Hydrogeology and hydrogeochemistry of Nileshwaram river basin of Kerala, southern India

A hydrogeochemical study was conducted in the Nileshwaram River Basin (NRB), Kerala, Southern India, to identify the mechanisms responsible for the chemical compositions of the groundwater and to document geo-hydrochemical behaviourwith respect to drinking and agricultural supply standards. The groundwater samples were collected from bore wells, and dug wells to assess water quality variations. Residents of the basin face severe groundwater scarcity during the pre-monsoon season, impacting drinking water and domestic use. Over depends of bore wells, lacks of groundwater recharge, and the topographicalfeatures are contributed to drinking water shortages. The dominant hydrochemical facies of NRB is Ca2+–HCO3 type. The concentrations of Fe and Mn, exceeding maximum permissible limits recommended by WHO. Detailed geochemical analysis, including petrography and X-Ray Fluorescence (XRF), revealed that these elements originate from the weathering of basement charnockite rocks and associated mafic and ultramafic rocks and subsequent rock-water interaction processes. This study aims to provide a multidimensional perspective to address this critical issue and ensure the implementation of appropriate strategies for sustainable water management to reduce water quality degradation of NRB.