Hydrogeochemical parameters for assessment of groundwater quality in a river sub-basin

Hydrogeochemical studies were carried out in the Ghataprabha River sub-basin to assess the quality and suitability of groundwater for domestic and irrigation purposes. In the present study, an integrated, geophysical and chemical investigation was carried out in the basaltic terrain. Groundwater samples were collected covering the entire major hydrogeological environment for one hydrological cycle. Comparison of the groundwater quality in relation to drinking water quality standards proves that most of the water samples are not suitable for drinking. Chemical indices such as sodium percentage, sodium adsorption ratio and chloroalkaline indices used for evaluating the water quality for irrigation suggest that the majority of the groundwater samples were good for irrigation. Positive values of 74% of groundwater samples indicated the absence of base exchange reaction (chloroalkaline disequilibrium) and negative ratio of 26% samples indicated a base exchange reaction (chloroalkaline equilibrium). Resistivity tomography studies revealed that the high concentration of total dissolved solids, chloride and sodium were due to the local anthropogenic activities and weathering of basalt rocks.