Abstract: This report describes levee setbacks as alternatives to traditional levees for flood risk management and environmental benefits. It is organized into five sections:
- Information about levees for reducing flood damage, emphasizing environmental considerations
- Description of the Engineering With Nature (EWN) concept for considering environmental benefits of U.S. Army Corps of Engineers (Corps) actions
- Explanations of relevant Corps policy (Executive Orders (EOs), Engineer Regulations (ERs), and Memorandums of Understanding (MOUs))
- Summary of environmental trade-offs between traditional versus levee setbacks
- Summaries of two Corps levee setbacks in the Sacramento and Omaha Districts that successfully completed the planning process
The summaries describe how hydraulic, flood risk management, and environmental benefits were quantified. The report includes environmental considerations for levee setbacks developed by Rock Island District for the Upper Mississippi River (UMR). Parts of the UMR are not leveed, which provides insight into the ecological response that could be expected from large-scale levee setbacks. Levee setbacks are valuable tools for reducing flood damages and provide environmental benefits consistent with the EWN concept, the Chief’s Environmental Operating Principles, and ERs, including the Resilience Initiative Roadmap. The report concludes that levee setbacks should be considered for appropriate sites.