Managing the Complex at Brightwater
Nestled among wildlife habitats and wetlands near Seattle, Washington, USA, is the new Brightwater wastewater treatment plant. A critical component of King County's regional wastewater services plan, this state-of-the-art membrane facility supports growth in the greater Seattle area, protects public health and the environment, and promotes water reuse.
The serene landscape belies the project's $1.8 billion multi-contract implementation, requiring the coordination of more than 115 contractors and subcontractors; some of the nation's deepest, soft-ground structures; and an extensive, geotechnically complex conveyance system. To help King County achieve their goals, CDM Smith provided comprehensive project and construction management, project controls, and resident engineering and inspection for the plant, while delivering project-wide geotechnical support.
Confidence through Construction Management
The $500 million treatment plant was built through two major construction contracts. Traditional design-bid-build (DBB) was used for the solids and odor control infrastructure, and general contractor/construction manager (GCCM) for all liquids facilities, including a 36-million-gallon-per-day membrane bioreactor technology process—the nation's largest. "Managing two different and simultaneous alternative delivery contracts for the same project presented challenges, but as the owner's representative, we needed to build trust with the contractors while instilling confidence in the county that they could depend on us," says Kevin McEvoy, CDM Smith vice president and construction manager.
Benefits were realized before construction began. CDM Smith partnered with the design engineer to clearly delineate the plans' scope to solicit more accurate bids, as well as performed detailed cost, constructability and proposed contract packaging reviews for the GCCM contract. "We worked with the county to generate contractor interest and competitive bidding on the DBB contract," says McEvoy. Since the GCCM contractor can self perform up to 30 percent of the work, we assisted with the public bidding process of the remaining contract packages and reviewed bids with the county to select the lowest responsive bids.
While the day-to-day management of field work rested with each contractor, we performed close coordination between contracts to identify where liquids and solids work would interface. The project team conducted weekly contractor meetings to promptly resolve field conflicts and schedule deviations with everyone’s concurrence, minimizing confusion in the field.
Vigilant review and processing of payments and other cost issues, as well as responsiveness to owner and contractor needs, prevented routine change orders from becoming costly claims. "Most importantly, difficult issues were addressed head on without a single issue brought before the Dispute Review Board," notes McEvoy. Overall, the project team negotiated more than 110 change orders and addressed a variety of scheduling conflicts; while keeping change orders to only 3.8 percent of project cost. "This was well within our expectations," states Gunars Sreibers, King County program manager. "Construction management was instrumental to completing this project on time and within budget. A spirit of mutual trust and cooperation was evident throughout."
The success of Brightwater can be applied to similar future projects, helping us fulfill our commitment to deliver reliable, high-quality wastewater services to King and Snohomish counties
Beyond and Below the Fence Line
Connecting the plant to the county's existing collection network are 13 miles of tunnels, portals, a pumping station, and a 1-mile-long marine outfall in Puget Sound that traverse topographically complex terrain and burrow beneath suburban and urban areas. For design continuity across the multiple-contract conveyance system, King County asked CDM Smith to serve as the sole geotechnical engineering firm to assist with tunnel alignment, investigation and reporting, design recommendations and contract documents, and permitting.
Ground freezing was used to install one of the portals, which at 216 feet deep was at the limit for conventional construction technologies. "This was a challenging, world-class project in difficult conditions, so our ground freezing and tunnel specialists supported design engineers throughout," describes John Newby, CDM Smith senior vice president. "King County knew they could rely on us for geotechnical answers, and we helped ensure the portal was successfully constructed." The firm collaborated with project stakeholders to avoid any groundwater impacts and developed a cleanup action plan after encountering unexpected environmental contamination.
CDM Smith partnered with the county to develop a risk management register and conducted meetings to review potentially significant program impacts and apply mitigation measures. We also supported system startup; coordinated commissioning; and developed and designed a Web-based operations and maintenance manual to access project specifications, AutoCAD files and equipment data. The manual's template is used by other consultants to prepare their respective manuals—testimony to the project's client focus.
Janelle Rogers, CDM Smith practice leader, is proud of the precedent-setting results. "This collaborative effort proved to King County that they can have unquestionable confidence in sound construction management to successfully manage one of their largest and most complex projects." Sreibers knows the benefits will have lasting effects. "The success of Brightwater can be applied to similar future projects, helping us fulfill our commitment to deliver reliable, high-quality wastewater services to King and Snohomish counties."