Use of earth observation images and GIS techniques for groundwater exploration in hard rock terrain

Prolonged drought and improper maintenance of water resources increased the demands on ground-water supplies resulting are focuses for the need to evaluate ground-water resources in the hard rock terrain. In recent years, Remote-Sensing methods have been increasingly recognized as a means of obtaining crucial geo-scientific data for both regional and site-specific investigations. This work aims to develop and apply integrated methods combining the information obtained by geo-hydrological field mapping and those obtained by analyzing multi-source remotely sensed data in a GIS environment for better understanding the Groundwater condition in hard rock terrain. In this study, digitally enhanced Landsat ETM+ data was used to extract information on geology, geomorphology. Hill-Shading techniques are applied to SRTM DEM data to enhance terrain perspective views and to extract Geomorphological features and morphologically defined structures through the means of lineament analysis. A combination of Spectral information from Landsat ETM+ data plus spatial information from SRTM-DEM data is used to address the groundwater potential of alluvium, colluvium and fractured crystalline rocks in study area. The spatial distribution of groundwater potential zones shows regional patterns related to lithologies, lineaments, drainage systems and landforms. High yielding wells and springs are often related to large lineaments and corresponding structural features such as dykes. The results demonstrate that the integration of remote sensing, GIS, traditional fieldwork and models provide a powerful tool in the assessment and management of water resources and development of groundwater exploration plans.