Umvoto’s Andrew Mkali (Junior Environmentalist) recently passed his MSc entitled “Developing a hydrogeological conceptual model for subterranean groundwater control areas using remote sensing techniques”. Andrew’s study at the University of the Western Cape’s Environmental and Water Science unit was under the supervision of Drs. Thokozani Kanyerere and Kevin Pietersen. In his study Andrew described the physical hydrogeological characteristics of crystalline basement aquifers of the Hout Catchment (Limpopo River Basin, RSA).

Arguing that the comprehensive characterization of fractured rock aquifers is essential in establishing the influence of fracture connectivity on groundwater recharge Andrew’s study characterised local and regional features. Features such as faults and dikes, which can significantly alter flow and discharge paths in unanticipated ways, controlling subterranean groundwater flows. In the Hout catchment, the impact of such geologic features on water flows, particularly recharge and groundwater-surface water exchanges are unknown and causes problems to the management of the groundwater resources in the region.

Approach

Andrew made use of multiple methods including remote sensing and geophysical techniques, analytical methods to collect and describe geological, hydrostratigraphic, pumping test and water level data. By combing the outputs of these approaches Andrew characterised the fracture networks and assessed pathways for groundwater flow. Various datasets such as geophysical and hydrogeological data were used to develop the hydrogeological conceptual model for an experimental site in the Ga-Mamadila community. The model demonstrated the influence of connectivity in fractured rock network systems at a site-specific scale. The overall study showed that the use of remote sensing techniques coupled with geophysical and hydraulic parameter estimation methods for groundwater evaluation provided an improved understanding on the influence on fractures and their connectivity on crystalline basement aquifers for water resource and supply.

Work at Umvoto

Since joining Umvoto in 2020, Andrew has used the skills refined during his MSc to in undertaking hydrogeological desktop and field monitoring data collection and analysis. He has also incorporated elements of GIS and remote sensing for suitability mapping, sand dam siting, wetland reclassification and his analytical skills when reviewing reports, drilling supervision and databasing.