Groundwater Potential Zoning in Upper Gadilam River Basin Tamil Nadu

The main objective of the study is to identify groundwater potential zones in the hard rocks area of the Upper Gadilam river basin in Vizhupuram district of Tamil Nadu. The study area lies between North Latitudes 11°40’ to 11° 58’ N and East Longitudes 78° 58’ to 79° 26’ 35” E. The drainage pattern in the area is dendritic to sub dendritic and at complex as trellis type. Based on drainage pattern, the study area has been divided into two watersheds viz., Gadilam watershed, and SeshaNadi watershed. The Gadilam stream is originate from MayanurGarudan spring of Garudan rock and traverses via.Pasarhill and Damal village before reaching the sedimentary contact near Thirunavalur. SeshaNadi is an ephemeral stream which is found almost to be dry throughout the year, excepting the surface water flow for few days in a year during rainy season. Hydrogeological, Geophysical studies has been carried out in the above aquifer. As a result the total groundwater abstraction has considerably gone up causing an overall decline of regional piezometric heads in this water table aquifer. With an integrated approach on using Remote Sensing and Geographical Information System (GIS). Topographic map has been used to prepare base map and generate thematic maps like geology, geomorphology, lineament and lineament density, drainage, drainage density, and slope maps has been prepared for the study area. A number of geomorphic units such as Inselberg, moderately buried pediplain, Pediment, Inselber complex, Pediplain, and Pediment Valley has been observed. A composite groundwater potential map has been generated as very high, high, medium, low and very low based on the groundwater availability in study area. The upper, middle and downstream of the basins have been identified as potential zones for groundwater exploration. The regions of lineaments and intersecting lineaments proved for groundwater potential zones. The data generated subjected to validate with field checks