Brightwater treatment system
Completed – Fall 2012
In response to increased growth in our region, King County has built a new $1.86 billion regional wastewater treatment system called Brightwater to serve the northern portion of the King County service area. Treatment plant operations began in September 2011. The conveyance system and outfall began full operations in fall 2012.
The new facilities include:
- The Brightwater Wastewater Treatment Plant is located in unincorporated Snohomish County, north of Woodinville. The plant is designed to have the capacity to treat an average of 36 million gallons of wastewater per day (mgd). By 2040, treatment capacity could be expanded to 54 million mgd.
- The conveyance system is the tunnels, pipes, and other facilities that carry wastewater to and from the treatment plant. The Brightwater system includes 13 miles of pipeline built in underground tunnels, shallower connector pipes, and an influent pump station to send wastewater to the plant.
- The marine outfall consists of twin, 5-foot-diameter pipes with a diffuser at the end where highly treated wastewater from the Brightwater Treatment Plant is discharged into Puget Sound. The mile-long, 600-foot-deep outfall extends off of Point Wells.
Background – siting the Brightwater facilities
Beginning in the summer of 2000, the County began searching for and analyzing sites. In May, 2001 the King County Council selected six sites and eight marine outfall sites for further evaluated as “systems” (including a plant site, conveyance system and outfall).
In June 2001, the county began a second round of evaluation. Based on this, the County Council selected two systems–including conveyance options and four marine outfall zones–to continue on into the environmental review process.
King County conducted a formal environmental review of the Brightwater project under the State Environmental Policy Act (SEPA). On November 19, 2003, a Final Environmental Impact Statement (Final EIS) was issued for this project.
Project siting decision
On December 1, 2003, the King County Executive made a decision on the location for the Brightwater treatment system .
On July 27, 2005 the King County Executive reaffirmed his earlier selection of the Route 9 - 195th St system alternative for the Brightwater project. To learn more, download the Regional Wastewater Services Plan: summary of the Executive's process to update the Brightwater system siting decision, July 2005 .
In December 2005, King County completed a systemwide mitigation package .
The following links point to DNRP Vimeo videos.
24 hour emergency and odor reporting:
Contact Brightwater Treatment Plant at 206-263-9500.
Brightwater plant test (May 2011)
Video length: 17 seconds
Installation of membrane bioreactor filters (MBRs) at the treatment plant (April 2011)
Video length: 2 minutes, 32 seconds
Earth week at Brightwater Center
Video length: 2 minutes, 4 seconds
Smooth sailing for Brightwater outfall pipelines (September 2008)
Part 1 – the first outfall pipeline was submerged on September 10, 2008
Part 2 – the second outfall pipeline was submerged on September 12, 2008
Brightwater Treatment Plant introduces tunneling equipment (September 2007)
Video length: 1 minute, 46 seconds
Take a tour of the Brightwater habitat restoration (April 2007)
Video length: 4 minute, 16 seconds
Background – environmental review
King County conducted a formal environmental review of the Brightwater project under the State Environmental Policy Act (SEPA). This review evaluated wastewater system alternatives in an environmental impact statement (EIS).
The purpose of an EIS is 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 the county issued a Final Environmental Impact Statement (Final EIS) for this project. The county also issued five addenda to the EIS to provide additional information or analysis that does not substantially change the analysis of significant impacts and alternatives in the Final EIS.
- A Draft Supplemental EIS was issued on April 11, 2005. This provided new information and its relationship to the Brightwater Treatment Plant site and evaluated the significant adverse environmental impacts that could result if an earthquake were to occur on the Southern Whidbey Island Fault and damage treatment plant facilities. A Final Supplemental EIS was issued July 19, 2005, and includes comments received and responses to these comments.
- On July 27, 2005 the King County Executive reaffirmed the county's choice of the Route 9 treatment plant and 195th St conveyance alternative for the Brightwater project . A notice of action was issued for this action on August 11, 2005.
- On October 2, 2006 the Court of Appeals issued a decision agreeing with King County regarding preparation of a Supplemental Environmental Impact Statement (SEIS). The Court's decision directed the superior court to prohibit the hearing examiner from conducting an appeal of the adequacy of the SEIS that was filed on the project.
