The Nooksack River Watershed (WRIA 1) located in northwestern Washington, spans parts of Whatcom and Skagit counties and also reaches northward into British Columbia. The watershed covers over 830 square miles with elevations ranging from sea level to the summit of Mt. Baker at 10,778 feet. The Nooksack River contains more than 1,000 miles of streams and rivers, combining three main tributaries the North Fork, Middle Fork and South Fork.
The Middle Fork sub-basin drains an area of 103 square miles. The Middle Fork’s headwaters are located at the Deming Glacier on the south slope of Mount Baker. The river flows in a northwesterly direction for about 16 miles where it joins the main stem of the Nooksack River. There are over 30 tributaries and 3 lakes, Canyon, Mosquito and Jorgensen, in the sub-basin.
The City of Bellingham operates a water diversion dam on the Middle Fork Nooksack River approximately 20 miles east of the city of Bellingham, at an elevation of approximately 838 feet above sea level. The City has diverted water from the Middle Fork since 1962 to supplement its main water supply source, Lake Whatcom.
Water from the Middle Fork is diverted intermittently, mostly during winter and spring high flows. The City voluntarily complies with a Department of Ecology instream flow rule that limits diversion amounts during periods of low flows in the river. From the river, the water flows through a 1.6 mile long tunnel and 9.5 mile long pipe into Mirror Lake and then into Anderson Creek, which empties into Lake Whatcom. The lake is the drinking water reservoir for over 85,000 City and County Residents.
No fish passage facilities were built when the diversion dam was constructed, because falls at the site of the dam and a gorge just downstream were designed to be naturally occurring barriers that severely limited anadromous fish access to the watershed above the dam site. However, it is now recognized that prior to construction of the diversion dam, several fish species utilized the upstream habitat. The dam obstructs access to approximately 26 miles of river and tributary stream habitat for three Endangered Species Act listed species: Chinook salmon, Steelhead and bull trout, as well as other fish species.
In 2000, the City was approached by Lummi Nation and the Nooksack Tribes, offering to work together to restore fish passage at the Middle Fork diversion dam. Since signing a formal partnership with the tribes and the Washington Department of Fish and Wildlife (the fisheries co-managers) in 2002, the City and its project partners have considered several options for a project that would provide fish passage as well as continue the City's ability to divert water for its municipal water supply needs. Feasibility studies were completed for three of the options: a fish ladder, instream abutments and a siphon. After extensive physical modeling and analysis of additional factors, including costs, these options were not pursued further. The City has recently revised elements of the project criteria and is now working with a private sector foundation and a non-profit interest group as well as the original project partners to design a project based on a simplified version of the instream abutment option. This type of alternative diversion structure will allow for complete or partial removal of the dam.
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