Estimation of Groundwater Recharge Using GIS Method: A Case Study of Makotopong Village-Polokwane, South Africa

摘要

South Africa is a relatively dry country, with most rural areas experiencing high demand for water supply. Groundwater is one of the best alternative sources that can be used to augment the demand. However, this cannot sus-tainably be achieved unless accurate prediction of recharge to the groundwater aquifer is done. The objective of the study was to accurately estimate the groundwater recharge using ArcGIS method with a view of ensuring adequate groundwater for water supply exploitation. The study was conducted in Makotopong village in Polokwane. Data used in the study were sourced from diverse governmental agencies. Borehole logs were obtained from National Groundwater Archives. Geological and hydrogeological data were obtained from Council for Geoscience. All captured data were analysed to show the rainfall variations and estimation of groundwater recharge in different years. Groundwater recharge was estimated using ArcGIS 10.5. The simulated annual groundwater recharge varied from 0 mm to 51 mm with a mean recharge value of 12.04 mm/yr. The estimation of groundwater recharge using GIS methods resulted in a mean recharge value of 12.04 mm/year which shows a close comparison with previous studies conducted using Chlorine Mass Balance (CMB) and Water-Table Fluctuation (WTF). This implies that GIS is a potential tool that can be used to estimate groundwater recharge. It is recommended that GIS Method of estimating recharge be used in designing optimal sustainable groundwater supply systems.