In this report
Flow Is Low for June — Fish Smart and Early
At 107 CFS, the Pueblo tailwater is running well below what you’d want to see this time of year. That’s not a winter flow (which fishes great at 70–150 CFS), and it’s not a healthy summer release either. For a tailwater fed by reservoir discharge, 107 tells you the dam is holding back — and on this water, that means gin-clear, warm-prone conditions and trout that have nowhere to hide and nowhere to go.
The consequence is immediate: wading is easy (you’ll barely get above your knees in the main current), but the thin water warms fast in the afternoon sun, and the fish concentrate hard into the deepest, coolest slots. This is a day-timing game, not an all-day game. Plan to be on the water at first light, be done by mid-morning or wait until dusk. If you’re arriving midday, bring a thermometer and be honest with yourself — if the water hits the mid-60s°F, stop targeting trout. The stress isn’t worth it, and neither is your skill.
Before you drive down, check the flow chart on this page. The dam can swing 40 or 50 CFS in a day. If it’s dropped further or spiked, adjust your tactics accordingly — but don’t assume what you read online an hour ago is what you’ll find.
Pale Morning Duns Are the Main Event
June on the Pueblo tailwater belongs to the Pale Morning Dun. Expect a good emergence starting late morning (9:30 or 10 a.m., depending on cloud cover) and holding strong through early afternoon. The duns are small — #16 and #18 — and they’re going to dominate your dry-fly game if you’re sight-fishing or working the softer current seams where fish will rise.
But here’s the wrinkle on low, clear water: the duns won’t come off in a thick enough carpet to trigger aggressive surface feeding. Fish will rise, but selectively. You’ll do better fishing the emerger than the dun itself. A #18 PMD emerger (body in pale yellow or cream, thorax in gray or tan, small tail or shuck) is your bread-and-butter dry during the hatch window. Fish it alone in the film, or pair it as a dropper under a heavier dry if you want to cover two zones at once.
Caddis will begin to show in the evening (#14–16), but expect them to be light until water cools — probably after 6 p.m. or later depending on air temp.
Midges are a given all day, every day here. Black Beauty and Mercury Midge patterns in #22–24, fished tight to the bottom in the deep slots, will catch fish when nothing else is working. These are your safety patterns when the PMD hatch dies or when the light gets too bright for selective rising.
The Right Rig for Thin, Clear Water
At 107 CFS and crystal clarity, you need to fish small and delicate. Here’s what works on the Pueblo tailwater right now:
Dry-emerger setup: A #18 PMD emerger as your point fly, 18 to 20 inches above a small indicator (use a yarn or foam postage-stamp size, not a fat bobber). Add a single micro split shot 6 inches above the emerger to keep it drifting just at the surface film. Tippet is 6X — non-negotiable at this clarity. The emerger doesn’t need to be deep; it just needs to be where the duns are trapped or just hatching, and your indicator will show you every take.
Nymph-dropper combo for deeper water: If you’re fishing the heavier slots away from the hatch window, rig a small Barr’s-style anchor nymph (like a Tungsten Black Beauty or small Pheasant Tail in #20–22) as your point fly, weighted enough to reach bottom in 3 to 4 feet of water. Add split shot 12 inches up the leader (or use a slightly heavier anchor and skip shot entirely — cleaner for low water). Tie a #18 PMD nymph or another emerger pattern 12 to 16 inches above the point fly on a 1X or 2X dropper tag. Use 5X tippet to the emerger, 6X to the point. This two-fly rig lets you fish the hatch and the holding zone simultaneously.
Dry-dropper hybrid: If you’re committed to staying on top, tie your #18 PMD emerger as a dry on 6X, and hang a small midge or PMD nymph (#22–24) 18 inches below on a 7X tippet tag. The emerger floats and shows you the zone; the nymph picks up subsurface takes. This is deadly on the Pueblo at low flow because trout will often refuse a dry but inhale the dropper in the same drift.
In all cases, stay patient. Cast upstream and let the current do the work. At 107 CFS, drag happens fast and fish see it instantly. Mend aggressively and often.
Fish the Deep Slots and Avoid the Flats
With thin water, there are no secret lies. Trout are in the deepest, coolest current you can find — the inside of bends, the dark slots where bedrock or silt creates a pocket, the tailouts of small pools where water slows and cools. Avoid the long, flat, sunlit shallows entirely; anything under 18 inches of water and exposed to direct sun is a waste of time right now.
Focus on the water character: look for places where current compresses into a narrow tongue, where boulders or channel breaks create depth, or where the riverbed drops enough to hold real shade. These trout aren’t roaming. They’re locked in, energy-conscious, and spooky.
A Stewardship Note
Low, warm water is stressful for trout. If you’re going to fish, fish early and fish responsibly. Keep fish in the water as much as possible, use wet hands, avoid prolonged air exposure, and consider catch-and-release only. If you’re not confident you can land fish quickly and safely at low water, skip the day. The fish will thank you, and they’ll still be there when the dam sends more water downstream.