Hydrogeochemistry and its relationship with land use pattern and monsoon in hard rock aquifer

Abstract

Abstract Influences of land use and monsoon recharge on groundwater geochemistry in the hard rock aquifer in south India are studied using geochemical modelling, geochemical and geospatial tools, and Pearson correlation analysis (PCA). Groundwater samples were collected from 2017 to 2019 (n = 267) and analysed for EC, pH, major ions, and minor ions. Water samples were classified into urban (n = 89) and agricultural (n = 178) regions based on land use patterns. Groundwater is very hard (Total Hardness > 180 mg/l; 74%), and the predominant water types are Ca–Mg–Cl followed by Na-Cl. In the agricultural region, groundwater is less mineralized (TDS 100 mg/l; 176 to 9 km2), Cl (< 200 mg/l, 1975 to 2747km2) and HCO3 − distributions. The outcome of this study highlights that urban wells are highly polluted and need proper management practices to protect this hard rock aquifer.

Keywords

• Groundwater
• Hydrochemistry
• Geochemical modelling
• Land use
• Monsoon
• Hard rock aquifer