Spatial assessment of groundwater vulnerability using DRASTIC model with GIS in Uppar odai sub-watershed, Nandiyar, Cauvery Basin, Tamil Nadu

Groundwater plays an important role in supplying water to much of the global population for use in agriculture, drinking water and industrial purposes. Physical and economic water scarcity occurs on all of the populated continents, with some parts of the world facing a genuine water crisis. Water quality problems are both natural and anthropogenic in nature and there is an urgent need to conduct studies on groundwater pollution. The objective of this paper is to find the groundwater vulnerable zones in Uppar-Odai sub-watershed using DRASTIC model with Geographical Information System (GIS). DRASTIC model uses seven data layers which acts as the input for the modelling. The seven data layers are Depth to water, Net Recharge, Aquifer Media, Soil Media, Topography, Impact of Vadose zone and Hydraulic Conductivity. ARCGIS 10.3 GIS software were used to map the groundwater vulnerable zones of study area. This GIS technique has provided a competent tool for analysing the vulnerability to groundwater pollution. The study reveals that 62 per cent of the sub-watersheds groundwater falls under medium vulnerability to water pollution which is the main cause for the people living in the study area. From the study, it is suggested that this model is an effective tool and can be used by the groundwater managing authorities.