Submitted by Allie Rigby on

Soft orange light at sunset reflects on water and cypress trees, as well as a red barn, on the shoreline of Tomales Bay.

“Living shorelines connect the land and water to stabilize shorelines, reduce erosion, and provide valuable habitat that enhances coastal resilience.” –NOAA Restoration Center

Living shoreline projects are nature-based approaches that provide shoreline protection services (e.g., long-term mitigation of shoreline erosion) while at the same time enhancing and protecting existing habitats and providing co-benefits such as sequestering carbon (e.g., blue carbon in eelgrass meadows) and promoting native oyster restoration.

What is a living shoreline project?

Unlike a concrete seawall or other hard structure, which impede the growth of plants and animals, living shorelines grow over time.

They are an innovative and cost-effective technique for coastal management (NOAA).

Why is ACR interested in living shorelines?

ACR’s coastal preserves in Marin County, including many of our buildings at Cypress Grove and the Martin Griffin Preserve, face a growing threat from sea level rise. The sea level rise projections for the San Francisco, CA region are for increases ranging from 1.6 to 11.8 inches by 2030 (County of Marin 2017).

ACR is committed to the concept of living shorelines versus building concrete walls and other hard barriers to help mitigate the effects of sea level rise caused by climate change.

Is there a living shorelines project planned for Tomales Bay?

Yes. The Marin County Community Development Agency (CDA) initiated The Tomales Bay Living Shoreline Feasibility Project, with funding provided by the California Climate Investments program for the State Coastal Conservancy’s (SCC) Climate Ready Grants Program. They are interested in testing two sites on the Bay for a “proof of concept.”

ACR’s Cypress Grove Preserve, located on the eastern shore of the bay, was evaluated along with several other sites and was selected based on criteria that included future flooding and erosion risks, expected ecological benefits, public access and recreation benefits, longevity of benefits, and cost and implementation considerations.

The other site identified in the plan is Martinelli Park on Tomales Bay’s western shore.

Following detailed design and permitting, these projects would be constructed to serve as pilot studies to be monitored for effectiveness over time, with the opportunity to draw from these to help inform future adaptations elsewhere within Tomales Bay.

  • Two Douglas iris blooms near a small pond at Cypress Grove, with Tomales Bay in the distance.
  • Egret on shore of Tomales Bay with Cypress Grove Research Preserve in the distance.

Why is ACR interested in a living shoreline project at Cypress Grove?

The Tomales Bay Living Shoreline Feasibility Project is an exciting opportunity for ACR to collaborate with the State and County, to help create a “proof of concept” that may be beneficial to future projects on Tomales Bay as well as other shorelines around the world.

The proposed project at Cypress Gove primarily addresses the site’s vulnerability to flooding. It seeks to:

• restore natural sediment transport processes,
• restore and preserve the beach habitats that have historically protected the site, and
• improve upland (dune and backshore) habitats through revegetation.

The beach restoration would work in concert with offshore native oyster restoration, which would act to stabilize the new shoreline and integrate with large woody debris features that would retain sediment and enhance shoreline habitats.

The project is expected to provide added protection to the site for up to 1.6 feet (50 cm) of sea-level rise. Beyond this point, ACR would likely need to include additional adaptive measures to be successful, such as relocation or raising of the existing buildings.

What is the cost of the proposed project?

The County currently estimates the costs for the proposed project at Cypress Grove to be $1.26 - $2.7 million. The proposed project comes at no financial cost to ACR.

What’s the timing?

We don’t yet know the timing for the work to begin at Cypress Grove. A feasibility study, linked below, has suggested several next steps.

Where can I learn more about The Tomales Bay Living Shoreline Project?

This is an exciting opportunity, and additional information can be found here: https://www.marincounty.org/main/county-press-releases/press-releases/20...

This feasibility report presented to the community in January 2022 is also a great resource for further learning: https://www.marincounty.org/-/media/files/departments/cd/slr/mcap_tomale...