A report commissioned by the Central Water Commission has recommended scrapping of 15 of the 44 dams planned across the Siang river in Arunachal Pradesh. It has also suggested stricter regulations for the ones that are to be built in future.
The report has warned that the proposed 44 dams, meant to establish a capacity of 18,293 MW, will affect the river ecology and biodiversity and the region all the way down to Assam. Cumulatively, the projects will impact more than 500 km of river stretch. Of this, 353 km will be converted into reservoirs, and water will travel through tunnels for another 160.8 km. More than 18,000 hectares of forests will be impacted.
The Union Ministry of Environment and Forests will consider the report at the next meeting of its Forest Advisory Committee before it assesses the controversial 700-MW Tato II project, which the UPA government has pushed hard to clear. But the CWC report notes that the downstream impact of the dams will be felt all the way to Guwahati.
The report notes: “Siang Lower HEP (2,700 MW), Siang Upper Stage II (3,750 MW) and Siang Upper Stage I (6,000 MW) are planned to cover almost the entire length of the Siang in India. 208.5 km of the river will be converted into one continuous reservoir as all three projects are planned back-to-back without any free flowing intermediate river stretch.”
The report only asks for the smaller capacity dams, with a total capacity of 473.5 MW, to be done away with.
“It is strongly recommended that after dropping these projects, these river reaches should be kept free. These projects should not be re-allotted by altering their features, locations and names. Also on other free stretches/tributaries, no further hydropower projects should be planned/allotted in the entire Siang basin even if they are small (less than 25 MW) and do not fall within the purview of the EIA notification,” says the report.
The Ministry has decided to assess the Tato II project for clearance, claiming it is the first project in the river basin, though it assessed the 1,000-MW Siyom (Middle Siang) project for environmental clearance as far back as 2004-05.
The Ministry’s panel for forest clearances will also review the Lower Yamne State I and II projects, which fall in the Siang river basin and add up to 184 MW. This CWC report has assessed the sub-basin to be of the highest biodiversity value in the overall Siang basin.