Woods Lake Creek Culvert Replacement on Lake Chaplain Road
The existing drainage culvert is undersized and has experienced flooding from backwater multiple times in the past. The Chaplain Lake Road embankment around this culvert has been compromised and it now poses a high risk of failure within the next year. The drainage structure crosses a roadway that is critical to the delivery of personnel, equipment, parts and chemicals to the city’s water filtration plant. This plant is crucial to the region’s water supply system, which serves over 600,000 residents or about 80 percent of people in Snohomish County.
The project is located at the Woods Lake Creek crossing of the Lake Chaplain Road northeast of Monroe, Snohomish County, Washington. The new culvert structure will accommodate larger flow events, improve fish passage across a larger range of flows and allow for more natural stream processes to occur.
The proposed pipe crossing will be a single radius open bottom structural plate arch culvert on precast concrete footings (80 feet long, 10 feet high and a 26-foot bottom width).
This will involve a MSE headwall on the upstream inlet and new rip rap on downstream outlet.
As part of the proposed culvert, approximately 150 feet of stream channel will be reconstructed and disturbed stream banks will be restored.