Environmental impact assessment of river valley projects in upper Teesta basin of Eastern Himalaya with special reference to fish conservation: a review

Abstract

<p>Teesta river basin in Eastern Himalaya is being subjected to cascade hydropower development. To assess the impacts of this developmental activity on fish fauna of the basin, fish habitats of the four largest tributaries in the basin were selected for the present study. A total of 18 large hydroelectric projects are planned on these rivers. Here, a total of 11 EIAs and 2 carrying capacity studies in Teesta basin were reviewed. Our investigations show that after commissioning all the projects, 52–88% of the free-flowing river stretches will be diverted and 7.6–24% of the riverine ecosystems will be converted into semi lacustrine ecosystems in different rivers. The cascade hydropower development is likely to affect more than 100 fish species. All the EIA reports reviewed have investigated fish species richness, impacts on fish fauna and fishery management plans. EIA studies and management plans, however, do not adequately address important ecological and conservation issues due to various limitations. An integrated fish conservation plan for the upper Teesta basin is suggested in this contribution.</p