Lagunitas Creek is the local celebrity of salmon spawning, with its miles of easy public access, dedicated viewing areas and the series of lawsuits that led to stringent watershed protections for local homeowners. But the Walker Creek watershed, 98 percent of which lies on private land, has become the focus of renewed restoration work and attention from local agencies.
The Marin Resource Conservation District has been leading floodplain restoration projects on the lower part of the creek since 2020, and in the past two drought-stricken years, Marin Water has heightened its monitoring of the stream’s fish populations. Last week, the R.C.D. and a group of other agencies presented their progress, painting a hopeful, if uncertain, picture of the creek’s future as a refuge for coho salmon and steelhead trout.
“Fish are coming back, maybe just in little trickles, but they’re coming back,” R.C.D. director Nancy Scolari told the Light. “There’s a little hope in there.”
The restoration of the Walker Creek watershed has been an ongoing project for two decades, and along with stocking efforts, it’s given new life to a population of coho that was extirpated in the early 1990s. Efforts kicked into high gear in early 2020 with help from a state fisheries grant. The R.C.D. began working with five landowners—David Sherwood, Jody Brazil, Phillip Raiser, Roth and Emily Martin and Joe Colliss—to study existing habitat conditions and plan enhancements on the lower, tidal-influenced reaches of the creek.
The resulting projects, whose designs will be finished by March 2024, include expanding low-flow areas that provide shelter for fish during high-flow events, adding new spaces for sediment to settle, planting more vegetation and widening the floodplain. To design these, R.C.D.’s advisory committee members and contractors need access to private property and cooperation from ranchers.
“Walker Creek is all about trusting relationships with the ranching community,” Ms. Scolari said. “You can’t just do that with one rancher.”
The creek is visible to the public mainly at two points: a quiet two-mile stretch of Marshall-Petaluma Road, and the channel where Highway 1 turns away from Tomales Bay toward Tomales and the creek’s wide estuary, known as Keys Creek, empties into the bay. For most of its run, the stream carves a lonely route through private cattle ranches, sometimes bare and uncovered, sometimes sheltered by a thick canopy of alders, oaks and laurels.
“Walker Creek is a surprisingly beautiful stream,” said Jonathan Koehler, the fisheries program manager for Marin Water. “There are not too many places to get to it, but the places I’ve been to are healthy and there’s a lot of opportunity.”
Marin Water surveyed the Arroyo Sausal, a tributary of Walker Creek that flows through the district’s Soulajule Reservoir, last winter, finding no salmonids in its turbid waters. But in the preceding dry summer months, the agency had to monitor habitat conditions in the main branch of Walker Creek, and reported juvenile coho and steelhead, even as the creek reached exceedingly low levels. Unlike Lagunitas Creek, Walker Creek does not support any chinook salmon.
Walker Creek’s salmon stock has also seen more human intervention than Lagunitas. Since 1979, the California Department of Fish and Wildlife has periodically attempted to reinvigorate the creek’s fish population by releasing juvenile and adult coho raised at the Warm Springs Fish Hatchery on Lake Sonoma, with genetic origins in the Lagunitas Creek watershed. Lagunitas has never been artificially stocked with salmonids, but a similar program placed coho bred in captivity into Redwood Creek at Muir Beach.
Fish and Wildlife and CalTrout have intermittently surveyed coho and steelhead as part of a pilot project with the county-owned Walker Creek Ranch, and Fish and Wildlife has installed a smolt trap, a cone-shaped fyke net that funnels fish into a box, in the lower reaches of the creek. By capturing and releasing the salmonids, the agency will be able to monitor them more reliably as they migrate toward the bay in spring, providing a more accurate picture of the watershed’s successes.
Because of the state’s ongoing stocking efforts, it’s still unclear whether Walker Creek can support a significant new population. Hatchery-raised fish carry coded wire tags that can be read by C.D.F.W.’s monitoring antennae, but tissue samples are the only way to determine whether the coho are descended from those fish.
Salmon populations writ large are in decline, and the R.C.D.’s efforts with local landowners could be bridled by factors far beyond their control. Rainfall and ocean conditions play as important of a role as stream habitat for anadromous fish, and the thresholds set by C.D.F.W. to indicate that the endangered coho population has recovered will be difficult to meet.
“I don’t want to sound doomy and gloomy, but when I see those numbers for Walker and Lagunitas, I just think: ‘Man, I’ll be happy if we get five, 10, 50 more fish,’” said Sarah Phillips, the urban streams program manager for the R.C.D. Even a higher fish count won’t positively confirm that the project was successful, she added, since “you can have correlation without causation.”
Yet Marin has had other local success stories resulting from restoration work. National Park Service officials spotted juvenile coho in Pine Gulch Creek last year for the first time in more than a decade, and the county’s other creeks saw among their largest coho salmon migrations in recent memory. Walker Creek may run through fenced pastures rather than protected redwood groves and parkland, but it could become another small-scale victory for conservation.
“We’re still at the mercy of the larger population decline,” Mr. Koehler said. “But if we could recreate Lagunitas in Walker Creek with restoration and good monitoring, those are the kinds of successes we’re looking for.”
This article was corrected on July 28 to reflect the status of the habitat enhancement projects for Walker Creek. The designs will be completed by March 2024, after which the R.C.D. can apply for implementation funding.