An Evaluation of Hydrogeochemistry of Groundwater in Upper Vellar Sub – Basin Using Mineral Stability and Solute Transport Modelling

The absence of perennial river, semi arid climatic condition and growing neediness of water increased the usage of groundwater. In the area proposed for the study, all the water necessities are fulfilled with groundwater. Hydrochemistry of groundwater is influenced by geogenic and anthropogenic sources. Hence to assess the chemical characteristics of groundwater in the study area, a total of 74 groundwater samples were collected and analyzed for physical parameters such as pH, conductivity and Total Dissolved Solids along with major cations and anions using standard procedures. The dominant cations and anions were, Na > Ca > Mg > K and HCO >Cl> NO3 > F > PO4 >SO4 respectively. Hydro chemical facies demarcated were NaCl, CaNaHCO3, CaHCO3 and CaMgCl. The facies suggests ionic exchange, dissolution, silicate weathering and anthropogenic sources are responsible for the variation in groundwater chemistry of the study area. The silicate group minerals show over equilibrium conditions sulphate and halide group minerals indicate under saturation condition. The saturation values trend increases along the flow path. Identified hydro geochemical process were verified and quantified using hydro geochemical inverse mass-balance modeling (net geochemical reactions along a flow path,PHREEQC,WATQ4F).