Marin County Parks and Open Space Department

Bolinas Lagoon Ecosystem Restoration Project

Presentations Now Available

POSTED ON: MAY 5, 2017

During the Bolinas Lagoon Advisory Council meeting on April 28, 2017, presentations were made on the Letter Property and the lagoon's bathymetry. If you are interested in obtaining a copy of the associated reports, contact Veronica Pearson at (415) 473-5086.

Background

Bolinas Lagoon is 15 miles northwest of San Francisco, between the communities of Bolinas and Stinson Beach. It provides rich habitat for shorebirds and waterfowl, fish, invertebrates, and special-status plants and animals. Located on the Pacific Flyway, Bolinas Lagoon is an important wintering area for scores of birds and provides habitat for breeding colonies of herons and egrets. The protected sand bars and islands provide pupping grounds and haul-out sites for harbor seals. Subtidal areas and extensive mudflats support diverse populations of invertebrates and provide nursery and feeding habitat for resident and migratory fish. The endangered steelhead and coho salmon move through the lagoon on their way to spawn in streams within the lagoon’s watershed. Together these estuaries provide a wetland complex of exceedingly rich ecological value in western Marin.

Bolinas Lagoon Management and Jurisdiction

Marin County Parks (Parks) has primary responsibility for managing the lagoon’s resources, but the management and restoration of the lagoon is shared with other agencies that have jurisdiction over the lagoon and its watershed, including:

Bolinas Lagoon Advisory Council

Marin County established the Bolinas Lagoon Advisory Council to provide the community with an opportunity to participate in the management and restoration of Bolinas Lagoon. The advisory council consists of representatives of the primary agencies managing the lagoon, other stakeholder organizations, and local communities. The advisory council is working on the following:

  • Communication Plan
  • Restoration Project Priorities
  • Bolinas Bulletin
  • State of the Lagoon Conference

To review past and current advisory council activities, please view its Agendas and Minutes.

History

The lagoon’s ecological significance and complexity require careful planning to ensure the soundness of restoration activities. Parks has been developing and refining plans to restore Bolinas Lagoon since 1996. Some restoration projects are already underway, concurrent with ongoing planning.


Current Restoration Projects

European Green Crab Removal at Seadrift Lagoon

Seadrift Lagoon is a man-made lagoon connected to Bolinas Lagoon. Both lagoons have been infested with the European green crab (Carcinus maenas), an invasive invertebrate that has all but driven out the native crab species from Seadrift Lagoon. Since 2009, researchers from the Smithsonian Environmental Research Center, Portland State University, and the University of California, Davis have been working with community volunteers to remove the crabs. Volunteers have ventured out into the lagoon during three consecutive seasons to trap these invasive crabs.


Invasive Spartina Control

Marin County Parks is the primary agency responsible for the control of invasive cordgrass (Spartina alterniflora) in Bolinas Lagoon. The Invasive Spartina Project is leading a regional effort to eradicate this plant, and other invasive Spartinas, from San Francisco Bay. Based on studies using drift cards, populations of the hybrid Spartina in Bolinas Lagoon have likely come from plant material transported by currents from northern San Francisco Bay. These existing clones in Bolinas Lagoon pose an immediate threat to the lagoon’s hydrology, and significantly alter its physical structure and biological composition. If allowed to spread, Spartina alterniflora promotes increased sedimentation that would quickly reduce the acreage of tidal shallows in the lagoon.

The ongoing efforts to control invasive Spartina in Bolinas Lagoon have been limited to digging plants out by hand and covering them with tarps. While labor intensive, these methods proved successful on the original infestations. Recent infestations have appeared that are lower in the lagoon where the saturation of the mud makes such manual work infeasible.

In partnership with the Invasive Spartina Project, Parks is developing a long-term control program aimed at managing and monitoring cordgrass invasion of the lagoon.


Kent Island Restoration

Kent Island was originally a mobile, flood shoal island in Bolinas Lagoon. In recent decades, it has been steadily colonized by non-native plants, including European beachgrass, iceplant, Monterey pine, and Monterey cypress. This vegetation has stabilized the island, reduced the amount of native habitat, and adversely affected the lagoon’s hydrological function and sediment transport. In 2009, Parks received a National Estuary Act grant to restore the island’s beach, salt marsh, and dune habitats. The following provides a complete description of the project:


Lagoon Bathymetry

Since 1968, Parks has been conducting bathymetric surveys of Bolinas Lagoon every ten years. As part of the grant for the Kent Island Restoration Project, Parks received funding for a new bathymetric survey of the lagoon using LiDAR (Light Detection and Ranging), Sonar (Sound Navigation and Ranging), and other state-of-the-art techniques to develop an accurate picture of the lagoon. This survey is necessary to test the accuracy of the 50-year projection of the lagoon, better understand the effects of sea level rise, and help guide restoration priorities.


North End Wetlands Enhancement and Sea Level Rise Adaptation Project

Please visit the new dedicated webpage for the North End Project


Rock Slope Protection

In 2011, the California Department of Transportation implemented the Highway 1/Bolinas Lagoon Rock Slope Protection Project that repaired and upgraded the rock slope, drainage systems, and pullouts along Highway 1 immediately adjacent to Bolinas Lagoon. The project benefits include floodplain restoration, invasive species removal, and improved water quality.