In this report
Low Water, High Stakes — Know Before You Drive
The gauge is running 107 CFS as of this writing. On the Pueblo tailwater, that’s squarely in the LOW column for August, and it matters. In summer, sub-70 CFS water becomes a real problem: gin-clear, easy to wade but hellish for fish welfare and presentation. We’re just above that threshold, which means the window is narrow and the tactics are unforgiving.
Before you load the truck, check the flow chart on this page. Pueblo Dam releases swing hard and fast — a swing from 177 to 42 CFS in two weeks is not unusual here. What reads at 107 right now may be 60 by the time you arrive, or 250. That changes everything about how you fish and where the trout will actually be.
Water Temp is the First Problem
Bring a thermometer. Full stop.
At 107 CFS in August, thin water heats fast under sun. The tailwater below the dam stays colder than the lower sections, but even that advantage evaporates (literally) by mid-morning on a hot day. If you’re fishing, target dawn and dusk hard. If you arrive and find the water already creeping into the mid-60s°F by 10 a.m., your best move is to fish the deepest, shadiest slots and call it a day by early afternoon — don’t add stress to already-vulnerable trout.
The upper section closest to the dam, where the cold hypolimnetic release keeps things more stable, is worth the drive. Fish welfare matters. Trout in thin, warm water are done for the day.
Midges and Tricos Own August Mornings
The seasonal primary for August is midge — always midge on this tailwater. Add trico spinners to the early-morning mix, and you’re looking at a genuinely productive window from first light through about 9 a.m., provided you stay in cold water and the trout aren’t thermally stressed.
Midge emergers are the meat here: #20–24 Black Beauty, Mercury Midge, zebra midge, or RS2. These are your anchor point flies. At 107 CFS, fish are concentrated, visibility is high, and they’re keyed on small stuff. Trico spinners (#20–24) will show up in the surface film on calm mornings — if you see them, a #22 or #24 midge spinner imitation or even a small black parachute will pull fish. But don’t wait for visible spinners; the emergers will produce all morning if you’re working the right water.
Don’t size up out of habit. Yes, this is August, but this is also a tailwater running low and clear. The trout here have seen thousands of tiny flies. Go #20 or #22 before you go #18.
The Rig: Deep, Weighted, Spooky
At 107 CFS, the holding water has shrunk. Trout aren’t scattered across the flats — they’re in the slots, the deeper pockets below current breaks, the shadier inside corners. You need to reach that water efficiently and present a fly that doesn’t spook them in gin-clear conditions.
Use a two-fly rig: anchor with a heavier nymph (a Barr’s style pattern, #18 Pheasant Tail, or a small weighted midge pupa — something with some bulk that takes weight), then hang a #20–24 emerger on a 12- to 18-inch dropper of 6X tippet. The anchor does the work of getting deep; the emerger rides above it in the zone.
Split shot on the main line, not the tippet. Place a single BB or two just above the upper fly — this keeps the rig from fouling and puts weight where you need it without sacrificing feel on the dry fly or adding drag to the emerger. Adjust up or down depending on depth; at 107 CFS, most good holds are 2–3 feet, and you want to tick bottom gently every third cast or so.
6X tippet on the point; 6X or 7X on the dropper. Low water demands fine diameter. If you’re worried about break-offs on the big rainbows this tailwater holds, remember: a trout that’s not eating because your leader is too thick is a zero. Fine tippet gets eats.
Skip the indicator. At this flow and in this clarity, a visible indicator spooks more fish than it helps. Tight-line or high-stick: keep the line slightly taut, feel for the tick or the stop, and set on contact. You’ll miss fewer fish and hook fewer that are just suspicious, not committed.
Where to Focus
The deep, current-tongued slots below the dam are your first choice — darker, cooler water, and trout will actually be there this week. Work the inside of any bend where water backs up and slows; on a narrow tailwater at 107 CFS, these are your fish-holding oases.
Avoid the thin, sun-exposed flats. They look fishable at 107 CFS because you can wade them, but the water warms fast and the trout abandon them by mid-morning.
If the upper section has special regulations and you’re not familiar with the exact water, verify access and bag limits before you go — they do vary by sub-section, and August is not the time to guess.
Evening: Caddis, But Light
As dusk approaches, caddis will stir. Expect small stuff — #16–18 tan or olive caddis larvae and pupae on a nymph rig, or a #16 emergent adult pattern if you see activity. At 107 CFS, the rise won’t be explosive, but the low-light window and cooler evening air can give you a second wind if the midges didn’t pan out.
Terrestrials (small ants, beetles) can work in the afternoon on warm days, but on a thin, clear, warm tailwater in August, they’re a lower-percentage bet. Stick with the tailwater staples.
Bottom Line
107 CFS is workable but tight. It’s not a sweet spot — it’s a challenge that demands cold water, fine tippet, precise placement, and honest attention to fish welfare. Fish early, fish deep, fish the slots. Check the gauge before you drive. Know your water temp. You’ll catch trout, but you’ll earn them this week.