A GIS based identification of groundwater recharge potential zones using RS and IF technique: a case study in Ottapidaram taluk, Tuticorin district, Tamil Nadu

This study is an approach to better estimate the groundwater recharge potential zones using geographical information system (GIS), influence factor and RS techniques. This concept has been applied in Ottapidaram taluk in Tuticorin district to determine the overall groundwater recharge potentiality. Survey of India toposheets and Indian Remote Sensing-1C satellite imageries are used to prepare various thematic layers such as: lithology, slope, land use, lineament, drainage, soil, and rainfall. These layers were then transformed into raster data using the feature to raster converter tool in ArcGIS 9.3 software. Subjective weights are assigned to the respective thematic layers and overlaid in GIS platform for the identification of potential groundwater zones within the study area. These potential zones were categorized as 'high', 'moderate', and 'low' zones with respect to the assigned weightage of different thematic layers. The results reveal that the areas of good groundwater potential are estimated to cover 260.25 km(2) (35 % of the study area), moderate potential 297.43 km(2) (40 %), and low potential 185 km(2) (25 %). Moreover, only 34 % of the total average annual precipitated water (680 mm) percolates into subsurface and ultimately contributes to recharge the groundwater. These results suggest that the high potential zones will have a key role in future expansion of drinking water and irrigation development in the study area.