Hydrogeochemical status and geoelectrical characteristics of the shallow aquifers of Kalanad Basin, Kasaragod, Kerala, India

Abstract

Abstract Groundwater demand has increased due to overpopulation and intensive irrigation which resulted in decline of water resources and deterioration of water quality. In this view, a microlevel study was conducted through hydrogeochemical investigation and resistivity survey (VES) in Kalanad river basin, Kasaragod, Kerala. The study aims to determine the spatial variations in physicochemical parameters with delineation of geological layers of the study area through VES. Hydrogeochemical investigation and water suitability assessment for drinking and irrigation purposes were confined to open well water samples of the study area. The sample analysis and comparison with various standards (WHO and BIS) show that the groundwater is not entirely fit for drinking with respect to pH. Almost all samples fall within standard values as per the irrigation water quality indices. The chemical nature of the groundwater samples was dominated by alkalies and majority of the samples belonged to sodium chloride type. This study also dealt with the interpretation of hydrogeochemical data using correlation and R mode factor analyses. VES was carried out at seven locations, and the apparent resistivity values obtained had been analysed. The interpretation delineated a maximum of four geologic layers in the study area. The sequence of geologic formation is composed of highly resistive top lateritic soil followed by saturated zone and then the basement topography in the entire basin.

Keywords

• Hydrochemistry
• Ground water quality
• Vertical electrical sounding
• Kalanad river basin