Biodiversity impact assessment of two large dam projects in India under long term multi-scenarios simulation

As global biodiversity is facing an existential threat, integration of biodiversity concerns into decision-making tools like EIA is more urgent now. Biodiversity impact assessment of Indira Sagar and Omkareshwar dams on the river Narmada that were conducted during 1990–94 is retrospectively analyzed to demonstrate the utility of the Habitat Evaluation Procedure as a quantitative method and its capability to predict long-term trends in habitat quality. Results of a multiple scenario simulation on habitat quality change over thirty years (1991–2020) indicate that there still exists an opportunity to conserve the biodiversity in the region by enhancing the protection status of the forests surrounding the dam reservoirs and proper resettlement and rehabilitation of project affected population. Further, limitations of Indian EIA with reference to biodiversity integration into Mitigation Hierarchy, Cumulative Impacts Assessment, Governance, SEA and post-audit are addressed. Indian policy needs to integrate biodiversity into earlier stages of decision making, not only to achieve its 2030 SDG targets, but also to ensure ecological security which is essential for the long-term socio-economic development of the nation.