King County's Department of Natural Resources has prepared this Final Environmental Impact Statement (Final EIS) on the Brightwater Regional Wastewater Treatment System. The Final EIS provides information and evaluation of the probable significant adverse environmental impacts of the Brightwater proposal and identify alternatives and reasonable mitigation measures.
What is included in the Final EIS
The first three chapters (included in Volume 1) contain a project description, comparison of alternatives, background, and summary of impacts and mitigation measures. The comparison of alternatives highlights key environmental issues and options. Impact comparison tables are located in Chapter 3.
Additional chapters 4-17 (in Volumes 2 and 3) sets forth this analysis in greater detail. Following Chapter 17, you will find a glossary, distribution list, and the summary of the Brightwater Summer 2003 technical seminars. Five addenda to the Final EIS have also been issued.
The remaining volumes include appendices that provide background and technical information for corresponding chapters in the Final EIS (in Volumes 4-10), Draft EIS comments and responses (in Volumes 11-15) and comments from the Summer 2003 technical seminars (Volume 16).
You can download and view documents (PDF files) using a PDF Reader.
Final Environmental Impact Statement (EIS) Table of contents
- Final EIS errata, November 26, 2003 (346KB)
- Cover letter, November 19, 2003 (126KB)
- Foreword (47KB)
- Fact sheet (89KB)
- Acronyms (37KB)
- Table of contents, includes list of tables and list of figures (263KB)
- Map of system alternatives (632KB)
- Chapter 1. Summary (1.5MB)
- Chapter 2. Background (2.3MB)
- Chapter 3. Description and comparison of alternatives (8.7MB)
- Chapter 4. Earth (3.1MB)
- Chapter 5. Air (1.7MB)
- Chapter 6. Water resources (3.7MB)
- Chapter 7. Plants, animals, and wetlands (8.6MB)
- Chapter 8. Energy and natural resources (1.1MB)
- Chapter 9. Environmental health (1.2MB)
- Chapter 10. Noise and vibration (1.8MB)
- Chapter 11. Land and shoreline use (2.3MB)
- Chapter 12. Aesthetics (5.8MB)
- Chapter 13. Light and glare (1.6MB)
- Chapter 14. Recreation (1.6MB)
- Chapter 15. Cultural resources (1.6MB)
- Chapter 16. Transportation (4.8MB)
- Chapter 17. Public services and utilities (2.5MB)
- Glossary (124KB)
- Distribution list (35KB)
- Summary of Brightwater Summer 2003 technical seminars (2.1MB)
Appendices for chapter 2, background
- 2-A. Population and flow analysis (5.4MB)
- 2-B. Portal screening level 1 and 2 documentation (37MB)
- 2-C. Portal 19 screening level 3 documentation (2.5MB)
- 2-D. Peer review of scientific investigations conducted for phases I, II, and III of the marine outfall siting study (1.5MB)
Appendices for chapter 3, description and comparison of alternatives
- 3-A. Project description: treatment plant (11MB)
- 3-B. Project description: conveyance (51MB)
- 3-C. Project description: outfall (26MB)
- 3-D. Reclaimed water technology review and evaluation of potential water reuse opportunities (25MB)
- 3-E. Flow management and safety relief point (3.5MB)
- 3-F. Nearshore alignment and construction methods alternatives (52MB)
- 3-G. Construction approach and schedule (1.4MB)
- 3-H. Diffuser predesign (19MB)
- 3-I. Proposed routine monitoring plan for the receiving environment in the vicinity of the Brightwater treatment system marine outfall (0.6MB)
- 3-J. Evaluation of the no action alternative (17MB)
- 3-K. Treatment plant disinfection alternatives (2.4MB)
- 3-L. Preliminary working draft facilities plan (25MB)
Appendices for chapter 4, Earth
- 4-A. Geotechnical data report for proposed route 9 treatment plant site (17MB)
- 4-B. Geotechnical progress report: conveyance (3MB)
- 4-C. Outfall geophysical surveys (5.3MB)
