Modeling Sea-Level Rise in San Francisco Bay Estuary

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With sea level rise, how will the coastal habitats of the San Francisco Bay Estuary change over the next 100 years? Mapping and modeling studies by Dr. Karen Thorne, WERC scientists, and partners have produced scenarios for this important coastal ecosystem.

Rising Concerns

Accelerating sea-level rise (SLR), shifting precipitation patterns, and frequency and intensity of storms will affect coastal ecosystems, including salt marshes. Global sea-level rise projections range from 1.0 to 1.9m by 2100 (IPCC 2007Jevrejeva et al. 2010Vermeer and Rahmstrof 2009), which will result in the loss of salt marshes and their associated wildlife species.

It is the aim of our program to provide site specific sea-level rise predictions to land managers through the intensive collection of field data and innovative predictive modeling.  In 2009 and 2010, thousands of elevation and vegetation survey points were collected in salt marsh at 12 sites surrounding San Francisco Bay. The elevation data was synthesized into a continuous elevation model for each site, providing land owners valuable baseline data.

A new marsh accretion model, WARMER, was developed to assess the risk of sea-level rise to salt marsh parcels around San Francisco Bay.  Additional sediment data was collected at four representative sites to provide inputs for the WARMER model.  The results of WARMER were then extrapolated to the remaining study sites.  WARMER indicates that most salt marsh around San Francisco Bay will transition from high to mid marsh by 2040, to low marsh by 2060 and to mudflat by 2080, however there is a great deal of variation around the bay.  The rate of sea-level rise and local accretion rates may be very different than the parameters used for the model, thus WARMER results are best characterized as one possible scenario of how the salt marsh platform may respond to rising sea-levels.

About Us

WERC’s Dr. Karen Thorne and scientists at WERC have over 20 years of experience pairing biological monitoring with research and management questions. WERC currently is working or has worked on numerous estuarine restorations and tidal wetlands in California, Oregon, and Washington.

With a focus on collecting and disseminating fine-scale baseline physical and ecological datasets and sea-level rise response models, the USGS provides land managers the information needed to make better informed decisions regarding their coastal resources. Sea-level rise and changing storm patterns, place coastal ecosystems at high-risk to irreversible change. Improving our understanding of the physical and ecological processes at the local scale is paramount to building accurate projections of coastal ecosystem response.

A Community of Partners

We are an interdisciplinary team with backgrounds in the natural and physical fields, including ecology, geology, biology, climatology, and geography. Collaborating or cooperating partners include UCLA, Oregon State University, UC Davis, NOAA NERRs, the FWS Refuge system, The Nature Conservancy, Skokomish and Nisqually tribes, California Department of Fish and Game, California State Parks, the U.S. Navy, PRBO, Marin County, East Bay Regional Parks, and Haywood Regional Parks.

WERC San Francisco Bay SLR project sites

Project study sites (Public domain.)


Study Sites

Click on the links below to explore all 12 San Francisco Bay study sites.

  1. Gambinini
  2. Petaluma
  3. Black John Ecological Reserve
  4. San Pablo Bay National Wildlife Refuge 
  5. Coon Island
  6. Fagan Slough Ecological Reserve
  7. China Camp State Park
  8. Corte Madera Ecological Reserve
  9. Arrowhead
  10. Cogswell
  11. Laumeister
  12. Colma