Relationship between lineaments and ground water occurrence in western Botswana

A semiarid region of western Botswana, the Ghanzi-Makunda area, is the focus of a study to determine the relationship between lineaments and well yield. This relationship is inferred from geologic maps, aerial photographs, and Landsat TM (thematic mapper) images in conjunction with a well yield map produced using indicator kriging and based on 226 globally positioned wells. A composite image of Landsat TM, digital well yield, lineament trace, and well location data, formed using a raster-based geographic information systems (GIS) technique, visually identifies a correlation between well yield, lineament density, and darker tones on Landsat TM images. Higher fracture densities correlate positively with higher well yields, Regression analysis identifies a statistically significant correlation between distance to lineament intersections and median well yield.