Logjams installed in 2005 in a side channel of the Sauk River continue to protect homes on the Sauk-Suiattle Reservation and create spawning habitat for salmon and numerous other species.
The area had been logged prior to the reservation being established in the 1980s, contributing to changes in the river. The side channel — now known informally as Reservation Slough — was formerly the river’s mainstem up until about 1949, but it has since migrated to the east.
The tribe and contractors installed the logjams to slow side-channel flows which, during storm events, might otherwise be strong enough to erode the bank and threaten nearby homes over time.
Seventeen years after they were installed, the logjams provide numerous benefits to the side-channel ecosystem. Salmon redds are evident in riffles, frog and salamander egg masses are attached to freshwater grasses and woody debris, numerous species of macroinvertebrates — a significant source of food for amphibians, birds, fish and reptiles — inhabit wood in and near the water.
On a cool morning in April, several staff members of the Sauk-Suiattle Tribe’s natural resources department planted numbered flags at amphibian egg mass sites and recorded them. They do this breeding survey once a week for a few months each spring.
“We’re mostly monitoring for population count and comparing across years, and also looking for unusual amounts of dead eggs,” said Scott Morris, water quality coordinator for the Sauk-Suiattle Tribe. “It’s a crude measure of water quality and health of amphibian species. The numbers have tended to be fairly steady since 2007.“
But the side channel is still precarious and conditions are monitored regularly. The erosive power of the Sauk River is readily visible in the channels it has carved and the banks it has sculpted. The Sauk-Suiattle Reservation, near Darrington and in the shadow of perennially snow-peaked Whitehorse Mountain, gets an average of 77 inches of rain.
“Channel migration happens during moderate storm events,” Morris said. “The logjams minimize the risk of the mainstem coming in here. It’s been successful so far, but it doesn’t mean the river won’t be here again. If the river wants to return here, logjams won’t necessarily keep it from happening.”
Logjams are a climate adaptation strategy, said Jason Joseph, the tribe’s natural resources director. “Increased flows during storm events caused by climate change could influence the channel migrating into the slough,” he said. “That’s why we’re monitoring the logjams and stream flow.”
In addition to the logjams, a riparian buffer planted in 2010 by the tribe and Skagit River System Cooperative is thriving. The tribe and SRSC planted Western red cedar, Douglas fir and red alder. Salmonberry, thimbleberry and ferns are thriving as well.
“The riparian planting was 3 acres,” Morris said. “Much of the slough already had a pretty good forested cover and the planting just filled in the opening near the mouth. There is one short stretch the tribe doesn’t own that we weren’t able to plant.”
Top photo: Joseph McConnaughy, field supervisor for the Sauk-Suiattle Tribe, records frog and salamander egg masses at Reservation Slough. Story and photos: Richard Walker
