While officials cite the successful restoration of the lower Sausal Creek watershed as a model for citizen-agency collaborations, runoff from its upstream neighbor, the recently built Chabot Space and Space Center, threatens to erase the entire project—the painstakingly restored trails, replanted habitat for native plants and animals, the natural flow of the creek. The developing crisis over Sausal illustrates a point too often ignored: watersheds work as a whole, not as a sum of parts.
The Sausal Creek watershed covers over 2,600 acres in the East Bay. From its headwaters in the Oakland Hills, the creek flows through Dimond Canyon in Oakland before entering a culvert under the Fruitvale Bridge and then into San Francisco Bay. Before flowing into the culvert, lower Sausal Creek nurtures a verdant oasis. According to citizens group Friends of Sausal Creek, the watershed is home to 80,000 residents, as well as over 250 plant and nearly 80 bird species.
The creek—once known for its salmon run—used to flow through forested hillsides. That began to change in the late 1800s, with logging and urbanization. Most of the creek was channeled, culverted, or otherwise buried. In 1996, Friends of Sausal Creek (FOSC) formed with support from the City of Oakland, Alameda County, and the Aquatic Outreach Institute, with the aim of restoring and maintaining the watershed. The Sausal Creek Restoration Project was soon launched at a cost of $322,000, with a $250,000 grant from the California Coastal Conservancy and the remainder from the Alameda County Flood Control District.
After years of preparation and planning and thousands of volunteer hours, the project was completed in November 2001. Three-foot-high concrete dams were removed along a 600-foot stretch at the lower end of Dimond Park, and moldering culvert walls were replaced with woven willow poles and other natural materials to stabilize banks. The creek itself reverted to a more natural meander. Besides enhancing flood control, the project has improved water quality and thus provided new habitat for native rainbow trout. New trails allow access to the creek. FOSC members have continued their work, replanting the watershed with starts grown in the group’s native plant nursery, organizing clean-up hikes in Dimond Canyon, and monitoring water quality.
But high above the restored area sit the two large parking lots of the Chabot Space and Science Center, which opened in 2000. Rainwater now runs off an impervious asphalt surface rather than percolating into redwood duff, and that water empties into the headwaters of Palo Seco and Shepherd Canyon creeks, which feed into Sausal. Parking lot runoff has created a 20-foot deep incision at the headwaters of Sausal—and erosion, like water, runs downhill.
The increased runoff is likely responsible for undercutting the Dimond Canyon trail where it crosses Sausal Creek. Larger amounts of storm water overwhelmed the culvert that ran under the trail, so half the width of the trail was dumped into the stream. “Structures that withstood the ’97 El Niño have collapsed since Chabot was built,” says FOSC president Karen Paulsell. She adds that the trail damage is not 100 percent attributable to increased runoff—“But that was the only thing that changed.” She says the city has allocated $170,000 to build a new bridge across the creek.
Sedimentation from erosion is not as easily solved. The heavier runoff gathers sediment from the point of fall and all along the length of the creek. The steep incline near the headwaters allows the sediment to move unimpeded, but when Sausal Creek reaches the flatlands, the flood of sediment settles. Some restored pools are filling with silt, undoing the work of the project.
These possibilities were cited in Chabot’s Environmental Impact Report, and staffers are aware of the runoff problem. “We are committed to exploring ways that we can help alleviate this,” says Eric Havel, Chabot’s environmental programs instructor. He points out that FOSC and Chabot have a history of working together, with the institution even serving as a meeting place for FOSC’s board.
A containment pond for Chabot’s parking lots would solve the problems caused by runoff—and it still may. But the creek illustrates a cautionary tale: while public agencies count on citizens groups like FOSC to implement physical restoration, only the agencies themselves can make policy to protect an entire watershed. Chabot is a nonprofit governed by the City of Oakland, the East Bay Regional Park District, the Oakland Public School District, and the East Bay Astronomical Society. The city and the park district have the means and the obligation to assess development in light of its impact downstream—no matter how public-spirited the development. Says hydrologist Laurel Marcus of the Watershed Assessment Resource Center: “Whether you’re building a building to teach kids or building a Wal-Mart, the effect on the watershed is the same.”
