Assessment of hydrological and hydrochemical vulnerability of groundwater in semi-arid region of Rajasthan, India

The aim of this study was to provide the overall assessment and identification of vulnerable area using the quantitative, qualitative and socio-economic assessment of groundwater resources in Kishangarh Tehsil of Ajmer district, Rajasthan, India. In quantitative assessment, the runoff and net recharge was estimated using the Soil Conservation Service Curve Number (SCN-CN) and water balance methods, respectively. While qualitative assessment was performed by conducting groundwater sampling and analyzing the different hydrochemical parameters. Finally, socio-economic assessment (SEA) was done by gathering information through questionnaire survey focused on groundwater issues with the native people. All three assessments were integrated to evaluate groundwater resource vulnerability. The water balance of area shows very low recharge rate, even during the monsoon season. The soil in the area has only a 0.04% total annual net recharge coefficient and extremely high concentrations of copper, and fluoride, as well as high salinity, and hardness. The hydro-geochemical condition of the drinking water was extremely worse. PCA analysis indicates that an increase in first principal component was associated with the increase in copper and chromium, while the increase in second component was linked to the increase in fluoride, iron and cadmium. Sampling locations tends to be clustered into three quadrants of the Cartesian plane. This suggests an increase in contamination when moving along the bisecting line away from the origin of the Cartesian plane. The groundwater from the location of the first group (Ankauriya, Sinodiya, Nosal, and Jajota) tends to be highly polluted because of the parameters of both first and second components. Furthermore, socio-economic assessment also reported that the groundwater resources showed high vulnerability. This study may help in planning groundwater management strategies and technological approaches for the sustainable natural resources development.