College of the Environment Graduate and Undergraduate Publications

Date Permissions Signed


College Affiliation

Huxley College of the Environment

Date of Award

Winter 2013

Document Type

Environmental Impact Assessment

Department or Program Affiliation

Department of Environmental Studies


Environmental Studies

First Advisor

Bodensteiner, Leo R.,1957-


The existing placement of the South Skagit Highway disconnects the Skagit River from approximately 62 acres of floodplain in the project area alone and has direct impacts on habitat conditions. Approximately, 5.2 acres of wetlands are completely inaccessible to fish due to the current highway alignment. An additional 21.7 acres of slough and wetland habitat have only partial fish access due to restricted hydrologic connectivity with the river. Routine dredging and maintenance is required for the 900 feet of Savage Creek which currently runs in the highway ditch. Savage Slough runs under the highway through an undersized culvert that is often blocked by flooding from Mill Creek. An alluvial fan of Mill Creek runs under an undersized bridge making the channel prone to migration, avulsion, and erosion. The channel has been subject to numerous maintenance projects, including dredging and channelization. Seattle City Light (SCL) purchased approximately 212 acres of property on the Skagit River near Mill and Savage Creeks. A large portion of the acquired property has been deforested and disturbed by the South Skagit Highway, which runs through the Skagit River's floodplain and disconnects a variety of existing tributary and wetland habitats. In order to implement habitat restoration and protect the property for conservation, SCL has been working with Skagit River System Cooperative (SRSC) and Skagit County to restore the floodplain to its original ecological functionality, providing habitat for several species. Maintenance costs of the current road would also be reduced. The restoration is likely to include demolition, riparian and floodplain plantings, and culvert removals. Possibilities for floodplain restoration were evaluated after an initial scoping procedure. Suggested restoration would either demolish and realign the existing road or install new bridges and culverts on the existing road. The initial scoping and evaluation narrowed the list of feasible projects down to two, mostly due to the Washington State Department of Transportation's (WSDOT) high cost estimate of the other projects. Project funding has come from both SCL and the Salmon Recovery Funding Board (SRFB, project #091450) and several additional sources.




Roads--Design and construction--Environmental aspects--Washington (State)--Skagit County, Environmental impact analysis--Washington (State)--Skagit County


Western Washington University

OCLC Number


Subject – LCSH

Roads--Design and construction--Environmental aspects--Washington (State)--Skagit County; Environmental impact analysis--Washington (State)--Skagit County

Geographic Coverage

Skagit County (Wash.)




environmental impact statements




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