Integration of Geology and Geomorphology for Groundwater occurrence in a hard rock region, Nakrekal basin, Nalgonda District, Telangana State, Using Remote Sensing and GIS Techniques

Abstract The Nalgonda district is one of the drought prone districts of Telangana and frequently being afflicted by famines. The study area, Nakrekal basin is a part of this district and covers an area of about 409 sq.km. Thematic layers of Drainage, Landuse and Landcover, Geology, Geomorphology, Thickness of Weathered zone, Second layer resistivity, Depth to Geo-electrical basement, Lineaments, Lineament buffers, Groundwater yields, Depth to water table have been generated by using toposheets (No. 56 O/8 and 56 0/12), IRS ID LISS III satellite imagery using remote sensing and G.I.S. techniques. In this study an attempt has been made to discern various geomorphological landforms in relation to understand fluviatile activity in the area and also classify various sub-surface lithology in the study area by field observations and on the base of satellite data. The land use/land cover analysis has been carried out using ERDAS Imagine 9.1 software package. Six types of land use/land cover categories have been identified in the study area. Also the drainage pattern is observed as medium to coarse textured and dendritic to subdendritic type, which is characteristic of hard rock terrain and develops in regions of homogeneity. The field data provides the information about the depth to water table, thickness of weathered zone, depth to geo-electrical basement, resistivity of the 2nd layer, the yields of the existing wells and the quality of the groundwater. The best suitable areas identified were mainly in shallow valley fill is mostly composed of sandy material, which are generally good to excellent of groundwater prospects. Areas with agricultural practice provided wide possibility for groundwater development with high lineament density and low drainage density. Most of the area posed good groundwater recharge capacity. The major lineament trends are northeast to southwest, northwest to southeast and north-south. It was observed during the field check that some of the wells falling in the influence zone of lineaments are showing high yields as compared to the well yields of the other area. Keywords: Hydrogeology, Nakrekal basin, Geology, groundwater and G.I.S.