- 4-D. Phase I environmental site assessment-route 9 parcels (15MB)
Appendices for chapter 5, air
- 5-A. Odor and air quality: treatment plant (1.6MB)
- 5-B. Odor analysis: conveyance (0.7MB)
- 5-C. Construction-related air quality impacts: conveyance (1.8MB)
Appendices for chapter 6, water resources
- 6-A. Affected environment: surface water (2.6MB)
- 6-B. Geology and groundwater (20.9MB)
- 6-C. Management of water quality during construction at the treatment plant sites (0.5MB)
- 6-D. Permanent stormwater management at the treatment plant sites (7.9MB)
- 6-E. Route 9 site runoff effects on the geomorphology of Little Bear Creek (23MB)
- 6-F. Groundwater and stormwater management at the candidate portal sites (0.6MB)
- 6-G. Assessment of buoyant materials and the microlayer (5.8MB)
- 6-H. Predesign initial dilution assessment (2.8MB)
- 6-I. Effluent quality evaluation for the membrane bioreactor and advanced primary system (2MB)
- 6-J. Summer season temperature effects of stormwater ponds on receiving streams (0.5MB)
Appendices for chapter 7, plants, animals, and wetlands
- 7-A. Affected environment: plants and animals (1MB)
- 7-B. Route 9 site sensitive areas technical report (13MB)
- 7-C. Unocal site sensitive areas technical report (16MB)
- 7-D. Assessment of potential influence of Brightwater discharges on harmful algal blooms in Puget Sound (1MB)
- 7-E. Eelgrass monitoring survey plan for the Brightwater marine outfall alternatives (1.5MB)
- 7-F. Eelgrass Survey Results for the Brightwater Marine Outfall Alternatives (15.8MB)
Appendices for chapter 10, noise and vibration
Appendices for chapter 11, land and shoreline use
Appendices for chapter 13, light and glare
- 13-A. Illumination modeling of Route 9 and unocal treatment plants (25MB)
- 13-B. Light and glare: conveyance (2.5MB)
Appendices for chapter 15, cultural resources
Appendices for chapter 16, transportation
- Volume 11. Federal agencies, state agencies, Native American tribes, Snohomish County (40.6MB)
- Volume 12. Cities and towns, sewer and water districts, other governmental entities (71.4MB)
- Volume 13. Groups, organizations, and businesses (82.9MB)
- Volume 14. Individuals: A-H (55.4MB)
- Volume 15. Individuals: I-Z (67.8MB)
Addendum no. 5 and final supplemental EIS addendum no. 2, issued January 3, 2007 (60 KB)
This addendum reports on the results of seismic trenching on the Brightwater Treatment Plant site in the summer of 2006 and the approach to seismic design on the site. The report and memo referenced in the addendum are available here.
Addendum no. 4, issued September 1, 2004 (317 KB)
Provides additional information on and/or evaluation of the impacts of constructing and operating:
- The influent pump station at portal 41;
- facilities along the conveyance corridor; and
- the safety relief point at a location 200 ft west of the location identified in the final EIS.
Addendum no. 3, issued April 30, 2004 (3.9 MB)
Provides the following:
- an updated evaluation of aeromagnetic and LiDAR imagery for the postulated onshore extension of the South Whidbey Island fault
- a review of boring data and a seismic refraction survey at the Route 9 site
- an analysis of ground motion studies at the Route 9 site
- a description of geotechnical data that will be used for design of the conveyance system and outfall
- additional discussion of the final EIS worst-case analysis of impacts and mitigation measures associated with major seismic events
Addendum no. 2, issued April 2, 2004. (3.7 MB KB)
Provides the following:
- Identifies selected portal sites
- Provides information and analysis of the impacts of using trucks, barge, or rail for transporting excavated materials away from the portal 19 site at the Chevron-Texaco Richmond Beach asphalt terminal.
