Logjams make the Cedar River unsafe for recreation, but they’re great for fish

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A cottonwood spans the Cedar River, one of many downed trees that have led to the river’s closure.

The King County Sheriff’s Office announced earlier this month that a portion of the Cedar River is closed to all in-river recreational use for the second season in a row due to numerous logjams, downed trees, hanging limbs and other blockages.

The river is closed from river mile 4.5 to river mile 13.5, a nine-mile stretch from Renton to Maple Valley. Twelve blockages – nine of them serious – make the river too dangerous for recreation, according to the Sheriff’s Office. The blockages are similar in number and severity to last year – and all are due to naturally occurring processes.

John Koon, a senior engineer in the County’s Rivers Section, recently walked the banks of the Cedar and could see why law enforcement made the decision. He saw two punctured rafts wrapped around a logjam, a sobering sight. John has been monitoring rivers in King County for more than two decades. “I don’t remember the Cedar ever having so many hazards.”

But there’s an important twist in this ongoing discussion over the state of the Cedar River. The strainers, spanners and logjams may be bad for those who want to float the Cedar, but they’re excellent for fish, including two runs – fall chinook and steelhead – that are listed as threatened under the Endangered Species Act (ESA) and protected under tribal treaty rights.

Adding to the situation is the unique nature of the Cedar, a river that brings this dilemma into focus like no other in the region. The Cedar is just the right size to be closed by a spanner and just slow enough for some of those spanners to remain in place. It’s near an urban center – and thus to people who want recreate in it, including boaters, anglers and those who like to float the river. And all that wood provides invaluable habitat to ESA-listed fish, fish that the state and tribes co-manage with an eye towards ensuring their survival and resilience.

“We’re working right now with the tribes, the state and other jurisdictions to try to figure out the best path forward with the Cedar. But there are no good models,” said Josh Baldi, director of the Water and Land Resources Division.

“How do you make a river safe for recreationalists while improving habitat for fish? We know how to do this when designing restoration projects, but it’s far trickier with natural wood recruitment. This is largely unchartered terrain.”

So why does wood in a river matter so much? Large pieces of wood trap other pieces of wood, creating complex habitat that supports salmon at several stages in their life cycle, explains Sarah McCarthy, a senior ecologist in the County’s Water and Land Resources Division.

Wood, for instance, retains gravel, which is needed for spawning. It encourages riverbed scour, which in turn creates pools where salmon can rest, find deep, cool refuge and hide from predators. Logjams slow down the flow and sometimes split a channel, creating new channels and backwaters critical to healthy salmon runs. Wood is also the basis for an aquatic food web – invertebrates live in the downed trees and logs and occasionally fall into the river, where they’re snatched up by hungry fish.

“The research is clear that wood in rivers and streams improves habitat quality,” Sarah said.

Western Washington’s rivers used to be filled with wood. But over the course of the past century or so, much of that wood was removed or prevented from falling into rivers – the result of logging and agricultural practices, navigational improvements and flood control efforts.

Those actions came with a cost. The removal of wood led to the destruction of salmon habitat and added to the steady decline of salmon in the Pacific Northwest. Today, 17 distinct salmon populations are listed as threatened or endangered under the ESA in Washington. And while wood removal was seen as a way to provide flood protection, in many instances it made the situation worse – causing faster, more unconstrained flows, erosion and channelization.

Government agencies, including King County, are now seeking a new path, trying to balance all of these competing forces in support of rivers that are healthy and resilient and that are good for both people and fish. As a result, the County routinely incorporates wood into both restoration and flood control projects, using the best science and engineering practices to do so and keeping stakeholders – including river safety advocates and recreationalists – informed throughout the process.

Earlier this month, project managers in the Water and Land Resources Division held two public meetings to discuss several current projects that will use placed wood either to improve habitat or provide flood protection.

As for the Cedar, where naturally occurring wood – not wood used in restoration or flood control projects – is making in-water recreation dangerous, Kate Akyuz, a senior environmental scientist in the Rivers Section, is working with the Sheriff’s Office, state officials, tribal biologists and others to determine a course that makes sense. It’s possible, for instance, that some of the wood could be shifted or removed, she said, noting that doing so would require the County to mitigate for that removal by creating salmon habitat elsewhere.

Josh attended one of the recent public meetings about large wood where he discussed his own love of river rafting as well as the environmental challenges at a place like the Cedar River.

“We have a lot of needs we’re trying to balance in a river that is important to many different constituents,” he said after the meeting. “Our goal is to approach this issue using both solid science and thoughtful public policy and to do what’s right for both people and fish.”

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This tree spans the Cedar at river mile 9.7.

