An Overview of the Groundwater Situation in Namkhana Block, Sundarban Biosphere Reserve, India, from the Pinnacle of a Propagating Delta Front: A Post-Monsoonal Survey

This study is a real-time hydrogeological investigation to appraise the groundwater scenario and spatial variations of its major physicochemical parameters at the southernmost apical fringe of the Indian Sundarban Biosphere Reserve area in mesoscale during the recent post-monsoon season (PoM). The study was based on the acquisition and analysis of primary field data collected from the southernmost apex of the river Ganga-Brahmaputra-Meghna delta and restricted to the Namkhana Development Block of South 24 Parganas district, West Bengal, India. Twenty-two groundwater samples were collected from bore wells post-monsoon (October 2022). Measurements of major physical parameters were done in situ. Geospatial contour maps representing variations of influencing parameters were prepared. The drinking and irrigation suitability of the water was validated by existing standard equations and plots. Chemical analyses were done to evaluate its hydrochemistry and suitability for drinking and agriculture. Obtained results primarily revealed that TDS and pH are at marginal ranges with significantly alarming concentrations for some major contributing ions, chiefly bicarbonates, and sodium. The overall suitability of groundwater for agriculture, drinking, and domestic purposes differs from acceptable limits. Indiscriminate groundwater exploitation from deeper aquifers for agriculture seemed to be the prime factor responsible for this situation.