GIS based seasonal variation of groundwater quality and its suitability for drinking in Paravanar river basin, Cuddalore district, Tamil Nadu, India

686-694Groundwater quality in Paravanar river basin has significant characteristics and its consideration is unavoidable, since it’s a major source of water for drinking, industries and irrigation usage. The present study was carried out to assess the groundwater quality suitability for drinking in Paravanar river basin, Cuddalore district, Tamil Nadu, India. The rainfall frequency analysis was carried out in the basin area from 1971 to 2015 to delineate rainfall prominence years as drought, average rainfall, 75 % dependable rainfall and recent rainy years. In this study, nine parameters i.e., Electrical Conductivity (EC), pH, Total Dissolved Solids (TDS), Total Hardness (TH), Calcium (Ca2+), Magnesium (Mg2+), Chloride (Cl-), Sulphate (SO42-) and Nitrate (NO3-) were considered for computing the Water Quality Index (WQI) for the rainfall dependability years (1974, 1991, 2009 and 2015) by using weighted arithmetic index method for drinking purpose. Weighted overlay maps were prepared from the spatial distribution layers pertaining to WQI for the post and pre-monsoon seasons for the rainfall dependability years using ArcGIS 10.3. The results showed that the quality of water in Paravanar river basin was highly affected during post-monsoon than pre-monsoon period. More than 50 % of the basin area water samples weren’t really good enough for drinking without taking up water quality managing activities during post monsoon. Further, the water quality was highly degraded due to industrialization and agriculture activities compared to urbanization. The pollution control measures to improve the hazardous environment of industrial and agricultural practices, may develop the suitability area for drinking water in the basin