4 states drawing too much groundwater

Punjab, Rajasthan, Haryana and Delhi are depleting at least 30% more of their groundwater resources than previously estimated by the government

New Delhi: Four north Indian states — Punjab, Rajasthan, Haryana and Delhi — are depleting at least 30% more of their groundwater resources than previously estimated by the government, a new report from the US National Aeronautical and Space Administration, or Nasa, says.

The study, conducted by a team of Nasa scientists is being published in Friday’s edition of Nature, a peer-reviewed scientific journal.

Unequal sharing: While only 58% of the country’s groundwater is recharged every year, Rajasthan, Punjab and Haryana are the only three states digging beyond the dynamic zone for groundwater. Ramesh Pathania / Mint

The scientists used satellite imagery from the Gravity Recovery and Climate Experiment, a pair of satellites launched by the space agency in 2002, that has to-date monitored Antarctic ice and the sea-floor displacement that triggered the Indian Ocean tsunami of 2004.

The scientists report these states depleted on average 17.7 billion cu. m. (bcm) of water annually between August 2002 and October 2008, more than the government’s estimates of 13.2 bcm in the same period.

They conclude that groundwater depletion in the region was equivalent to a net, irreplaceable loss of 109bcm, or nearly 20% of India’s annual water consumption of 634bcm.

The four states account for almost 114 million people, or almost 10% of the country’s population, and are dependent largely on irrigation for farming.

According to the Planning Commission, irrigation consumes 83% of the country’s annual water budget.

“We computed the uncertainty in our estimate to be about plus/minus 4.5 km3 per year, so the two estimates are reasonably close, but based on our analysis the annual deficit is a bit larger than previously believed,” Matthew Rodell, lead author of the study said in an email to Mint.

The authors of the study say that average rainfall was nearly the same during the period, thereby ruling out climate variability as the culprit for these depleting storage levels.

“The paper clearly says there’s a plus/minus 4.5 bcm error in the estimate. So on the lower side, that’s close to our estimate,” said B. N. Jha, chairman of the Central Groundwater Board, which monitors groundwater levels, using a reliable method of measuring water levels in a national network of 15,000 wells.

“When you take satellite measurements over such a large area, as opposed to physical measurement, there are bound to be errors,” Jha added.

Economic boom threatens water crisis: study

The study of three states in northwest India, found water was being extracted at an unsustainable rate as the region undergoes rapid economic development

New Delhi: Rocketing domestic use and farm irrigation have seriously damaged groundwater supply, and drinking water may become scarce, according to a study released on Wednesday.

The study of three states in northwest India, including the capital New Delhi, found that water was being extracted at an unsustainable rate as the region undergoes rapid economic development.

Water shortages are a growing concern in the country, with this year’s monsoon so far delivering only a fraction of the rainfall needed by farmers to save their crops.

Satellite and land data between 2002 and 2008 showed that the groundwater level was being depleted by about four centimetres a year, said the report by three US scientists and published in Nature magazine.

The extraction in the states of Rajasthan, Punjab and Haryana was the equivalent to 109 cubic kilometres (26 cubic miles) of groundwater which is far more than government estimates.

“The consequences for the 114 million residents of the region may include a reduction of agriculture output and shortages of potable (drinking) water, leading to extensive economic stresses,” the study’s authors said.

They said population growth, irrigation and development had put pressure on water supplies across India, where groundwater management is poor, and added that shortages could trigger social conflict.

In the short-term, the government this week warned that 80% of the country was threatened by drought due to the weak monsoon.

India’s hundreds of million farmers rely on the annual rains to soak the rock-hard earth and turn it into fertile soil.

Prime Minister Manmohan Singh moved to quash fears of hunger, saying that grain stores were adequate after two years of good harvests.

The study was conducted by Matthew Rodell of the NASA Goddard Space Flight Center in Maryland and Isabella Velicogna and James Famiglietti of the University of California.