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Watershed Projects

A man reaches toward a fence on a retaining wall along a hillside. A culvert runs down the hillside.

Multi-benefit projects continue in several key areas across the watershed lands as guided by Marin Water’s Biodiversity, Fire, and Fuels Integrated Plan. The projects are meant to restore forest health, conserve valuable native habitat, improve wildfire resiliency, and increase understanding of forest ecosystems. Learn more.

Ongoing Watershed Resiliency Projects

On October 18, 2023, the Marin County Fire Department, in coordination with Marin Water, applied a prescribed fire to the southern end of the Mount Tamalpais Watershed. Prescribed fire is one of many methods that contribute to Marin Water's proactive approach to addressing fire fuel management and a more resilient, ecologically healthy watershed. By mimicking the natural effects of wildfire, the carefully planned burn of overgrown vegetation is a safe and efficient way to restore forest health, improve open-woodland conditions for wildlife habitat and create fuel breaks that help protect our water quality, water system and the surrounding community. Funding for the burn site preparation work for this project provided by the California Department of Forestry and Fire Protection's Forest Health Program. 

We thank our partners at the Marin County Fire Department for all of their efforts to ensure the safe execution of this 11-acre vegetation management operation. Building on this success, the District will continue to coordinate with Marin County Fire on additional potential prescribed fire treatments in the fall and/or early winter timeframe to complete remaining planned work in the Rock Spring area of Mt. Tam. The specific date of any prescribed fire operation on the watershed will always be announced the morning of ignition and will always be dependent on air quality, weather and other environmental conditions, as well as available fire department resources.

Meanwhile, other fuel reduction and restoration efforts – including mechanical removal, manual pulling, and others – remain ongoing on the watershed, and an addendum to the Districts’ Biodiversity, Fire, and Fuels Integrated Plan in July added an additional roughly $1 million in funds for further scaled up work in the 2023-24 fiscal year.

Investment in the scaled-up work is made possible through a water rate adjustment that took effect on customer water rates beginning July 1, 2023. The adjustment was necessary to help the District recover from consecutive years of drought and inflationary pressures while also allowing for additional investments in water supply reliability and resiliency -- including to mitigate wildfire risk on the watershed, the primary source of the District's water supply. In total, the increased funding will allow the District to add hundreds of acres of treatment to its vegetation management plans annually. In the last four years the District has treated up to 1,500 acres of fire fuels annually. Marin Water will leverage the additional funding to treat close to 2,000 acres annually, including an additional 40 acres of forest fuel reduction and 200 more acres of forest fuel maintenance. 


In May of 2019, Marin Water adopted an Amendment to the Mt. Tamalpais Watershed Road and Trail Management Plan (RTMP) for the Restoration of Azalea Hill (Project). This watershed project will:

  • Remove approximately 4.4-miles of non-system roads and trails and restore those routes to natural conditions to improve habitat and water quality.
  • Adopt and improve a 1.9-mile Class IV road comprised of the existing Liberty Gulch Road (1.2 miles) and convert an existing non-system trail (0.7 miles) to the wider, small vehicle route.
  • Improve the hiking and equestrian route over Azalea Hill by correcting erosion and drainage problems along approximately 1.1 miles of existing Class VI trail, rerouting the trail around sensitive plants and adopting 250 feet of an existing non-system trail.
  • Treat the Azalea Hill parking lot to correct its erosion problems and improve the visitor amenities. Upon its completion, the project would prevent up to an estimated 219 cubic yards of sediment from entering Azalea Hill’s creeks and Alpine Lake annually, and would restore approximately one acre of habitat.

The Project consolidates use on the two existing routes proposed for upgrades and provides a much-needed connection and safety improvement between the “Lakes” and “Pine Mountain” areas. The District will continue to apply for grants to support the major trail segments as funding solicitations become available. For additional project details and construction updates, visit Azalea Hill Restoration Implementation.

If your local organization and community group is interested in funding portions of this project, contributions for the project can be made to the Mt. Tamalpais Watershed Fund. Future volunteer opportunities will be available in coordination with major construction phases.

Marin Water manages about 22,000 acres of land surrounding seven water supply reservoirs in western Marin County. When combined with easements on other public and privately held lands, the District is responsible for managing and maintaining over 700 stream crossings which include bridges, culverts, and rock fjords (crossings). The Culvert Maintenance and Replacement Project is being implemented according to our Mount Tamalpais Watershed Road and Trail Management Plan and the associated Programmatic Environmental Impact Report (PEIR).

The main purpose of the project is to improve water quality and strictly minimize sediment input into creeks and reservoirs fed by the District’s watershed lands. This improves fisheries habitat, prolongs the life of our reservoirs and facilitates the water treatment process, among other benefits. These projects are also designed to reduce environmental impacts of the road and trail network on the flora and fauna of the District’s watershed lands and ensure safe access for recreational visitors and maintain access to water resource infrastructure.

The project is necessary to enhance the resiliency of the watershed and “storm-proof” specific road and trail segments. Marin Water completed a road and trail related erosion site study performed on the entire watershed that looked at more than 1,200 possible erosion sites. In 2018, the District completed a stream crossing condition assessment of 724 culverts as part of a new asset management program looking to prioritize the expenditure of limited capital resources to maximize system resiliency. During this assessment, 37 crossings were identified that required near-term repairs because they posed an immediate risk to ongoing District operations and another 60 that would require future repairs. The District’s staff completed the necessary hydrological analysis, and biological surveys to inform the environmental permitting process and resource agency review for Phase I in early 2019.