20 miles of Upper Alameda Creek Set to Open to Fish Passage
A Mighty Creek
Sustained by the largest local watershed in the Bay Area, the mighty, 45-mile-long Alameda Creek is a perennial beauty.
Flowing from the slopes of Packard Ridge east of San Jose down to the San Francisco Bay, the creek is one of the most scenic and biodiverse areas in the Diablo Range.
Massive changes to the creek and watershed started early, with the former Tulare Lake and marsh complex in Pleasanton drained by canals in the late 19th century for agriculture.
Then came three major dams: Calaveras Dam was completed in 1925, San Antonio Reservoir by 1964, and Del Valle Dam and Lake Del Valle by 1968. Yet salmon and steelhead trout runs persisted in Alameda Creek until the late 1960s.
For the next half century, the watercourse below the major dams was interrupted by over a dozen barriers, including small dams, culverts, and drop structures, which blocked fish migration.
Jeff Miller recognized this early on. An environmental advocate for the creek for decades, Miller organized, advocated, fought, and applied pressure to remove these barriers.
Jeff Miller, founder of Alameda Creek Alliance. Photo: courtesy Jeff Miller
He created the Alameda Creek Alliance in 1997 to advocate for restoration, which spawned the Alameda Creek Fisheries Workgroup.
The workgroup, a coalition of stakeholders, pursued dam and fish passage barrier removals and creek restoration from 1999 through today.
Their main goal was to restore steelhead trout to the creek, leading to habitat restoration that opened the floodgates (literally) for anadromous, or migratory, fish to re-enter the creek.
Just one major fixable fish barrier remains, a massive concrete mat covering a PG&E gas pipeline in the Sunol Valley. That barrier is currently being removed and will be gone by October.
The Final Barrier
The concrete mat covering the PG&E gas pipeline, set to be removed this year. Photo: Jeff Miller on behalf of Alameda Creek Alliance
Upper Alameda Creek has the potential to host 20 miles of spawning habitat for anadromous fish pending the removal of the pipeline.
Led by California Trout (a Bay Area–centered nonprofit), and supported by the Alameda Creek Fisheries Workgroup, PG&E is moving the gas pipeline and burying it deeper underground, allowing the concrete barrier to be removed from the stream.
Cal Trout will then stabilize the stream channel and revegetate the stream banks.
This restoration project follows the construction of three major fish passage facilities from 2019–2023.
The Alameda County Water District constructed two fish ladders in lower Alameda Creek, critical infrastructure that allows oceangoing steelhead and chinook salmon to migrate upstream into the watershed for the first time in half a century.
The first two winters of operation saw steelhead and rainbow trout, chinook salmon, and Pacific lamprey using the new fish ladders.
Chinook salmon, an anadromous fish whose range includes the San Francisco Bay and that spawns in Alameda Creek. Photo: Dan Sarka
The San Francisco Public Utilities Commission also built a large fish ladder in upper Alameda Creek in the Sunol Regional Wilderness Preserve to allow fish to bypass the Alameda Diversion Dam into the headwaters of Alameda Creek.
These changes mean that fish swimming upstream from the San Fransico Bay to lay their eggs in freshwater will have expanded spawning and rearing habitat.
National Oceanic and Atmospheric Administration Fisheries has set an ambitious recovery goal for Alameda Creek, hoping the waterway can eventually support up to 2,000 spawning adult steelhead trout.
Jeff Miller explains that “Currently we have so few steelhead that we name them rather than count them, but with all of the restoration progress we can foresee a viable steelhead run returning.”
Alameda Creek could contribute to the recovery of the central California coast population of steelhead trout, which declined from more than 100,000 spawning fish in the region to fewer than 10,000 throughout the greater Bay Area currently.
Other migratory fish species such as chinook salmon and Pacific lamprey can access upstream spawning grounds as well, bolstering the aquatic biodiversity of the Diablo Range.
One Major Watershed
The Alameda Creek watershed, 660 square miles spanning most of the East Bay. Map: Alameda Creek Alliance
The massive Alameda Creek watershed is the largest in the Bay Area, spanning over 660 square miles, five times the size of both the Marsh Creek and Walnut Creek watersheds.
Rainfall and runoff from across the East and South Bay drain into the Alameda Creek watershed.
Water flows from Mount Hamilton, the southern slopes of Mount Diablo, and the west side of Altamont Pass into Alameda Creek, down Niles Canyon, and out 12 miles of flood control channel into San Francisco Bay.
Some of the watershed’s geography includes iconic Diablo Range locations like Mount Hamilton, Brushy Peak Regional Preserve, Del Valle Regional Park, and the Ohlone and Sunol Wilderness Regional Preserves.
Mount Hamilton, one of the tallest mountains in the Diablo Range, is within the Alameda Creek watershed. Photo: Ian Abbott / CC BY-NC-SA
The Alameda Creek watershed is one of the largest and most important land areas in the Diablo Range.
It contains critical habitat for aquatic species like
- the previously listed fish;
- amphibians like the federally threatened California red-legged frog, foothill yellow-legged frog, and California tiger salamander;
- reptiles like the northwestern pond turtle and Alameda whipsnake;
- and countless other animals like mountain lions, golden eagles, and bobcats.
The protection of the creek and focus on the larger watershed is just one of the many major success stories of ongoing Diablo Range conservation.
To support the ongoing work of the Alameda Creek Alliance, visit the Alameda Creek Alliance website.
Alameda Creek flowing on a summer afternoon. Photo: Steven dePaschalis
