Author(s): Dhyan Singh Arya; Shivendra Jaiswal; Ranendra Sarma And Debajit Das
Linked Author(s): Dhyan Singh Arya, DEBAJIT DAS
Keywords: Dam safety Dam breaks Flood risk assessment Hydrodynamic modeling Flood hazard mapping
Abstract: Hydraulic structures such as dams are major facilities for regulating water supplies, flood prevention and hydroelectric energy. However, the potential failure of such structures can have disastrous consequences for downstream communities, necessitating extensive safety assessments and flood risk modelling. This study quantifies the risk of sequential dam failure for the Tuirial Dam and its associated Saddle Dam on the Tuirial River in Mizoram, India. A two-dimensional dam break model was developed using HEC-RAS to route the dam break outburst flood up to approximately 84 km (confluence of Tuirial River with Barak River) downstream. Simulations were conducted for a complete breach with different failures (overtopping and piping) and inflow conditions (PMF and 100-year return period flood) to identify the worst-case scenario among various failure cases. Five probable breach scenarios were analyzed to determine peak flow rates and the resulting flood wave propagation. When the main dam failed due to piping and the saddle dam due to overtopping, is identified as the worst case. The hydrograph is generated at various locations downstream for the worst case identified, i. e. when the main dam failed due to piping and the saddle dam failed due to piping and the peak flow obtained near the dam site is 38373.84 m3/s attenuated to 3035.34 m3/s near the confluence. The results highlight substantial flood hazards and risks posed to downstream areas, with potential inundation reaching significant depths across critical infrastructure. Findings from this study highlight the need for early warning systems and targeted emergency action plans to mitigate the impacts of such events. The generated flood hazard and risk maps will aid local and disaster management authorities in prioritizing at-risk areas, optimizing resource allocation, and enhancing preparedness efforts for flood mitigation and recovery.
Year: 2025