theory of regional groundwater flow, however, puts previous observations in a different context. In case of redox-sensitive parameters, such as the uranium or radium, understanding groundwater flow systems is especially important. Areas of different hydraulic regimes – recharge, throughflow and discharge – as well as different order flow systems – local, intermediate, regional – even within the same aquifer are characterized by different geochemical environment. Groundwater flow system evaluation thus contributes to the understanding of the measured radioactivity in drinking water by providing explanation of the origin and transport of radionuclides. Furthermore, it helps to successfully predict favourable conditions for elevated radionuclide content enabling efficient and successful decision-making, resource management and involvement. Presented case studies based on the combination of flow system evaluation and nuclide specific analyses support the applicability and significance of this approach.
        This study was supported by the ÚNKP-17-4 and ÚNKP-18-3 New National Excellence Programs of the Ministry of Human Capacities. This topic is part of a project that has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 810980.

        Speaker: Ms Petra Baják (Eötvös Loránd University, Department of Geology, József and Erzsébet Tóth Endowed Hydrogeology Chair)
      • 11:30
        New evidence of recent recharge of the Continental Intercalaire transboundary aquifer, north-west of Algerian Sahara, using hydrochemical and isotopic technics 15m

        The northern Sahara contains vast transboundary aquifer system, including the Continental Intercalaire aquifer (CI) which is the main water reserve for those hyperarid regions. It is shared between Algeria, Libya and Tunisia.
        The piezometric map shows that the main groundwater flow comes from the “Occidental basin” considered as the principal recharge area of CI aquifer. However, it is the less studied part of all the aquifer.
        The hydrogeochemical data are really scare in the occidental basin even that some recent researches have demonstrated, using mathematical modelling of fluxes and satellite technics, that CI aquifer should receive more important recent recharge below dunes of occidental basin, where CI is unconfined, than it was expected in older studies.
        Our study has identified processes that control hydrochemistry of CI groundwater and discussed information got from stable and radioactive isotopes in the northern part of the occidental basin (Ghardaia region and neighbouring cities).
        We concluded that CI groundwater, there, behaves as two distinct groups, according to geographical localisation (north: Ghardaia region, and south: El Goléa region); the dissimilarities are much contrasted. Samples situated between 31.55° and 31.57°N of latitude represent a transition within the occidental basin. This finding corroborates previous observations from regional piezometry suggesting groundwater divide situated in this zone.
        In north, samples are highly mineralized, they belong to SO4-Cl-Na type; in south, they are poorly mineralized and predominantly belong to HCO3-Ca type. Actually, in north, CI aquifer is clay and gypsum-enriched, however, toward south it is almost totally sandy.
        Stable isotope data (δ18O and δ2H) shows that all samples are much depleted in both δ18O and δ2H comparing to the actual rainfall isotopic signature, but in south CI groundwater are more evaporated than in north. Such pattern suggests that CI groundwater has infiltrated under climate regime cooler than the current one. Moreover, southern samples seem to indicate a mixture with recent evaporated water.
        36Cl cosmogenic isotope results show that 36Cl/Cl ratio in south region is higher than 116×10-15 at/at considered in literature as “the initial ratio”. This finding gives two indications:
        • First, it confirms that CI groundwater in south is younger than it was expected previously.
        • Secondly, the initial 36Cl/Cl ratio supposed in literature is less than its real value.
        Later, we will use 14C and noble gases to reinforce our results and calibrate an initial 36Cl/Cl ratio more accurate with real data.
        As perspective of this work, we suggest to implement a monitoring network of CI in the occidental basin in the aim of more sustainable management of this valuable resource.

        Speaker: Mr YOUCEF HAKIMI (UNIVERSITY of LIEGE)
      • 11:45
        Groundwater assessment in sand rivers in adaptation to climate variability and water scarcity: opportunities and challenges in semi-arid Africa 15m

