The monsoon-groundwater nexus, impacts and adaptation strategies in the northern part of Chennai region, South India

Abstract

The variations in groundwater quality and their influence on hydrochemical and microbial properties in the metropolitan cities of North Chennai have been scientifically examined in an attempt to comprehend the effects of urbanization. For this ongoing investigation, 50 groundwater samples from surface bore wells were collected in and around north Chennai, South India, during the pre-monsoon (PRm) season in June 2022 and 50 samples during post-monsoon (POm) in January 2023. Southeast of the desired extent, where urban enclaves predominate, has elevated salinity (12,500 mg/L) and electrical conductivity (EC) of 21,200 μS/cm. The predominant types shown in the Piper and Chadha models were sodium-chloride (Na-Cl). Additionally, the Gibbs diagram revealed the observation of evaporation dominance. The interaction between freshwater and seawater has been shown using ionic ratio analysis. A majority of the sample locations indicated the levels of standard plate count (SPC) and total coliforms (TC) contamination in the groundwater were above allowable limits (WHO). There was a slight improvement in groundwater quality during the post-monsoon session suggesting to a possible effect from recently recharged groundwater. In general, the groundwater quality of the research area is impacted by lithological changes, land use, and urban development. Water quality study may be useful in identifying potential health concerns and notify decisions about water management and treatment policies.