Creek work in Sonoma Valley to remove barriers for steelhead
Steelhead trout once returned in strong numbers to Sonoma Valley from the ocean and San Pablo Bay, swimming up Sonoma Creek to the sheltered waters of Stuart Creek, an ideal stream for spawning and rearing with its rocky bed and abundance of aquatic vegetation and insects.
For decades though, it’s been rare to spot steelhead upstream in the creek near Glen Ellen. Man-made barriers and steep drop-offs formed by erosion have blocked their access, further imperiling a fish that has disappeared from much of its former range on the North Coast.
However, work is underway to restore a section of Stuart Creek in hopes of bringing back its once sizable steelhead run.
Work crews last week were out at a 3.5-acre property on the creek north of Sonoma Valley Regional Park building a series of five pools and chutes to ease the upstream journey for the federally threatened species.
“Once we deal with these, there are no other barriers for their movement,” said Tony Nelson, stewardship project manager with Sonoma Land Trust.
The nonprofit group in 2011 purchased the so-called Stuart Creek Run property, a pivotal piece of land that could help?the group open up access to?2.5 miles of protected spawning habitat.
When it first bought the property, the trust was aware of only one major barrier - a bridge culvert on Stuart Creek Run, according to communications director Sheri Cardo. She said they found after purchasing the land that two other barriers needed to be resolved: a culvert under a bridge on Arnold Drive in the heart of Glen Ellen just southwest of Stuart Creek Run and a historic dam on Glen Oaks Ranch, a 234-acre property across Highway 12 that the group owns.
Developing a plan for what to do about the trio of barriers took time and money.
“The whole project had to be redesigned,” Cardo said.
To remove the obstacles, the Land Trust earlier this year received nearly $700,000 from the state Department of Fish and Wildlife’s Fisheries Restoration Grant Program.
Nature helped with some of the demolition. The bridge on the Stuart Creek Run property came down in a storm last winter, Cardo said. Workers last month removed the remaining concrete culvert.
“It created a steep drop-off, about 7 feet,” Nelson said about the channel that had eroded near where the bridge once stood.
The chutes and pools now being constructed in that area will help the fish move upstream with no problem, he said. Boulders and rocks pulled from the creek were used to build the new streambed structures.
The creekbanks will also be mulched and seeded, and future plans call for a small picnic area with a trail and interpretive signage on the property, just off Arnold Drive less than a quarter-mile from Highway 12.
Mike Morrison, a foreman with Hanford ARC, a Sonoma-?based firm handling the restoration, said they’re using 3- to 5-ton boulders to build the pools.
“That’s to prevent the water from pushing these rocks down into the pools or stream and blocking the channel again,” he said.
Much of the creek remained dry as workers put in the rocks. However, some of the pools contained water that appeared after last month’s magnitude-6.0 earthquake. It jumpstarted flow in several creeks around Sonoma and Napa County, which was hit the hardest by the quake.
The unexpected flow complicated efforts for workers who were widening a notch in an old flash dam on the Glen Oaks Ranch, Nelson said. They had been pumping out water in the area to work on the dam. On Thursday, three workers cut into it to extend and lower the opening, which will make it easier for fish to make their way to the Bouverie Preserve, a 535-acre property overlooking Highway 12 on the western side of the Mayacamas range. The dam won’t be torn down because it’s a historic structure, likely built in the mid-1800s, Nelson said.
The culvert under the Arnold Drive bridge presented an easier fix. Concrete baffles were put in under the bridge to concentrate the water flow and prevent it from spreading out across the paved surface, making it too shallow for fish to swim through, Nelson explained.
All the work along the creek should be completed by the end of October, in time for the winter spawning season, Cardo said.
The California Coastal Conservancy funded the designs, which were done by the Sebastopol-based firm Prunuske Chatham.
The Sonoma Ecology Center is set to replant the project areas with trees, shrubs, sedges and rushes once rains moisten the soil, said restoration project manager Cassandra Liu.
Liu said they’ll be putting in 530 plants, including oak trees, coyote brush, sticky monkey flower and coffeeberry shrubs.
Nelson isn’t worried about the quality of the habitat, which rainbow trout already use to spawn and rear their young. An adult steelhead was spotted upstream a decade ago after it managed to hurdle the steep barriers.
Nelson and Cardo voiced hope that greater numbers of the species will soon make their way back to Stuart Creek.
“I do believe they’ll get back here,” Nelson said.
“It’s in their DNA,” Cardo said. “They keep trying to fulfill their ancestral mission.”
You can reach Staff Writer?Eloísa Ruano González at 521-5458 or firstname.lastname@example.org.