Minter Creek culvert project to clear way for salmon

As money for salmon recovery begins to trickle down from the state Legislature, Pierce County engineers are making plans for a project on Minter Creek that will make it easier for fish to swim upstream to spawn.

The project envisions removing a concrete culvert under 118th Avenue Northeast, expanding the structure to widen the stream from bank to bank, and restore the natural habitat of the streambed.

However, actual work probably will not begin until 2022, according to Brian Stacy, the county engineer. So far, a state grant of $90,000 will provide only for design work.

The 118th Avenue culvert is one of literally thousands of stream crossings in the state that will have to be re-engineered to meet new standards for salmon recovery.

Several Native American tribes with treaty fishing rights sued the state in 2001, and won a court order requiring the state to restore 90 percent of potential salmon habit blocked by culverts by 2030. The Washington State Department of Transportation has estimated the cost to taxpayers at $3.8 billion.

While county-owned crossings like the one on Minter Creek are not included in the court order, the Legislature established a program in 2014 to distribute funds to local governments for culvert removal.

Culverts allow water to flow under roads, but wildlife biologists say they also constrict the streams, which makes the water flow faster. This makes it harder for salmon to swim upstream, and also washes the stream bed of natural spawning habitat, such as gravel and wood.

The culvert at Minter Creek is only 10 feet wide, substantially narrower than the creek bed.

“The fish struggle to get through the culvert,” Stacy said, so the structure, which is actually a small concrete bridge, will have to be torn out and replaced with a wider structure, spanning the natural streambed from bank to bank.

“We will try to restore the natural environment.of the streambed,” he said,.

Minter Creek is used by Puget Sound steelhead, listed as an endangered species, as well as by Chinook, chum, coho and pink salmon and coastal cutthroat trout.

Up until the mid-1970s, Minter Creek was the only stream with consistent pink salmon returns on the Kitsap Peninsula, according to a 1975 survey.

The grant for the design work comes from the state’s Brian Abbott Fish Barrier Removal Board, a panel established by the Legislature in 2014 to identify and remove impediments to salmon and steelhead migration.

Stacy said the grant will pay for site survey, hydraulic modeling, geotechnical assessment, a cultural review required by state law, and preliminary and final designs. That work will probably begin in 2020 and may be completed by 2021, he said.

Construction is as yet unfunded, he said. Costs can vary widely, depending on local geography and other conditions. Cost estimates for similar projects have ranged from half a million to $20 million, he said.

The most likely source will be another state grant, Stacy said.

“There are no guarantees, but we feel good about the possibility of getting a construction grant to complete the work,” he said.

The culvert is directly upstream from the Minter Creek Hatchery, but the project won’t affect the domestic salmon raised there, as they usually return to spawn in the hatchery ponds and don’t swim farther upstream.

Stacy said the Minter Creek project is part of an ongoing effort to reduce “literally hundreds” of fish barriers that exist across the county. A recent road project on Crystal Mountain Boulevard in the eastern county, for instance, included six culvert replacements, he said.

“We just keep chipping away, knocking out a couple a year, and hopefully that will begin to have an effect,” he said.

This story was originally published August 7, 2019 at 12:00 AM.