Global rainfall patterns over the last few decades have shown that areas already wet are getting more rains, while rain-deficient areas are receiving increasingly less rainfall. In India, however, the reverse might be happening, a new study by two IITs has said. Academics from IIT Madras and IIT Bombay have presented evidence to suggest that the differences in mean rainfall at separate locations in India were actually decreasing. Mean rainfall across the country was getting more and more uniform. This could have important implications for India’s water management policies, particularly the ambitious river linking project that the government is implementing. Sachin Gunthe of the civil engineering department of IIT Madras, one of the authors of the study, said the findings showed that river basins with excess water were getting reduced amount of rainfall while those with water shortage were receiving more rain. This can prompt a rethink on the river-linking project. “In simple terms, for example, if location A and location B used to get, say, x and y mm of rainfall respectively during monsoon, our study shows that the differences in the rainfall at these two locations [x — y] will decrease in future, and these will become more uniform,” Gunthe said. “It strongly contradicts the traditional notion that wet areas are getting wetter and dry areas drier over India.” The study, carried out using more than 50 years of daily rainfall data, also says instances of extreme events were showing an opposite trend. Basins with excess water were having more extreme precipitation events. So, it is not just that the mean rainfall was decreasing over an already wet area, it was also getting increasingly concentrated over a very small period of time. In their paper, the authors say such a trend “warrants the reconsideration of the ambitious development of inter-basin water transfer planning via river linking, which not only has ecological and financial implications but also may not be sustainable”. The river interlinking programme of the government, conceptualised in the 1980s, seeks to join major rivers across basins to ensure equitable water availability in all regions. As of now, droughts and flooding sometimes occur simultaneously in different parts of the country. At present, 30 inter-basin transfer links are proposed, involving rivers across the country. The first of these projects to be taken up for implementation, the Ken-Betwa link in Madhya Pradesh, has been approved by the cabinet and is awaiting environment and forest clearance. “We are hoping to get some good news on the Ken-Betwa project in the next 15 days,” Water Resources Minister Uma Bharti, one of the strong supporters of the idea, said Tuesday, indicating that she was expecting some sort of regulatory clearance to this project. However, the concerned environmental appraisal committee met only last week and the Ken-Betwa project was not on its agenda. No further meeting is scheduled this month. The application for forest clearance is yet to be moved. A proposal for wildlife clearance was turned down a few months ago after the Wildlife Board raised a few objections. The water resources ministry has responded to those objections and the Board is expected to consider them at its next meeting. The authors of IIT study say the findings call for a review of the inter-linking programme with “proper and detailed” analysis of historical rainfall data supplemented with numerical model simulations.
