Central Water Commission overestimates the country`s usable water resources

Central Water Commission overestimates the country`s usable water resources   If the government is to be believed there is enough usable water in the country to meet projected demand until 2050. Stumped by this claim, scientists at iit Delhi and Jamia Millia Islamia, New Delhi, pored over official calculations for estimating the country's water resources. They say the government has overestimated its usable water resources by at least 66 per cent.

How could the estimate be so grossly inflated? "The government bodies have ignored the interaction between surface and ground water and calculated the groundwater that comes to the surface and flows in the river twice. Hence usable water resources estimated by it are much higher than the actual amount,' says N K Garg, professor, Department of Civil Engineering, iit.Garg, along with Q Hassan of Jamia Millia Islamia, has contested government claims in a paper published in Current Science, October 10, 2007.

The Central Water Commission (cwc) estimated in 1988 the total utilizable water in the country at 1,110 billion cubic metre (bcm), which is more than the projected demand of 897 bcm in 2050. "We have estimated the utilizable surface water from the data collected at 945 hydrological observation stations in the country. This came to 690 bcm. To that we have added 418 bcm, which is the utilizable groundwater estimated by the Central Ground Water Board (cgwb). Within these calculations we have already subtracted the groundwater that comes to the bed of the river. Garg is asking us to subtract it twice which is not correct,' says S K Sinha, chief engineer, Basic Planning, cwc.

Garg stresses that cwc has not been able to explain its surface water estimate of 690 bcm and doubts it was taken from observation stations. "It is the same figure as used by the National Commission on Agriculture (nca) in its 1976 estimates. I have shown this by matching the figures basin-wise,' he says.

The paper claims that while nca was careful to break the total usable surface water into usable storage of reservoirs and base flow