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Brightwater-to-Sound wastewater conveyance system begins full operation


King County's state-of-the-art Brightwater Plant sent its first flows through 13 miles of new tunnel on Nov. 9, essentially completing the region's largest clean-water project of the last half century.


King County’s state-of-the-art Brightwater Plant sent its first flows through 13 miles of new tunnel on Nov. 2, essentially completing the region’s largest clean-water project of the last half century.

“Meeting this critical milestone fulfills the promise we made to ratepayers a decade ago to integrate the need for more wastewater treatment capacity with the regional environmental goal of protecting Puget Sound,” said King County Executive Dow Constantine.

The 600-foot-deep outfall, which rests on the floor of Puget Sound a mile off Point Wells, serves as the primary discharge point for the Brightwater treatment plant serving both south Snohomish County and north King County. A 13-mile-long tunnel from the treatment plant north of Woodinville to Point Wells conveys highly treated wastewater to the outfall.

“We are proud of what this new treatment system will accomplish to protect the environment and the economy for our next generation of Puget Sound area residents,” Executive Constantine said.

The successful completion of the complex Brightwater conveyance tunnels last year earned prestigious international honors for the contractor and King County’s project management team. Joint venture contractor Jay Dee Coluccio (JDC) won the coveted 2011 International Tunneling Contractor of the Year Award, presented by New Civil Engineer magazine.

JDC had successfully completed mining of the four-mile Brightwater West Tunnel in early 2010, when King County had to address the Central Tunnel contractor's inability to complete that tunnel on time. Executive Constantine selected JDC in April 2010 to complete the remaining 1.9 miles of the four-mile-long Central Tunnel.

The new Central Tunnel contract called for JDC to complete mining of the 13.3-foot-diameter tunnel by September 2011, but JDC finished ahead of schedule.

Earlier this year, Brightwater’s East Tunnel won an engineering excellence award from the American Council of Engineering Companies of Washington state. The 2.7-mile-long tunnel between Bothell and the treatment plant site was designed as a joint venture by MWH/Jacobs Associates.

The outfall’s operation marks Brightwater’s commissioning as a fully operational facility. Phased construction on the $1.86 billion Brightwater project began in 2006 with the treatment plant, followed by four deep-bore tunnels that comprise the 13-mile-long conveyance line, and an influent pump station that conveys untreated wastewater to Brightwater from Bothell. Construction on the marine outfall was completed in 2008.

One of Brightwater’s most notable features is its membrane bioreactor technology that produces effluent that is 70 percent cleaner than conventional wastewater technologies.

The advanced treatment technology will also enable the plant to become a significant source of high-quality reclaimed water for non-drinking uses, such as irrigation and industrial processes.

Brightwater’s first major reclaimed water user, the Willows Run Golf Course, will begin irrigating in the summer of 2013 and significantly reduce the amount of water being taken from the Sammamish River as a result. Reducing the amount of effluent discharged to the outfall also supports the state’s Puget Sound cleanup strategy.

King County selected the Brightwater outfall location after years of environmental review that included detailed study of Puget Sound oceanography and marine biology as well as an extensive permitting process involving state and federal agencies.

In order to protect the marine environment at Point Wells contractors adhered to stringent environmental regulations during both design and construction. The outfall project, led by King County, Triton Marine Construction and designers Dayton & Knight, was the recipient of numerous awards including the Engineering News Record’s national “Best of the Best” award in 2009.

Additional information about the Brightwater marine outfall is available at:



This release is also posted on the website for the Department of Natural Resources and Parks at

Note to editors and reporters: Visit the WTD Newsroom, a portal to information for the news media about the Wastewater Treatment Division, King County Department of Natural Resources and Parks:


Residents enjoy clean water and a healthy environment because of King County's wastewater treatment program. The county’s Wastewater Treatment Division protects public health, the environment and the economy by serving 17 cities, 17 local sewer districts and more than 1.5 million residents in King, Snohomish and Pierce counties. Formerly called Metro, the regional clean-water agency now operated by King County has been preventing water pollution for nearly 50 years.