The relationship between lineaments and borehole yield in North West Province, South Africa: results from geophysical studies

Airborne magnetic data and Landsat imagery, as well as time-domain electromagnetic soundings, were used to assess groundwater potential of the region around the town of Mafikeng in North West Province, South Africa. Lineaments were extracted based on on-screen digital data derived from magnetic and Landsat 7 imagery. The relationship between lineament-intersection density and borehole yield was assessed using statistical analysis. The results were discussed with respect to factors that determine the groundwater potential of the area. Correlation between lineament-intersection frequency and borehole yield is 60–65% in the south and southeastern parts, and 45–50% within 5–30 km radius of Mafikeng. The eastern and western parts of the study area are characterized by weak or no correlation. Areas that correspond to high correlation between lineament-intersection frequency and borehole yield suggest the significance of cross-cutting structures in controlling groundwater potential zones, while results that suggest low or no correlation represent the influence of other factors. The overall results demonstrate that the combined analysis of airborne magnetic data, satellite imagery, borehole yield and ground-based time-domain electromagnetic soundings provide the best approach for groundwater assessment within the hard rock and carbonate terrains of the study area.