Colorado Parks and Wildlife has asked anglers to voluntarily avoid fishing a portion of the Arkansas River tailwater in Pueblo from noon to midnight daily, beginning Thursday, August 6, as low flows and rising water temperatures create increasingly difficult conditions for trout.

The voluntary closure applies to the Arkansas River from Pueblo Boulevard East downstream to where the river meets Fountain Creek. Cold-water releases from Pueblo Reservoir continue to keep the upper tailwater cool enough for trout, but lower flows and prolonged summer heat cause temperatures to rise quickly in the lower reach.

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Recent monitoring shows how quickly conditions change downstream from Pueblo Reservoir. Near the dam, afternoon water temperatures remained about 65 degrees. Near Dutch Clark, temperatures climbed above 73 degrees, and farther downstream near Moffat, they exceeded 80 degrees during the same afternoon sampling period.

"We're already seeing afternoon water temperatures in the lower reach approach levels where catch-and-release becomes much harder on trout, and their overall health is affected. Giving fish a break during the hottest part of the day can make a meaningful difference while still allowing anglers to enjoy quality fishing during the cooler morning hours," said Carrie Tucker, Colorado Parks and Wildlife aquatic biologist. "We appreciate anglers and guides helping to protect this fishery by respecting the voluntary closure and using catch-and-release practices that reduce stress on fish until conditions improve."

"The Arkansas River tailwater below Pueblo Reservoir is one of southern Colorado's most popular trout fisheries, and boasts trophy rainbow and brown trout," Tucker said.

As water warms, it holds less dissolved oxygen. Combined with reduced streamflows, those conditions make it harder for trout to recover after being caught and released. As water temperatures approach or exceed 71 degrees, even a brief fight can significantly reduce a fish's chance of survival.

Colorado Parks and Wildlife may enact a mandatory fishing closure if any of the following criteria are met: daily maximum water temperature exceeds 71 degrees; streamflow drops to 50 percent or less of the daily average; fish condition deteriorates, showing visible signs of fungus or stress; or daily minimum dissolved oxygen levels fall below 6 parts per million.

Aquatic biologists will continue monitoring river flows, water temperatures, and fish condition. If conditions deteriorate further, the voluntary closure area could be expanded or converted to a mandatory closure.

Anglers can help protect fish by following these practices: fish early when water temperatures are coolest; carry a stream thermometer and consider moving to cooler, higher-elevation waters if temperatures approach 71 degrees; use heavier tippet and line to land fish quickly; wet hands before handling any fish; keep fish submerged while removing the hook and releasing them; leave fish in the water rather than lifting them out for photographs; and avoid overcrowded areas with an alternative fishing destination planned.

Anglers should check river conditions before traveling. A current list of voluntary and mandatory fishing restrictions is available at Colorado Parks and Wildlife's 2026 Weather and Drought Closures page.