The LaPrele Dam, which stood for 116 years, has been mechanically deconstructed. Engineers, state officials, federal agencies and contractors now turn their focus to the design and construction of a new dam.
Updates
Rod Cross, a member of the board of directors for the LaPrele Irrigation District, and Cory Foreman, a design engineer with engineering and design company HDR, gave a presentation to the Wyoming Water Development Commission on May 7. The event was meant as a workshop to help bring the public, officials and lawmakers on the Select Water Committee up to speed on related projects and infrastructure in the state.
Foreman provided the committee with a recap of the dam demolition. As the LaPrele Irrigation District privately owns the dam, it hired Big Sky Civil Constructors and Montana Civil Contractors for both removal of the old dam and building a new one.
LaPrele Irrigation District signed a contract with the joint venture on Jan. 15 and work began on Jan. 31. Foreman said that the two companies were operating ahead of schedule, reporting to the State Engineer's Office that the work necessary to prevent a “catastrophic dam failure” had been completed on March 28, three days ahead of the original breach-by date set by the State Engineer's Office last year.
Construction equipment and dirt roads now take up a waterway formerly blocked by the century-old LaPrele Dam. However, not all of the dam has been erased. According to Foreman, they've removed “the bulk of the dam,” with some remaining infrastructure, like outlet works, in place to help manage water until the new dam is completed.
In the event of excess spring runoff while no dam is in place, the Converse County Conservation District has installed early warning sensors, and local sheriffs would be notified if waters reached concerning levels.
New dam expected in 2028
If everything goes according to schedule, an operational dam is expected to wrap up in 2028. Foreman and Cross, however, explained the project is still at the point of reviewing construction schedules, holding engineer workshops and working with federal agencies.
“We are finalizing, today, the impact analysis and getting ready to submit an EPA [Environmental Protection Agency] document, hopefully later this month, to the Bureau of Reclamation, which starts about a four-month window between public comment and agency review,” said Foreman.
The Bureau of Reclamation will supplement state funds, pulling $98 million from the Bipartisan Infrastructure Act. That money will be routed to the project through the Wyoming Water Development Office.
Commissioners inquired as to the storage capacity of the new dam, which is expected to match that of the LaPrele Dam's original storage amount at 20,000 acre feet. Another commissioner inquired as to the potential to generate energy from a new dam. Engineers believe the amount of water moving through a future dam wouldn't be enough for consistent power generation.
