HYDROGEOLOGICAL ASSESSMENT OF HIGH SALINITY IN GROUNDWATER IN PARTS OF BHARATPUR DISTRICT, RAJASTHAN, INDIAVikas Rena, Vikas Kamal, Deepali Singh, Nidhi Roy, Anamika Shikha and Saumitra Mukherjee
Hydrochemical analysis of groundwater characteristics and statistical interpretation assist to evaluate the development of high salinity in groundwater. The present study comprises of a watershed catchment boundary covering parts of Deeg, Kaman, Nagar, Pahari and Kumher tehsils of Bharatpur district in Rajasthan, India. Groundwater plays a key role to meet the water demand for various purposes in the study area having no perennial river-system. Therefore, groundwater samples were collected during Pre- and Post-monsoon seasons for a comprehensive understanding of hydrochemistry within the region. The hydrochemical results of groundwater samples for both the season revealed the dominance order of major anions as Cl- > HCO3- > SO4-2 > NO3- > CO3-2 > F- > PO4-3 and the major cations as Na+ > Ca+2 > Mg+2 > K+. The hydrochemical analysis results indicated the Na-Cl water-type as governing character of groundwater with higher salinity during Post-monsoon season as compared to Pre-monsoon season. The seasonal variation of salinity level in groundwater within the tehsils are confirmed by the spatiotemporal distribution maps based on (Inverse Distance Weighted) interpolation method using ArcGIS 10.2. The scatter plots between different hydrochemical attributes suggested the direct-ion exchange, mineral dissolution, rock dominant weathering and crystallization contributing high salinity in groundwater. The weathering of aquifer materials and mineral (halite) dissolution with the infiltration of recharge water augmented the total dissolved solids in the groundwater. The prevalence of shallow aquifers, overdraft of groundwater and semi-arid climatic conditions also supported the hydrogeochemical processes associated with the development of salinity in the groundwater.