SEATTLE, Wa. -- For the first time since its construction in the 1940s and '50s, the Pilchuck Levee near the City of Snohomish is set to receive reinforcement and strengthening under Public Law 84-99. Extensive repairs commenced July 5 on the Pilchuck River to safeguard a valuable area comprising of a mix of residential, agricultural, and commercial properties valued at $25 million.
The Pilchuck Levee is the inaugural project among nine levee repairs scheduled for this summer under PL 84-99, which grants authorization to the U.S. Army Corps of Engineers (USACE) for the repair of non-federal levees in support of state and local governments.
The $505,800 project will repair 600 feet of levee damaged in a 2020 flood event and is expected to take four weeks to complete. Under a cost-share agreement, USACE pays for 80% of the project and French Slough Flood Control District covers the remaining 20%.
Due to its damage, the levee's flood defense has been reduced to a one-year flood level protection, or a 99% chance of flooding in any given year. Repairing the slope armor and deflecting flows will also help minimize erosion caused by fast-moving water and restore the levee to its originally designed and constructed 10-year protection, or a 10% chance of flooding annually.
USACE officials will also remove damaged riprap armor and other materials from the levee slope, salvaging any usable materials for the river embankment, if permissible.
While various recreational sites are located nearby, popular public areas like Pilchuck Park and DoodleBug Sportz Outdoor Paintball Park will not be impacted by construction closures.
Janet Curran, USACE levee rehabilitation program manager, emphasized the importance of the levee repairs and a busy construction season ahead.
“This repair, and the others to follow, exemplifies the strong partnership between the Corps of Engineers and our state and local partners,” said Curran. “It’s going to be non-stop this summer to deliver critical repairs that reduce flood risk to local communities.”
The repairs will be completed within the designated "fish window" period between June 15 and August 31, allowing construction crews to operate in the water with the least interference to salmon populations.
Because of a long history of riverbank modification, additional work will be done simultaneously to help with stream habitat conditions and remove invasive vegetation. Crews will plant 150 willow tree bundles to create an overhang along the river’s edge and invasive Japanese knotweed will be removed and replaced with 38 native trees.
Throughout the planning process, USACE Seattle District officials coordinated, consulted and worked with federal, tribal and state agencies, including: Environmental Protection Agency, National Marine Fisheries Services, U.S. Fish & Wildlife Service, Snoqualmie Indian Tribe, Stillaguamish Tribe of Indians, Swinomish Indian Tribal Community, Tulalip Tribes of Washington, Sauk-Suiattle Indian Tribe, the Confederated Tribes and Bands of the Yakima Indian Nation, Washington State Department of Ecology, Washington State Department of Archeology and Historic Preservation and Snohomish County.
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