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This SEPA determination is related to maintenance of waterways draining agricultural fields in unincorporated King County in a manner to protect salmonids. These maintenance projects may include removal of the accumulated sediment and noxious or invasive vegetation that encroaches into and chokes  waterways or field drain tiles, and may also include culvert replacement or beaver dam removal.

King County worked with regulatory agencies to develop best management practices (BMPs) for waterway maintenance in unincorporated King County agriculture areas. The BMPs are provided as attachments 1 through 10 below and cover the time of year for the project, sediment and erosion control, fish removal from the construction area, and planting requirements. Application of BMPs may depend on the type of watercourse and the likelihood of salmonids present during the project. Waterways are classified as artificial, modified, or natural channels based how they were created. The likelihood of salmonids being present is based on known fish presence and the quantity and quality of the water. Waterways within the Agricultural Production Districts (APDs) have been classified and waterways outside the APDs will be classified on a case-by-case basis.

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Alluvial Fan Demonstration Projects in the Snoqualmie River Watershed
Determination of Non-Significance Under the State Environmental Policy Act (SEPA)

King County proposes to adopt two ordinances to authorize Alluvial Fan Demonstration Projects in the Snoqualmie River Watershed for a period of up to one year from ordinance approval. One of the ordinances would authorize up to five pilot projects outside of shoreline jurisdiction. The other would allow up to five pilot projects within the shoreline jurisdiction, primarily within the 100 year floodplain of the Snoqualmie River. Authorized by King County Code 21A.55, a demonstration project is a mechanism to test and evaluate alternative development standards and processes prior to amending King County policies and regulations. In this case, sediment management facilities will be “allowed alterations” under K.C.C. 21A.24.045, to determine whether sediment management facilities are a viable way to address the buildup of deposited materials on alluvial fans.

The two ordinances differ only in the allowed locations of the pilot projects. We chose to propose a separate ordinance for projects that will occur within the 100 year floodplain of the Snoqualmie River, which is within the designated shoreline, because that ordinance will be a temporary amendment to the County’s Shoreline Master Program, and as such, will require approval by Washington Department of Ecology before it goes into effect. The ordinance for projects outside the shoreline designation does not need Ecology approval.

King County Water and Land Resources Division prepared an environmental checklist for each ordinance and associated pilot projects and has determined the proposals do not have a probable significant adverse impact on the environment. The checklist and Determination of Non-Significance are available at the links below.

THE DETERMINATIONS OF NON-SIGNIFICANCE (DNS) are issued under Washington Administrative Code (WAC) 197-11-340(2). The county will not act on this proposal until after May 8, 2014. Comments must be submitted or postmarked by that date.

For additional information, please contact:

Brian Sleight
Supervising Engineer
Stormwater Services Section
King County Water and Land Resources Division
201 South Jackson Street, Suite 600
Seattle, WA 98104-3855

DNS and SEPA Checklist – Alluvial Fan Demo Project in the Snoqualmie River Watershed:

For questions about the SEPA Determination of Non-significance for King County's Agricultural Drainage Assistance Program, please contact Brian Sleight, Supervising Engineer, King County Stormwater Services Section.