Denver Water to Empty Massive Reservoir to Save Millions of Gallons from Evaporation
Denver Water has announced plans to transfer water from Antero Reservoir to Cheesman Reservoir as part of a drought response effort driven by historically low snowpack levels across Colorado.
The move is expected to preserve roughly 5,000 acre-feet of water, about 25% of Antero’s total storage capacity, that would otherwise be lost to evaporation. To put that in perspective, one acre-foot supplies the annual water needs of three to four average households. Antero carries the highest evaporation-to-storage ratio of any reservoir in Denver Water’s system, making it particularly vulnerable during dry years.
“A lot of forethought and planning went into our collection system and reservoirs. 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.” – Nathan Elder, manager of water supply for Denver Water.
The transfer also gives the utility more flexibility to draw from South Platte River Basin supplies, easing pressure on sources west of the Continental Divide that are also running below normal following what officials described as an abysmal snowpack and runoff season. In a typical year, evaporative losses are replenished by the following runoff season. That recovery is not expected in 2026.
Denver Water is coordinating with Colorado Parks and Wildlife to relocate fish before the reservoir closes. The public will have a brief window to access Antero before it shuts down, after which no recreation or camping will be permitted for the remainder of 2026.
Drought conditions will dictate when, or whether, the reservoir can be refilled. Antero was previously drained during the 2002 drought and was emptied again in 2015 for dam rehabilitation. A planned drainage in 2013 was avoided only after late-season snowstorms provided relief.
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