San Geronimo Valley Upland Habitat Restoration
San Geronimo Creek watershed provides some of the best remaining habitat for Coho salmon in California. Habitat protection and enhancement begins with the collaborative stewardship of watershed lands and drainages that feed the San Geronimo Creek. While the roads and trails that crisscross these drainages are necessary for public access, recreation, maintenance, and fire protection, they can also degrade habitat and water quality through the contribution of sediment. For these reasons, the Marin County Open Space District (MCOSD) has embarked on a multi-year effort to correct and improve the condition of fire roads and trails in our Gary Giacomini Preserve, which comprises 1,476-acres (or 25%) of the 5,943-acre San Geronimo Creek watershed. For information about MCOSD’s road and trail planning efforts on all 34 preserves, visit the Road and Trail Management Plan/EIR webpage.
San Geronimo Creek is a watershed of statewide significance for Coho salmon. Although it supports one of the most important remaining Coho runs on the Central Coast, and is also an important steelhead run, these salmonid populations declined substantially between the 1950’s and 1990’s, from several thousand to only a few hundred. While many variables can affect their numbers, excess sediment is considered to be a principal culprit. Studies conducted in these watersheds have identified excessive fine sediment yield as the single most important factor limiting salmonids. Unpaved roads (e.g. fire roads, ranch roads, former logging roads, narrow trails, etc) are often both a chronic source of fine sediment, through continual gullying or erosion, and a source of excessive sediment loading through episodic failures of entire sections of roads. The San Geronimo Valley Salmon Enhancement Plan provides comprehensive information about salmonids in the San Geronimo Valley and recommendations to improve and maintain habitat conditions.
The goal of MCOSD’s road and trail improvement work is to reduce the amount of fine sediment generated by roads and trails in our preserves. An added benefit, however, is that the work also reduces the need for MCOSD to maintain roads as frequently. The initial investment of grant and MCOSD funding aids salmonids in the watershed and reduces MCOSD’s road maintenance costs in the long run.
MCOSD road and trail projects have been generously funded with more than half a million dollars in grant funding from the California Department of Fish and Game’s Fisheries Restoration Grant Program (FRGP). MCOSD has cost-shared a similar amount through funding, staff time, and in-kind services.
The Road and Trail Improvement Projects
In 2007, MCOSD conducted a road and trail assessment of our preserves in the San Geronimo Creek watershed. The purpose of the assessment was to identify current and potential erosion problems existing on MCOSD lands. The assessment yielded 112 sites that posed a threat to water quality and salmonid habitat. To date, MCOSD has received funding for 84 of the 112 sites. Since 2008, MCOSD has applied the funds to three road and trail projects.
San Geronimo Creek Upland Habitat Restoration Project
Year awarded: 2008
Award amount: $207,363
Number of sites funded: 36
Years for implementation: 2007 - 2010
Roads affected: Sylvestris Fire Road and Contour and Candelero Trails
Woodacre Creek Upland Habitat Restoration Project
Year awarded: 2009
Award amount: $138,426
Number of sites funded: 26
Years for implementation: 2008 - 2011
Roads affected: White Hill, Hunt Camp, Sylvestris and Conifer Fire Roads, and the Willis Evans Trail.
Lagunitas-Sinaloa Upland Habitat Restoration Project
Year Awarded: 2010
Award Amount: $147,452
Number of sites funded: 22
Years for implementation: 2009 - 2012
Roads affected: Sinaloa and Haute-Lagunitas Trails
View project locations on map
Decades ago, what is now known as the Edgewood Trail on the Gary Giacomini Preserve was a fire road that was eventually abandoned. When MCOSD acquired the property, it functioned as a shared use trail. When erosion on abandoned fire roads such as the Edgewood Trail must be addressed, it is necessary to remove vegetation to access the problem sediment sites. The first image (below) is the Edgewood Trail in October of 2009, just after erosive areas were fixed during the summer of 2009 as part of the Woodacre Creek Upland Habitat Restoration Project. The next image is taken from the same location, one year later in October of 2010. Although the roads and trails look dramatically “scraped” after initial improvements, native grass seeds in the soil usually have the site back to a natural condition within a year.
These road and trail improvement projects are part of a larger comprehensive effort being made by both MCOSD and the Marin County Department of Public Works Fish Passage Program, along with local entities such as SPAWN and MMWD, to restore the Lagunitas watershed and its tributaries located in the San Geronimo Valley. The Fish Passage Program recently completed a series of fish passage restoration projects in the San Geronimo Creek watershed aimed at supporting and increasing salmon populations.
MCOSD thanks SPAWN, the San Geronimo Valley Planning Group, and San Geronimo Valley community volunteers for their hard work restoring native habitat on January 28 and 29, 2011. Native plants were harvested from a section of the Willis Evans Trail, where work will occur this summer, and were replanted along the recently restored Candelero Trail.