STANWOOD — The sprawling Stillaguamish River delta once was covered with toppled old-growth trees ripped out of mountain soil and washed down the river by raging winter floods.
The giant logs would clump together and their roots would tangle, creating areas for young salmon to hide and forage before they headed out to sea.
Those big old trees are gone now, leaving the delta devoid of anything but mud and grass. Salmon, especially endangered chinook, have few places to hide as they move through channels carved into the mud flats.
On Tuesday, some of those logs came back, thanks to a helping hand from The Nature Conservancy and a Boeing Vertol 107-II helicopter.
The Nature Conservancy flew in 26 logs with roots intact and put them into six clumps. Fish experts say that at a minimum, the logs will re-create some of the long-lost habitat that young chinook and other salmon depend on, and at best, form the beginnings of some new logjams.
“If there’s no wood and no cover, there’s no salmon,” said Rick Rogers, a project coordinator for the Stillaguamish Tribe. “When there is wood, they congregate and hide underneath that.”
The tribe twice tried to drop giant “lawn darts” — logs with plywood wings and weighted tips — into the same delta. The idea was to have the tree trunks sticking up out of the mud catch and trap wood debris that flow down the river.
The first time, heavy winds blew the darts sideways. The second time, they shattered on impact.
The Nature Conservancy’s technique was to drop 1,000-pound blocks of concrete into the mud, and then to cable the logs to the blocks. Shaped like spinning tops, the concrete blocks sank into the mud with ease, some of them sinking several feet below the surface.
“This worked a lot better,” said Rogers, working on the crew that bolted the logs together on Tuesday.
Danelle Heatwole, a Nature Conservancy ecologist, spent a year planning the log drop.
“I’m glad that today finally got here,” Heatwole said. “I feel like it went really smoothly.”
Humans have degraded salmon habitat in many ways, but the near-shore habitat that fingerling salmon use before they head out to sea has seen perhaps the most impact, Heatwole said. This project is a way to get some of that back, she said.
The Nature Conservancy project is a good first step, said George Pess, a research fish biologist with the National Oceanic and Atmospheric Administration’s Northwest Fisheries Science Center.
“The change in the amount of habitat is by far greatest in the estuarine habitat — 70 to 80 percent has been lost,” Pess said. “It’s a small step in the right direction. Obviously, you need to do things at a larger scale if you really want to see any significant change.”
The NOAA contributed most of the $70,000 in grants used to fund the log drop, said Robin Stanton, a spokeswoman for The Nature Conservancy.
Reporter Lukas Velush: 425-339-3449 or firstname.lastname@example.org