northwest pipeline replacement

Northwest Pipeline, a Williams company, is proposing to remove a 5.82 mile segment of an existing 8-inch diameter mainline lateral natural gas pipeline and replace it with 5.82 miles of 20-inch diameter pipe.  The project is necessary to increase peak load delivery capacity on the existing North Seattle Delivery Lateral as requested by Puget Sound Energy.  The proposed improvements will result in short-term temporary and/or long-term temporary impacts to numerous wetlands, streams, and buffers across two Water Resource Inventory Areas (WRIA 7 and WRIA 8). 

The Watershed Company delineated all wetlands and streams along the project corridor and provided regulatory assistance and coordination between Snohomish County, the Corps of Engineers, the Muckleshoot Indian Tribe, multiple wetland mitigation banks, and the King County Mitigation Reserves Program. 

The Watershed Company prepared a comprehensive wetland and waterbody delineation report, delineation maps, a wildlife habitat report, a wetland mitigation bank use plan, and provided assistance developing the wetland and waterbody mitigation plan. In an effort to maintain and preserve fish populations, we safely relocated over 6,396 fish from numerous creeks that were to be dewatered as part of the pipeline replacement.  Fish species that were relocated included, juvenile coho, cutthroat trout, lamprey, stickleback, and juvenile chum.

SERVICES

• Fish exclusion

• Delineation report and map

• Wildlife habitat and wetland mitigation bank use plan