After 25 years of work, a geomorphologist has a deep understanding of how rivers change

For a quarter of a century, Terry Butler has been observing the way rivers course through King County.

He has seen some, like the Tolt, transform overnight, when an avulsion – the rapid abandonment of a river channel to create a new one – has occurred. He has seen others migrate gradually, moving laterally across a basin over the course of years. He has watched side channels become main channels, witnessed erosion and sedimentation and has seen the dramatic changes a landslide can trigger.

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Terry Butler, a fluvial geomorphologist with King County’s Water and Land Resources Division, tracks ever-changing river conditions.

“That’s why my work has been endlessly fascinating,” he said. “Rivers are dynamic. They’re prone to change. And yet people generally live near rivers and construct things near rivers. We’re drawn to rivers. And that can create problems.”

Though his position has changed over the years, Terry is now considered a fluvial geomorphologist – a person who studies the physical processes that shape rivers and streams. And as he retires after 25 years from what is now called the River and Floodplain Management Section in the Water and Land Resources Division, he carries with him a vast knowledge of river processes, public policy and channel migration – a trove of information born of years of research and in-the-field observations.

“The body of work Terry has accomplished is significant,” Jeanne Stypula, supervising engineer in the Rivers Section and Terry’s boss, said. “He has a unique blend of skills. He understands policy, code, technical issues and of course science. He’s done a lot of heavy-lifting over the years.”

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Terry is a lanky man with a gentle manner. He’s patient with non-technical people in the section, suggesting books they might read to deepen their understanding of riverine processes. He’s funny, warm and easy-going. He’s also deeply admired in the Rivers Section. At a recognition for him at a recent staff meeting, many people wiped away tears as Jeanne read a poem she had written about him.

Terry was hired as an engineer in 1992 and began working in the Green River Basin. The staff in the section numbered about a dozen, and the section was within what was then called the Department of Public Works. Since then, the King County Department of Natural Resources and Parks was created – where the Rivers Section now lives – followed by the King County Flood Control District in 2008. Section staff today number around 50.

Over the course of his years, Terry has helped to shape a new and progressive approach to riverine public policy. He was part of the team that moved the county away from flood control and towards floodplain management – “a paradigm shift,” according to Steve Bleifuhs, the section manager, that recognizes flood-risk reduction doesn’t always translate into controlling a river.

“Terry’s role was to provide the scientific foundation for how channels migrate and how rivers work, which in turn influenced hazard mapping and public policy. It was his work on channel migration zones that influences so much of what we do today,” Steve said.

Much else has changed over the course of Terry’s 25 years, including a technological revolution that has altered the way he and other river scientists work. When Terry started, LiDAR – aerial imagery that uses laser to map river-basin topography – didn’t exist. Nor were GIS – Geographic Information Systems – or, for that matter, high-tech sonar-based river surveys in widespread use. Terry recalls doing river surveys by standing in the middle of a channel with a survey rod while Jeanne stood on the bank taking measurements.

A commitment to science, however, has been a constant. Throughout his 25 years, Terry said, “I’ve tried to bring scientifically based information to people, from decision-makers to property owners. I’ve also stressed the importance of understanding hazard vs. risk. Hazard in and of itself is not the issue. It’s the risk. Sometimes flood risk reduction can meaning getting people out of the way of the hazard, not controlling the hazard.”

What he will miss most about his job, he added, are those interactions when people concerned about a river’s channel migration or some other risk suddenly understood what the science was showing about the situation – those “aha moments” when someone began to see the larger picture.

“It’s deeply satisfying when people get it. For a scientist who works in the public realm, that’s what matters most,” he said.

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Learn more about King County river channel migration hazards.

 

Amphibian survey in Cavanaugh Pond

King County ecologists were up to their hip waders in Cavanaugh Pond recently as they surveyed amphibian eggs to document what species are present as part of the Riverbend Levee Setback and Floodplain Restoration Project.

Cavanaugh Pond and the area that was the former Riverbend Mobile Home Park will be reconnected to the Cedar River to restore approximately 40 acres of floodplain, which will reduce flood risks and improve the quality and quantity of salmon habitat.

Efforts to document current species prior to construction allows the project team to plan for protection and relocation efforts, if needed. Construction to restore floodplain is anticipated to begin next summer.

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Alexis Kleinbeck, with King County’s Watershed and Ecological Assessment Team, holds an amphibian egg mass found in Cavanaugh Pond
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Northwestern Salamander (Ambystoma gracile) eggs
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Pacific Treefrog (Pseudacris regilla) eggs
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Steve Brady, with King County’s Watershed and Ecological Assessment Team, conducting field survey work.