Samples of deep groundwater, river water and rainwater were collected for δ18O and δ2H analyses from an area of ∼22,000 km2 in the arsenic-affected districts of West Bengal, India, in order to examine groundwater recharge. A plot of δ18O versus δ2H of groundwater falls subparallel to the constructed local meteoric water line (δ2H = 7.2 δ18O + 7.7), suggesting a predominance of meteoric recharge with some evaporation. The stable isotopic signature of groundwater from the deeper part of the semiconfined main aquifer is similar to that of shallower groundwater, which suggests that deeper groundwater has been recharged in the present-day climatic regime, mostly from monsoonal rainfall. Groundwater in deeper isolated aquifers falls within the isotopic range observed for the main aquifer. A trend of isotopic depletion of groundwater that extends northward and westward from the Bay of Bengal (the monsoonal moisture source area) indicates a rain-out process following Rayleigh-type distillation. Some recharge may have taken place from the rivers Ganges and Bhagirathi-Hoogly, with minimal inflow from other rivers (Jalangi and Ichamati).
|Number of pages||11|
|Journal||Journal of Hydrology|
|State||Published - Feb 20 2007|
Bibliographical noteFunding Information:
This project could not have been executed without the cooperation of the Public Health Engineering Directorate, Government of West Bengal. However, the ideas presented in this paper are those of the authors and have not been officially endorsed by the Government of West Bengal or any other person or organization. Special thanks to P.K. De, A. Banerjee, A. Bhattacharya, and G. RoyChowdhury (PHED) for helping with selection of sampling sites. The authors gratefully acknowledge the immense assistance provided by T. Datta and B. Hazra (PHED), Barindra Lal Mukherjee and Murali Singh (Calcutta), Sudipta Rakshit (Plant and Soil Science, University of Kentucky), and Basanamoy Moitra (Shantipur) in sample collection; B.M. Engineering (KrishnaNagar) in supplying lithologs; Bob King (UK ERTL) and Dr. Chris Eastoe (University of Arizona) with sample analyses; Dr. Helena Truszczynska (UK) for helping with statistical analyses; and Dr. Steve Fisher (Kentucky Geological Survey) and an anonymous reviewer for comments on the manuscript. The project was financially supported by the University of Kentucky (Department of Geological Sciences, College of Arts & Sciences, and the Graduate School), the Kentucky NSF-EPSCoR program, and the Geological Society of America (Grant No. 7751-04). Last but not least, the authors are sincerely grateful to the inhabitants of West Bengal for the hospitality and cooperation provided during the fieldwork.
- Stable isotopes
- West Bengal
ASJC Scopus subject areas
- Water Science and Technology