        Warm semi-arid regions, covering vast areas of the African continent, are frequently considered of low potential for agricultural development, due to a limited and highly irregular access to water. Notwithstanding, significant amounts of freshwater can be stored in thick sand beds of wide ephemeral rivers, formed as a consequence of pronounced dryland weathering and erosion. Additionally, the storage capacity of these so-called sand rivers can be enhanced through sand dams. Here we present the combined results from three studies on sand river storage potential, recharge, hydrodynamics and water quality, in Tigray Ethiopia, Shashane Zimbabwe and Limpopo Mozambique. Results were obtained through a combination of remote sensing, fieldwork, data analysis and numerical modelling. Fieldwork involved: i) data collection on climate, river discharge and groundwater levels; ii) drone surveying of sand river geometry and groundwater levels in large diameter wells; iii) field testing on aquifer hydraulic parameters; iv) geo-electrical surveying; v) manual borehole drilling and vi) sampling for hydrochemical and isotope analysis. Data obtained from the field and laboratory were used to improve the conceptual understanding of these sand river systems and subsequently build numerical models to simulate their behaviour under natural conditions and possible scenarios of sand river abstraction. All areas show very rapid recharge at moments of surface runoff, revealed by piezometry, major ion chemistry and stable isotope signatures. Recharge is so quick that it is believed to delay runoff significantly in its early stages. Hydraulic connection between the sand river and its banks appears generally limited, except where paleochannels are in connection with the main sand river. Drone imagery in combination with drilling did reveal influent and effluent reaches of the sand river in Tigray (Ethiopia), of a much smaller magnitude (20-30 m wide and 2-4 m thick) than those in the other two areas (200-500 m wide and 5-10 m thick). High water salinity forms a major challenge in Tigray, as the large hydraulic gradient within the sand river promotes continuous groundwater outflow at the two constructed sand dam sites, also revealed by isotope analysis. Pumping groundwater directly from the sand river, rather than using shallow wells dug in the river banks, could mitigate the salinization problem. Numerical models show that flow within the system is in the order of meters per day, that available storage is naturally depleted by evaporation, and that sand river abstraction results in lower evaporation losses, with the potential to irrigate up to several ha per km in the largest sand rivers. Seasonal depletion of storage will be rapidly restored upon river flow in the following wet season, but will also lead to a partial reduction in runoff, possibly affecting users downstream, including dependent ecosystems, which is a topic of further study.

        Speaker: Dr Tibor Stigter (IHE Delft Institute for Water Education)
      • 12:00
        Delineation of wellhead protection zones for the control of point pollution sources in the Lusaka Aquifer System, Zambia 15m

        The protection of groundwater resources is worldwide considered a task of high importance and imperative necessity due to their rapid deterioration and the subsequent risk of public health. A task that in its most common practical implementation is equivalent to the protection of water-supply wells through methods and techniques that result in the determination of site-specific protection areas around the individual wells. In the interior of these areas activities that might deteriorate the fresh water physical status, and particularly its chemical properties, are controlled and very often prohibited. In this study, we delineate water field protection zones for the Lusaka aquifer system. A numerical modelling process that consists of: a) the simulation of groundwater flow in the Lusaka Dolomite aquifer by applying the three-dimensional finite difference model MODFLOW and b) the delineation of protection zones for the domestic water-supply wells by applying the particle tracking post-processing package MODPATH. Regarding the flow model, a steady state model was developed and a calibration process was performed. The estimation of the hydraulic conductivity distribution was optimized using a trial-and-error technique. With regard to the particle-tracking process, two simulations were performed. The first simulation tracked from the water supply wells, while the second one tracked from point pollution sources. Finally, suggestions are given for the control and management of the identified potential point sources of pollution, especially if they are located within the protection zones of the examined water-supply wells.

        Speaker: Dr Kawawa Banda (University of Zambia)
      • 12:15
        DETERMINATION OF GROUNDWATER LEVEL INDICATORS AND THRESHOLDS LEVELS FOR GROUNDWATER DROUGHT MANAGEMENT 15m

        Monitoring the groundwater levels is required to predict groundwater drought and mitigate its impacts, so as to ensure sustainable water supplies and protection of the aquatic ecosystems. The quantitative status of the groundwater resource is assessed against specific groundwater thresholds levels, which constitute trigger levels that initiate and/or terminate management actions, e.g. early warning, enforcement of water restrictions, emergency responses, etc.
        While a vast majority of the published literature is proposing methods and indicators to characterise hydrological droughts, such as the threshold level method on river flow time-series or quantifying the rainfall deficit, very few are addressing the groundwater drought. In addition, methods suitable for hydrological time-series, mostly derived from statistical analyses, are seldom applicable to groundwater level time-series, because their characteristics do not fulfil the basic hypotheses for such analyses: due to aquifer inertia, groundwater level time-series are commonly auto-correlated, featuring significant trends and shifts, presenting data gaps and covering a relatively short time span. One notable exception is the recently developed Standardised Groundwater level Index (SGI), based upon the same methodology as the Standardized Precipitation Index (SPI). It can be applied to all type of aquifers, including those with multi-years cycle or displaying strong piezometric trends, and offers promising perspectives for the study of extremes events.
        Such study is currently carried out in the Grand-Est region in France to improve the existing drought management trigger levels. It aims at: (i) characterizing each groundwater level time-series from the main aquifers of the Grand Est region; (ii) establishing clusters of piezometers based on similar behaviour after a prolonged rainfall deficit; and (iii) proposing relevant drought management threshold levels determination methods for each group.
        For each time-series, in addition to basic univariate exploratory data analysis (EDA), the correlogram, the periodogram, the recession curve analysis, the SGI and its correlogram are computed. Correlations between the SGI and the SPI are assessed to characterize the potential relationship between a prolonged rainfall deficit and groundwater drought.
        Several parameters are tested to determine relevant groundwater indicators and thresholds, including:
        - The mean of the mean annual minimum (MAM for groundwater time-series, by analogy with the MAM for river flows) on a monthly groundwater level time-series;
        - The MAM-5 (5-years return period) when a statistical analysis is possible;
        - The SGI calculated for a period relevant to the aquifer’s dynamic (e.g. 1 month, 3 months, 6 months, etc.).
        Statistical tools are developed in the R environment and will be made available. Methods to determine groundwater level indicators and related drought threshold levels are formulated to each identified group of piezometers of the Grand-Est region. Thresholds levels are applied to documented historical drought episodes to test their relevance and robustness.

