A framework for evaluating island restoration performance: A case study from the Chesapeake Bay

The use of natural habitats for coastal protection (also known as Nature‐Based Solutions or NBS) in place of engineered structures like breakwaters and seawalls can yield a wide range of ecological and economic benefits. Despite these advantages, NBS are not commonly implemented for shoreline protection due to uncertainty over the amount of protection afforded by each unique feature and how protective capacity and ecological benefits are likely to change over time as NBS mature and adapt to changing environmental drivers. Here, we highlight the recent restoration of Swan Island in the Chesapeake Bay, Maryland, USA, and the collaborative approach used to evaluate post‐construction performance, as a framework for quantitative evaluation of NBS projects. At Swan Island, 60 000 cubic yards of dredged sediment were used to elevate and restore the island's footprint with an emphasis on increasing its protective and ecological benefits and long‐term resilience to sea‐level rise. Five entities have leveraged resources to quantify the benefits and efficacy of island restoration by conducting pre‐ and post‐restoration monitoring, which supports the development of an integrated, simulation model that includes three “measured” system parameters: wave height, vegetative biomass, and island profile (i.e., elevations). The model will be used to predict island performance under a range of different system scenarios and used to inform adaptive management options. Results will demonstrate the efficacy of leveraging natural and engineered processes to restore island systems while providing a framework for quantifying NBS. Integr Environ Assess Manag 2022;18:42–48. © 2021 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC). This article has been contributed to by US Government employees and their work is in the public domain in the USA. KEY POINTS Evaluations of NBS performance at the scale of the individual project are needed to address uncertainties about when and where natural solutions can afford adequate levels of coastal protection. A consistent approach to NBS project evaluation will help to foster confidence in the use of natural approaches.