Two Long-Lost San Francisco Creeks Could Soon See the Light of Day
There are many reasons to restore urban waterways, and as the climate changes, they all lead to a more sustainable future.
A growing movement to restore San Francisco’s long-vanished creeks is connecting communities with their local ecosystems, and also creating a new type of “green infrastructure” that may help the city adapt to climate change and seasonal flooding.
The latest efforts are in two very different parts of town, and they are playing out in distinct but complementary ways.
Woodland Canyon Creek is on a tangled slope of Mount Sutro, squeezed between Cole Valley and UCSF’s original campus and smothered under a blanket of invasive ivy and blackberry. It only comes to life in the rainy season. Yosemite Creek seeps out of a spring in McLaren Park year-round, gathers in a holding pool (marked on maps as “Yosemite Marsh”), then disappears into local sewer pipes.
The problem is that with climate change, stronger winter storms douse watersheds such as the one surrounding Yosemite Creek, and the surging waters flood the city’s sewer system and wash effluent from sinks, showers, and toilets into San Francisco Bay. This in turn feeds noxious and harmful algae blooms.
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“No matter how much we try to alter them, with our concrete and engineering, we will always be overwhelmed and underprepared for what nature will bring back to us,” says Josh Bradt, director of the California Urban Streams Partnership.
Good for nature, good for us
By restoring a segment of Yosemite Creek to the surface — a process called daylighting — city planners hope to work with natural systems rather than against them, by diverting rainfall away from the sewer system and into the soil.
Flood control isn’t the only benefit. When an urban creek is daylighted, the land and watershed are healthier, and so are the surrounding communities. “What’s good for nature and wildlife is good for us,” says Letitia Grenier, a researcher with the San Francisco Estuary Institute. “Quite a bit of research shows that human health has great benefits from complex ecosystems, rather than being in a park with a lawn and trees,” including improvements in cognition, and in mental, emotional and physical health.
She also says creeks help cities adapt to climate change by capturing carbon dioxide and creating a “climate refuge” from hot days in an urban heat island.
Bigger picture, there’s an element of environmental justice here. “We can’t just daylight creeks in the rich neighborhoods,” Grenier says. “I feel like Yosemite Creek is a place where that would be meaningful,” as it’s situated at the intersection of the historically working-class Portola and Excelsior districts.
The creek seeps down out of the hills of McLaren Park near the corner of Bacon and Harvard streets, then travels in underground pipes before trickling into the bay north of Candlestick Point, two miles away. Only a sliver of its course — about a third of a mile along the park — will be exposed by the daylighting project, which will also include a revamped soccer field. The adjacent walkway will become a mini-nature trail with interpretive signs.
The SF Public Utilities Commission is leading the $19 million project and deploying sewer improvement dollars. Planning has begun, and construction will run through 2025.
“We just completed mapping the historic ecology for Yosemite Creek,” says Bronwen Stanford, a San Francisco Estuary Institute ecologist and a project consultant. “It’s a mix of habitat types, where the stream might have flowed prior to colonization and landscape changes.”
Through old maps, journals, and land surveys, Stanford and her colleagues have rediscovered former features such as patches of “wet meadow” — seasonal marshes — and remnants of foothill and serpentine grasslands related to the soil found in the region.
Once restored, these habitats will “increase connectivity for species that move through the landscape,” according to Stanford.
When it rains, it flows
Unlike the Yosemite Creek project, Woodland Canyon Creek’s restoration five miles to the north is more grassroots.
The canyon runs down a forested slope on the northeast corner of Mount Sutro, passing through UCSF property as well as land managed by the SF Recreation and Park Department. The creek — sometimes just called Woodland Creek — comes to life during the rainy season, and flows through the canyon before entering the sewer system above the intersection of Stanyan and 17th streets.
Flood control is not an issue; the whole point is ecological restoration and community engagement. The creek restoration here is an opportunistic follow-on to UCSF’s removal of dead and dying eucalyptus trees on its land, which is happening in advance of an expansion of campus student housing.
Sutro Stewards, the nonprofit leading the Woodland Canyon restoration, runs a native plant nursery on UCSF property, and its volunteers help maintain Mount Sutro’s trails and tear out invasive ivy and blackberry.
Those same volunteers are the muscle behind the creek restoration. Because there’s no flood control problem to bring in sewer-improvement money from the city, Sutro Stewards must turn to private donors; Craigslist founder Craig Newmark, a part-time neighbor, just gave $25,000 to kickstart the effort.
On a recent Friday, Sutro Stewards executive director Ildiko Polony led a walk along the north rim of Woodland Canyon with Newmark and others.
Newmark, whose net worth was once estimated by Forbes as more than $1 billion, asked questions and nodded as Polony pointed out the dividing line between UCSF and Rec and Park property. It’s easy to spot once you know what to look for.
UCSF has cut down a host of eucalyptus and is revegetating the land with mostly native plants and trees. It’s a remarkable vista onto a landscape in transition. Red elderberry bushes are springing up in droves, which Polony says can grow as tall as a human being in just one season. She also points out fairy bells, bleeding hearts, elk clover, and native blackberry. Some have been reintroduced, others have lain dormant waiting for an opportunity to reclaim their habitat.
Downslope in Rec and Park territory, tall eucalyptus crowd the space, and a carpet of ivy and Himalayan blackberry covers the creek’s course, sucking up massive amounts of water that would otherwise nourish native habitat.
Polony wants to uncover the Rec and Park land down to Stanyan Street — goats will help — and restore native plant habitat on the creek bank to make it visible from trails and accessible to animals. It’s an epic task that would restore about 25 acres of the larger watershed. “The deal is that you do need other funders,” Newmark says. “Hopefully with serious money. That’s hard.”
Sutro Steward volunteers can only work on that land with Rec and Park staff present. Right now that’s once per quarter. Polony is working to increase that to once a month.
“The staff is really enthusiastic,” she says, “it’s more like, is the city willing to put the resources there?”
A funding appeal posted on YouTube by Sutro Stewards calls this a “multi-year, multi-million-dollar” project; Polony frames it in broader terms. “The California landscape evolved with human intervention, care and culture,” she tells The Frisc. “We need to shift our culture from that of the colonizers to the way that native peoples have been for thousands of years.”
Woodland Canyon and Yosemite creeks will be among the first big restoration projects in San Francisco outside the Presidio, where creeks, marshes, and Mountain Lake have been part of a broader ecological rebound that has seen the return of coyotes, checkerspot butterflies, herons, Olympia oysters, and Pacific chorus frogs.
They are notable for their differences in geography, socioeconomic status, funding sources, and more, but they’re also instructive in how their priorities overlap. San Francisco needs environments better suited for a warming planet. The city’s path to this sustainable future brings together flood control, resilient native landscapes, and environmental equity and justice.
And water runs through it all.
Josh Wilson is a journalist and editor in San Francisco.
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