In this report
107 CFS and 57°F: A Manageable Week on the Pueblo Tailwater
We’re sitting at 107 CFS this week—right in the pocket where the Pueblo tailwater actually fishes well for early September. This isn’t a summer crisis flow, and it’s not the high-volume release season either. What it means is stable wading, concentrated trout, and gin-clear water that demands respect in your presentation, but rewards it hard.
At 57°F, the water is still cool enough to keep the fish from feeling stressed, even during the day. The dam’s influence shows here: you’re getting consistent, cold water release that’s held its temperature through the late summer. That’s the tailwater’s real gift this time of year—while freestone creeks upstream are warming and thinning, Pueblo stays fishable and cool. Don’t take that for granted. Check the live gauge before you drive down, because these flows swing fast and hard (the reference range for this water moves between extremes), but what you see right now is workable.
BWO Season Opens; Midges Never Leave
September brings the fall Baetis back. Overcast afternoons—and we often get them this month—trigger the #20–22 BWO hatch on this water. It’s not the blitz you see on some tailwaters, but it’s consistent enough that nymphs fished 12 to 18 inches off the bottom will produce all day, and dries will matter when the light gets soft and the air temperature drops.
More important to your actual success right now: midges are still the anchor. They’ve been the anchor since spring and won’t stop until December. A #22 or #24 black or dark gray emerger fished tight-line or under a small indicator will out-fish everything else on this water, hour for hour. The Pueblo tailwater’s trout think like midge feeders year-round. Build your rig around that reality. Tricos are tailing off—still worth fishing in the early morning if you want to, but don’t waste a calm afternoon waiting for them.
Terrestrials still work, especially grasshoppers near the banks, but they’re secondary now. The water is clear, the fish are not desperate, and they’re keying on small stuff.
The Rig That Works This Week
Fish a two-fly nymph setup. Tie a heavy Barr’s-style midge (black, mercury-bead, or dark olive; #22–24) as your anchor fly. Tie a #20–22 BWO emerger or a second midge in olive or tan off a 12-inch dropper of 5X tippet. Use 6X for the point, especially on the dropper—this water’s clarity demands delicate tippet, and at 107 CFS you’re not fighting current; you’re hunting in a fishbowl.
Add one small split shot (BB or smaller) to the bend of your anchor fly or 3 inches above the dropper. You want to tick the bottom of the deeper holding slots without hanging constantly. This is not a heavy-lead situation. Dead-drift or very slight tension—tight-line works best on clear tailwater this time of year.
Use a small strike indicator (a yarn indicator or a micro-shot indicator) set about 5 to 6 feet above your flies. The Pueblo tailwater is narrow and doesn’t demand the long drifts of a bigger freestone; you’re working concentrated water, and a short, controlled drift is more effective than a long one.
Where to Spend Your Time
At 107 CFS, the deep slots—the channels where faster current has carved deeper troughs—hold the majority of the fish. These are the stretches where the water darkens visibly because of depth, where current seams mark the transition from slow to faster flow. Fish those seams hard. That’s where trout lie in clear, moderate flow: in the transition zone where they can see food coming but don’t have to fight heavy current to stay put.
Skip the thin, flat water. Not because there are no fish there, but because your odds are lousy compared to the deeper slots. In a tailwater at this flow and clarity, trout are not spread across every inch of riverbed. They’re concentrated. Find the depth and you find the fish.
The sections of softer water immediately downstream of bends or behind any structure (a rock, a deeper channel) are also worth a drift or two, but keep moving if you don’t get interest in two or three casts. The holding water is defined by depth and current, not by geography.
A Note on Fish Welfare and Timing
At 57°F, the water is cool, but September afternoons still warm the shallows and the air. If you’re targeting trout, fish early (dawn through late morning) and late (late afternoon into dusk). Midday is not a dead zone—you’ll catch fish—but you’re working against thermometer reality. If you have one, carry it. The moment water starts approaching 65°F, even in a slot, you’re stressing fish that have already had a long summer. Fish the deep, cold holding water only. Skip the flats. Release fish quickly and gently.
The Pueblo tailwater’s reputation is built on winter consistency and big browns and rainbows. That doesn’t happen because we catch and release every fish year-round; it happens when we respect the seasonal limits on how hard we should work the water.
The Week Ahead
107 CFS is stable enough that you won’t have to check the gauge obsessively between trips, but these flows can shift in 48 hours. Verify before you go. Bring 6X and 7X tippet, small dark emergers, and a thermometer. Fish the deep slots at dawn or late light. Expect the water to be clear and the fish to require finesse. This week, the Pueblo tailwater is genuinely fishable—not a bonus or a surprise, but exactly what it does best in early September.