Background - siting the Brightwater facilities

Following adoption of the Regional Wastewater Services Plan in late 1999, King County began a process to site the Brightwater wastewater treatment facilities to serve portions of King and Snohomish counties (see Service Area Map). This process has been divided into phases, each culminating in a major decision or milestone in the project.

Siting Process - Phase 1

Beginning in the summer of 2000, King County formed an interdisciplinary team to work on the Brightwater siting process.

Searching for Sites. The project team worked to identify land areas that might be suitable for the new facilities. Ninety-five areas were identified using a Geographic Information System (GIS) and an industrial/commercial lands search. These efforts were supplemented through a community nomination process.

Analysis of Constraints. These 95 areas were then analyzed for serious engineering and environmental constraints that would limit the construction or operation of a wastewater treatment facilities. Such constraints included steep slopes, long and narrow site shape, presence of developed parkland, flood zones and other limiting factors. This analysis revealed that approximately 38 of the 95 areas were largely unconstrained.

Creating Policy Site Screening Criteria. Criteria were proposed that were based on project goals, and were developed to select the best candidate sites. The policy site screening criteria were adopted by the King County Council, in February 2001, and would be used to further screen the initial list of sites.

Applying Policy Site Screening Criteria. The team developed a set of detailed evaluation questions to systematically apply the policy criteria and began to gather more information about each of the sites. In this phase this included considerations such as site elevation, documented wetlands, and existing land uses. Based on this analysis, the project team recommended that seven sites be selected for further screening in the siting process.

In May, 2001 the King County Council selected six sites for further consideration and adopted Policy Site Selection Criteria that would be refined and applied in the next screening round.

Siting Process - Phase 2

The second phase of the siting process began in June 2001 following the King County's adoption of six candidate sites, eight marine outfall zones and refined policy site selection criteria. This phase of the process was broadened to evaluate complete "candidate systems" that included a treatment plant site, conveyance facilities (the pipes and pumps that carry wastewater) and a marine outfall.

Applying Policy Site Selection Criteria. Once again a set of detailed evaluation questions were developed as a way of applying the adopted criteria. These were more refined than in the previous phase and more detailed information was gather on each of the sites. Usable site area, total conveyance length, legal restrictions on title, Endangered Species Act compliance, wetlands and other factors were considered.

The project team found that four candidate systems met the site selection criteria and were found to be suitable for further consideration. After considering these four systems, King County Executive Ron Sims found that two of the systems offered significant opportunities that could benefit surrounding communities and further regional goals addressing efficient use of urban land, provisions for multi-modal transportation options, revitalization of land, and the balancing of urban land uses with environmental protection.

Based on the recommendation of the Executive, the County Council selected two candidate systems - including conveyance options and four marine outfall zones - continue on into the environmental review process. These are Unocal and Route 9 systems.

Environmental Review

King County conducted a formal environmental review of the Brightwater project under the State Environmental Policy Act (SEPA), to inform decision makers and the public about the probable significant adverse environmental impacts and potential mitigation measures for the proposed project.

On November 19, 2003, a Final Environmental Impact Statement (Final EIS) was issued for this project. See Environmental Review section for more details.

Project siting decision

On December 1, 2003, the King County Executive made a decision on the location for the Brightwater Treatment System. This included a wastewater treatment plant at the Route 9 site in unincorporated Snohomish County, a conveyance pipeline along Northeast 195th Street and the King/Snohomish County line, and an outfall in Puget Sound off Point Wells. Refer to the Project Library for siting and environmental documents for this project.