Life-Cycle Considerations for Swan Island, Chesapeake Bay, Maryland

Coastal communities are highly vulnerable to climate-change associated flood hazards. While hard-engineering solutions (i.e., gray infrastructure) have been widely used to address hazards posed by climate change, demand for natural and nature-based features (NNBFs) as flood risk management alternatives has grown more recently. However, life-cycle analysis frameworks used in traditional planning processes limit comparisons between gray infrastructure and NNBFs by failing to account for non-economic costs and benefits, such as environmental impacts or co-benefits. This study proposes the use of an expanded life-cycle analysis framework that better accounts for traditionally unaccounted benefits and costs. We apply the framework to assess the life-cycle needs of a gray infrastructure project alternative and those of a NNBF alternative to demonstrate how flood risk management alternatives can be compared more effectively and equitably. We leverage dredging and placement cost, post-placement monitoring, and modeling data from the Swan Island Restoration Project, which utilized sediment dredged from nearby navigation channels to restore a highly erosive island in the Maryland portion of the Chesapeake Bay, to describe the application of a life-cycle analysis framework.