Webgis enabled integrated approach for identifying groundwater prospect zones in sita-Swarna Basin, Karnataka, India

Groundwater is an important natural resource which is used for meeting domestic, industrial and agricultural requirements, but its availability is depleting due to overexploitation, misuse and intensive urbanization. Therefore, the assessment and management of groundwater resource in an integrated method is a need of the hour. The Remote Sensing (RS) and Geographic Information System (GIS) techniques have been used in the present study to estimate the groundwater prospect zones in Sita River and Swarna River basins of Udupi district, Karnataka. The study area falls between Latitudes 13°08’00” & 13°35’00” N and Longitudes 74°41’00” & 75°11’00” E and covers an area of 1228.05 sq. km. The assessment of prospective groundwater zones for the study area is carried out using satellite data in conjunction with conventional methods to characterize the terrain and aquifer parameters, followed by their integration and public serving using GIS tools. A groundwater prospect map has been prepared by considering the major controlling factors, such as geomorphology, geology & structures, lineament density, soil, slope, drainage density, surface runoff and land use/land cover. Based on the-contribution to groundwater, all these themes and their individual features were assigned weights and their corresponding normalized weights were obtained based on Saaty`s (1980) analytical hierarchy-process (AHP). The thematic layers were finally integrated using weighted overlay analysis in GIS software to yield a groundwater prospect zone map of the study area. Different groundwater potential-zones were marked as ‘very good’, ‘good’, ‘moderate’, ‘low’ and ‘very low’. The prospect zones so delineated were validated with the existing borewell data collected from secondary sources. It is con-cluded from the study that the integration of remote sensing and GIS technologies are very efficient and useful tools for the identification of groundwater prospect zones.