Denver Water plans to drain Antero Reservoir. Here’s what that means for anglers

Antero Reservoir has the highest evaporation-to-storage ratio of any of Denver Water's reservoirs, according to the utility company. The move follows an abysmal snow year for the state. As of April 22, Colorado's snowpack sits at 17% of historic median levels, lower than any other year on record.

"Moving the water to Cheesman Reservoir will prevent about 5,000 acre feet of water (about 25% of the reservoir's storage capacity) from evaporating," Denver Water said in an April 20 press release. 

But the decision to drain the reservoir is likely to hurt recreation in the area. Antero Reservoir is a popular fishing, camping and boating destination. 

Denver Water previously drained the reservoir in 2002 due to drought conditions and again in 2015 to repair the Antero Dam. Water will travel via the South Platte River to reach Cheeseman Reservoir. 

Following the announcement, Colorado Parks and Wildlife authorized an “emergency public fish salvage for the reservoir.” Anglers can take as many fish as they catch until May 13. Anglers must possess a fishing license and continue to follow legal fishing methods. Motor boats and commercial fishing will not be allowed.

“[Antero Reservoir] is a prime resource for us in late spring, early summer when the Arkansas is in runoff stage,” said Stuart Andrews, head guide and backcountry specialist with Ark Anglers,  an outfitter based in Buena Vista. 

Antero Reservoir’s notorious for producing gigantic trout. This year, in particular, had the makings of a bonanza. 

“There was very limited ice fishing on Antero, so there wasn’t a lot of harvesting. The fish were allowed to stay there and grow. We were looking forward to a record year with good numbers and very large fish,” Andrews said. 

On a trip to the reservoir Tuesday, Andrews and his party netted 40 fish. The largest was a seven pound, 27 inch cutthroat trout. 

In most years, Ark Anglers leads 50 to 60 trips to Antero Reservoir. Andrews is currently rebooking trips for clients who planned to visit the reservoir after May 13. Low snowpack could allow outfitters to take clients to alpine lakes or parts of the Arkansas River earlier than usual, he said. 

Certain species, such as Brown Trout, may actually benefit from lower-water levels in the Arkansas River, said Andrews. “The last time we had a drought like this, we saw the fish populations take a huge leap upward both in numbers and quality of the fish.” 

In addition to suspending the number of fish anglers can take, Kyle Battige, CPW senior aquatic biologist said that the organization is “evaluating the feasibility of a CPW-led salvage.” 

The last time Denver Water drained Antero Reservoir in 2015, CPW performed a similar operation to save sport fish. 

As water exits the reservoir, fish are corralled into a narrow spillway. Wildlife officers then use nets to capture and sort fish. In 2015, they transported trout in high-tech fish hatchery trucks to nearby reservoirs in the South Platte River Basin. 

Wildlife officials plan to restore the fishery once the reservoir is filled in the future. But it could take years for fish populations to rebound. 

“When the reservoir is drained, all of that invertebrate life will cease to exist. It takes time for that food chain to regenerate after they refill it,” Andrews said. 

CPW urges anglers who plan to fish Antero Reservoir to thoroughly clean, drain and dry all of their gear before using it in another body of water. The reservoir is positive for New Zealand mud snails, which can survive up to 50 days out of water. 

​​“We're currently on this trajectory of Colorado expanding and growing that…for our water is going to be hard to sustain. I think we can negotiate getting through one or two years like this, but if this were to be a five to 10 year trend I don't know that we've got an accurate estimate of what that would look like,” Andrews said.