Dam break analysis on cascade dams using HEC-RAS: A case study of Sengguruh, Sutami and Wlingi Dam, Brantas River Basin, Indonesia

This paper presents a dam break analysis on the cascade dams of Sengguruh, Sutami, Lahor and Wlingi in the Brantas River Basin, Indonesia, utilizing HEC-RAS hydraulic modeling to evaluate potential flood hazards and impacts. Recognizing the critical risk posed by dam failures to downstream communities and infrastructure, this study aims to delineate flood inundation zones, classify risk levels according to national standards, estimate evacuation needs and potential economic losses, and develop coordinated emergency response plans. The methodology integrates detailed topographic and bathymetric surveys, hydrological assessments, and dam break simulations across multiple scenarios using HEC-RAS, complemented by socio-economic surveys and stakeholder consultations to inform vulnerability and evacuation logistics. Results highlight clear hazard mapping, identification of at-risk populations, and the significant potential for economic damage, underscoring the necessity of multistakeholder collaboration and data-driven planning in emergency preparedness. This research provides a vital strategic and operational framework to enhance risk management and resilience for cascade dam systems in similar hydrological and socio-economic contexts.