Yosemite Creek's watershed: opportunities and challenges for urban wetland restoration

One of San Francisco's five east-draining creeks, Yosemite Creek once wended from the north slope of the hills we now call McLaren Park to meet the Bay in a tidal salt marsh surrounding what is now the intersection of Jennings and Yosemite Streets. Most of the creek has been buried in culverts and combined with sewage and polluted runoff, but two wetlands remain to evoke the creek's memory: the freshwater Yosemite Marsh in McLaren Park and a tidal salt marsh in Yosemite Slough, just bayward of the historic creek mouth.

Yosemite Marsh is about to receive a welcome restoration. The marsh at Yosemite Slough is also a candidate for restoration, but city planners now talk of building a bridge over it, which would severely impair existing habitat and limit possibilities for future revitalization.

Good news at the headwaters: Yosemite Marsh

Yosemite Marsh was designated a "significant natural resource area'' by the city in 1995. After years of delay, the Recreation and Parks Commission in December awarded a contract for the first phase of the marsh restoration and expansion. The area is home to a number of rare and endangered species, including the federally listed San Francisco fork-tailed damselfly and the rare flowering quillwort. Great-blue herons also frequent the area, feeding on a variety of small creatures including gophers.

McLaren Park is one of the hidden jewels of San Francisco. An engaged "Friends of" group is working to revitalize the park with the active participation of many park neighbors. The non-profit Kids in Parks brings schoolchildren to the park to teach them about ecology and the wonders of nature. Last April Sierra Club volunteers, along with other grassroots environmental organizations coordinated by Nature in the City, participated in a fabulous Earth Day celebration there.

The Yosemite Marsh project is important because so many naturally occurring wetlands have disappeared from our city, along with the habitat they offered to wildlife. The renovation will include erosion control, removal of excess sediment, expansion of the marsh, trail improvements, new picnic tables, and a viewing platform with benches. Groups from neighborhood schools will be involved in planting through the Recreation and Park Department's innovative Youth Stewardship Program. Projects such as the Yosemite Marsh restoration show how conservation goals can be combined with increased public access and an enhanced visitor experience for the benefit of both humans and wildlife.

Down by the Bay: Yosemite Slough

The news is not so good downstream, where, after traveling in underground culverts, combined with sewage and contaminated runoff, the watercourse is diverted to the Southeast Sewage Treatment Plant. Accumulated sediment that drifted downstream from hydraulic mining in the Sierra, along with purposeful human filling of the Bay, have significantly altered the shoreline, while industrial waste, sewage discharges, and toxic dumping have transformed Yosemite Slough into a contaminated backwater.

Despite the degradation, wetland vegetation colonized the shallow areas, and a variety of shorebirds and waterfowl began using the slough. More than 20 years ago, neighborhood activists, conservation groups, and city and state planners recognized the potential for wetland restoration here and the need for a plan to transform the blighted industrial "brownfield" into habitat for birds and other critters, while providing opportunities for neighbors to access the waterfront and badly needed open space. Based on that, the 1988 General Plan for Candlestick Point State Recreation Area, which includes the slough, called for the creation of a 32-acre nature area along with wetland restoration.

The proposed wetlands project lagged due to toxics and funding issues, but in 2003 a feasibility study showed that restoration of this area was possible. Under the auspices of the Yosemite Slough Watershed Restoration Partnership, local conservationists from groups such as Golden Gate Audubon, along with neighborhood youth activists and environmental-justice advocates, conducted a detailed biological survey of the area. They discovered that even in its degraded state the slough supported abundant wildlife (over 138 species), including lots of rare birds stopping over on their seasonal journeys along the Pacific Flyway.

Planners proposed a $10-million plan to turn the once-forlorn industrial site into the "Crissy Field" of the southeast through removal of fill, restoration of 12 acres of tidal wetlands and marsh, removal of contaminated soils in the upland areas, and creation of two nesting islands for endangered birds (see map). The plan would provide increased opportunities for viewing wildlife, an environmental area that local schools can use for field trips, and a multi-use trail along the shoreline connecting to the Blue Greenway. The clean-up phase has recently begun, jump-started with a $1.5-million grant from the locally based Goldman Foundation.

Everything seemed on track until about a year ago, when the 49ers opted out of the proposed redevelopment project at Candlestick Park, and the city offered the former Hunters Point shipyard, just northeast of the slough, as an alternative site. Seeking to satisfy the unique land-use needs of the 49ers, city planners have recently proposed a massive bridge over the mouth of the slough to move thousands of cars from a proposed new freeway exchange on Highway 101 to the new "green" parking spaces surrounding the stadium.

The bridge, as currently proposed, would carry buses, bikes, and pedestrians, as well. Planners claim that the bridge will be used by private cars only on game days, and - as with the aforementioned green parking spaces (which will supposedly double as playfields) - will be as green as green grass during the remainder of the year.

Regardless of whether the 49ers stay in the city, the proposed bridge is a horrible idea. It would cut off the restored wetland from the rest of the Bay, creating an obstacle for birds traveling between the two habitats. It would be located within a few feet of one of the proposed nesting islands, so that birds learning to fly are likely to end their short lives in collision with the bridge. It would also preclude further expansion of the wetlands either along the shoreline of Candlestick Point or towards the shipyard.

The Sierra Club is opposed to a bridge over the slough, and urges the city to pursue alternatives, in accordance with the city's transit first-policy. Viable alternatives do exist at a comparable cost. The economic benefits of ballpark fans patronizing Third Street businesses - instead of bypassing them - should be looked at. At this early stage in planning, the city must consider alternatives so that it is not locked into a fait accompli for the future of the southeast.

Yosemite Slough is perhaps the most important feature of the southeastern waterfront, and can become the focal point of a truly great shoreline park. Wildlife specialists identify it as the area with the most significant habitat potential, and the greatest environmental benefits to the community. These considerations far outweigh a couple of extra minutes of game-day driving for some 49ers patrons.

WhatYouCanDo

Contact Mayor Gavin Newsom at:

City Hall, #200
1 Dr. Carlton B. Goodlett Place
San Francisco, CA 94102
(415)554-6141
fax: (415)554-6160
gavin.newsom -at- sfgov.org

Tell him that city planners need to identify and flesh out authentic transit-first alternatives which do not involve a bridge over Yosemite Slough. The Environmental Impact Report must include, at the very least, no-bridge alternatives for both the stadium and non-stadium proposals.

Also contact Gov. Arnold Schwarzenegger at:

State Capitol
Sacramento, CA 95814
(916)445-2841
fax: (916)558-3160.

Tell him to stand up for the integrity of the State Parks System and not to allow San Francisco to build a bridge over Candlestick State Recreation Area.

Steven Chapman, conservation chair, Sierra Club San Francisco Group