PARLEY’S CANYON (ABC4 Utah News) – Two major dams in Parley’s Canyon suffered no apparent damage in a magnitude 3.3 earthquake 6 miles from Park City in Lambs Canyon Monday morning.
Both Mountain Dell Dam, a concrete structure finished in 1925 and Little Dell Dam, an earthen structure completed in 1993, hold millions of gallons of water.
Dave Marble is Utah’s Assistant State Engineer for Dam Safety.
“Tremendous amounts of stored water,” Marble said. “I think as all of us have seen in various situations when that water can be released in some way it has a tremendous destructive potential.”
Right after Monday’s quake the Department of Natural Resources, which regulates the dams, told their owner Salt Lake City Public Utilities to inspect them. Deputy Director Jesse Stewart says his people were already on the case.
“They’re going to go up and look for anything that’s abnormal,” Stewart said. “They look for any cracks that might have appeared, any damage to any concrete infrastructure, look for any kind of seepage that might not have been there before.”
A dam failure at Mountain Dell Reservoir would be catastrophic sending water down Parley’s Canyon into Salt Lake City. Luckily the dams withstood the shaking Monday just like they were designed to do.
“The design standards for dam call for it to be designed for what we call the maximum credible earthquake,” Marble said. “Designed to withstand earthquakes in he range of a magnitude 7 to 7 and a half event.”
Stewart says Monday’s seismic event was a good test for his department.
“It gave people a chance to run through our protocols,” Stewart told ABC4 Utah News. “Llooking at not only the dams and infrastructure but…all our major conveyance lines down here in the city, our major reservoirs and pipelines up along the hillside.”
Stewart says that employees of the nearby Parley’s Canyon Water Treatment Plant regularly monitor the condition of both dams.