Seattle Public Utilities Mami Hara, General Manager/CEO

North Queen Anne Ship Canal Water Quality

NQAShipCanal

The north Queen Anne site for the Ship Canal Water Quality Project.

What & Why

Seattle Public Utilities (SPU) and King County’s Ship Canal Water Quality Project is a 2.7-mile, approximately 14-18-foot diameter tunnel that will capture and temporarily hold more than 15 million gallons of stormwater mixed with some sewage during heavy rains. When the storm passes, flows will be sent to King County’s West Point Wastewater Treatment Plant in Magnolia.

The Ship Canal Water Quality Project includes the following activities in north Queen Anne:

  • Building a new microtunnel under the Ship Canal to convey polluted stormwater and sewage to the storage tunnel
  • Building a drop shaft to direct flows down into the microtunnel
  • Installing new pipes to convey polluted stormwater and sewage to the drop shaft

What’s happening now?

Elements of the Ship Canal Water Quality Project in Queen Anne are currently in the design phase. Construction is expected in 2019.

Project goals and benefits

Once complete, the Ship Canal Water Quality project will prevent 60 million gallons of raw sewage and polluted stormwater from flowing into Lake Union, the Ship Canal, and Salmon Bay each year.