GIS and Spatial Evaluation of Groundwater Quality for Drinking and Irrigation Purposes in Thalaivasal Block, Southern India

Abstract

The knowledge of groundwater quality is useful in effective management of water resource in a basin. The present study was carried out to evaluate the groundwater quality for domestic and irrigation purposes in Thalaivasal block. The study area Thalaivasal block is located in Salem district, a typical hard rock terrain in the State of Tamil Nadu. The block is already categorized under ‘dark area’ by the State Groundwater Department. Groundwater quality data were collected for 54 locations from State Surface and Groundwater Resource Organization to understand hydro-geochemical characteristics of the groundwater in the block. The major elements and various hydro-geochemical parameters such as total hardness, TDS, salinity, SAR and Na% were studied to understand the groundwater quality. The Piper trilinear and Gibbs diagrams were plotted to know the dominance of groundwater chemistry and type. The results have shown that the majority of the groundwater samples fall in category I (Ca-Mg-Cl-SO₄) and IV (Ca-Mg-HCO₃) with normal earth alkaline water. The GIS spatial integration of various quality parameters indicates that about 40% of the area is not suitable for drinking and irrigation practices either in terms of undesirable or doubtful category. The final GIS output provided drinking water quality mapping with desirable, permissible, permissible water with hardness and unsuitable category. Similarly, irrigation water quality map was generated with excellent, good, doubtful and unsuitable category in the block.