Ground water depletes in North

In Punjab, Haryana, Rajasthan and Delhi, table came down by 4 cm every year between 2002-08

Using images from a NASA  satellite that can sense water stored in all levels including groundwater, US scientists have estimated that in Punjab, Haryana, Rajasthan and Delhi, the groundwater table has come down by four cm every year between 2002 and 2008.

This means, almost 18 cubic km of water is getting vanished from underground aquifers in these states, leading to a 109 cubic km of groundwater in 6 years –– more than the water stored in some of world’s big surface reservoirs. Total water loss is equivalent to double the capacity of India’s largest surface reservoir (Upper Wainganga in Madhya Pradesh) and triple the capacity of the US’ largest man-made reservoir, Lake Mead. The deficit is much more than what the government has estimated, the team reported in the online edition of Nature on Wednesday. The unsustainable rate of groundwater depletion, they said, could lead to severe water shortages and reduced farm productivity.

Researchers from NASA’s Goddard Space Flight Centre and University of California warned that unless quick counter measures were adopted, 1,14,000,000 residents of the region might face a shortage not only agriculture produce but potable water too.

The new findings are contrary to the estimates made by the Union Ministry of Water Resources.  “Our result implies that the portion of irrigated water that replenishes aquifers and the rate of (groundwater) withdrawal is more than the government estimate,” they said. While 2002 was a dry year, 2003 and 2008 were wet years and rainfall in the other years was within a few centimetres of normal. According to researchers, the reduction cannot be attributed to natural climate variability –– there was no rainfall decline in those six years –– but is probably caused by excessive irrigation and other human activities.

The findings come a day after the Meteorological Department indicated towards the alarming possibility of a drought by downgrading its seasonal forecast for the country to 87 per cent of its regular monsoon quota (88 cm) from its June forecast of 93 per cent.

Lower rainfall leads to more pressure on the ground water further lowering the water table.