Bolinas Lagoon Restoration

Wetland and transitional marsh (gradual blending of habitat types from intertidal to upland) provide critical habitat and are crucial for protecting wildlife from the impacts of flooding and erosion, yet they continue to degrade and are increasingly threatened by climate change. Historical impacts at Bolinas Lagoon have diminished much of its wetland and marsh habitat. Most of Bolinas Lagoon’s perimeter is hardened by development, which limits the width of shoreline habitat and restricts its ability to shift upslope as water levels rise. This results in a loss of transition zones, and increasingly eroding and unnaturally steep shorelines. Climate change is exacerbating this erosion and habitat loss through sea-level rise and increased precipitation and storm events. 

Enhancing the existing shoreline and restoring transitional marsh is critical for the long-term health and resilience of Bolinas Lagoon and its wildlife. Greater Farallones Association and Greater Farallones and Cordell Bank National Marine Sanctuaries are co-leading the South End Living Shorelines Project to enhance important wetland and upland marsh along the Dipsea Road and Calle del Arroyo Road shoreline, one of the only remaining locations with adequate space to accommodate transitional habitat. Wildlife and human communities in this area already face impacts from flooding and erosion, and this project will reconnect and rebuild those critical habitats to not only improve the lagoon’s southern shoreline, but the overall health and resilience of the Bolinas Lagoon ecosystem. See the 2019 Technical Memo.

Greater Farallones Association, in partnership with UC Davis and Smithsonian Environmental Research Center, leads the removal of invasive European green crabs in Seadrift Lagoon, a man-made lagoon tidally linked to Bolinas Lagoon. The green crab is a highly adaptable predator originating from Western Europe and Africa, and first appeared on the US West Coast in 1989. These invaders threaten native species and marine habitat by eating shrimp, clams, oysters, and small Dungeness crabs, which are important food sources for birds and critical to the economic stability of local commercial fisheries.

Since 2009, volunteers have participated in the removal of thousands of green crabs at Seadrift Lagoon, reviving biodiversity and reducing the threat of spread to Bolinas Lagoon. This community-building project increases local knowledge of the threats posed by aquatic invaders, and fosters stewardship of West Marin’s ecological resources. Plus, all removed crabs are donated to local farms for use as fertilizer; the crabs bring important nutrient and mineral content back to the soil, making this a truly surf-to-turf project! Sign up to volunteer for Green Crab removal and help us protect Bolinas Lagoon while supporting local farms.

Kent Island is a dune capped barrier island on the interior of Bolinas Lagoon that is a geomorphic feature unique to California. Historically, Kent Island’s plants adapted to saltwater inundation, sand burial, and erosion, allowing the island to recover from storms and earthquakes, and changing shape depending on wind, wave, and geologic factors. In recent years, invasive plants have impacted the function and health of Kent Island, shifting native plant communities and causing the island to grow.

The project includes hand-removing nonnative plants such as fennel, ice plant, French broom, and European beachgrass that are anchoring the island and trapping unwanted sediment. Removing invasives helps restore the island’s naturally-shifting dune habitat, facilitates return of native plants and the animals that depend on them for food and shelter, and improves water and sediment transport throughout Bolinas Lagoon. Thanks to the project, captured sediment is being released and native plants are returning to Kent Island.

From 2013 through 2022, Greater Farallones Association, in partnership with Greater Farallones National Marine Sanctuary, Marin County Parks, the US Army Corps of Engineers, and hard-working volunteers, implemented the Kent Island Restoration Project. The project is now managed by Marin County. This important effort would not be possible without the help of volunteers who have successfully restored over 20 acres of habitat since 2013. Removal seasons generally occur from April through October each year, and are a great way for the public to actively support the Greater Farallones Marine Sanctuary and help restore a local ocean ecosystem. See the Marin County website for information on volunteering opportunities.