22-27 September 2019
Trade Fairs and Congress Center (FYCMA)
Europe/Madrid timezone

How ground gets wet: physical experiments of variably saturated flow

23 Sep 2019, 11:30
15m
Auditorium 2 ()

Auditorium 2

Oral Topic 5.3 - Advanced modelling tools for subsurface hydrology: from the vadose zone to deep environments Parallel

Speaker

Dr Matthys Dippenaar (University of Pretoria)

Description

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.

Primary authors

Dr Matthys Dippenaar (University of Pretoria) Ms Mampho Maoyi (University of Pretoria) Dr Brendon Jones (GaGE)

Presentation Materials

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