As Denver Water girds for ongoing drought, recreation at Park County’s Antero Reservoir will cease so the utility can divert water to Jefferson County’s Cheesman Reservoir.
Denver Water said in a statement that Antero Reservoir has “the highest ratio of evaporation to storage of any of Denver Water’s reservoirs,” meaning it loses lots of water to evaporation.
In moving the water to Cheesman, Denver Water aims to prevent about 5,000 acre-feet of water from evaporating. That amount of water is equivalent to what 20,000 single-family households could use in a year.
Sitting at 8,900 feet above sea level, Antero fills a former lake-bed. It has 11 miles of shoreline and covers about 2,300 acres. It is the utility’s farthest upstream reservoir on the South Platte River, sitting west of Hartsel.
Most years, water losses due to evaporation are recovered during the following year’s runoff. But 2026 had low snowpack levels, making it impossible to recover evaporation losses, according to Denver Water.
In part, diverting the water will allow Denver Water to pull less water from west of the Continental Divide and instead rely on the South Platte River Basin.
“A lot of forethought and planning went into our collection system and reservoirs,” said Nathan Elder, manager of water supply for Denver Water, in a statement. “Antero is a drought reservoir, designed to provide water to our customers during a severe drought. Consolidating this water into Cheesman will help us make the most of the water we have.”
Colorado Parks and Wildlife will do what it can to minimize fish deaths. The agency will briefly open the reservoir to recreation before closing it later this year. After fish are relocated, all recreation, including camping, will be halted.
Denver Water last drained Antero to help with a drought in 2002. It was also emptied in 2015 for dam rehab.
Antero will be refilled when the drought eases up.
Timelines and concrete plans will be announced later.
