Williams Northwest Pipeline, of Salt Lake City, is replacing nearly 4,000 linear feet of a natural gas transmission pipeline it owns in a hilly residential area west of Whitworth University.

The company recently awarded a $1.7 million contract to Snelson Cos., a Sedro-Woolley, Wash.-based pipeline contractor, to do the work, and is supplying Snelson with the 16-inch diameter pipe needed for the project.

Lori Dalton, a project manager with Williams, says the company will pay for the work out of its maintenance budget. She declines to disclose the total cost of the project.

The section of pipeline being replaced is along the northeast slope of Five Mile Prairie and passes beneath North Five Mile Road and several residential streets south of there.

Initial work began at the site on July 8. The new pipeline is scheduled to be connected on Aug. 27, and landscape replacement above the pipeline will begin after Sept. 15, says Dalton. About 28 landowners were contacted to inform them of impacts from the project, including landscape disruption and street and road closures. No one will have their natural gas delivery disrupted as a result of the project, Dalton says. A preliminary schedule for street and road closures is posted at www.northwestreplacementproject.com, and will be updated as needed.

Todd Knapp, a spokesman for Snelson, says it is replacing the pipe, which was laid in 1956, with a higher-grade pipe in the same trench. Snelson has worked for Williams for years on various pipeline projects, Knapp says.

Snelson is bringing about 20 workers to the project, and will hire an additional 20 here, Knapp says.

Michele Swaner, a spokeswoman for Williams, says a natural-gas pipeline normally lasts about 50 years. She says the company uses an electronic tool called a "pig" to inspect the insides of pipelines. If the pig locates stresses on sections of the pipe, such as pits or dents, the company replaces those sections.

Williams operates three interstate natural-gas transmission pipelines in the U.S.—the Northwest Pipeline, the Transco Pipeline, and the Gulfstream Pipeline—comprising about 15,000 miles of pipe, about 1,300 miles of that in Washington state.

Northwest Pipeline has its office in Salt Lake City, and its major markets are Seattle and Portland. Transco Pipeline serves New York City, the Mid-Atlantic region, and Atlanta, and has its headquarters in Houston. The Gulfstream Pipeline primarily serves Florida, and has an office in Tampa,

The company estimates it provides 12 percent of the natural gas consumed in the U.S., and its Northwest Pipeline delivers about 89 percent of the natural gas consumed in Washington state.

It says the natural gas transported via its pipelines is delivered to local distribution companies, marketers, producers, electric generators, and various industrial users. Puget Sound Energy, Avista Corp., and Cascade Natural Gas are three of its largest customers in Washington state, it says.