August 13, 2009

life in general: largest rate of groundwater loss on earth

"This is probably the largest rate of groundwater loss in any comparable-sized region on Earth." that study said.

Now, thats chilling .

Its the last line of a latest news story on water woes on our Mother Earth. The focus is on India but coming from a study conducted by a non-Indian entity. Many affluent, educated Indians tend to arrogantly disregard any warnings given by Indian ecologists/environmentalists but do not mind being open to reading about the same coming from international groups. I know of a Editor-in-chief of a top business magazine in India who with unabashed arrogance criticises everything that is written by the head (who is Sunita Narain) of an Indian enviro
nmental group, Delhi-based Centre for Science and Environment.

Anyway, even as many urban and semi-urban Indians use water in an excessi
ve, wasteful manner (see the pic alongside for one such wasteful use -- it is of a water park in Bombay, Water Kingdom, operated by a Zee Group company -- I took this pic in Dec '03 specially for a water story i wrote in a Bombay-based NGO's montly magazine), I am reproducing the news report in totality below and after that a summary of the original report in Nature magazine's latest issue. Study sees dramatic drop in Indian groundwater By TIM SULLIVAN (AP)
NEW DELHI — Excessive irrigation and the unrelenting thirst of tens of millions of people are causing groundwater levels in northern India to drop dramatically, a problem that could lead to severe water shortages, according to a study released Wednesday.
The study comes as India's struggles with water have become a major political issue. The problem reaches across the country's vast class divide, touching everyone from residents of elite neighborhoods where the taps regularly go dry to poor farmers in desperate need of irrigation to grow their crops.

Giving free electricity to farmers — who use that electricity to pump more groundwater — has become a common promise by campaigning politicians. That, though, simply makes the problem worse.
"This issue is of grave importance," said K. Sreelakshmi, a natural resource economist at New Delhi's Energy and Resources Institute, TERI. Sreelakshmi, who was not connected to the study, noted that previous research projects had revealed lowering groundwater, though this one used a new approach by relying on satellite data. "The question is what do we do about the problem," she said. "How do we recharge" India's dropping water table?
The study, led by Matthew Rodell of the United States' NASA Goddard Space Flight Center in Maryland, indicated that groundwater across a swath of India from New Delhi into heavily farmed agricultural belts dropped at a rate of 1.6 inches (4 centimeters) per year between August 2002 and October 2008. That decrease in groundwater is more than double the capacity of India's largest reservoir.

The study noted that the drop in groundwater came in years where there was no shortage of rainfall to cause a natural decline.
The region, though, has seen an enormous increase in water use since the 1960s. Part of that is because of the growing population, though even more resulted from the so-called Green Revolution, which dramatically increased India's agricultural production — in part by exponentially expanding the use of groundwater for irrigation.
"Severe groundwater depletion is occurring as a result of human consumption," the researchers concluded in the study, released online in the journal Nature.
The study was based largely on data provided by GRACE — the Gravity Recovery and Climate Experiment — a satellite system launched in 2002 by NASA and the German Aerospace Center. GRACE allows scientists to estimate changes in groundwater storage by measuring tiny variations in the Earth's gravitational pull.

Another recent study based on GRACE data, using results from a 1,200-mile (2,000-kilometer) swath across eastern Pakistan, northern India and into Bangladesh, showed about 1.9 million cubic feet (54 cubic kilometers) of groundwater lost per year.
That study, in Geophysical Research Letters, was led by geophysicists Virendra Tiwari of the National Geophysical Research Institute in Hyderabad, India; John Wahr of the University of Colorado, Boulder; and Sean Swenson of the National Center for Atmospheric Research in Boulder.

"This is probably the largest rate of groundwater loss in any comparable-sized region on Earth," that study said.

On the Net: Nature magazine:
Copyright © 2009 The Associated Press. All rights reserved.

Satellite-based estimates of groundwater depletion in India

Matthew Rodell1, Isabella Velicogna2,3,4 & James S. Famiglietti2

1. Hydrological Sciences Branch, Code 614.3, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
2. Department of Earth System Science, University of California, Irvine, California 92697-3100, USA
3. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109-8099, USA
4. Department of Physics, University of Udine, 208 Via delle Scienze, 33100 Udine, Italy

Correspondence to: Matthew Rodell1 Correspondence and requests for materials should be addressed to M.R. (Email:

Groundwater is a primary source of fresh water in many parts of the world. Some regions are becoming overly dependent on it, consuming groundwater faster than it is naturally replenished and causing water tables to decline unremittingly1. Indirect evidence suggests that this is the case in northwest India2, but there has been no regional assessment of the rate of groundwater depletion. Here we use terrestrial water storage-change observations from the NASA Gravity Recovery and Climate Experiment satellites3 and simulated soil-water variations from a data-integrating hydrological modelling system4 to show that groundwater is being depleted at a mean rate of 4.0 plusminus 1.0 cm yr-1 equivalent height of water (17.7 plusminus 4.5 km3 yr-1) over the Indian states of Rajasthan, Punjab and Haryana (including Delhi).
During our study period of August 2002 to October 2008, groundwater depletion was equivalent to a net loss of 109 km3 of water, which is double the capacity of India's largest surface-water reservoir. Annual rainfall was close to normal throughout the period and we demonstrate that the other terrestrial water storage components (soil moisture, surface waters, snow, glaciers and biomass) did not contribute significantly to the observed decline in total water levels. Although our observational record is brief, the available evidence suggests that unsustainable consumption of groundwater for irrigation and other anthropogenic uses is likely to be the cause.
If measures are not taken soon to ensure sustainable groundwater usage, the consequences for the 114,000,000 residents of the region may include a reduction of agricultural output and shortages of potable water, leading to extensive socioeconomic stresses.

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