Rapid City dam ‘was doomed to fail’

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This article was published 12/01/2021 (1784 days ago), so information in it may no longer be current.

The Rapid City dam needs to be completely torn out and replaced.

This, Infrastructure Minister Ron Schuler said, is why it’s a two-year project, minimum.

“It was never really engineered in the first place, because no engineer would put their stamp on that kind of a dam,” he said. “It was basically doomed to fail.”

Schuler spoke to the dam’s shortcomings in response to community outrage about what some consider a long wait to see the dam reinstated.

Rapid City’s dam across the Little Saskatchewan River breached in June as a result of heavy rainfall, when water cut through the earth embankment to its immediate south.

The reservoir the dam typically maintains, which drained when it breached, is necessary for not only the community’s popular beach, but also the wells that approximately 22 households north of the river rely on.

As reported earlier this month, several properties’ wells have already gone dry, resulting in people installing tanks to keep water flowing through their pipes.

Area resident Edie Evans, 85, is one of several of these property owners. She had a 330-gallon tank installed in her garage, which she has refilled every two weeks with water she has trucked in.

Another area resident didn’t have a garage to keep their tank warm, and has already contended with frozen pipes on a couple of occasions.

“Absolutely, we would like everything built yesterday, but that’s probably not the right way to do it,” said Schuler. “What we have to do is ensure that what we put back is to today’s standards … One thing you do not rush is engineering.”

By comparison, Schuler pointed to the provincially-engineered dam at Lake Wahtopanah in Rivers, which was built to withstand a maximum of 10,000 cubic feet per second, but faced 12,000 cf/s last summer.

“It was stressful, but it could withstand that pressure, and the reason is, it was so well engineered,” said Schuler. “They took their time and they built something that could withstand something it was never engineered for.”

Even so, there was some bank erosion around the Rivers dam that Schuler said will be repaired in such a manner that should not happen again.

By comparison, the Rapid City dam, whose origins are unclear and which consists of a few layers of dam built over the years, including wood timber, concrete and steel structures, suffered a “massive fail.”

Another patch on what is already a mess of patchwork is not the way to go, Schuler said, adding that this also applies to the existing fish ladder, which he describes as “nothing more than a glorified pipe.”

The replacement dam and corresponding fish ladder will be engineered to modern standards, with everything involved in the project going through an approvals process with Fisheries and Oceans Canada and Transport Canada.

Although the expected timeline is two years, Schuler said “if there are a lot of complaints on the environmental side, that will slow it down.”

“The point is that we don’t want to keep looking in the rearview mirror. We’re going to build a dam that can stand at least what came at us this past June.”

» tclarke@brandonsun.com

» Twitter: @TylerClarkeMB