Water Pipeline

Installing 3,900 ft. of pipe under the Willamette River
Installing the final piece of 10.5 miles of pipe on McVey Avenue
Cutting a piece of pipe on Highway 43

Facility Overview

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As part of the project, a new, larger water pipeline was constructed to replace the aging and undersized 45 year old pipeline, which is the backbone of the water system. The new pipeline is designed to provide over 75 years of continuous service. Water collected from the Clackamas River travels through approximately 10.5 miles of large diameter transmission pipe from Gladstone, under the Willamette River, to the water treatment plant in West Linn, and then onto reservoirs and pump stations through Lake Oswego to Tigard. 

The new, large-diameter water pipeline was constructed from steel with double welded joints to provide added strength. This improved design is based on the performance of similar large pipelines that survived earthquakes in Japan.

Much of the steel pipe was assembled right here in Oregon at a local company, watch this video to learn more.


It took over two years to construct the pipeline from Gladstone to Tigard and three different contractors. Pipe was installed under the roadway from the river intake pump station, through Gladstone, across 99E and through Meldrum Bar Park. A 3,900 foot segment of 36-inch pipe was tunneled under the Willamette River, emerging at the end of Mapleton Drive, just north of Mary S. Young State Park. From there, a new pipeline travels up Mapleton Drive to the Water Treatment Plant. This section of pipeline carries raw (untreated) water for treatment and disinfection at the plant. An emergency intertie provides drinking water from the plant to the West Linn community in an emergency.

The finished water pipe is the portion of pipe that carries treated (clean) drinking water from the Water Treatment Plant to customers in Lake Oswego and Tigard. The newly installed pipeline runs from the treatment plant, north along Highway 43, through Lake Oswego to the Waluga Reservoirs near Waluga Park - almost eight miles of new finished water pipe. The new pipe provides increased system reliability because the pipeline is stronger and able to withstand a large earthquake. The Partnership also installed a new, 24-inch diameter pipe under I-5 and along Bonita Road to the new pump station on Milton Court in Tigard. This new pipeline connects the pump station to existing pipelines in Tigard. 

More information:

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