Sustainable Flood Mitigation: Returning Rivers to Their Natural Course

Abstract

Community participation in flood planning has recently emerged as a successful approach to addressing and restricting the traditionally structural methods of flood control. Flooding, the most costly natural hazard worldwide, causes economic damages in spite of flood control efforts throughout the 20th century. To control flooding while allowing development, localities have traditionally used structural controls, such as levees and floodwalls, to physically separate floods from people. In light of the continued failure, high costs, and environmental degradation associated with structural flood controls, localities are now increasingly focusing on non-structural flood mitigation methods to reduce flood risks and losses. Furthermore, communities throughout the country are incorporating innovative flood projects that balance structural and non-structural flood mitigation in an attempt to better address environmental concerns. This approach involves returning previously damaged rivers and floodplains to their natural state. This evolution from structural approaches to environmentally conscious flood planning is illustrated through a case study of Napa, California’s model flood plan. Through an analysis of the flood plan and interviews with government representatives and project engineers, this case study illustrates how localities can design and implement flood plans to provide for environmentally sustainable flood mitigation. Building on a model of best management practices which incorporates the “living river” concept in the Napa River Flood Protection Project, this report suggests how other communities with severe river flooding can develop similar sustainable flood plans. Napa’s flood project represents a paradigm shift in which local residents were the driving force behind designing an environmentally sustainable and locally supported flood plan that would be carried out by the U.S. Army Corps of Engineers. The key lessons learned from Napa’s flood project are that community involvement and consensus building among stakeholders are crucial to developing and implementing an environmentally sustainable flood management project.