North King County/South Snohomish County projects

Brightwater Treatment System 

Construction continues on Brightwater, the county’s largest clean-water project in 40 years. Construction was completed in 2008 on the North Mitigation Area, the 40 acres of public space at the north portion of the plant campus that features habitat enhancement and trails. In 2009, the county will complete the liquids processing facilities, the odor control system, and associated earthwork at the treatment plant site.

Construction progresses on the conveyance system, which includes a pump station in Bothell and a 13-mile-long wastewater pipeline that will run up to 450 feet below ground from the Brightwater Treatment Plant north of Woodinville to Point Wells near Shoreline. Contractors completed the first 2.6-mile tunnel segment in November 2008, and expect to complete the remaining three tunnel segments by mid-2010. Construction on the mile-long, 600-foot-deep marine outfall was completed in October 2008.

Learn about construction activities at the plant site and conveyance portals. View construction contracts and RFPs.

Brightwater reclaimed water backbone 

In 2009, contractors will complete construction on a significant portion of a project that will bring reclaimed water from the Brightwater Treatment Plant to irrigators and industrial customers in north King and south Snohomish counties beginning in 2012. Other components of the project include converting an existing force main into a reclaimed water pipeline that will run from the North Creek Pump Station in Bothell to the York Pump Station in Redmond, and installing reclaimed water pipes in the tunnels being built for the Brightwater conveyance system.

North Creek Interceptor

In 2009, King County and Alderwood Water and Wastewater District (external link) will continue working on a project replacing a 16,000-foot segment of the North Creek Interceptor, which carries wastewater from a large portion of south Snohomish County to King County’s regional system for treatment. Through an interagency agreement, King County will provide $25 million in project funding in 2009 to the Alderwood Water and Wastewater District to manage permitting and construction. King County will assume ownership of the North Creek Interceptor when the project is completed in 2011.