Landscape-scale loss of scarce water resources due to gully erosion

Large-scale gully erosion of Quaternary deposits is a widespread problem in parts of Kwa-Zulu Natal province, South Africa. Gully erosion reduces access to valuable agricultural land. This presents a grave threat, particularly in areas where people continue to rely on subsistence agriculture. Recent research has suggested that, geomorphically speaking, such gully erosion may be inevitable and that it will continue into the future. The impact of changing climate on the susceptible colluvial hillslope deposits is unknown.

The hydrological consequences of gully erosion of shallow groundwater aquifers represented by colluvium-filled bedrock depressions on hillslopes is an area that has not received adequate research attention. The widespread gully erosion of Masotcheni Formation deposits has led to the virtual elimination of a whole class of hillslope wetlands.

A major research objective is understanding the storativity and transmissivity of the shallow groundwater aquifer characteristics of Quaternary colluvial deposits. It is likely that incision of the shallow aquifers leads to permanent lowering of the vadose zone and results in reduced baseflow contribution to tributaries. Considering the vast scale of erosion of these deposits, the impact on future seasonal groundwater contributions to rivers could have a significant impact on water availability to communities downstream during the winter period. This is of national importance for South-Africa because the rivers in KwaZulu-Natal provide water for the large rural population, feed the iSimangaliso Wetland Park World Heritage Site and even contribute to sustaining the industrial centre around Johannesburg

Students: 1 or 2 students
Required: SGL-33306 Geology and landscapes of the world; SGL-31806 Field training land science; Knowledge of ArcGIS;
Duration: minimum of 18 ECTS
Location: KwaZulu-Natal, South Africa and Wageningen
Period: can be negotiated
Supervision: Arnaud Temme
Theme: Theme 1