Planning and land acquisition occurred from 1999-2012. Construction occurred in 2009, 2013, and 2014.
Canyon Creek is a tributary to the North Fork Nooksack River. In 1989 and 1990, three very large debris floods destroyed four homes and damaged a private resort, a county road, and salmon habitat in the lower mile of Canyon Creek in the Glacier Springs community west of Glacier. Whatcom County built a 3,000-foot long levee in 1994 as an interim measure to prevent further damage to the county road, homes in Glacier Springs, and the Mt. Baker Highway (SR 542); however, flooding in 1995 damaged the new levee.
The 1995 flood demonstrated that the levee constrained Canyon Creek’s channel and floodplain. This channel confinement caused the stream to scour the structural toe of the levee during flood events. In addition, increased stream energy created by channel confinement scoured and transported spawning gravel used by spring chinook, steelhead, and bull trout, impacting critical habitat for these species listed as “threatened” under the federal Endangered Species Act (ESA). Habitat used by pink and sockeye salmon and cutthroat trout was also impacted. Furthermore, a bedrock section of channel blasted during the 1994 levee construction became a barrier to salmon as the streambed lowered, blocking nearly four miles of historic salmon habitat. Action was needed to better manage flood risk while restoring key habitats critical to the recovery of multiple salmon species.
The Lower Canyon Creek Fish and Flood Project was developed and implemented in phases over approximately 15 years. Geomorphic and alluvial fan flood risk analyses completed in 2003 built a better understanding of the risks to life and safety. This guided acquisition of the highest risk properties from willing landowners along the eastern side of Glacier Springs between 2003 – 2012. Twenty-nine parcels totaling over 80 acres in high hazard debris flood zones were acquired to reduce the potential for loss of life and property and to provide the land necessary for habitat improvements and a new flood protection structure setback farther from the stream. Next, alternatives analysis and design led to three phases of construction.
In 2009, a 500-foot section of the 1994 levee was removed to open up a hydraulic constriction and allow access to the floodplain. Armor rock was salvaged and stockpiled away from the stream for later use and old access roads were blocked with berms to redirect flood waters away from SR 542. The bedrock fish barrier was modified to allow passage upstream and disturbed areas were replanted with native trees.
In 2013, all but 140 feet of the remaining levee was removed and a setback revetment structure was constructed at the western edge of Canyon Creek’s historically active floodplain. Fourteen log jams were installed, the reconnected floodplain was contoured, and the site was planted in native plants. In 2014, an additional nine log jams were installed and the remaining disturbed area was planted with native plants. Planting assistance was provided by the Washington Conservation Corps, Sheriff’s Department Alternative Corrections Crews, and volunteers organized by Whatcom County Public Works, Nooksack Salmon Enhancement Association, and Whatcom Land Trust.
With all three phases of construction and restoration complete, Canyon Creek now has access to its historic floodplain, flood risks are more predictably managed for adjacent properties, and the stream processes that support formation of critical salmon habitat are restored. New log jams create pools with complex woody cover, stable spawning gravels can accumulate, and new riparian trees will shade the creek and provide future woody debris recruitment. Activities post construction include:
Total cost of all phases from acquisition and alternatives analysis through final construction was $5.6 million.
John N. Thompson, L.E.G., Senior Salmon Recovery Planner