Seattle and King County to bore 2.7 mile tunnel from Ballard to Wallingford

SEATTLE — The City of Seattle and King County are boring an underground tunnel to collect and hold stormwater and sewage that would normally flow into the Ship Canal.

During heavy Seattle rains the water often exceeds the pipes’ capacity, which often will send untreated sewage and stormwater directly into the Ship Canal.

These types of overflows can harm fish, wildlife, the environment and the public.

In 2018, 84% of the overflows came from the sewers in Crown Hill, Ballard, Fremont, Wallingford, Queen Anne, Downtown and Capitol Hill.

This new tunnel will capture and temporarily store more than 29 million gallons of untreated stormwater until the treatment plant is ready for it.

The tunnel will improve water quality locally by keeping more than 75 million gallons of polluted rainwater and sewage from flowing into the Ship Canal, Salmon Bay and Lake Union.

Crews are busy assembling the new tunnel boring machine in Ballard and the Ship Canal Water Quality Project is looking for a name for the machine.

You can submit naming ideas via Twitter using the hashtag #NameThatTBM or through their online form. Entries are due by March 12.

Ship Canal team members will select their favorites and put them up for a public vote. Voting will take place March 18-24.

Comments on this article