Water Resource Management (WRM) is being getting attention, due to overexploitation and climate change affecting water quality and quantity. Conjunctive use of ground- and surface-water is increasingly being a common practice, especially in rural areas, for ensuring crop production sustainability. ICT (Information and Communication Technology) solutions, such as GIS-integrated simulation models, are suitable candidates to evaluate water resources optimization for reducing the impacts of agricultural practices.
WRM in rural environments represented a hot topic within the HORIZON 2020 FREEWAT project. The main result of the efforts spent for this purpose is an open source and public domain, QGIS-integrated modeling platform for the simulation of several processes involved in the hydrologic cycle (e.g., groundwater dynamics, interaction with surface water, solute transport, conjunctive use of ground- and surface-water).
Within the FREEWAT platform, conjunctive use of ground- and surface-water is accomplished by the Farm Process (FMP) embedded in MODFLOW-OWHM (MODFLOW One-Water Hydrologic Flow Model). FMP integrates the hydrological budget calculated by MODFLOW-2005 with supply-and-demand components of irrigated agriculture on a farm scale.
Within the FREEWAT platform, FMP was coupled to the Crop Growth Module (CGM), a radiation-based model belonging to the EPIC family models, which simulates the crop growth cycle, and estimates crop yield at farm and basin scale, under different climatic and water supply constraints. The coupling between FMP and CGM is guaranteed by water availability in the unsaturated zone, and crop water demand and water uptake, as computed by FMP.
The FMP-CGM approach has been demonstrated through a synthetic application, where the growth cycle of irrigated sunflower in a Mediterranean area is simulated between 1st April and 31st August 2017. Model results show that the irrigation demand over the cropping season can be fully satisfied by natural uptake and surface water resources up to the end of May, while groundwater pumping is needed during the summer season, due to poor surface water availability and increased evapotranspiration demand. Supply-and-demand components of the irrigated area are quantified (e.g., rainfall recharge, irrigation by ground- and surface-water resources, root uptake, water percolation to the aquifer, evapotranspiration). Sunflower yield at harvest was also inferred according to weather and water availability conditions.
The proposed solution is thought to support the design of irrigation schemes for managing conjunctive use, thus reducing unplanned and unmanaged use of private irrigation wells. In this view, capacity building activities are needed to boost digitalization in the agricultural water sector for improving WRM.
This paper provides exploitation of the H2020 FREEWAT project (FREE and open source software tools for WATer resource management; www.freewat.eu) results. The FREEWAT project received funding from the European Union’s HORIZON 2020 research and innovation programme under Grant Agreement n. 642224.