GIS Techniques to Assess Groundwater Potential Zones

The availability of surface water is reduced by deficit rainfall due to global climate change, rapid urbanization, and industrial developments, which induced the need for the identification of groundwater potential zone. A case study was conducted to find out the groundwater potential zones in Kattakulathur block, Tamil Nadu, India with an aerial extent of 360.60 Sq. Km. Initially, the thematic maps such as geology, geomorphology, soil hydrological group, land use/land cover, and drainage map were prepared for the study area. The Digital Elevation Model (DEM) has been generated from the 10 m interval contour lines (which is derived from SOI, Toposheet 1:25000 scale) and obtained the slope (%) of the study area. The groundwater potential zones were obtained by overlaying all the thematic maps in terms of weighted overlay methods using the spatial analysis tool in ArcGIS 9.2. During the weighted overlay analysis, the ranking was given for each parameter of each thematic map, and the weightage was assigned according to the influence such as soil – 25%, geomorphology – 25%, land use/land cover – 25%, slope – 15%, lineament – 5% and drainage/streams – 5% and find out the potential zones in terms of good, moderate and poor zones with the area of 49.70 Km2, 261.61 Km2 & 46.04 Km2 respectively. The groundwater potential zones have been derived for the entire Kattankulathur block and it had been divided into three categories as good, moderate and poor zones. The village boundary map was superimposed over the potential zone-wise study region, yielding the village-wise groundwater potential zones classified as good, moderate, and bad zones. The validation of this GIS-based output result was carried out through a field survey in which GPS sensors were used to randomly identify wells in various settlements. The coordinates of each well location was obtained by GPS and plotted in the GIS platform and it was clearly shown that the well coordinates were exactly seated with the classified zones.