Coastal Structures and Sea Level Rise: Adaptive Management Approach

There is an impetus by the scientific community in general, and federal agencies like the U.S. Army Corps of Engineers and the U.S. Environmental Protection Agency in particular, to include the effects of global warming and sea level rise (SLR) within the design life of all federally funded projects. However, no mandates or policies have been issued. In many coastal states, specific policies and mandates have been issued to agencies to include the effects of climate change, which has resulted in relevant coastal management agencies taking on the mantle of addressing sea level rise issues in terms of development permits for new projects, and some on existing projects. Since there is no generally-accepted, specific guidance on ranges of SLR or management strategies for the future, coastal developments are seeking guidance for an understanding of the issues and associated economic implications and other risks. An illustrative example of an adaptive management strategy for a typical coastal protection structure (seawall) is presented including a net present value analysis of various strategies. Finally, an implementation strategy that integrates Adaptive Management and a Monitoring Framework based on recent experience in San Francisco Bay is presented. Scientific projections, illustrative cases, and the evolving nature of SLR projections are discussed.