Flood Risk Assessment of Complex Riverine Systems

For over two decades, the U.S. Army Corps of Engineers has required that all of their planning processes address the Nation's water resources needs in a systems context. Corps policy requires that all flood risk management studies adopt risk analysis. Although the Corps has a requirement for systems approaches using risk analysis, there is little guidance and few tools to support these requirements. For this reason, the Corps' Institute for Water Resources sponsored investigations into the development of a new application to analyze complex riverine systems while implementing the flood risk analysis and systems requirements. This new application, currently called HEC- FRM (Flood Risk Management), will eventually become the next generation of the Hydrologic Engineering Center's Flood Damage Analysis (HEC-FDA) model. It will include a systems approach, event-based sampling, the ability to do scenario analysis, and structure-by-structure, cost, non-structural, loss-of-life, and agricultural damage analyses. The tool will accommodate many, if not all, of the recommendations that the Corps concurred with from the National Research Council report on the Corps' implementation of risk analysis for flood damage reduction (NRC, 2000), and it will also aide in implementing the Chief of Engineers' Actions for Change. This presentation will introduce the modeling concepts including sampling and solution techniques, uncertainty definitions, and system component fragility and performance interactions/relationships.