February 18, 2002
Last section of new Tolt pipeline installed
by Lisa Allen
Valley View Editor
LAKE FOREST PARKŠEastside and north Seattle communities will soon have a more reliable water supply, thanks to the completion of the new Tolt II, Phase 4 water pipeline.
The final link, a five-foot-long, five-foot-diameter section of pipe, was installed last week by Seattle Public Utilities (SPU) workers in a trench adjacent to the Lake Forest Park Reservoir. The pipeline will begin carrying water in early March.
"We're excited to get the last of the pipeline into the ground," said Dave Garrison, SPU senior engineer. "All we have left to do is to complete final pipe connections for this phase of the project and the pipeline will soon be in service."
Tolt II is a 24-mile-long pipeline that runs parallel to the existing Tolt 1 pipeline, which has been in use since 1962. The old pipeline will be upgraded and will serve as a backup.
Garrison said the new pipeline will enhance the utility's ability to deliver water to more than 400,000 customers.
"By investing in a new water pipeline to serve our customers, we're not only increasing the reliability of our water delivery, but we'll have a backup in case of a system emergency," he said. "Because the old pipeline has been in use all these years, we have never had a chance to do any maintenance."
The pipelines run from the South Fork Tolt Reservoir southeast of Duvall to the Lake Forest Park Reservoir at the north end of Lake Washington. Water coming from the Tolt Reservoir is treated at the new Tolt Filtration Facility, completed just a year ago.
The pipeline is steel, polyethylene tape, epoxy or polyurethane coated, and cement mortar lined. The anticipated flow is 50 million gallons per day.
Much of the construction over the last several years has been visible as the pipeline crossed the Snoqualmie Valley and headed west along Novelty Hill Road.
About one-third of the 1.3 million people served by SPU receive their drinking water from the South Fork Tolt River. The remaining two-thirds of the customers receive their drinking water from the Cedar River, east of North Bend.