ABSTRACT
ABSTRACT: For protection and management of groundwater resources it is essential that groundwater recharge is calculated. In semi-arid Namaqualand (South Africa), a recharge assessment was conducted using a geographical information system (GIS). The approach taken was based on assigning recharge probabilities, based on field experience, to a number of data sets and then combining these layers. The data sets included: geological lineaments; lithology; land cover; soil type; soil thickness; soil texture; slope and depth to groundwater. A groundwater recharge percentage map was produced and the results were applied to the mean annual precipitation to obtain the spatial distribution of recharge. As the data processing is GIS based, new data sets can easily be included and the processing swiftly completed. The GIS based recharge results correlated closely with point recharge calculations. Although the approach simplifies groundwater recharge mechanisms, knowing the spatial distribution of recharge enables improved resource protection and management.
