Baylands Corridor


A Victory for the Environment


The Baylands Corridor, which establishes strong environmental protections for lands along San Pablo Bay from the Sonoma County line in the north to Tamalpais Valley in the south, is a major new component of the 2007 Marin Countywide Plan. It represents an important victory for MCL and other conservation groups, which have advocated this policy since 1991.

The original 1973 Countywide Plan established three environmental corridors—Coastal Recreation on the west, Inland Rural in central Marin,  and City-Centered in the east, where development is concentrated near existing communities. These corridors set a clear, effective framework for conservation and development. Before the 1973 plan, the County would have allowed subdivisions along the shore of Tomales Bay and through San Geronimo Valley. With the plan, it became clear that central and west Marin would remain rural, and new development in the east would be focused rather than sprawling over ridges that separate towns. Establishing these policies was difficult and controversial, but they have become clearly understood and respected for more than 35 years.

The 1973 plan, however, did not recognize the special ecological value and constraints of lands along the Bay. In fact, it proposed major commercial and residential development on the St. Vincent’s/Silveira parcels, north and east of San Rafael. At the time there was inadequate information and awareness about sensitive bayshore marshes and diked historic tidelands, and they were seen as simply vacant land available for development.

The 1982 revision of the Countywide Plan made a step in the right direction by establishing a Bayfront Conservation Zone, requiring environmental assessments before development. This change, however, did not set forth environmental protection as the fundamental principle for these lands.

The 2007 plan adds the fourth environmental corridor: “The Baylands Corridor, encompassing tidal and largely undeveloped diked historic tidelands along the shoreline of San Francisco and San Pablo bays, provides heightened recognition of the unique environmental characteristics of this area and the need to protect its important resources. Based on maps and information provided by the San Francisco Estuary Institute, the area consists of marshes, tidelands, and diked lands that were once wetlands or part of the bays, and lands that were previously included in the Bayfront Conservation Zones and may include adjacent, largely undeveloped upland habitat.” (page 3-8)

MCL, Marin Audubon Society, Sierra Club Marin Group, and Marin Baylands Advocates commissioned the Estuary Institute study, “Ecological Connections: Baylands and Uplands.”

The Baylands Corridor designation supported the Countywide Plan’s policies for low density and strong environmental protections on the St. Vincent’s/Silveira properties, long a major goal for Marin conservation groups. Up to 221 housing units would be allowed on the 1,110-acre site, consisting of 12 market rate units plus up to 100 additional units for very low and low-income households. As an alternative, senior care facilities could be permitted, provided that peak hour traffic impacts do not exceed the traffic impacts of 221 residential units. Total new development is restricted to 5% of the land area and must observe environmental resource constraints such as habitat protection, streamside conservation, ridge and upland greenbelt, wetlands, tidelands, views, and community separation.

To date there have been no major development proposals for the Baylands Corridor. When there are, MCL will observe and critique them carefully, to assure the highest standards of environmental protection.


MCL continues to work on preserving important natural features of Marin. Projects have included the San Rafael Shoreline, Corte Madera marshes, Bahia, Rush Creek in Novato, Bel Marin Keys and other creeks, wetlands and ridges.


pt reyes drakes bay

Drakes Bay Beach
photo by Bob Grace

North Ridge

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MCL's Legacy: An Interactive View of Our Successes