#Runoff news: Efforts underway to mitigate Lake City flooding potential from the Hidden Treasure Dam

The historic Hidden Treasure Dam above Lake City on Henson Creek will be removed to avoid a surge of debris which could impact the community of Lake City. Efforts will begin immediately. Hidden Treasures Dam owners, the Hurd Family, made the hard decision to remove the dam after it was determined it would likely not survive the high flow spring runoff. The decision was made following analysis conducted by an advisory group which included the Hurd Family as well as representatives from the Bureau of Land Management, Colorado Office of Emergency Management, Hinsdale County, Town of Lake City, Colorado Geological Survey and Colorado Division of Water Resources – Dam Safety. All available options to save this historic structure were considered. The Hidden Treasure Dam dates back to the 1890s when both the Hidden Treasure and Hard Tack mines were in operation. Photo credit: Hinsdale County

From The Summit Daily (Allen Best):

Lake City, which got its name in 1873, during the first flash of the mining boom in the San Juans, has a population of 400 people. Its population swells during summer, when it’s a popular destination for Texans but also mountain climbers. Several 14,000-foot peaks, including Uncompahgre and Wetterhorn, are located nearby, above Henson Creek.

Henson Creek is what concerns Hinsdale County as well as state and other authorities. There were many avalanches during snow season. One left snow and ice 200 to 300 feet deep and a half-mile wide across the creek. The trees, boulders and other debris in the snow create the makings of a dam. Should the dam back up melted snow and then burst, Lake City could be flooded.

“It is a totally different animal if we’re talking about a debris field of logs and trees as opposed to clear water,” explained Michael Davis, public information officer with the Hinsdale Unified Coordination Group.

A masonry dam, called Hidden Treasure, compounds the problem. Created in 1890 to produce electricity, it lost that function long ago. It has a gaping hole in its face, the result of a breach in 1973.

But a half-dozen experts who gathered to study it this past week concluded that trees and other materials could build up behind the dam. They say complete failure of the dam is likely, which could result in a “catastrophic flood surge,” according to the Hinsdale County website. To avert that possibility, the dam is being preemptively destroyed.

High runoff normally occurs by June 10, Davis told the Crested Butte News, but because of the cool spring, that high runoff as of late May was expected to occur on or around June 18. The snow-water equivalent in the snowpack of the Gunnison River Basin, where Lake City is located, was 727 percent of normal as of June 2, according to the SNOTEL measuring sites. Farther south, in the Telluride-Durango area, the same measuring matrix reported 1,174 percent of average.

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