| The site of the Lower Subansiri hydroelectric project |
Guwahati, Oct. 17: An expert panel of the Union ministry of environment and forests has stated that certain hydel projects on the Subansiri basin in Arunachal Pradesh could be dropped in the overall interest of the environment.
Sources said the panel, after going through the draft report of the cumulative environmental impact assessment of Subansiri sub-basin in Arunachal Pradesh made by consultants appointed by the Central Water Commission, has asked them to drop certain projects if necessary in the overall interest of the environment.
This was decided in a meeting of the expert appraisal committee for valley and hydroelectric projects recently. Out of 19 hydel projects planned in the Subansiri basin, seven pre-feasibility study reports and two detailed project reports are available, of which one — the 2,000MW Lower Subansiri project — is already under construction.
The report said with the completion of proposed dams, the flow in the downstream stretch of the Subansiri river would be reduced considerably, more so during the lean period.
The most important changes that can be expected include reduced flow rate, increase in water temperature, reduction in availability of stenothermal aquatic animals — animals which can adapt to only narrow temperature range — and near desiccation (state of extreme dryness) of river stretches at certain places unless the desired flow is maintained downstream.
The panel, after going through the report, found that development of proposed hydropower projects in Subansiri would affect the forest area of the Subansiri basin and terrestrial and aquatic flora/fauna. The total area that would submerge for dam and other project requirements is 10,032 hectares for the eight proposed hydel projects. A total of 55 endemic species representing 21 families reported from Subansiri basin might be affected.
Among the aquatic animals, the fishes would be affected the most, particularly migratory fish species like mahseer and snow trouts. In fact, the ministry of environment had to face a lot of criticism from civil society organisations when it had allowed diversion of 4030.56 hectares of forestland for construction of the Lower Subansiri project.
The panel has asked the consultants to provide the report on downstream impact study and cross-section of river to facilitate visualising the rise of water level in the downstream area.
It has asked the consultants to submit the final report only after incorporating public opinion. The draft report has to be uploaded on the ministry’s portal and published suitably for seeking comments/opinions from the public.