This article appeard on www.thehindu.com on January 14, 2009.
Gargi Parsai
Climate change will have serious implications for dams, says study
NEW DELHI: With predictions of extreme changes in river flows due to global warming, a new study has underscored the need for a comprehensive assessment of the impact of climate change on dam building in the Himalayas.
The impact of global warming was already being felt in the Himalayas, resulting in accelerated melting of glaciers and depletion of the massive water store of the region. Already, the threats of glacial lake outburst floods were on the rise with possible failures of downstream dams. There are predictions of dramatic decrease in flows in the Indus basin in 100 years, the study said.
The study titled ‘Mountains of Concrete: Dam Building in the Himalayas,’ released here on Monday, asserts that climate change was likely to have the most serious implications for dams. There were real fears that the “abode of snow” would no longer be left with any and this would have tremendous impact all the way into the Indo-Gangetic plains aggravated by the construction of hundreds of dams.
The study, undertaken by Sripad Dharmadhikari of Manthan Adhyayan Kendra for International Rivers, points out that that there was a renewed push in recent years for building dams in the Himalayan region, including in Pakistan, India, Nepal and Bhutan, which could lead to the highest concentration of dams in the region. Significantly, the study did not look at the dams in China for reasons of “insufficient resources, difficulty in access to information and issue of language.”
As glaciers melt, water in the rivers will rise and dams would be subjected to much higher flows, raising concerns of dam safety, increased flooding (as in the Kosi in Bihar last year) and submergence. And with the subsequent depletion of glaciers there would be much lower annual flows, affecting the performance of dams with huge investments. “Unfortunately, dam construction was being planned without any assessment of these impacts.”
The study has identified 24 lakes as potentially dangerous in Bhutan based on criteria of water level rise, the associated mother glacier, the conditions of the dams and topographical features. It said that the frequency of glacial lake outbursts floods was on the rise in Nepal, Bhutan and Tibet. It predicts dramatic decreases in the Indus river flows in 100 years after glacial retreat.
Presenting his study, Mr. Dharmadhikari pointed out that the dam building in the Himalayas will transform the landscape, ecology and economy of the region. It will have far-reaching impact all the way down to the river deltas. Submergence of lands, homes, fields and forests on a large scale will displace hundreds of thousands of people. It will severely disrupt the downstream flows, impacting agriculture, fisheries and threatening livelihoods of entire populations.
Degradation of nature and massive influx of migrant workers will have great implications for the culture and identity of local people.
As the region was seismically active, the dams that were being planned faced high risks. By far, the most serious issue was that of climate change and its impact on the Himalayas, he said.
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