On a cold, windy, Tuesday morning, engineers, contractors and leaders stood in front of the culmination of a quarter of a billion dollars and three years of work. The theme of the May 19th ribbon-cutting ceremony was “partnership;” officials from the Army Corps of Engineers and Barnard Construction, alongside local leaders, expressed gratitude for a successful collaboration aimed at protecting lives and properties in Jamestown.
Sam Sobczyk, co-lead engineer for USACE, said that upon completion of the project, he was most proud of the partnership. “Everybody united very quickly behind the goal of delivering this project. It was special,” he said.
The Army Corps of Engineers Omaha District and a large team of contractors from Barnard Construction completed a project that officials say fortified the dam’s spillway, and ensures Jamestown, 4 miles downstream, will be protected against a “100 year” flooding event. Pipestem Dam was built in the early 1970s in reaction to a 1969 flood that devastated Jamestown. Though the spillway has never been used since its completion, the potential for a dam breach was brought to the attention of the Corps in 2009. If the dam were to fail, Omaha District’s Makenzie Leonard says that “potential property damage resulting from a failure of Pipestem Dam is estimated at more than $450 million.”
The 2009 flooding that occurred at Cottonwood Creek Dam near Lamoure showed that a dam with a similar spillway to Pipestem would experience severe erosion in the case of a flood. Andrew Barry, chief of the Dam and Levee Safety branch at the Corps, explained that the geology of Pipestem and Cottonwood is similar, and that the original 70s design of the dam made an assumption about erosion rates that was decidedly not accurate. “We needed to do something to prevent any erosion similar to [the Cottonwood flooding] from happening here, which would cause a surge of water to go through the town of Jamestown,” Barry explained.
Jamestown Mayor Heinrich said that the spillway modification project is like an insurance policy that you hope you never have to use.
Omaha District’s commander, Col. Robert Newbauer, said that “we can proudly say that we’ve delivered on our commitments to reduce the flood risk here in Jamestown, North Dakota. It’s also a shining example of our dam safety program. It represents our pledge to deliver modern, effective, engineering solutions that reduce risk and protect communities.”
The project didn’t come without challenges. “Probably the biggest challenge we had was last year; we had a slide that occurred on the right side of the spillway… We thought it would have extended the construction period another year, or increased the cost. We got together with the Barnard engineering team, pulled people in from all over the nation within the Corps to get together and come up with a solution,” Barry said. “That was probably one of the best partnering examples that you could have.”
Despite these improvements, flooding can still occur, and experts advise flood preparation is still necessary. In the case of high water levels in the reservoir during flooding conditions, Pipestem Dam has always been designed to release a controlled amount of water, 110,000 cubic feet of water per second, to preserve dam integrity. Though the amount of water the dam can support and release has not changed, the risk of the dam failing due to spillway erosion has significantly reduced.
“This project provides a lot of resilience to the dam,” he said, “in the event of a flow event, we’re confident in its operation,” Sobczyk said.
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