The northeastern edge of India ranks among the wildest, most gorgeous parts of the country. This is where the Tsangpo cleaves its way south from Tibet, gathering the waters of several tributaries before announcing itself as the mighty Brahmaputra. As the rivers descend, high forests with spectacular biodiversity, breathtaking gorges and mountain farms give way to fertile plains, braided riverine islands, masses of fish and birdlife, and a landscape dense with human settlement. The ecological and economic well-being of the areas downstream—Assam and Bangladesh—hinges upon the integrity of these rivers.

Large dams, many proposed, some already under construction, are to come up across each river flowing into the Brahmaputra. Since 2006, the government of Arunachal Pradesh alone has signed MoUs for 103 large projects on the Kameng, Subansiri, Siang, Dibang and Lohit rivers and their tributaries. These projects are aimed at generating 30,000 MW, doubling India’s entire hydel capacity. There are plans for more dams that will contribute another 27,000 MW. They are all being presented as a win-win proposition, helping to meet the nation’s exploding energy demands while bringing scarce infrastructure to “underdeveloped” areas and welcome revenues to the state government. The terrain is sparsely populated and human displacement, the prime obstacle in projects like the dams on the Narmada, is not a major issue. In 2005, the World Bank stated that these “hydropower sites are, from a social and environmental perspective, among the most benign in the world”. This claim is endorsed by the Arunachal government, which gets Rs 7 lakh per MW upfront as earnest money for each MoU it signs with a private power company. With Rs 2,100 crore already in hand, thanks to this epidemic of MoUs, it is no surprise that the Arunachal hydroelectric power policy states that “if the available potential can be harnessed, the state would be floating in ‘hydrodollars’”.

‘Hydrodollars’ have, however, not won over everyone. The scale of the projects and the speed at which they are being pursued has sent shock waves of concern, especially in Assam, which stands to be most drastically affected by changes in the upper reaches of the Brahmaputra. As Dulal Goswami, a fluvial geomorphologist who headed the environmental sciences department at Gauhati University, points out, when large dams impound water, they also trap the silt essential for fertilising downstream plains. The Brahmaputra, famous for its silt load, keeps the soil of Assam alive. Dams also interfere with the rhythms of a river and the aquatic life it sustains, besides changing its erosion patterns. In a region known for seismic volatility and marked by “geological surprises”, existing uncertainties are exacerbated by building dams. Worried by the huge risk to local ecology and livelihood, an Assamese farmers’ organisation has demanded an immediate assessment of the downstream impact of the Arunachal dams; the Assam legislative assembly has set up a panel to investigate the issue.

That the potentially devastating downstream impact of these dams is being ignored is a legitimate and serious concern. For most dams in Arunachal, the environmental impact assessments (EIAs) required by the ministry of environment & forests have shockingly limited terms of reference. The eias have a narrow geographical focus and a tight time-frame, precluding any detailed investigation of hazards. Moreover, they are carried out by consultants for whom positive appraisals translate into repeat contracts: not one EIA in Arunachal has recommended that a dam cannot be built. Such shoddy EIAs allow the ministry to approve potentially disastrous dams. As Neeraj Vagholikar, an environmentalist with voluntary group Kalpavriksh, points out, studies of individual dams do not reveal the combined effect of hundreds of dams in the Brahmaputra basin, effects that people in Assam and elsewhere will have to face in the years to come. Their fate is threaded together by the Brahmaputra and tied to its imperilled future.

(The writer is an associate professor at the Institute of Economic Growth, New Delhi.)