Groundwater replenishment noted in west, south India: Scientists

An international team of researchers, including experts from IIT-Kharagpur and NASA, has reported discernible groundwater storage replenishment in certain Indian regions, in a new study, attributing it to changes in strategy in the public and private sectors.

Published in the Nature Scientific Reports in August, the study says this groundwater storage (GWS) rejuvenation may possibly be attributed "to implementation of ingenious groundwater management strategies in both Indian public and private sectors".

A research team from IIT-Kharagpur in collaboration with NASA scientists, has observed regional-scale groundwater storage replenishment through long-term (1996-2014, using more than 19,000 groundwater observation locations) ground-based measurements and decadal-scale (2003-2014) satellite-based groundwater storage measurements, in large parts of India.

While the northern and eastern parts of India are still undergoing acute usable groundwater depletion and stress, encouraging, replenishing groundwater scenarios are detected in western and southern India under proper water resource management practices, the study notes.

"Our study shows that the recent paradigm shift in the Indian groundwater withdrawal and management policies for sustainable water utilization, probably have started replenishing the aquifers by increasing storage in western and southern parts of India," said research leader Abhijit Mukherjee from IIT-Kharagpur on Friday.

The team used numerical analyses and simulation results of groundwater management policy change effect on groundwater storage changes in western and southern India for this study.

Mukherjee drew attention to the recent changes in Indian central/state government policies on groundwater withdrawal and stress on management strategies.

Strategies such as restriction of subsidized electricity for irrigation, separate electricity distribution for agricultural purposes (e.g. Jyotigram Yojana), construction of large-scale, regional enhanced recharge systems in water-stressed crystalline aquifers (Tapti river mega recharge project), Pradhan Mantri Krishi Sinchayee Yojana, enhanced recharge by interlinking of river catchments (e.g. Narmada-Sabarmati interlinking), will probably start replenishing the aquifers by increasing groundwater storage in near future.

Chief of Hydrological Sciences Laboratory Matthew Rodell at NASA Goddard Space Flight Center, helped in interpreting the NASA satellite (GRACE) data (2003-2014) of groundwater storage changes in India for this study.

The co-authors are -- Yoshihide Wada affiliated to International Institute for Applied Systems Analysis, Austria; Siddhartha Chattopadhyay of Indian Institute of Technology, Kharagpur; Isabella Velicogna and Kishore Pangaluru from University of California, the US; James S. Famiglietti of Jet Propulsion Laboratory, California Institute of Technology in Pasadena, the US.

"We conclude that in India, where huge groundwater consumption is widely known to be leading to severe dwindling of groundwater resource in recent times, previously unreported, discernible GWS replenishment can also be observed in certain Indian regions," said lead author Soumendra Bhanja affiliated to Hydroscience and Policy Advisory Group, Department of Geology and Geophysics at the Indian Institute of Technology, Kharagpur, as well as to Hydrological Sciences Laboratory, NASA Goddard Space Flight Center.

--IANS

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