Drought claims a Colorado trophy trout lake | Hatch Magazine

The ongoing western drought has claimed perhaps its biggest victim — a trophy trout reservoir in the upper reaches of the South Platte River drainage in Colorado’s fabled South Park. Denver Water announced plans this spring to completely drain Antero Reservoir, moving its water to more efficient reservoirs in the South Platte drainage.

In response, last week, Colorado Parks and Wildlife announced that all trout are now fair game in the high-elevation reservoir just 25 miles south of Fairplay. All bag limits are suspended through May 13 while Denver Water — the powerful water management utility in charge of delivering water to 1.5 million metro area residents — opens up the lake’s dam and sends the water downstream via the South Platte River to other reservoirs where the water is less likely to be lost to evaporation. Antero sits on a vast, open prairie and much of the water it stores simply evaporates into the thin air. In a normal year, water levels in the reservoir are replenished by meltwater from high-mountain winter snowfall.

Downstream reservoirs, like Spinney Mountain, Elevenmile, Cheesman Canyon, and Chatfield will receive Antero’s water (most will make its way to Cheesman, Denver Water says) and hold it for municipal use in the Denver metro area. This is the second time Antero Reservoir has drained due to drought. In 2002, the lake was also drawn down because the state was water-starved. Denver Water planned to drain the lake again in 2013, but a spate of spring rain and snow saved the reservoir and its fish that year. That’s not the case this year, where Colorado’s snowpack is the lowest in recorded history. It’s not likely any amount of late-season snow can change the trajectory for Antero, where, even at about 9,000 feet in elevation, its fate for 2026 is sealed.

The lake is a contender every year for trout anglers seeking catches of big brown, brook, cutthroat, and rainbow trout. The upper South Platte River is among the most targeted waters in the West by fly fishers wishing to test their mettle against sophisticated fish that see a lot of flies over the course of a season. The river is designated as a “quality water” by Colorado Parks and Wildlife, and Antero is an angler favorite. Its shallow waters are nutrient-rich, and fish stocked in the lake grow quickly and they get big, largely by eating a diet of scuds. While the lake is Denver Water property, its fishery is managed by CPW. Since 2020, CPW has stocked about 5.4 million fish in Antero Reservoir, and it sees year-round use — it’s a popular ice-fishing destination in the winter.

“A lot of forethought and planning went into our collection system and reservoirs,” said Nathan Elder, manager of water supply for Denver Water. “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.”

Denver Water also says that draining Antero will reduce the pressure on the other water-storage reservoirs it operates, including those in the upper Colorado River basin that require Denver Water to pump the water through aqueducts over the Continental Divide.

In all, Denver Water operates 17 water storage reservoirs on both sides of the Continental Divide. The lakes include some notable stillwater fisheries, like Dillon Reservoir in Summit County, and Williams Fork Reservoir in Grand County. In all, Denver Water has storage for just over 700,000 acre feet of water when all of its reservoirs are full.

Once all the fish have been harvested or relocated, Denver Water says, the reservoir site will close, and no summer access will be granted. As for when Antero might fill again? Keep an eye on the weather.

“Drought conditions will determine when the reservoir can be refilled,” a Denver Water news release reads.