- Describes and analyzes the impacts of a proposed temporary construction access road at the southern end of the Route 9 site and installation of a traffic signal at the SR-9/SR-522 Westbound ramp intersection to reduce construction-related traffic along SR-9 north of SR-522
- Provides more information and analysis of impacts of demolition and construction on the Route 9 site, particularly in relation to the StockPot Culinary campus
Addendum 1, issued January 27, 2004. (288 KB)
Provides the following:
- an updated analysis of traffic impacts and mitigation measures using alternative assumptions related to background traffic growth rates for the eastern portion of the project area
- additional information about potential improvements to and use of the existing barge dock at the Chevron Richmond Beach asphalt terminal for transporting materials and spoils during construction of the conveyance pipeline and the marine outfall at Point Wells
King County prepared this final supplemental Environmental Impact Statement (final Supplemental EIS) on the Brightwater regional wastewater treatment system. The final supplemental EIS is a supplement to the final EIS issued in November 2003.
A 16-page summary (2 MG) of the final supplemental EIS is also available.
The final supplemental EIS includes:
- comments made on the draft supplemental EIS and responses to comments
- changes made to pages in the draft supplemental EIS, organized by chapter and appendix
- updated cover letter, foreword, fact sheet, acronyms and abbreviations, glossary, and distribution list; and errata sheet
- the two-volume draft supplemental EIS, issued April 11, 2005
Final supplemental EIS
Cover letter (32KB)
Fact sheet (67KB)
Acronyms and abbreviations (19KB)
Table of contents (20KB)
Summary responses to comments (220KB)
Individual responses to comments (22.4MG)
Government agencies, organizations, individuals
Changes in the supplemental EIS text made in response to comments (5.6MG)
Appendix G (added)
Distribution List (28KB)
The May 4, 2005, public hearing transcript (56KB)
Draft supplemental EIS, issued April 11, 2005
Cover letter (26KB)
Fact sheet (60KB)
Chapter 1 – Introduction (1.74MB)
Chapter 2 – Seismic background and context (1.3MB)Chapter 3 – Design of the Brightwater Treatment Plant (2.22MB)
Chapter 4 – Worst-case earthquake scenarios assumed in the impacts analysis (1.41MB)
Chapter 5 – Environmental impacts if a major earthquake were to damage Brightwater facilities and mitigation of impacts (1.0MB)
Scenario tables (79KB)
Distribution list (31KB)
Draft supplemental EIS appendices (note large file sizes)
Appendix A – Surface-fault-rupture hazard evaluation (14.2MB)
Appendix B – Revised probabilistic seismic hazard analyses (3.8MB)
Appendix C – Building code regulations and seismic studies used in the structural design of the Brightwater facilities (108KB)
Appendix D – Emergency overflow surface water impacts analysis (343KB)
Appendix E – Analysis of flooding and water quality effects in Little Bear Creek following a major earthquake (2.1MB)
Appendix F – Brightwater SEPA supplement groundwater evaluation (5.8MB)
Note: though not issued as part of the draft supplemental EIS, an appendix G has been added – see above under: "Changes in the supplemental EIS text made in response to comments"
Seismic and geologic studies
Treatment plant – approach to seismic design. CH2M Hill, Brown and Caldwell, Mithun. Oct. 9, 2006 (235 KB)
Note: this memo has been updated and the updated version, above, was posted on this web site on Jan. 8, 2007. Changes have been made on the following pages:
- Pg 1: New engineering stamps and signatures have been provided
- Pg 5: "Snohomish PUD substation" has been added to seismic use group III in table 1
- Pg 6: The first sentence regarding the peak level of ground shaking has been revised.
In addition, a footer has been added to the updated document. Otherwise, the remainder of the document is unchanged.
This report and memo are referenced in Brightwater final EIS addendum no. 5 and final supplemental EIS addendum no. 2, issued January 3, 2007
Chemical building seismic trenches, Brightwater Wastewater Treatment Plant site, Oct. 19, 2006, pages 1-27 (225 KB)
Report figures, pages 28-59 (5.5 MB)
Appendix A - Trenching investigations of the proposed buildings (3.4 MB)
Appendix B - Radiocarbon dating results (75 KB)
Appendix C - Liquefaction article (4.5 MB)
Appendix D - Comments relevant to USGS site visit report, July 6, 2006 (102 KB)
Appendix E - Comments relevant to Dr. Yeats’ e-mail letter, transmitted July 12, 2006 (38 KB)
Appendix F - Responses to report of August 21, 2006 by Earth Consultants International (411 KB)