PWB wants earthquake-safe pipe beneath Willamette

Proposed pipe would cost $57 million -- or more

The Willamette River at Portland's South Waterfront, Sept. 16, 2015 (KOIN)
The Willamette River at Portland's South Waterfront, Sept. 16, 2015 (KOIN)

PORTLAND, Ore. (KOIN) — If an earthquake hits the Portland area, residents on the west side of the Willamette River would likely be without water for up to 6 months.

The worst case scenario is 6 water pipes — including the 2 on the Ross Island Bridge and 2 under the Willamette that serve downtown Portland and the Washington Park reservoirs — would likely be in shambles.

That’s why the Portland Water Bureau wants to spend $57 million on a new pipe that would go deep below the water just north of the Marquam Bridge. The bureau admitted that price may rise.

“Our various crossings we have right now that feed the west side across the Willamette River are not likely to survive an earthquake,” said PWB Director Michael Stuhr.

Chief engineer Teresa Elliott said, “None of those have been designed for earthquakes. They’ve all been designed prior to us knowing we had an earthquake risk.”

The bureau wants the Portland City Council to sign off on an expensive solution: a new 42-inch diameter pipe buried 80 feet deep beneath any liquefiable soils below the Willamette River, crossing east to west just north of the Marquam Bridge.

A Portland Water Bureau graphic on their proposed plan to build a 42-inch pipe beneath the Willamette River (PWB)
A Portland Water Bureau graphic on their proposed plan to build a 42-inch pipe beneath the Willamette River (PWB)

Among those that could be left without water after an earthquake are 3 major hospital complexes and the entire downtown core.

“There are some 130,000 Portlanders who live on the west side of the river and we also supply wholesale contractors on the west side of the river,” Stuhr said. “So this project is extremely important.”

But city officials have a low level of confidence in the $57 million estimate and believe the price could go up.

“We desperately need to be able to provide water on the west side of the river and that is the purpose of this project,” said Stuhr.

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