Guwahati, Oct. 16: A panel of experts of the ministry of environment and forests has called for studies on the downstream impact of the hydel projects in the Kameng and Dibang basins in Arunachal Pradesh till Guwahati in Assam.
Sources said this was decided by the panel on river valley and hydroelectric projects in its recent meeting while finalising the terms of reference to conduct cumulative impact assessments of these hydel projects. The panel says currently the norm for studying downstream impacts is a 10km radius, which is inadequate for major projects.
While 25 projects (above 25MW) are envisaged in the study area to be covered in the Kameng basin, 14 projects are planned in Dibang basin.
The ministry of environment and forests had directed on May 28 this year that carrying capacity studies or cumulative environment impact studies of all the river basins have to be completed within two years. The Central Water Commission has now proposed cumulative basin studies of these two new river sub-basins. The basin study is a step beyond the environment impact assessment as it incorporates an integrated approach to assess the impacts.
The cumulative impact assessment study of a river/river basin is an important and effective tool to assess the viability of hydroelectric power projects.
Among other things, the study will speak of an optimum number of projects that could be planned on a river and its basin in an environmentally sustainable manner.
Downstream issues are a major concern in Assam with civil society organisations calling for massive protests, which have halted hydro-electric projects.
The 2,000MW Lower Subansiri hydel project has been delayed on account of this.
The group of ministers (GoM) formed by the Assam government to study different aspects of the Lower Subansiri hydropower project and other dam schemes in the region has also stressed a cumulative impact assessment of these dams on the downstream areas in Assam before any of these projects are effectively taken up.
Considering the total length of the main river in the basin and the hydel projects already existing and planned for future development, the study should find out how many more projects may be allowed to come up without disturbing the integrity of the river.
The main objective of the study is to reveal the impact of dams being planned on the main river and its tributaries and the impact assessment should also include “impact due to construction of approach roads for the hydroelectric projects”.
The impact on terrestrial and aquatic ecology should also be studied. The final report should be shared with the ministry of power and state government concerned, which will ensure that only recommended projects are implemented.