Analysis of coastal protection under rising flood risk

• We incorporate risks under changing climate into decisions for coastal protection.
• We use a statistical/deterministic hurricane model to project changes in storm surge.
• We combine storm surge, sea level and subsidence risks to project rising flood risk.
• We apply dynamic programming to the sequential decision to adapt to the rising risk.
• The analysis method is demonstrated using a sample energy facility in Galveston Bay.

Infrastructure located along the U.S. Atlantic and Gulf coasts is exposed to rising risk of flooding from sea level rise, increasing storm surge, and subsidence. In these circumstances coastal management commonly based on 100-year flood maps assuming current climatology is no longer adequate. A dynamic programming cost–benefit analysis is applied to the adaptation decision, illustrated by application to an energy facility in Galveston Bay. Projections of several global climate models provide inputs to estimates of the change in hurricane and storm surge activity as well as the increase in sea level. The projected rise in physical flood risk is combined with estimates of flood damage and protection costs in an analysis of the multi-period nature of adaptation choice. The result is a planning method, using dynamic programming, which is appropriate for investment and abandonment decisions under rising coastal risk.