Abstract
Decommissioning large dams brings a tangle of environmental, social, and regulatory risks, and the Mullaperiyar Dam in Kerala, India (built in 1895 and now flagged for aging fabric, seismic exposure, and downstream hazards) offers a timely test of Environmental and Social Risk Management (ESRM). This research analyzed the case with a mixed-methods approach: reviewing environmental impact assessments (EIA) and regulatory filings; compiling baseline biophysical and socioeconomic data with GIS/remote sensing; conducting risk assessment and dam-break analysis; and running a structured engagement program that included two public consultations (April 15 and June 10, 2022) and a perception survey. Flooding, habitat disruption, and community displacement emerged as the highest-impact risks, while sediment management (rated lower in probability) still proved consequential for downstream conditions. By 2023, implementation tracking showed strong progress in habitat restoration (\approx 80 {\%}) and community reallocation (\approx 60 {\%}) , moderate gains in flood-risk reduction (\boldsymbol{\approx} \mathbf{5 0 {\%}}) , and lagging sediment control (\approx 35 {\%}) . Stakeholder feedback was mostly positive (about 65%), but it also underscored ongoing concerns about accountability and long-term livelihoods. The main takeaways are practical: embed adaptive management with clear monitoring triggers; accelerate sediment routing and controls; and institutionalize co-monitoring, open data, and third-party audits, especially to strengthen Kerala-Tamil Nadu coordination. The study's limits include its single-case design, reliance on project documents and self-reported perceptions, and interim outcome metrics. Even so, the case shows how proactive, inclusive ESRM can improve trust, reduce harm, and guide measurable mitigation, linking compensation and ecosystem restoration to transparent reporting and revisiting risk weightings when "lowlikelihood" issues, like sediment, persistently hinder delivery.