Marin County, California Ocean Coast Sea-Level Rise Adaptation Report
Marin County’s “Collaboration: Sea-level Marin Adaptation Response Team” (C-SMART) is a multi-stakeholder, inter-governmental partnership that collaborates to determine sea level rise impacts and adaptation options for the county. This comprehensive analysis from C-SMART presents strategies for increasing resiliency of Marin’s coast with options to accommodate, protect against, or retreat from the threats of sea level rise and coastal hazards.
This report is based on the findings from the Marin Ocean Coast Sea Level Rise Vulnerability Assessment which analyzed the vulnerabilities of natural and built assets to near- and long-term sea level rise and storm surge scenarios for Marin County. The Assessment identified vulnerabilities of the county’s parcels and buildings, transportation, utilities, working lands, natural resources, recreation, emergency services, and historic and archaeological resources. The coastal vulnerabilities for each West Marin town were assessed also. The focal strategies in this report were identified for these same sectors and communities of: Muir Beach, Stinson Beach, Bolinas, Inverness, East Shore, Point Reyes Station, and Dillon Beach.
Table 2: Priority Sea Level Rise Adaptation Strategies found within the Executive Summary, includes a list of all of the potential near-term, medium-term, and long-term adaptation strategies for coastal Marin County - which are discussed in detail in the report.
An Adaptation Framework was built around broad sea level rise strategies for hard protection and nature-based protection, accommodation, and retreat. Table 7 illustrates these strategies in terms of the projected onset of impacts; cost estimates (both initial and ongoing); calculated effectiveness; timing and duration of the strategy; full spectrum of environmental, recreational, and habitat benefits; and legal, political, and community acceptability.
Section 4 on Governance describes how to support the integration of sea level rise adaptation by leveraging existing local governance structures and policies, including: Public Outreach and Education, Emergency Management, Local Assessment Districts, Interagency Governmental Collaboration, Land Use and Zoning, Public Trust Doctrine, and County Permitting Agencies.
The 5th section, Asset Adaptation, addresses the eight focal sectors for Marin County:
- parcels and buildings
- working lands
- natural resources
- emergency services
- historic and archaeological resources
Resilience strategies are offered for each asset type based on projected coastal vulnerabilities as well as active plans, policies and agencies in Marin. In some cases the adaptive responses described have been adopted, and some projected funding and feasibility constraints are considered.
For example, the discussion of Parcels and Buildings describes solutions in terms of the development requirements in the Marin County coastal zone, design principles, home retrofitting options, relocation, elevation, amphibiation (“an amphibious structure floats on a buoyant foundation when flooding occurs”), wet and dry floodproofing, site improvements, flood walls, and landscaping.
Regarding Transportation assets, some roads in Marin County will be vulnerable to temporary flooding and increased temporary closures, in some cases preventing emergency access. The report points to the Local Hazard Mitigation Plan and adaptation options already prepared by the Marin County Department of Public Works (DPW), that will be used to guide evaluation of actions.
Section 6: Community Alternatives includes a profile for each West Marin coastal community with priority adaptation actions. Each has a “No Action” section that describes general SLR impacts if adaptation is not undertaken, along with community alternative options to protect assets, accommodate sea level rise, and relocate or engage in managed retreat.
Publication Date: February 27, 2018
Authors or Affiliated Users:
- Marin County Collaboration - Sea-level Marin Adaptation Response Team (C-SMART)
- Adaptation plan
- Policy analysis/recommendations