It doesn’t look like much, this ditch by the side of the road. But to King County’s culvert hunters, this isn’t a throwaway landscape.

Kat Krohn, an engineer and fish passage specialist for King County, chopped right into a fierce bramble of blackberries and got into the ditch as traffic roared by on a busy thoroughfare in Lake Forest Park. Here, Lyon Creek flows through Lake Forest Park before draining into the northwest corner of Lake Washington, crossing in culverts under roads and even private driveways all along the way.

That’s where Krohn and her teammates at King County come in. They are working in the field to compile an inventory of culverts on country roads, bridges and properties — the good, the bad, and the truly ugly in terms of whether a salmon can get through them to spawn or journey to the sea.

Urban creeks are the arteries and veins of the region carrying the lifeblood that animates the region’s ecology: salmon. Food for more than 123 species of animals — including endangered southern resident killer whales that frequent Puget Sound.

It’s no desk job, being a culvert hunter. These are the field medics looking for the blockages impairing the health of the region’s signature fish in their home waters.

As Krohn cut back the brambles, Ben Gregory, another engineer and fish passage specialist on the county’s culvert survey crew, bushwhacked into the muddy ditch and into thickets of roadside weeds.


It’s a landscape most would never notice — let alone think is important to salmon. Garbage cans lined the road where Krohn helped Gregory trace the ditch to a tiny, crushed culvert under a driveway, where it then crossed under the road to the other side.

The driveway culvert was way undersized for managing high flows, creating a fire hose that would slam back a salmon trying to get upstream. It also would probably flood, creating a risk for the roadway infrastructure.

On the other side of the road, where the culvert exited, they looked for more problems, a slope too steep for a salmon to manage, or an opening of the culvert perched too far above the stream bed for a salmon to leap into.

“It is helpful to think like a fish,” Gregory said, eyeing the pipe.

The team uploaded their field notes into handheld devices to feed their day’s reconnaissance into a growing inventory of blockages.

For this stream is typical in this largely developed watershed, thickening with houses and driveways and cars since at least the 1970s. The creek is routed through dozens of culverts crossing under the road in just a few miles — challenging the coho and steelhead traveling this creek to and from Lake Washington, on their way to Puget Sound.


Both the orcas and Puget Sound Chinook are threatened with extinction. To help them survive, the county is committed to spending $9 billion over the next decade on a Clean Water Healthy Habitat strategy, said Abby Hook, environmental affairs officer for King County’s Department of Natural Resources and Parks.

The goal, Hook said, is to guide investments to boost salmon populations and water quality, and conserve essential habitat for the good of orcas, salmon and future generations of county residents — even as the climate changes and county population grows.

The initiative also is intended to unify efforts across programs and jurisdictional boundaries to achieve watershed level results, from the Cascades to Puget Sound. The work includes everything from storm water and wastewater projects to road repairs and land conservation and ecological restoration. The cross-disciplinary approach is intended to align and deliver projects to achieve the most improvement the fastest.

That’s the big picture. Getting there is in the hands of people doing the day-to-day, on-the-ground work. This is combat biology, in environments mostly built to benefit and transport humans, not salmon.

“We are so unaware when we drive a road like this, we don’t realize fish are under the road, we don’t even know we are crossing a stream,” Krohn said. Everything matters in their streambed world: how wide the banks are, how deeply cut the channel, how steep the slope.

Her work has taught her to see landscapes differently. “I notice culverts everywhere I go now,” Krohn said.


Standing on the roadside amid the whizzing traffic, Gregory said the work can be daunting.

But then, there was the thrill last year of watching chum salmon barrel into Mary Olson Creek under Green River Road near Kent. County roads crews replaced a culvert carrying the creek that blocked most salmon from making it upstream. A deep, wide box culvert fixed the problem — and opened 2,000 feet of habitat for salmon and steelhead.

