Vadose Zone Hydrology in Engineering Geology and Hydrogeology (UP)
About this event
|The vadose zone stretches from land surface to the groundwater table, where moisture in intergranular pore space and rock defects occurs at variable water saturation and at negative pore water pressures.
Theory in the occurrence and movement of water in unsaturated conditions in soil and rock media is developing, with improved understanding reducing the uncertainty in conceptualizing and characterizing these complex systems. The vadose zone dictates how water exists and moves in the shallow subsurface.
This, in terms of engineering geology, inevitably leads to volume change of ground, changes in the corrosiveness of the subsurface, and seepage problems (such as seasonal perched systems and waterlogging), requiring mitigation. In terms of hydrogeology and hydrology, the vadose zone links the subsurface water cycle with the surface.
This directly determines groundwater recharge (preferential through complex soil-rock systems), advection rates and attenuation of contaminants, and greater interactions with surface water through interflow and eventual surface discharge. Applications are vast, expanding into hydropedology, foundation design, land use planning, and so forth, with specific examples to be presented around cemeteries, ingress in karst, pressure testing, slope stability, and/ or groundwater vulnerability.
This is a workshop deliverable to showcase research output from a Water Research Commission grant.
Matthys Oippenaar is presently employed as an associate professor of Engineering Geology and Hydrogeology at the University of Pretoria. His work and research are focused on the poorly understood cross-disciplinary field of water impacts on land-use change. Unsaturated flow and changes to the water budget in urban areas impact development and influence groundwater and surface hydrology, resulting in damage to infrastructure, change in water quality, and/ or loss in environmental integrity.