A satellite-based study covering the states of Rajasthan, Punjab, Haryana and Delhi has revealed that ground water in northern parts of the country is depleting at an alarming rate of 4.0 (±1.0) cm a year or 17.7 (±4.5) cubic km a year.
The study on 'Satellite-based estimates of groundwater depletion in India' was published in the August 2009 issue of scientific journal 'Nature' by scientists from the National Aeronautics and Space Administration (NASA) and University of California, Sanwar Lal Jat informed the Rajya Sbha today in a written reply.
The scientists have estimated ground water depletion in north-western India using terrestrial water storage (TWS) change observations from NASA Gravity Recovery and Climate Experiment (GRACE) satellite data for the August 2002 to October 2008 period.
The study covering an area of about 4.4 lakh sq km across the states of Rajasthan, Punjab, Haryana and Delhi, was taken up without actual field mapping of ground water levels.
The Central Ground Water Board (CGWB), however, disagrees with what was observed in GRACE mission's ground water storage studies and says its own studies based on field data shows only smaller scale variations in the ground water storage pattern over a vast region.
Excessive withdrawal of ground water for various purposes, including irrigation, domestic and industrial are some of the factors responsible for decline in ground water levels and in many areas ground water recharge is reduced due to varied and erratic rainfall pattern as well as change in land use. The central government, meanwhile, said it has taken several steps to manage ground water level in the country which include:
- Mahatma Gandhi National Rural Employment Guarantee Act (MGNREGA) has special focus on water conservation and water harvesting structures to augment ground water.
- The government had taken up demonstrative artificial recharge projects were taken up during XI Plan under central sector scheme, ''Ground Water Management & Regulation''. The scheme on artificial recharge project under Ground Water Management and Regulation Scheme has been discontinued during the XII Plan period.
- A conceptual document entitled ''Master Plan for Artificial Recharge to Ground Water in India'' has been prepared during the year 2013, which envisages construction of different types of artificial recharge and rainwater harvesting structures in the country in an area of 9,41,541 sq.km for harnessing surplus monsoon runoff to augment ground water resources. The Master Plan has been circulated to all state governments for implementation.
- Ministry of urban development in its draft model building bylaws (2015) has incorporated a chapter on provision of rain water harvesting.
- Central Ground Water Authority (CGWA) constituted under 'The Environment (Protection) Act, 1986' for the purpose of regulation and control of ground water development and management has issued advisory to states/ union territories and the ministry of urban development to take necessary measures for adopting rain water harvesting/ artificial recharge in all the government buildings. Besides, 30 states/UTs have made rainwater harvesting mandatory by enacting laws / formulating rules and regulations / by including provisions in building bye-laws / through suitable government orders etc.
- CGWB has been organising mass awareness programmes in the country to promote rain water harvesting and artificial recharge to ground water.