Restoring Bolinas Lagoon

Aerial view of Bolinas Lagoon: Credit: Dan Howard

By Sage Tezak

Bolinas Lagoon lies within the Gulf of the Farallones National Marine Sanctuary, 15 miles northwest of San Francisco.  Recognized by the Ramsar Convention as a Wetland of International Importance, the lagoon is located along the Pacific Flyway, making it an ideal staging ground and stopover site for migratory birds. 

This 1,100 acre tidal estuary provides critical habitat for shorebirds and waterfowl, marine mammals, fish and invertebrates.  The Lagoon also offers fishing, boating, bird watching and other recreational opportunities for thousands of area residents and visitors.

The ecological and physical functions of Bolinas Lagoon are influenced by ongoing interactions among sea level dynamics, earthquakes and sedimentation.  Since the early 19th century, human land uses, including logging, farming, grazing, woodcutting, and road building, have increased erosion and sediment availability in the watershed.  The result is a human-induced acceleration and alteration in the natural processes, leading to a loss of tidal prism and change in the composition of plants, animals and habitats.

In August 2007, the Gulf of the Farallones National Marine Sanctuary partnered with the United States Army Corps of Engineers and Marin County Open Space District to develop a plan to minimize the adverse human impacts to Bolinas Lagoon.  By mid-September 2007, a GFNMS Advisory Council Bolinas Lagoon Working Group was assembled. 

The Working Group includes members of the Bolinas, Stinson, and Seadrift communities, Sierra Club and Audubon Canyon Ranch representatives, and several renowned scientists from throughout the Bay Area.  The scientists’ areas of expertise range from landscape and avian ecology to hydrology, geology, and marine fisheries.

Throughout seven Working Group meetings, recommendations to restore and protect Bolinas Lagoon were developed.  The recommendations are organized under three objectives:

1. Restore natural sediment transport and ecological functions of Bolinas Lagoon by reducing the negative effects of human induced changes.
2. Identify and manage introduced species in the Bolinas Lagoon watershed.
3. Protect water quality by minimizing negative human impacts.

Together, the suite of recommendations addresses the direct and indirect human impacts affecting Bolinas Lagoon and aim to reduce or slow the anthropogenic influences.  Overall, the recommendations work together synergistically to restore hydrological and ecological functions in the Lagoon and its watershed.  Some key recommendations include:

* Conduct a quantitative sediment source analysis of the Bolinas Lagoon watershed to identify current and potential problem areas that contribute excess materials from the watershed into Bolinas Lagoon. 

* Restore floodplain functions to the extent possible.  Restoring the natural floodplain functions will increase the ability of the floodplain to trap sediment during storm events and thus reduce the amount of sediment entering the Lagoon. 

* Restore eelgrass.  Eelgrass is an extremely valuable habitat for invertebrates and fish.  Eelgrass serves as a nursery ground for larvae and juvenile fish and provides protection from predation by bigger fish and birds.  Currently, it is uncertain why eelgrass has largely disappeared from Bolinas Lagoon.  Further investigation is needed to determine if there is habitat suitable for eelgrass at Bolinas Lagoon.

* Actively plan and manage for sea level rise.  Sea level rise is a threat to the coastline of Bolinas Lagoon.  In anticipation of sea level rise, recommendations have been proposed including:  developing a model to reflect the consequences of sea level rise for Bolinas Lagoon; and reducing the dam-like effects of roadways bordering the Lagoon to support tidal and fluvial processes.

Other recommendations focus on managing invasive species, protecting water quality and monitoring programs that will conserve the rich ecological diversity of Bolinas Lagoon and its watershed.

A draft plan will be released May 19, 2008.  A public comment period will follow the release of the draft plan.  Written comments will be accepted from May 19, 2008 to June 22, 2008.  A Public Workshop will be held June 11, 2008 at the Stinson Beach Community Center.  The Workshop will provide a forum for additional public comments.  For more information or to download a copy of the draft plan click here.

 

“Bird species diversity at Bolinas Lagoon rivals or exceeds that of every other tidal wetland on the Pacific Flyway.”  
          -Rich Stallcup, Ornithologist