Climate change increasingly puts the City and its critical built and natural resources at risk of coastal flooding and erosion due to sea level rise. The City proposes a Coastal Resilience Master Plan, which will identify specific resilience and conservation needs along the coastline and develop a portfolio of nature-based solutions to promote resilience, protect critical coastal habitats, and support coastal access. The Coastal Resilience Master Plan will engage the public; analyze 10 sites based on feasibility, risk, and benefits; develop nature-based solutions for six of the most feasible locations; and select a pilot project, as described further below.
The Coastal Resilience Master Plan will evaluate 10 locations for nature-based solutions at a conceptual level and narrow the scope down to up to six locations most appropriate for nature-based solutions. The six locations will be analyzed at greater detail in the Coastal Resilience Master Plan and PEIR for suitability of nature-based solutions with up to three concepts for further development. One location (the pilot project) will be analyzed at 15 percent design level. The Coastal Resilience Master Plan will evaluate nature-based solutions, including both green and natural infrastructure. Green infrastructure encompasses a wide range of built or engineered solutions modeled after nature while natural solutions often refer to restoration activities. Both support purposes such as stormwater management, flood mitigation, urban heat island reduction, and climate adaptation. Nature-based solutions that achieve multiple benefits, such as habitat and wildlife protection, water quality improvements, flood storage, resilience from potential upstream impacts, recreational opportunities, and increased coastal access for Communities of Concern, would be prioritized. Solutions to be considered include, but are not limited to, the following:
-Wetland creation/restoration for ecosystems characterized by permanent or seasonal
inundations, which help mitigate flooding, provide habitat, improve water quality, and
absorb wave energy.
-Living shorelines, which stabilize and protect the shoreline using a combination of plants, sand, rock, and other natural materials. They can help reduce wave energy, slow erosion, and minimize flooding.
-Oyster reefs, which provide natural barriers to the shoreline, protecting it from erosion, strong waves, and storm surge.
-Waterfront parks, including open space parks or recreational spaces in coastal areas that are designed to flood during extreme events, minimizing flooding elsewhere.
-Engineered dunes designed to or above the 100-year Stillwater elevation. Dunes can be designed to combine the aesthetic and habitat benefits of a dynamic beach and dune system with the robust storm protection provided by a structural core.
-Landward realignment involves moving the coastline boundary inland to reduce both
coastal flooding and erosion.
-Living levees/ecotone slopes that, instead of dropping down sharply, slope gently
downwards in the same way that the land naturally would. This allows for natural, gradual transitions—from open water, to tidal mudflat, to tidal marsh, to “ecotone” or transitional upland habitat—to be re-established in these areas.
The nature-based solutions will be developed through gathering relevant data to assess each site’s unique opportunities and constraints in order to ensure feasibility. The concepts will be presented graphically (i.e., plan and section views or illustrations) and clearly described. The concepts for each site will be compared in a multi-criteria decision matrix to support the City, stakeholders, and community members in understanding the proposed solutions for each site. The matrix will include an assessment of the community, resilience, economic, and ecosystem benefits.
The City will engage the public and stakeholders throughout the project to develop nature-based solutions.