Spot Satellite Data For Exploration Of Fractured Aquifers In A Semi-Arid Area In Southeastern Botswana

In areas with little primary porosity and low bedrock hydraulic conductivity, hydrogeological properties are mainly determined by secondary factors, such as fracture zones and associated weathering. Fracture zones in areas with limited regolith cover are often detectable on satellite images as linear features originating mainly from pronounced vegatation anomalies, topographic effects or both. SPOT multispectral and panchromatic data of a 2000 km² semi-arid area in southeastern Botswana have, in this study, been merged and interpreted in an image processing system resulting in a detailed lineament map and a delineation of dry season vegetation. The lineament data have been analyzed in a geographical information system and correlation studies of borehole and geophysical data with satellite lineaments have been carried out. The study shows that a digital approach, using satellite data in combination with existing field data, can provide a time- and cost-effective tool for the identification and narrowing of target areas for groundwater exploration in semi-arid areas.