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Improvement projects

Find information about construction and improvement projects at Brightwater.

Staff on top of digesters
View of the solids management area of Brightwater looking south.

As we do at all of our wastewater treatment facilities, the Wastewater Treatment Division (WTD) continuously looks for ways to keep Brightwater efficient and reliable. We design and build projects to:

  • Meet updated regulations
  • Save energy
  • Improve water quality
  • Increase capacity for growing communities
  • Improve efficiency and reliability
  • Repair, replace, or upgrade equipment which has come to the end of its life

Inside the treatment plant, projects help us manage today’s wastewater flows in a treatment system built for the future. Many of these projects help conserve energy while maintaining or even increasing performance. Brightwater engineers and operators continuously scan the plant for energy savings.

These projects range in size from small lighting retrofits to large-scale process improvement projects requiring major construction. For example, in 2019 we completed a project to upgrade key components of the existing membrane aeration system. Aeration is necessary to keep the bacteria that processes wastewater thriving.

Currently, there are many projects underway in the treatment plant to save energy and increase efficiency.

Outside the Brightwater facility on King County’s property, you may see projects to maintain landscaping, trails, public art, and more. Environmental projects help us to manage the landscape and meet permit requirements. WTD landscapes like the Brightwater trails area help to filter stormwater and provide wildlife habitat. After we create or restore landscapes, we monitor them and adapt practices as needed.

Projects in the trails area

Alpha Hill Erosion Control Project

Update: Project expected to begin May 2024

Visitors to the Brightwater trails area will see a transformation in Alpha Hill, a large landform that towers over the south trails area. In 2024, King County’s contractor will plant landscaping such as shrubs and trees on the hill and install a rock wall and fencing around the base of the hill. Alpha Hill’s new look will blend in with the trails area outside the fence line and prevent erosion into nearby salmon-bearing streams. Adding vegetation will also provide wildlife habitat and improve drought tolerance.

As a result of this project, Alpha Hill will be permanently closed to public access, including walking, hiking, running, and sledding. Although there are no developed trails up Alpha Hill, informal paths on the steep hillside can inadvertently send dirt into Little Bear Creek, a home to endangered salmon. Our goal is to protect a salmon-bearing stream from the effects of erosion.

We expect construction to begin May 2024 and last approximately three months. To maintain safety for trail users and crews, King County’s contractor needs to temporarily close a section of trail in the south trails area. Visitors should watch for signs and stay on open trails to protect the surrounding landscape.

We welcome visitors to continue visiting the three miles of established trails along the Brightwater property. You can view a map of the Brightwater trails here.

Sign up for Brightwater emails to stay up to date.

Contact Emily Berry at 206-848-0698 or with any questions or concerns.


Past updates:

Soil Sampling on Alpha Hill planned for April 10. No trail disruption expected from this work.

Learn more: