Salt Marsh Vulnerability Assessment and Adaptation Plan Development in San Francisco Bay, California

Rachel M. Gregg
Posted on: 3/30/2010 - Updated on: 10/28/2021

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Rachel Gregg

Project Summary

The San Francisco Estuary Partnership (SFEP) and the San Francisco Bay Conservation and Development Commission (BCDC) assessed the vulnerabilities of local salt marsh ecosystems to climate change. Using conceptual models, the project leads identified links between climate drivers, stressors, and ecosystem processes in the process of developing an adaptation plan. While this pilot project was completed in 2012, SFEP continues to work on climate change through other initiatives, including the Estuary Blueprint, a comprehensive planning and management document for the San Francisco Estuary.


SFEP and BCDC, collaborated with the U.S. Environmental Protection Agency’s (EPA) Office of Research and Development through a grant from the EPA’s Climate Ready Estuaries Program, to conduct a vulnerability assessment focused on salt marshes and to create a plan to adapt to climate change impacts. Sea levels have risen approximately eight inches over the last century in California. An additional 20 to 55 inch rise is expected by 2100; a 55 inch rise would flood about 150 square miles of wetlands in the area. Other impacts of concern to the Bay Area include wetland inundation, erosion, shifts in species range and composition, decreased water quality, alterations to freshwater flows, larger and more frequent storms, increased sedimentation, and warmer water temperatures.

Components of this project included:

  1. using management goals from the SFEP Comprehensive Conservation and Management Plan;
  2. identifying key ecosystem processes;
  3. conceptual modeling of climate drivers that will affect management goals;
  4. identifying baseline conditions and summarizing observed and projected climate change impacts in order to track any variation from the baseline;
  5. assessing climate change stressors, cumulative impacts, and interactions among stressors and ecosystem processes;
  6. identifying adaptation options;
  7. incorporating expert and stakeholder input; and
  8. developing a climate change adaptation plan.


SFEP and BCDC convened scientists and resource managers to discuss vulnerabilities, identify climate indicators, and cooperate on climate research and information-sharing. In October 2008, a kickoff workshop was held to share findings on climate change impacts to Bay Area habitats and wildlife. Participants identified salt marshes and mudflats in San Pablo Bay––a shallow tidal estuary in the northern part of San Francisco Bay––as priority areas for assessment and adaptation planning. Using conceptual models, sediment retention in salt marshes and community interactions in mudflats were identified as the key ecosystem processes essential to climate adaptation efforts in the region. These models demonstrated the links between ecosystem processes, climate drivers, and stressors, and identified indicators.

In 2010, another workshop was convened to examine the conceptual models, identify the vulnerabilities of ecosystem processes (e.g., sediment dynamics and species interactions) under different climate scenarios, and develop adaptation options, all through an expert elicitation process. The process and findings were documented in the 2012 report Vulnerability Assessments in Support of the Climate Ready Estuaries Program: A Novel Approach Using Expert Judgment, Volume I: Results for the San Francisco Estuary Partnership. A second volume of the report focuses on a similar process piloted in the Massachusetts Bays Program.

Outcomes and Conclusions

The EPA also funded the development and implementation of the SFEP comprehensive conservation and management plan (CCMP), required of all National Estuary Programs by the Clean Water Act. A major revision of the CCMP was completed in 2016 and renamed as the Estuary Blueprint. The Blueprint has guided the implementation of additional climate science and adaptation projects since the completion of the pilot vulnerability assessment effort, including an ocean acidification monitoring project and a transition zone mapping project. The latter, also funded as part of the Climate Ready Estuaries program, identified areas that act as transitional zones between wetlands and upland areas that serve critical ecological and social functions. These zones support wildlife habitat and movement, sea level rise accommodation, and a variety of human uses, such as public access and recreation, housing, transportation, and industry. The project compared mapping methodologies and used the North Richmond area as a demonstration site for creating equitable approaches to shoreline community planning.


Gregg, R. M. (2021). Salt Marsh Vulnerability Assessment and Adaptation Plan Development in San Francisco Bay, California [Case study on a project of the San Francisco Estuary Partnership]. Version 2.0. Product of EcoAdapt’s State of Adaptation Program. (Last updated August 2021)

Project Contacts

Affiliated Organizations

The San Francisco Estuary Partnership is a coalition of resource agencies, non-profits, citizens, and scientists working to protect, restore, and enhance water quality and fish and wildlife habitat in and around the San Francisco Bay Delta Estuary.

The Environmental Protection Agency is an independent executive agency of the United States federal government tasked with environmental protection matters. The Environmental Protection Agency has ten Regional offices, each of which is responsible for the execution of the Agency's programs within several states and territories.

The Bay Conservation and Development Commission (BCDC) is dedicated to the protection and enhancement of San Francisco Bay and to the encouragement of the Bay's responsible use. When BCDC was established, only four miles of the Bay shoreline were open to public access. By drawing attention to the Bay, the Commission has played a major role in making the Bay and its shoreline a national recreational treasure. The Golden Gate National Recreational Area and numerous local, regional, and state parks and recreation areas have been established around the Bay since the Commission was established.

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