King County dedicates new Seattle facilities to control overflows of untreated stormwater, sewage

After more than four years of construction, King County celebrated completion Thursday of its newest and largest system for controlling overflows of untreated stormwater and sewage into Elliott Bay and Lake Union.

"These new clean-water facilities are typical of so much that we do," said King County Executive Ron Sims. "They won't be visible to most people and will be quietly doing the hard work of reducing pollution in our waters. But the value of this new system to water quality and its impact on our quality of life and aquatic life will live on and on.

"Because of these new facilities, Seattle's urban waterfronts will be cleaner and healthier for us to enjoy for generations to come," Sims said. "This joint project with the City of Seattle is one of the most significant public investments so far by King County. It's a sound investment for clean water."

King County's new Denny Way/Lake Union combined sewer overflow (CSO) control facilities will reduce controlled discharges during storms. They'll take place an average of only once a year at the Denny Way CSO outfall in Elliott Bay and several city and county outfalls on the south and east sides of Lake Union.

"I've been awed by this massive clean-water project -- the largest system for controlling combined sewer overflows in King County," Sims said. "It's an extraordinary new quintet of facilities that will work in harmony."

He described the new facilities (click on map for a larger view):

• the Elliott West CSO Control Facility for managing the flow, storage and treatment combined wastewater and stormwater.
• a pair of pipelines ranging from 6 to 8 feet in diameter in Myrtle Edwards Park.
• a package of four pipelines tunneled and trenched south of Lake Union.
• two outfalls up to 340 feet offshore and 60 feet deep in Elliott Bay.
• a huge 14-foot-diameter tunnel running more than a mile under Mercer Street through the base of Queen Anne Hill.

"Our new system will work seamlessly with new and improved City of Seattle combined sewer pipelines," Sims said. "Together, our combined sewer systems will handle hundreds of millions of gallons of dirty water that flow from homes and business and off streets, parking lots and rooftops."

The new facilities will reduce both the volume and the frequency of untreated overflows. Until now, untreated CSOs discharged into Lake Union between 10 and 115 times a year, depending on rainfall and other weather conditions. And they discharged up to 50 times a year into Elliott Bay at Myrtle Edwards Park.

But with this new system, King County will store flows in the new Mercer Street Tunnel during small and moderate storms. After a storm subsides, the system will send the flows to the county's West Point Treatment Plant for treatment when capacity is available.

When the new Mercer Street tunnel completely fills with combined flows during major storms, the new CSO Control Facility will screen, disinfect and dechlorinate the flows. Those treated flows will discharge four to 20 times a year. Untreated overflows will take place an average of only once a year at each remaining outfall.

"Most of the new Denny Way/Lake Union facilities are underground or under water -- and out of sight," Sims said. "But they won't be out of mind -- and forgotten -- by the people who planned, designed and built them -- and by the people who operate and maintain them."

He noted that some people have dedicated nearly 15 years of their careers to planning, designing and building the new system for controlling overflows.

The U.S. Environmental Protection Agency awarded King County a $35 million grant to reduce the direct cost of the $140 million county project to sewer system ratepayers.

Companies involved in the project included the following:

• For designing the facilities, Black and Veatch, Cosmopolitan Engineers, Streeter and Associates Architects, and RoseWater Engineering
• For managing construction, the MWH consulting firm
• For building the facilities, the Frank Coluccio Construction Co., Robison Construction and MKB Constructors.

"This project is another example of our growing experience and expertise in building tunnels to carry wastewater with minimal impact on the communities above," Sims said.

Metropolitan King County Council Chair Larry Phillips, who represents the communities affected by the CSO project, called the facilities a triumph of cooperation that crossed jurisdictional boundaries.

"King County came together with the Seattle Department of Parks and Recreation and the Port of Seattle to accomplish this work," Phillips said. "Everyone had to exercise a little patience during construction, so we need to extend thanks to park and port officials and the users of Elliott Bay Park, Seattle's Myrtle Edwards Park and South Lake Union Park. The result of their patience is a system that will prevent untreated sewage discharges into a body of water that we all hold precious -- Elliott Bay."

B.J. Brooks, Seattle's deputy superintendent of parks and recreation, said, "At Parks, we're very pleased with how this project went. King County did a great job of managing the needs of Myrtle Edwards Park users with a minimum of disruption -- and restored the park beautifully."

King County's 4Culture public arts program enhanced the Denny sewer-regulator station in Myrtle Edwards Park. Integrated with the enlarged facility is an artist-designed plaza that serves as a gathering place and viewing area to Elliott Bay.

"The plaza is a strong example of enhancing a community as we build an essential facility," said Phillips, an ex officio member of the 4Culture Board. "Working with the people in the community, the architecture of the Elliott West CSO Control Facility is compatible with the neighborhood, and it prevents odors noticeable to nearby businesses and residents."

He said since much of the work for this project occurred in the "front yard" of a thriving business district, those businesses had a right to updates on the construction impacts.

"The county's community relations team was the most important 'tool' used in this project," Phillips said. "They worked with businesses to ensure that they were never left in the dark during construction. What could have been a source of contention was a source of cooperation."

Affected businesses included the Port of Seattle's Grain Facility terminal, West Farm Foods, British Motor Coach, Bucca de Beppo's Restaurant, Athletics Awards, Glazer's Cameras, Courtyard Inn by Marriott and the annual Fourth of July-var's celebration.

Sims also recognized the cooperation and support of other businesses and agencies in building the project, including the Burlington Northern Santa Fe Railway, Port of Seattle, Seattle Department of Transportation and state Department of Ecology.

"Logistically speaking, we literally crossed paths with them," Sims said. "But rarely did we have cross words as we cooperated to keep the project moving ahead."

Sims noted that Liz Anderson, project manager for Seattle Public Utilities, helped coordinate many issues with various city departments involved in the project. She also managed design and construction of the city facilities that are part of the joint project.

He also expressed appreciation to King County staff in the Wastewater Treatment Division "for ensuring a safe and well-built project." He listed Project Manager Judy Cochran; Don Theiler, division director; Christie True, capital improvement program manager; and Randy Brunke, Bill Burman, Jim Faccone, Chris Foss, Gary Ikeda, Calvin Locke, Bud McJimsey, Bryon Slatton and Clayton Wiek, all of the project team.

King County's Wastewater Treatment Division protects public health and water quality by serving 17 cities, 17 local sewer utilities and more than 1.4 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 40 years.