The National Green Tribunal (NGT) has issued notices to the Union ministries of power and environment and forests, the governments of Assam and Arunachal Pradesh and National Hydroelectric Power Corporation (NHPC) on a petition accusing authorities of neglecting the downstream impact of the Subansiri Lower Hydroelectric Power Project. The petition sought release of minimum flow in the tributary of the Brahmaputra, which is also home to the Gangetic dolphins.
The petition, filed by non-profit Assam Public Works (APW) says that NHPC planned to release only 6 cumec (cubic metre per second) water from the dam for 20 hours in a day during lean season. This is abnormally low as there is 850 cumec water in the river even during the lean season, according to the petition.
The petitioner, Abhijit Sarma of APW, said that after eight years of start of the project work in 2005, because of public protests, NHPC announced it will release 220 – 250 cumec of water by keeping one turbine running. This gesture is not based on any rational basis. This is not the same thing as release of “sustenance water” from the dam for the ecology of the river as needed, automatically, without human control, the petition reads.
“Any release of water through turbines will release the water about half km downstream of the dam through the power house, thereby completely killing the river for about half km or so from the dam up to the power house,” the petition states.
Sarma pleaded for a suitable opening through the dam at a suitable level through which “sustenance water” of 450 cumecs, which is the average minimum of the lean water flow over a period for survival of the dolphins, to be incorporated in the dam which will allow the “sustenance water” to flow automatically, especially in the lean months. He complained that NHPC did not plan for a fish ladder or fishway, built along dams and locks to allow natural migration of fish.
Sarma also pleaded that technologically sound embankments should be provided up to the confluence with Brahmaputra so that flushed sediments from the reservoir do not destroy the agricultural fields of the villages as has happened in North Eastern Electric Power Corporation’s Ranganadi project in Arunachal Pradesh.