SUNOL — Dams and barriers placed on Alameda Creek have prevented migratory fish from entering their native spawning grounds for more than 50 years, but an $80 million effort to raze the last significant obstacles and restore trout, salmon and other fish to their historical habitat are now underway.

A PG&E gas pipeline is the last major barrier to restoring 20 miles of upstream spawning habitat for Chinook salmon and steelhead trout and will be relocated and buried by a coalition that includes the Alameda County Water District, PG&E and the San Francisco-based nonprofit California Trout. The project lies along Calaveras Road, one mile south of Interstate 680 and sandwiched between two basins of the Sunol Valley Aggregate Quarry.

“It’s protecting our heritage and ensuring the future generations get to see and learn about and interact with these species down the road,” said Pat Samuel, Bay Area director for California Trout. “The fact that we still have them here in the Bay Area is remarkable.”

The project is a generation in the making, involving half a dozen public agencies, PG&E and community advocacy groups. Thomas Niesar, the resources planning manager for the county water district, said the barriers placed in Alameda Creek over the past century helped the Bay Area’s population boom, but have stymied Chinook salmon and steelhead trout from completing their lifecycles.

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“The remnants of any salmon populations would have been completely cut off and disrupted their life cycle,” Niesar said. “As for the steelhead, they have that unique ability to live completely a freshwater life as rainbow trout … but their ability to migrate into the ocean and become steelhead was completely disrupted.”

In 1999, the Alameda Creek Fisheries Restoration Working Group was founded to come up with a plan to remove these hurdles and bring back the natural ecosystem. A concrete erosion control mat that protrudes above the creek waters and protects the PG&E pipeline are all that stand in the way, Niesar said.

The plan is to remove the concrete barrier and move the gas pipeline 100 feet downstream and bury it 20 feet underground to reopen the creek for migratory fish, according to California Trout senior project manager Claire Buchanan.

A group of environmental workers electrofishes in Alameda Creek on Tuesday, June 24, 2025, in Sunol, Calif. Workers with the East Bay Regional Park District, Sequoia Ecological Consulting, the San Francisco Public Utilities Commission, and California Trout removed fish from a section of Alameda Creek for a de-watering and gas line trench digging project. (Aric Crabb/Bay Area News Group) 

Construction will need to move quickly in order to return the creek to its natural flow by Oct. 31, ahead of the fish migration season, Buchanan said.

Because the stream is home to a federally threatened species, “we’re only allowed to disrupt that habitat during certain windows of time,” Buchanan said. “Once PG&E starts digging, there’s really no turning back.”

As a first step, project engineers are removing fish from the creek in preparation for a temporary dam to be placed upstream of the site. Then, contractors will connect a 2,000-foot pipeline to pump the dammed water around the project and deposit it downstream.

PG&E will trench a new gas pipeline downstream to replace the three-foot diameter pipeline that currently serves as a major conduit to South Bay cities. Once the new pipeline is complete, PG&E can remove the concrete erosion control mat that has inhibited the migratory fish.

Workers installed a dam and pumps to move water from a section of Alameda Creek on Tuesday, June 24, 2025, in Sunol, Calif. Workers with the East Bay Regional Park District, Sequoia Ecological Consulting, the San Francisco Public Utilities Commission, and California Trout removed fish from a section of Alameda Creek for a de-watering and gas line trench digging project. (Aric Crabb/Bay Area News Group) 

“The (current) barrier can be undermined via erosion through time, which is a direct threat to the security of gas to the South Bay,” Buchanan said. “By removing the infrastructure that’s in the creek now and putting a new line that’s buried under the creek, it’s actually a much safer location, so at a much lower risk of failure or rupture.”

For Samuel, the Bay Area director for California Trout, the culmination of this project after so many years is an example of how collaboration can protect the environment while balancing the needs of people and nature. Of course, the main beneficiaries of the project will be steelhead trout, Chinook salmon, amphibians like yellow- and red-legged frogs, the Northwestern pond turtle and the healing of the riparian corridor in Sunol Valley.

“We’re really excited for this opportunity to have steelhead and salmon running back in this habitat for the first time in over 50 years,” Samuel said. “Who even knows how many cars per day drive right over this creek, or if you go out to the mouth of Alameda Creek, how many people are passing over and without even realizing it on a daily basis?”

Members of the East Bay Regional Park District and Sequoia Ecological Consulting electrofish in Alameda Creek on Tuesday, June 24, 2025, in Sunol, Calif. California Trout is overseeing an operation to remove fish from a section of Alameda Creek for a de-watering and gas line trench digging project. (Aric Crabb/Bay Area News Group) 
Trout caught in Alameda Creek on Tuesday, June 24, 2025, in Sunol, Calif. Workers with the East Bay Regional Park District, Sequoia Ecological Consulting, the San Francisco Public Utilities Commission, and California Trout removed fish from a section of Alameda Creek for a de-watering and gas line trench digging project. (Aric Crabb/Bay Area News Group) 
Members of Sequoia Ecological Consulting wade through Alameda Creek on Tuesday, June 24, 2025, in Sunol, Calif. Workers with the East Bay Regional Park District, Sequoia Ecological Consulting, the San Francisco Public Utilities Commission, and California Trout removed fish from a section of Alameda Creek for a de-watering and gas line trench digging project. (Aric Crabb/Bay Area News Group) 
Captured fish from Alameda Creek swim in a holding container on Tuesday, June 24, 2025, in Sunol, Calif. Workers with the East Bay Regional Park District, Sequoia Ecological Consulting, the San Francisco Public Utilities Commission, and California Trout removed fish from a section of Alameda Creek for a de-watering and gas line trench digging project. (Aric Crabb/Bay Area News Group) 
Randy Renn, right, a biologist with the San Francisco Public Utilities Commission, electrofishes in Alameda Creek on Tuesday, June 24, 2025, in Sunol, Calif. Workers with the East Bay Regional Park District, Sequoia Ecological Consulting, the San Francisco Public Utilities Commission, and California Trout removed fish from a section of Alameda Creek for a de-watering and gas line trench digging project. (Aric Crabb/Bay Area News Group) 
A scanner is used to check a trout for an identification tag near Alameda Creek on Tuesday, June 24, 2025, in Sunol, Calif. Workers with the East Bay Regional Park District, Sequoia Ecological Consulting, the San Francisco Public Utilities Commission, and California Trout removed fish from a section of Alameda Creek for a de-watering and gas line trench digging project. (Aric Crabb/Bay Area News Group)