Sea Level Rise Vulnerability Assessment for San Juan County
The Sea Level Rise Vulnerability Assessment for San Juan County identified areas in which coastal flooding and coastal erosion are likely to occur. Inundation and bluff or bank recession vulnerability were mapped across two climate change scenarios (moderate, high) and planning horizons (2050, 2100). The study was completed by Coastal Geologic Services Inc. (CGS) of Bellingham, and was led by Andrea MacLennan MS. The assessment was completed in 2014 as part of a larger Healthy Beaches effort by Friends of the San Juans (FOSJ,http://www.sanjuans.org/NearshoreStudies.htm ). CGS and FOSJ have since been presenting and distributing assessment results with local stakeholders; from County Public Works managers to local conservationists and private property owners. Collaborations with FOSJ and local stakeholders are helping to improve long-term planning, conservation of critical habitats, priorities for Public Works such as threatened roads, and decision tools (to guide adaptation planning) for local landowners.
For more information, contact Andrea MacLennan
“These projects have directly benefited from collaboration and technical guidance provided by CHRN team members. [The} CHRN could better support these types of projects by emphasizing the need for better tools to conduct similar assessments, such as quality baseline data (like region-wide high resolution LIDAR), state-recommended, current sea level rise projections, relative sea level rise calculations, and policies that will facilitate the development of better long-term planning.”
-Andrea MacLennan
Other Projects
Several other recent CGS projects have entailed measuring and compiling bluff recession rates throughout the Puget Sound region to inform nearshore restoration planning and to better understand the range of rates and variables affecting local bluff recession rates. Bluff recession rate data was used to identify feasible parcels for bulkhead (shore armor) removal without threatening existing structures and to prioritize those parcels based on the potential resulting benefit to down-drift shores and habitats. Landowner outreach to priority parcels including educational workshops and on-the-ground site assessments were later performed to verify or modify armor removal feasibility, gain landowner willingness, and inform restoration design. The CGS design team including Jim Johannessen, Andrea MacLennan, Alexis Blue and staff is now developing several (5) bluff sediment supply restoration designs that will likely be implemented in the near future. Ample bluff sediment supply is critical to the long-term climate change resilience and natural adaptation to rising sea levels in Puget Sound.
For more information, contact Andrea MacLennan
