water Article Groundwater of the Modder River Catchment of South Africa: A Sustainability Prediction Saheed Adeyinka Oke 1,* and Rebecca Alowo 2 1 Department of Civil Engineering, Centre for Sustainable Smart Cities, Central University of Technology, Bloemfontein 9301, Free State, South Africa 2 Department of Civil Engineering, University of Johannesburg, Doorfontein 2094, Gauteng, South Africa;
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[email protected] Abstract: This paper presents a spatial interpolation of the hydrological and socioeconomic processes impacting groundwater systems to predict the sustainability of the Modder river catchment of South Africa. These processes are grouped as climatic (factor A), aquifer sustainability (factor D), social-economic and land use (factor B), and the human-induced parameters of rights and equity (factor C). The parameters evaluated for factors A and D included climatic zones, precipitation, sunshine, evapotranspiration, slope, topography, recharge, yields, storativity, aquifer types, and lithology/rock types. Factors B and C included population in the catchment, use per capita, water uses, tariffs and duration of the permits, pump rate per year, number of issued permits per year in the catchment, and number of boreholes in the sub-catchment. This paper, therefore, looks at the impact of the average values of the chosen set of parameters within the given factors A, B, C and D on groundwater in the C52 catchment of the Modder River, as modelled in a sustainability index. C52 is an Upper Orange catchment in South Africa. The results are presented in sustainability Citation: Oke, S.A.; Alowo, R. maps predicting areas in the catchment with differing groundwater dynamics.