Final piece of Lake Oswego-Tigard pipeline installed
After two years of construction, the last segment of the Lake Oswego-Tigard Water Partnership's 10.5-mile pipeline has been lowered into place
When crews for the Lake Oswego-Tigard Water Partnership lowered an elevated segment of pipe into place over Oswego Creek next to the McVey Avenue bridge last week, it was an historic moment: The pipeline that stretches over 10.5 miles from the Clackamas River to Tigard is now complete.
We reached a really huge milestone last week," said project spokeswoman Katy Fulton, "by installing the final portion of pipeline in Lake Oswego."
This week, crews are continuing to weld the last piece of pipe to its bridge supports over Oswego Creek. Fulton says the next phase of the project will be a pressure test, which has already taken place for most of the pipeline.
When the entire system is completed, it will pump 38 million gallons of raw Clackamas River water per day from an intake facility in Gladstone through a pipeline under the Willamette River to the water treatment center in West Linn. From there, the treated water will be pumped to the Waluga Reservoir, which will supply water to Lake Oswego and the Tigard area via a new pump station.
Testing for the final 15,000-foot segment of pipe between Laurel Street and Iron Mountain Boulevard in Lake Oswego is scheduled to begin next Monday and be completed after a few days. Once those tests are finished, the pipe will be disinfected to prepare it for transporting treated water.
This pipe will be pumping finished or treated water from the treatment plant in West Linn, so they need to disinfect that with chlorine and flush it out, Fulton explained. And then theyll complete a bacteria test. Once that comes back, then the pipeline will be fully placed online.
The disinfection process is fairly speedy; Fulton says the pipe could be online by the end of this month or in early April. Construction will also be wrapping up soon the major work is already finished, but there are a few smaller pieces still on the to-do list.
There will still be some activity over the next month or so for final paving on McVey Avenue where the pipe was installed, and on some other remaining streets, says Fulton. That will all be taken care of in the next month or so, depending on the weather. Theyll be out there as soon as they can.
Other parts of the project are also nearing completion. The new Bonita Pump Station, which was completed last year, will pump water from the Waluga Reservoir to Tigard-area residents; it is currently being tested and has already begun to send some Lake Oswego-Tigard water to residents on Bull Mountain. The water treatment plant in West Linn is also in the process of testing several new components that will increase its capacity, including new water filters that will be brought online in a few months.
By the end of June, the pump station will be pumping water to Tigard, said Fulton, so by this summer, Tigard will be online with the Clackamas River, and that will be their new water source.
The finished system represents more than two years of construction work. The upgrades to the West Linn treatment plant began in late 2013, while construction of the pipeline started in early 2014. According to Fulton, three different contractors were hired for different segments of the pipe between Gladstone and Tigard.
The project has been touted as a way to meet Lake Oswegos future water needs and to provide Tigard with its own direct water source. And it has another benefit: According to Fulton, it will be the most seismically resistant water system in all of Oregon, designed to withstand even a Cascadia Subduction Zone earthquake.
The new large-diameter water pipelines are made mostly from steel, and each of the joints are double-welded, which adds strength to the pipeline, says Fulton. That design is actually based on a similar performance to the large pipelines that survived earthquakes in Japan. And the treatment plant and the new river intake pump station are also seismically resilient.
A few final pieces of the project demolition of the old filters and administrative buildings at the West Linn plant, for example wont be finished until late 2016 or early 2017. But Fulton says the system itself will be online and working at full capacity by July of this year.
The major construction of the pipeline is done, which is a huge milestone for the partnership and for our two cities, says Fulton. So were pretty proud of that achievement, and we appreciate all the patience of the four cities that have endured construction for the last four years.