LAKE STEVENS — The Trouts have lived on the lake for nearly two decades.
“All of a sudden we get hit,” Rick Trout said.
Their mortgage company called and said their home now lies in a Federal Emergency Management Agency designated flood hazard area.
When FEMA updates its maps, homeowners may find themselves slapped with a policy through the agency’s National Flood Insurance Program. For the Trouts, it was initially $2,000. Flood insurance is mandatory for those with mortgages, but homeowners can shop around.
Trout said it came as a surprise.
But flooding is a regional threat, and those living near any freshwater may expect to see more flooding in the future because of the warming climate.
Warmer air holds more water vapor, allowing atmospheric rivers to carry more water — meaning more rainfall, according to Cliff Mass, professor of Atmospheric Sciences at the University of Washington.
It’s already begun.
“We’ve seen several substantial, big atmospheric rivers in the past few weeks,” David Radabaugh, flood-insurance coordinator for the state Department of Ecology, told The Daily Herald. “Most of the major flooding in Western Washington is caused by atmospheric rivers so … we will see larger floods in riverine systems moving forward in the future.”
Back-to-back heavy rains coupled with human activity can drive rising lake levels, researchers have found.
Over the past two winters, the Trouts’ lawn held nearly a foot of standing water, and the rising lake level bent their floating dock to the “max.”
“The last two years — holy smokes,” Rick Trout said.
Beyond the lake shore, downtown Lake Stevens has been hit with a spate of annual flooding for years. And in 2020, residents started a petition asking Mayor Brett Gailey to address the flooding along Hartford Drive.
The outlet channel — the only outflow from the 1,000-acre lake — runs parallel to the one-way road. It was dug for the Rucker Mill in the late 1800s or early 1900s.
In Lake Stevens, the city plays a big role in controlling lake levels, using a weir on the outlet channel.
Every spring, the city adds boards to the weir to preserve the lake level. All of the boards come out in the fall to allow the maximum outflow from the lake, said Surface Water Management Coordinator Shannon Farrant.
In 2020, the city contracted engineers to complete an outlet study. It found the existing weir does not provide adequate control of the lake level in the wet season. Instead, the width, height and slope of the outlet channel is the control in winter.
So the city has been “triaging” the channel, including clearing out sediment and other blockage to improve flow, said interim Public Works Director Aaron Halverson.
This fall, the city dredged 300 feet of the outlet channel, and it made a noticeable difference for those living along the water near North Cove Park and along Hartford Drive.
It’s a temporary fix: November’s record rainfall still forced the outlet channel to spill over the road.
Restoring the outlet to its historic path would likely alleviate much of the downtown flooding.
“It would increase the capacity in the outlet channel, simply because you’d be creating a longer path,” Farrant said.
If the historic path is restored, the outlet channel would wind through the wetlands behind the homes on the northern side of Hartford Drive, recreating the natural confluence with Catherine Creek and restoring fish habitat. That could be on the horizon if the city moves forward to conduct a feasibility study.
It would cost millions. A single culvert replacement costs a couple million dollars, Halverson said.
In the meantime, the city has shared FEMA resources on flood safety and insurance with affected residents and has invited them to discussions about future projects. Atop the list is replacing an outdated culvert under Hartford Drive.
Both the city and county have developed flood management plans to be eligible for FEMA’s National Flood Insurance Program. The program requires local governments to enforce floodplain management to reduce future damage. In exchange, homeowners can buy federally supported flood insurance in Snohomish County’s flood hazard areas.
“I’m happy with how it’s been so far, but we’ll have to see what it looks like in February,” Trout said. “When we start getting the rains, especially if we have a decent snowpack … a lot of times that’s when the flooding really, really picks up.”