HARTSEL, Colo. (AP) – A safety upgrade is underway at Antero Dam in Park County to reduce water pressure and seepage on the dam.
Denver Water, Colorado Parks and Wildlife and the Office of the State Engineer lowered Antero Reservoir by 2 feet in 2011 as a safety precaution. The first phase of the $14 million project beginning Monday will provide a sand trench to filter the normal seepage from the dam to help ensure the safety of the foundation.
Embankment grading and improvements to the spillway should be completed by 2015, and state officials hope the water line at Antero will return to sustainable levels after the spring runoff in April 2016.
The dam is expected to be kept open to recreation, and Colorado Parks and Wildlife will continue to manage the fishery during the project.
Antero Dam was built in 1909 and bought by Denver Water in 1924. The dam has experienced substantial seepage since it was built and as a result, has been operating under reservoir storage restrictions by the state since the early 1900s to ensure public safety.
The state inspects high-hazard dams yearly. Dams that present significant hazard are inspected every other year and low-hazard dams every six years.
The average age of dams across the country is 52 years, with many needing prompt attention, said Keith Ferguson, an engineer with Denver-based HDR One Co. and incoming president of the Association of State Dam Safety Officials.
The American Association of Civil Engineers gives the nation’s dams a letter grade of D overall, the Durango Herald reported on Thursday.
Dam failures have happened before in Colorado.
On Aug. 3, 1933, Castlewood Canyon Dam in Castlewood State Park failed, releasing water into Cherry Creek and flooding Denver 30 miles away. Two people were killed.
On July 15, 1982, Lawn Lake Dam in Rocky Mountain National Park failed and flooded downtown Estes Park. Three people died.
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