A Modelling Framework for Groundwater Sustainability in the Upper Orange Catchment of South Africa

Sustainability modelling of the C52 Upper Orange Catchment was done for 52 boreholes. This Modelling framework was developed because in arid and semi-arid areas of South Africa, farmers and communities only have a limited number of water provision points. This has put more pressure and increased the number of wells and boreholes being drilled where they can access groundwater which is needed for multiple purposes especially agriculture and drinking water provision. Excessive pumping can lead to groundwater depletion, where groundwater is extracted from an aquifer at a rate faster than it can be replenished. This will put undue pressure on aquifers and catchments such as the Upper Orange (Modder). The methodology involved a detailed understanding of the parameters and ranking of the physical processes affecting groundwater system of the upper orange river catchment for 51 boreholes such as the climatic factors, aquifer system, rights, and equity. This model assessed whether there is undue pressure on the Upper Orange Catchment. The result and findings have been presented in a sustainability index. The outcome was a sustainability map showing areas depicting the most to least sustainable aquifers in the catchment. The developed sustainability index and maps are useful tools for future groundwater management.