About one of every two culverts found in eight North King County and Snohomish County watersheds blocks fish passage, an Adopt-A-Stream...

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About one of every two culverts found in eight North King County and Snohomish County watersheds blocks fish passage, an Adopt-A-Stream Foundation study reports.

For five years, the foundation has surveyed streams within the county for fish barriers. The foundation, headquartered outside Everett, reports that 391 culverts out of 678 surveyed — about 58 percent — were barriers to fish.

The largest number of culverts on the list — 191 — are on private property, according to the study. Forty-five are part of King County’s infrastructure and 99 are under Snohomish County jurisdiction. The remaining culverts are within the purview of other municipalities and agencies, including the state Department of Transportation.

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Because chinook salmon and bull trout are protected under the federal Endangered Species Act, such numbers are troubling, says foundation Executive Director Tom Murdoch.

The foundation, which has spent nearly $500,000 to study the Bear Creek and Little Bear Creek basins, as well as the basins for McAleer, Lyon, Quilceda, Allen, North and Swamp creeks, hopes the information will spur government agencies and private landowners to replace or fix aging culverts that no longer adequately funnel rainwater under roads in growing urban areas.

Many of the culverts were legal when installed, but most fail today’s state standards and need to be repaired, Murdoch said. They prevent fish from using about 62 miles of streams for habitat.

The foundation has supplied the list to each jurisdiction involved and is trying to alert property owners.

Snohomish County officials say they’re prioritizing the list of culverts and will replace or repair them as money allows. The county has had a culvert-replacement program for about 10 years, said Joan Lee, director of the Surface Water Management Division.

“At the end of 2001, we had a backlog of $86 million in [total] drainage-improvement needs,” she said. “We’ve been making good headway on that.”

Since the 1990s, the division has opened up 22 miles of stream habitat once blocked by bad culverts. Five to 10 culverts are replaced yearly.

Some culverts are simply too small to handle increasing stormwater runoff from growing cities, said Tom Hardy, the foundation’s senior ecologist. Deep pools caused by erosion make other culverts impassible for jumping fish. Still others have collapsed from the weight of roads above them.

On Snohomish County projects, culvert size is being increased to accommodate growth.

“Now we put in an 8-foot-wide culvert where a 2- or 3-foot culvert would be,” said Jake Jacobson, a Snohomish County watershed steward. “This allows gravel materials to move downstream, which is more natural.”

Local municipalities have made strides in improving fish passage, but state agencies have been slow to act, said Daryl Williams, the Tulalips’ environmental liaison and a member of the Adopt-A-Stream Foundation board.

Washington tribes sued the state two years ago to correct serious culvert problems. The two sides still are negotiating on which to replace and when, Williams said.

Only two bad culverts were found on Tulalip land, he said, and they were fixed during larger stream-restoration projects.

The foundation doesn’t expect private landowners to fix their culvert problems on their own. Costs can run up to $250,000 for repair or replacement, depending on a culvert’s size and location.

The foundation hopes to use grants and work with landowners over the long term, Murdoch said.

Faster results are hoped for from government.

“Typically, we’d like to see barriers belonging to public agencies removed within the next five years,” Murdoch said.

Christopher Schwarzen: 425-783-0577 or cschwarzen@seattletimes.com