As rising sea levels threaten communities and ecosystems at the coast, a “living shorelines” approach to resilience in estuarine environments has been embraced by public stakeholders. Living shorelines – for example, layering oyster reefs and wetlands – are praised for being ecologically robust and recreationally attractive. However, the role of living shorelines in reducing the impact of coastal hazards is not well understood. For example, appreciable wave attenuation has been demonstrated for oyster reefs that are regionally wide and vertically tall, but reef restoration efforts rarely accomplish geometries of such historical magnitude. Furthermore, these natural systems evolve in different ways in different settings, potentially changing their energy-dissipating performance. Mature oyster reefs, for example, maintain their structural characteristics differently than newly restored saltmarsh. Likewise, the performance of these natural features in attenuating waves is known to depend on incident wave and water level conditions. However, particular performance under a range of varying wave conditions has not been systematically tabulated. 

This presentation explores in the impacts of oyster reefs and wetlands on wave energy in estuarine environments through a spectral wave modeling (SWAN) parameter study. The parameter study focuses on distinguishing the specific wave environments that these systems attenuate most effectively, as well as the effects of varying system geometries. Through this broad analysis, the importance of large-scale, continuous restoration plans for shoreline resilience will be more clearly demonstrated. The results of the study will provide more grounded insights to coastal resilience planners and restoration specialists regarding optimal reef and wetland design.

DOI: https://doi.org/10.1061/9780784484258.080

Wave Attenuation from Living Shorelines: a Parameter Study

Created in 1999, the Environmental & Water Resources Institute (EWRI) is the recognized leader within ASCE for the integration of technical expertise and public policy in the planning, design, construction, and operation of environmentally sound and sustainable infrastructure impacting air, land and water resources.