A Review of the USACE Risk Management Center's Advancements in Flood Hazard and Risk Analysis Tools

Código

I-EBHE0097

Autores

Keil J. Neff, Derek Kinder, C. Haden Smith

Tema

WG 1.10: Hydrologic Design - Solutions & Communication

Resumo

In support of the Dam and Levee Safety Programs of the United States Army Corps of Engineers (USACE), the Risk Management Center (RMC) develops tools and software; advances policy, methodology, and guidance; provides technical advising and training; and performs complex analyses, design services, and construction oversight for the highest priority projects in the USACE portfolio. Within the RMC, the flood hydrology group has advanced the state of practice by developing methods and tools to produce reliable estimates of flood hazard with uncertainty. These tools are used to support assessment and design of over 700 dams and 10,000 kilometers of levee segments in the USACE portfolio, and are increasingly being used by other agencies, owners, and their consultants across the United States and worldwide to support development of flood hazard estimates for dams, levees, and other critical infrastructure. Risk analysis for dams and levees requires a probabilistic flood hazard analysis (PFHA) to estimate the magnitude and likelihood for a range of floods. The resulting flood hazard curves are typically peak stage, volume-duration, and peak flow versus annual exceedance probability. Different levels of risk analyses, from screening level to comprehensive, are performed to support the USACE dam and levee safety programs. The RMC has developed methodology and workflow, along with supporting software, to develop flood hazard curves at these different levels of study. This workflow involves using a suite of flood hazard estimation tools to provide probabilistic flood hazard input for a new event tree modeling software (RMC-TotalRisk) to calculate the risk of specific potential failure modes and the total risk of a facility. The primary flood hazard tools, typically used in stepwise progression when assessing dams, include: (i) RMC-RRFT (Rainfall-Runoff Frequency Tool), (ii) RMC-BestFit (Bayesian Estimation and Fitting Software), and (iii) RMC-RFA (Reservoir Frequency Analysis). Additionally, RMC-TotalRisk can be used to integrate complex flood frequency information to account for dam systems and joint probabilities of flooding from different sources. The RMC has also developed two web-based applications to quantify the risk of levees and dams respectively. The Levee Screening Tool (LST) 2.0 quantifies risk estimates for levees based on the likelihood of flood loading, expected performance of the levee under those loadings, and the potential consequences of a levee breach or overtopping. Similarly, the Dam Safety Tool (DST) quantifies risk estimates for dams, but in its current beta version only includes consequences analysis. Both applications apply HEC-RAS 2D hydraulic modeling, simplified version of RMC?s LifeSim consequences estimating software, USACE?s 2022 National Structure Inventory (NSI), and USGS?s National Elevation Dataset (NED). The vision is to include components of the flood hazard software suite and RMC-TotalRisk into the LST and DST applications in the near future. This presentation will provide an overview of these tools, methodology, and workflow as well as describe anticipated future advancements.