        Speaker: Mrs Delphine Allier (BRGM)
    • 11:15 12:45
      Parallel: Tuesday Morning 2: Topic 2 Conference room 2.2 ()

      Conference room 2.2

      • 11:15
        Response of spring discharge to climate changes in hard rock aquifers of different lithologies 15m

        Hard rock aquifers, either sedimentary (turbidites and arenites) or igneous (ophiolites), dominate the landscape of the northern Apennines (Italy), in a climatic framework midway between sub-tropical mediterranean and mountainous humid. The main rainfall events occur in autumn and spring, providing an average annual precipitation between 1000 and 3000 mm/y. On the northern slope of the Apenninic chain an increased interannual variability in precipitation and temperature regime was observed in recent years with extreme droughts (e.g. in years 2012 and 2017) alternated to more rainy years, e.g. 2014 and 2018 when extreme rainfall events were concentrated over short time periods. The effects of these recharge pattern modifications on spring discharge are still mostly unknown. Exploiting the available rainfall, snowfall, air temperature and spring discharge data from the monitoring network of Emilia-Romagna region, an analysis was carried out to assess the relationship between direct aquifer recharge and the discharge of springs on a hydrologic year time scale. Discharge was monitored on 77 springs draining 44 aquifer bodies pertaining to 7 different lithologies. The relationship between recharge and discharge was determined for 3 hydrologic years that were selected based availability of monitoring data (i.e. 2010-2011, 2013-2014, 2016-2017). The 62% of the investigated aquifer bodies showed a positive correlation between aquifer recharge and spring discharge. The 19% of aquifers didn’t show a clear recharge-discharge relationship whereas the remaining 19% showed a negative correlation. Positive correlations dominate in aquifers with large recharge areas located at high elevation and characterized by extended woodland cover. From a lithologic viewpoint, the aquifers showing the most positive correlation were calcareous turbidites and arenites followed by siliciclastic turbidites. Ophiolites and fewer outcrops of dolomites and limestones did show a neutral to negative trend. The occurrence of such negative trends may be related to increased runoff due to extreme rainfall events (i.e. more than 30 mm/h) over less forested and steeper recharge areas. The overall high percent of positive trends observed between direct recharge and average spring discharge proves that changes in rainfall regime are likely to cause significant effects on spring discharges even in the short term (i.e. over a year time scale). Moreover, the modification of rainfall patterns observed in the northern Apennines (e.g. increased rainfall compared to snowfall, lower on ground permanence of snow cover, increased occurrence of extreme rainfall events) are likely to cause significant decrease of direct recharge and thus a decrease of spring discharge. The significant interannual variability of rainfall occurred in the last years provided a good platform to evaluate the effects of climate change on aquifer recharge and spring discharge. The results may be used as well to evaluate the effects of future climate changes forecasted via emissions scenarios and global circulation models.

        Speaker: Dr Maria Filippini (University of Bologna)
      • 11:30
        A GIS-based water budget procedure used to evaluate groundwater resources under climate change scenarios 15m

        In the last years, water scarcity and drought severely affected southern Europe. Drought particularly afflicts Italy in different ways, mainly depending on the area hydrogeological setup and on the physical processes of precipitation-recharge interaction; the groundwater recharge decreases, due not only to rainfall reduction, but also to temperature increase. In southern Italy, the 1987-1993 period was probably the most critical,