National vision needed to achieve comprehensive risk reduction along Atlantic, Gulf coasts

Coastal risk management strategies can include built or natural infrastructure to reduce flood hazards and wave damage in at-risk areas as well as steps to move people and property out of harm’s way. Structural strategies to reduce storm-related hazards include seawalls, levees, flood walls, and storm-surge barriers, as well as beach nourishment, dune building, and restoration or expansion of natural habitats. Conversely, elevating existing structures, relocation, and land-use planning to deter future development in high-hazard areas can reduce the number of people or buildings at risk. The committee found that in the past, most risk reduction projects have focused on fortification, with few efforts to limit redevelopment in high-risk areas and steer development toward safer, lower-risk areas.

Strategies for coastal risk reduction differ in terms of their benefits, costs, and ecosystem impacts. At the local, state, and national levels, society needs to determine which investments to make and whether they are justified. One method for choosing investments is a risk-standard approach, which focuses on strategies to reduce risk below an acceptable level.

Alternatively, a benefit-cost approach recommends strategies in which the benefits exceed the costs, and therefore results in varying levels of risk along the coast. The report recommends a hybrid approach that emphasizes investments that optimize net benefits, but puts constraints on what is considered acceptable risk, particularly for human fatalities and cultural and social resources, which can be difficult to account for in monetary terms.

A national perspective is needed to achieve the most benefits from federal investments and provide regional solutions, rather than piecemeal, project-by-project approaches. To achieve a national vision, the federal government should work with states to develop a national coastal risk assessment along with objectives and metrics for risk reduction to identify appropriate actions and measure progress. The resulting geographic patterns of coastal risk, represented by human fatalities, economic losses, and social impacts, could illustrate areas most in need of targeted risk reduction interventions. The assessment should include an inventory of present and future coastal conditions — especially in light of long-term sea-level rise.

Leadership at the federal level and consistent collaboration with clear delineation of responsibilities for local, state, and federal agencies is needed. The report recommends that the federal government provide stronger incentives for cost-effective coastal risk management strategies and land-use planning at the local level. The U.S. Army Corps of Engineers, which requested the Research Council study, could also capitalize on opportunities within its existing framework, such as rigorously accounting for social and environmental costs and benefits, to support a more holistic view of coastal risk management. 

The study was sponsored by the U.S. Army Corps of Engineers.

— Read more in Reducing Coastal Risks on the East and Gulf Coasts (National Academies Press, 2014)