Climate change can dry south Indian river, says new study

[NEW DELHI] Climate change could lead to huge water shortages in southern India’s fertile Godavari river basin, a new study based on computer simulations shows.

The study by scientists from India and Norway, started in February 2009, is part of several compiled into a book, 'Water and Climate Change: an integrated approach to adaptation challenges', released last month (1 February). 

The study — funded by Bioforsk, the Norwegian Institute for Agricultural and Environmental Research — was implemented by the Indian Institute of Technology (IIT), Delhi, and the International Water Management Institute, Colombo.

The team used water flows and soil data in the Godavarai basin from 1961 to 1990 as the baseline; and simulated avilability from 2021 to 2050 in the near-term and from 2071 to 2098 in the long-term.

"Though the basin may get excess rains, everything seems to be getting lost to the atmosphere due to heat and evapo-transpiration (loss of water due to evaporation from the surface) caused by an increase in climate temperature," Ashvin Kumar Gosain, professor at the civil engineering department of the IIT- Delhi, told SciDev.Net.

Gosain also said that the fertile topsoil could get washed away into the rivers and deposited in dams as sediment. 

The simulations showed rainfall increase in the river basin due to global warming, but with variations in quantity and intensity in different areas. This would result in floods and droughts; soil erosion and deposition of soil sediments in river basins, said Rajesh Kumar Rai, an IIT- Delhi research scholar associated with the new book.  

An increase in soil sediments would lower the capacity of dams and hydroelectric power stations due to clogging, while higher temperatures would reduce the availability of soil water, affecting crops, and calling for conservation practices, Rai said.

The Godavari study is the offshoot of a series of studies on river basins conducted by the Indian government as part of its national communication (NATCOM) project for the 2007 meet of the Intergovernmental Panel on Climate Change.

The present study and the NATCOM project provide inputs into the national water policy that is being revised by the Indian government to incorporate adaptation strategies to cope with global warming.

The revised draft of the policy, made public on 31 January, suggested options like more storage reservoirs including hydropower plants, creating basin committees to decide on local water issues and pricing of water.