DEQ begins work on landmark cleanup project

Contaminated sediment is being removed and put onto a barge to be hauled away. The orange fabric marks the moon pool where sediment curtains drop down to the river bottom to prevent contamination from going outside the removal area.

This week, DEQ began overseeing the cleanup of the last legacy contamination site in Portland’s downtown reach. From the mid-1800s to early 1900s, Portland Gas Manufacturing created the compressed gas that lit the street lamps. Today, the site is occupied by Naito Parkway and Tom McCall Waterfront Park between the Burnside and Steel Bridges.

NW Natural, which is responsible for the cleanup, entered the site into DEQ’s voluntary cleanup program in 2008. Since then, NW Natural has been working with DEQ to assess the extent of contamination, evaluate risk, create a cleanup plan and engineer how to remove the contaminated material. The cleanup will cost NW Natural $8 million.

“This really is an exciting moment,” said DEQ Project Manager Dan Hafley. “It’s the last significant cleanup on this part of the Willamette River and DEQ is using some new technology to ensure protection of humans and the environment during the cleanup.”

The project requires dredging contaminated sediment out of the river, hauling it away by barge and replacing it with clean fill combined with activated carbon to promote natural remediation of remaining contamination. During the dredging, NW Natural is using a system called a moon pool — a type of curtain that drops down to the bottom of the river around where the dredging will occur. As the contaminated sediment is dredged, the moon pool keeps the contaminated sediment from leaving the area. This is the first time such a device has been used on the Willamette River.

The work will take place between July and October. This time of year is called the “in-water work window.” It is the best time to do this kind of work because migrating fish, like salmon, won’t be in the area, and the river tends to be shallower and calmer since there is less rain.

To keep up with the latest news about this cleanup, you can follow along on the project webpage here. OPB and KGW have also covered this story.

– Lauren Wirtis, public affairs specialist

Published by Oregon Department of Environmental Quality

DEQ’s mission is to be a leader in restoring, maintaining and enhancing the quality of Oregon’s air, land and water.

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