Climate Change, Unprecedented Floods, Dam Failures, Dam Hazards & Safety Aspects – An Indian Perspective

Climate change is exacerbating extreme weather events globally, leading to unprecedented floods, particularly in South and Southeast Asia, including India. These events pose significant hazards to dam safety, as demonstrated by recent failures and damages to hydropower infrastructure in India, often linked to extreme hydrological events like intense rainfall, cloudbursts, and glacial lake outburst floods (GLOFs). Many Indian dams, including a significant number over 50 or even 100 years old, were designed using historical data that may not account for current climate change impacts, increasing their vulnerability.Overtopping due to inadequate spillway capacity is a primary global cause of dam failure, though piping failures are historically more frequent in India. This paper reviews the impacts of climate change on flood frequency and intensity, examines dam failurestatistics and causes (emphasizing hydrological factors), and discusses the concept of Inflow Design Flood (IDF) selection. It compares international practices for dam classification and IDF selection (including riskbased approaches used in countries like Australia, Canada, and the UK) with current Indian standards (IS 11223-1985 and recent CWC hazard potential guidelines). The review highlights a disconnect between current IDF estimation methods (including PMP/PMF concepts) and the need to incorporate non-stationary climate change effects. Key findings emphasize the need for India to adopt a comprehensive, risk-based dam safety framework, update IDF guidelines to explicitly account for climate change projections, improve data sharing and transparency, and enhance emergency preparedness, including the implementation of Early Warning Systems (EWS). The paper concludes that ensuring long-term dam safety requires integrating climate science into engineering practices, strengthening legal frameworks like the Dam Safety Act 2021, adopting design innovations, and fostering better coordination among stakeholders. Striking a balance between risk minimization and cost management through risk-informed IDF selection is crucial for mitigating potential disasters.