Marsh Restoration

Marin County Parks and CSA 6 remain committed to working together to restore wetlands at McInnis Marsh and beneficially reuse dredge sediment from the CSA 6 South Fork Gallinas Creek dredging project. For the past year, staff have been working to address design constraints and costs posed by the Las Gallinas Sanitary District’s force main that runs through the wetlands. At this time, we are developing potential design alternatives that could allow for the placement of dredge sediment on site as a stand-alone project while issues associated with the force main are resolved. Staff will be meeting with regulatory agencies this spring and summer to discuss feasibility. Marin County Parks and CSA 6 staff plan to share feasible project actions with the community later this summer to gather comments and suggestions.

Marin County Parks continues to work with project partners – the Department of Public Works and Las Gallinas Sanitary District – to develop a project that will create, expand and enhance the resiliency of the tidal marsh wetland habitat and uplands. Preliminary designs are complete and intermediate designs are in development..  

Parks staff led an educational walk at McInnis Marsh on Tuesday, May 21, 2019 from 10am to 1pm, speaking about restoration opportunities along the lower sections of Las Gallinas and Miller Creeks. James Raives and Sarah Richards, who are heading up this project, discussed the vision for the McInnis Marsh restoration. Naturalist Shannon Burke led a walk along the levees for a closer look at the project area and the animals that will benefit.  

The McInnis Marsh project proposes to restore subtidal and intertidal habitat at an 180-acre area of diked wetlands within McInnis Park, home to protected species including black rail, Ridgway's rail, and salt marsh harvest mouse. It will also help protect McInnis Park golf course from sea level rise and maintain the San Francisco Bay Trail connection to Las Gallinas Valley Sanitary District..

• County news release
• Fact sheet PDF

Through a grant from the California Department of Fish and Wildlife and Measure A funding, Marin County Parks has hired Environmental Science Associates (ESA) to design the project and prepare plans and specifications. ESA has prepared an initial draft of the project designs, which is currently under review. We also hired Prunuske Chatham Inc. to prepare an environmental assessment of the project.

• Lower levees that separate the marsh from Miller Creek, Gallinas Creek, and San Pablo Bay.
• Breach Miller and Gallinas Creeks to allow flow into the marsh at lower tides..
• Construct an ecotone levee between McInnis Park Golf Course and the marsh.
• Install a new Bay Trail connection to Las Gallinas Valley Sanitary District property.

• Expand ecologically significant marshland.
• Maintain and enhance the Bay Trail experience.
• Increase the ecological value and diversity of the Miller Creek and Gallinas Creek marsh complex.
• Provide habitat for sensitive species living in the wetland.
• Increase the natural geomorphic capacity of the corridor to adapt to sea level rise.
• Protect existing park and sanitary district facilities from impacts associated with climate change.

In February 2018, a community workshop was held to discuss the evolution of the marsh and draft design options.

• McInnis Marsh Workshop Presentation PDF

• McInnis Marsh Site Report PDF
• McInnis Marsh Feasibility Study PDF

Marin County Parks is the lead agency for the McInnis Marsh Restoration Project with support from the following agencies. The local project partners signed a Memorandum of Agreement (MOA) in September 2012 to collaborate in the study, funding, and implementation of restoration actions.

• California Department of Fish and Wildlife
• California State Coastal Conservancy
• Las Gallinas Valley Sanitary District

McInnis Marsh lies within the historic confluence of Las Gallinas and Miller Creeks. During periods of flood and high tide, these creeks once flowed unimpeded through a network of tidal wetlands, converging in the Gallinas Baylands.

Historically, Miller Creek flowed into delta network that spread over a broad swath of bay margin. When Miller Creek flooded, water flowed south to Gallinas Creek. This connectivity was lost in the early 1900’s when levees were constructed, confining Miller Creek to a narrow 150-foot wide channel flowing to San Pablo Bay.

The property was acquired by Marin County in 1972, and developed for park use. McInnis Marsh is currently an undeveloped area within the park. The public currently enjoys hiking, biking, and dog walking on the levee top trails on the perimeter of the marsh and the project would includes the construction of a new Bay Trail connection to the Las Gallinas Valley Sanitary District. 

Historic map of McInnis Marsh circa 1912: