115-Year-Old LaPrele Dam Close To Failure, Will Be Breached

A huge crack was found in the 115-year-old LaPrele Dam upstream from Douglas, Wyoming, and state officials have decided to preemptively breach the dam.

Wyoming State Engineer Brandon Gebhart issued an order to breach the dam to probably happen sometime before the spring 2025 runoff season, according to Gov. Mark Gordon’s office.

The Wyoming Legislature during its upcoming 2025 session will be scrambling to decide the next steps for the dam, which has been a concern for years, two legislators told Cowboy State Daily.

It’s not certain whether the dam will be breached and then rebuilt or replaced entirely.

The reservoir behind the dam has been preemptively drawn down, so there’s no immediate danger to people downstream, Gebhart said in the statement from Gordon’s office.

If the dam collapsed on its own with a full pool behind it, the resulting deluge would cause catastrophic damage to downstream homes, a key bridge along Interstate 25 and the Ayers Natural Bridge Park.

Will It Be Replaced?

The LaPrele Dam being breached, and then possibly replaced, is a matter of public safety as well as ensuring a water supply for farmers in the area to irrigate their crops, said state Sen. Cheri Steinmetz, R-Lingle.

“We’ve been working on replacing this dam for years, but we’ve been running into so much federal bureaucracy,” said Steinmetz, who co-chairs the Legislature’s Select Water Committee.

“We’re committed to getting that dam rebuilt as soon as possible,” she added.

There will also be the matter of water rights and other effects of the breaching to deal with, said Sen. Brian Boner, R-Douglas.

Roughly 1,000 people will be affected by the dam’s breaching, he said.

“There’s going to be huge natural consequences of not having that water retained in that area anymore,” Boner said.

The dam helps control the flow of runoff in the area, Steinmetz said.

Without a dam there, natural runoff will cause problems, although “maybe not the surge you’d see if the dam burst,” she said.

Too Risky To Keep

It’s too risky to try squeezing any more use out of the dam, according to Gebhart.

“This dam has significant structural deficiencies and has exceeded its useful life,” Gebhart said.

Recent inspections revealed a “large, new crack above the dam’s outlet works,” according to Gordon’s office.

“I want to commend the state engineer and his staff for recognizing the significant risks of a potential dam failure and proactively addressing them before a disaster occurred,” Gordon stated. “This decision was not made lightly, and we recognize the impact this will have on those who rely on that water for irrigation.”

The dam was built in 1909, and was originally intended to have a 50-year lifespan.

Contact Mark Heinz at mark@cowboystatedaily.com

Mark Heinz can be reached at mark@cowboystatedaily.com.