Water utilities and project engineers discuss the good and bad of past projects to help others looking at the same type of work


Dave Duprey was ready to learn on Monday. As the NASTT & ISTT International No-Dig Show kicked off in Washington, D.C., he came with questions and wanted to spend the week learning as much as he could.

“The utility I work for is planning some pipe rehabilitation projects in the near future and this the best place possible to learn about some techniques that were used in other projects and what we can learn from those,” Duprey says. “It’s going to be a busy few days, but it’ll be productive.”

Duprey was attending an education session Monday afternoon in which the city of Folsom, California, and HydroScience Engineers representatives talked about a large-diameter water pipeline rehabilitation project taking place in their community.

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Folsom’s Willow Hill Pipeline Rehabilitation Project focused on about 4 miles of 30-, 42- and 48-inch-diameter pipes constructed in segments over the last 40 years. The existing pipeline exhibited deterioration of varying degrees and leakage losses totaling 1 million gallons per day.

“We’re hoping the lessons we’ve learned on this project can help those looking at similar projects,” says Todd Eising, with the city of Folsom environmental and water resources department.

Kennedy/Jenks Consultants and HydroScience Engineers teamed together to provide design services for the city for rehabilitating and realigning the system, broken into two separate segments in order to phase construction.

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The first segment included 7,700 feet of pipeline, of which 5,200 was sliplining rehabilitation using fusible PVC. Construction for the first segment began in 2014 and was completed in late 2015.

Lessons learned from the first phase included rethinking what a reasonable level of design investigation should include for sliplining; important differences between sliplining in dry versus wet environments; impacts of temperature on the pipe fusion process; and identification of critical submittals for constructing a successful project.

Construction of the second segment, including almost 9,000 feet of sliplining rehabilitation using HDPE and FPVC, and 2,400 feet open cut, was wrapped up at the end of 2016.

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The No-Dig Show continues today and Wednesday with exhibition floor hours from noon to 3:30 p.m. on April 11 and 9 a.m. to 12:30 p.m. on April 12.

“It’s going to be a jam-packed week, but I’m ready to take it all in,” Duprey says. “It’s a lot of education. Hopefully we can then use some of it on our project when it gets going later this year.”


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