Migration of the Dungeness River is threatening the longevity of the Hurd Creek Hatchery.
As the river moves toward the Washington Department of Fish and Wildlife-owned and operating fish hatchery off Fasola Road, it’s eroding the bank and increasing risk of flood damage and habitat loss.
The river’s migration was initiated in 2009 by a large tree that fell into the river, and serving its function, began collecting additional woody debris.
“This effectively pushed the flow over and it’s eroding the bank along the side of the hatchery,” said Shawn Stanley, Washington Department of Fish and Wildlife project engineer. “The movement of the river is migration at this point, but it’s headed toward avulsion (rapid shift of river to a new channel on the floodplain).”
Winter flood events in both February and November 2015 amplified the erosion, scour and risk of avulsion. Already the hatchery has experienced flooding that caused damage to facility and unwanted flows into the ponds used to rear the various species, such as Dungeness spring chinook, Elwha fall chinook and Dungeness winter steelhead.
“This winter we had increased over-bank flows, which is a big concern because that can fill the hatchery ponds with sediment or flush fish out into the river before they’re supposed to be released or flush fish from other drainages into the Dungeness,” Stanley said.
To protect the facility, its two wellheads and fish, state officials are in the midst of planning a temporary bank stabilization project.
“We’re trying to balance a project that will protect our infrastructure, but still will have habitat value and the least negative impact on habitat,” Stanley said.
In the longterm, state officials plan to relocate portions, if not all of the hatchery upland. The process to move the hatchery is anticipated to take seven to nine years and thus Stanley is piecing together a bank stabilization project intended to protect the facility and surrounding habitat while legislative funding, design, permits and construction necessary to move the hatchery is sought.
Channel surveys and aerial photos from 1914 to present and hydrology models and studies in cooperation with local, state, tribal and federal agencies, have informed the development of a bank stabilization project estimated to cost $300,000.
“Right now have two alignments that we’re proposing,” he said.
The options parallel each other, but one alignment requires working in the current river channel, whereas the other option would be built along side it. Either alignment includes, but is not limited to, a combination of strategically placed engineered log jams, floodplain fencing, plantings and removal of the riprap placed following the past flood events to slow river migration and protect the hatchery through the winter.
Working in the river to stabilize its current bank would maintain a larger buffer between the river and the hatchery and it would be immediately usable by fish in the river, Stanley explained.
However, the cost of the project would increase because of added complications when building in water and construction likely couldn’t occur until next year given the sensitivity required when fish are present or spawning.
The other alignment option potentially could be built this fall because it would be constructed in the “dry,” Stanley said. Additional planning and meetings with federal, state and county agencies will provide “a lot more input” and help direct what option is pursued, he said.