It was completed in August at a cost of $900,000, and the chum moved right in. Prime orca chow, spawning right there in South King County.

“They are powerful creatures,” Gregory said of salmon. “The opportunity is there for us to help them, and they are ready to take advantage. You will see coho in ditches you wouldn’t even think were an actual stream. There is hope in their resiliency.”

Evan Lewis left a long career at the U.S. Army Corps of Engineers to lead the fish passage team for the county, at King County’s Water and Land Resources Division. He wanted to make a difference for salmon, Lewis said, by working to help salmon travel as smoothly through the watershed as we do.

Since April 2019 the culvert hunters have identified 684 county culverts and other structures that are barriers to fish passage. That includes 376 total blockages, and 249 partial barriers.


A technical team with county, tribal and state representatives is collaborating to develop a final prioritization method to score and rank the barriers, based on their relative priority for potential benefit to salmon. The county has estimated that fixing less than half the total number of county barriers would deliver two-thirds of the total habitat presently blocked. That work would come first, the rest later.

Meanwhile, other work is underway to advance the Clean Water Healthy Habitat strategy all over the county — even in fast-growing places where many may have forgotten salmon are their neighbors.

The Bear Creek Basin near Redmond today is cut through with roadways thundering with traffic and burgeoning development. But that isn’t the whole story. King County, and the cities of Redmond, Sammamish and Woodinville, have been working in partnership to stitch together places for salmon to persist even here.

Laird O’Rollins, senior ecologist with King County, helped lead a recent tour of sites where the county is working to revive the creek with a combination of strategies. “Ideally you would start at the headwaters and work to the mouth,” O’Rollins said. “But this is urban combat biology: You do what you can, where you can.”

It works:

The wetlands at a restoration site at the Lower Bear Creek Natural Area were alive with songbirds. A heron cruised overhead, and a song sparrow belted it out like a diva.

Work is underway here to grow trees including cottonwood and willow along the creek to shade the water and cool temperatures, and increase the amount of downed wood in the stream. That creates more of the pools and meanders and side channels baby salmon need to rest, feed and grow big.


A beaver dam attested to the help from nature’s primo wetland engineer, noted Jen Vanderhoof, a senior ecologist at King County working to support the coexistence of beavers in the watershed.

Beavers can help boost biodiversity in a creek like this, Vanderhoof said, which is challenged by the effects of development, including both elevated temperature and pollutants.

The dams beavers build create pools that benefit baby salmon, and grow the insects and invertebrates that feed everything from fish to birds. Pools created by their beaver busyness also help recharge the hyporheic zone of the creek — where the water flows unseen, underground — maintaining flow and cooling temperature.

“Let the rodents do the work,” Vanderhoof said.

Not a wisecrack, but an insight, to not just treat symptoms, but instead restore natural processes that create healthier habitat and cleaner water in this creek. It is an important county stronghold for wildlife, home to not only coho, sockeye and Chinook, but freshwater mussels and sponges, river otters, crayfish and a teeming community of aquatic insects that stoke a web of life.

Nearby, just steps from busy Avondale Road, Bear Creek wound through cedars, alder and fir, shading clear waters. This natural area, long stewarded by the Hussey family, was recently purchased for preservation.

King County acquired the 7.6-acre property for $740,000, using a county parks levy approved by voters in 2019 and the Conservation Futures program, funded with a county property-tax levy. The purchase was made as part of the county’s Land Conservation Initiative, created to conserve 65,000 acres of the last remaining, most at-risk open spaces within a single generation before those opportunities are lost.


Indeed, imbued in all of these projects is a sense of urgency in a fast-changing place.

“We have to rectify some of the damage done by remaking of natural systems in our county, to restore natural fish runs for people with treaty rights and also for the fish themselves; they have a right to exist,” said King County Executive Dow Constantine.

Constantine grew up here, when the county was alive with orcas and salmon now threatened with extinction.

“It feels like a mission to bring back these fish.”