Mapping groundwater prospect zones in an intermontane basin of the Outer Himalaya in India using GIS and remote sensing techniques

In India, groundwater is the major source for fulfilling domestic and commercial water requirements. Since groundwater levels in various regions have been decreasing at a much faster rate in the last few decades, it has become important to delineate potential new zones of groundwater to meet future requirements. The intermontane basins in the Outer Himalaya have the potential to hold significant amount of subsurface water in a region that is currently water deficient. The present study discusses groundwater prospect zonation in the Soan Basin of the Outer Himalaya in Una District of Himachal Pradesh in India. ASTER DEM, LANDSAT 8 satellite data and existing geological mapping of the Himalayan foothills were used to prepare a groundwater prospect map of the Soan Basin. Various thematic maps including maps of geomorphology, drainage and land use map were prepared using LANDSAT 8 Satellite data and a geological map of Himalayan foothills using ARC GIS 10.0. Watershed and slope maps were extracted from ASTER DEM with 30 m resolution. A groundwater prospect map was prepared by overlaying the various thematic maps and was subdivided into five potential zones on the basis of potential discharge conditions. These are: regions bearing very low [< 50 L per minute (LPM)]; low (50-100 LPM); moderate (100-400 LPM); high (400-800 LPM); and very high (> 800 LPM) potential zones of groundwater. The high and very high potential zones are located in the central synclinal valley along the fluvial terraces, alluvial fans and piedmont deposits. The low and very low potential zones lie in the hilly areas with high slopes and rugged topography causing rapid downslope movement of water, which results in less infiltration and consequently deeper groundwater levels with a low groundwater potential.