Marin County supervisors have approved a project aimed at restoring wetlands in Bolinas Lagoon and reducing flooding on the only road leading into Bolinas.
“This is a very exciting day, but there’s been a lot of work leading up to it,” County Parks Director Max Korten told supervisors Tuesday. “This seed started over 10 years ago and really came out of the community.”
Before voting unanimously to approve the project, regulators approved a “mitigated negative declaration” certifying that the project would not cause unmitigated adverse environmental impacts. This declaration eliminates the need for a more detailed environmental impact report.
The project aims to restore the northern end of the lagoon to its pre-19th century transformation state. Anthropogenic modifications (rerouting streams, residential embankments, shoreline hardening roads) increase the amount of sediment in the lagoon, which affects the health of the lagoon and the health of the species that depend on it for survival. It had a negative impact.
“Right now, the system is disrupted and needs to make way for future sea level rise,” said Veronica Pearson, the county’s aquatic ecologist and restoration planner who oversaw the project. “Bolinas Lagoon is also home to a number of special status species that could greatly benefit from this project.”
Pearson said the plan came from community opposition to a 2002 Army Corps proposal to dredge the area and remove 1.4 million cubic yards of sediment.
“We’ve had a tremendous response from the community,” she said. “We realized that we needed to change the way we thought about what restoration was.”
Recognized as a Wetland of International Importance by the 1971 Ramsar Convention, Bolinas Lagoon contains more than 1,100 acres of wetlands, tidal flats, and habitats that are home to a variety of special status flora and fauna species.
The project will restore floodplains at the northern end of the lagoon, making the region more resilient to climate change and expected to improve ecosystem health. The project is also expected to reduce the potential for Bolinas to become isolated due to the closure of the Olema-Bolinas Road due to flooding.
One watershed change made in the 19th century was the redirection of Lewis Gulch Creek, which once flowed from the Wilkins Ranch to the north end of the lagoon. The creek was diverted to the west side of Olema Bolinas Road. As a result, roads frequently flood during wet years.
Changes in streams in the lagoon basin have also caused loss of riparian habitat and stream functions. Flooded roads impede fish migration. Sea level rise due to climate change is expected to worsen flooding and cause further loss of wetlands and sensitive species habitat.
This project is designed to prevent that by reorienting Lewis Gulch Creek closer to its original route. To make this possible, the project will remove the portion of Olema-Bolinas Road that intersects with Highway 1, known as Bolinas Y.
The project will also raise a portion of the Olema-Bolinas Road above what would become a floodplain again and install a bridge to allow the stream to pass under the road and return to Bolinas Lagoon. The intersection with Highway 1 will also be slightly modified to make it more at right angles and safer.
Pearson said the project will recreate a brackish wetland that provides habitat for special status species such as steelhead, California red-legged frog, California railhead and possibly coho salmon.
“Coho are back in Bolinas Lagoon,” she said.
The county has secured a grant that will cover most of the $8.7 million it will cost to complete the project, and will pay an additional $3 million for invasive species removal. Marin County will contribute $2 million. More than $3 million in grants have been received from the California Wildlife Conservation Commission and the National Fish and Wildlife Foundation.
Pearson said the county plans to begin soliciting construction bids early next year. Construction, which will take two years, could begin in June.