In this report
218 CFS — A Solid Summer Window, But Water Temp Is the Real Conversation
The gauge is holding at 218 CFS this week on the Pueblo tailwater, and that’s genuinely good news for August. We’re well above the stress threshold that plagues this water in midsummer — you’re not looking at thin gin-clear flats that turn bathwater by noon. This is the kind of release that gives you room to work and depth in the holding water that matters. But before you load the truck, get your thermometer out of the glove box and keep it accessible. The water is cold off Pueblo Reservoir, but August sun is relentless, and the shallow edges and exposed runs warm fast. This week’s real job is fishing smart about temperature, not just about flow.
The Hatch Window: Midges Carry the Morning, Tricos Own First Light
August on this tailwater is all about small — and the primary show is the midge emergence running through the first two hours after dawn. These aren’t the fat black attractors of spring. You’re looking at genuine #20–24 patterns: Black Beauty, Mercury Midge, zebra midge, and RS2 emergers in olive and black. Fish them tight to the surface film as the light comes up. The Pueblo tailwater’s unique character here is that the dam-controlled water stays consistent and cold enough that real midge hatches stick around year-round, even in August. This isn’t a mayfly river in midsummer the way the freestone stretches upstream are; the tailwater’s rhythm is its own.
Behind the midge window, watch for a light Trico spinner fall from roughly 8 to 10 a.m. — females dropping on the water column in that #22–24 range, blacks and olives. These are genuine small bugs, not a major event, but a #24 Trico spinner dun fished dead-drift in the slower seams will pick up trout that have already seen the emerger crowd. Don’t overestimate the hatch; it’s there if you’re there, but it’s not the kind of blitz that draws you away from other tactics.
Caddis — again, small and tailwater-controlled — begin showing in the evening, #16–18 tan and olive patterns. On 218 CFS, the deeper slots and the runs with a bit of current hold the best pods. Fish a #16 olive caddis dry, or better yet, a #18 olive caddis emerger just under the surface, in that last hour before dark when the light flattens.
Terrestrials (ants, small beetles, hoppers in #12–14) work on hot afternoons, but they’re secondary to the midge-and-small-fly foundation this week. Save them for the mid-afternoon lull if you’re fishing through the heat.
Where the Flow Matters Most: Depth, Not Flatness
At 218 CFS, you’ve got real water to work. The benefit here is that the deeper slots — the fast, darker runs closest to the dam and the pockets where water has genuine column — hold concentrated trout. This is a tailwater; it doesn’t have the spread-out anatomy of a freestone. The deep slots, the undercuts, and the narrow seams under high banks are where the fish live. On a summer low-flow day (under 70 CFS, which thankfully we’re not seeing now), those same slots become the only fish, and they get hammered. You’re in a better position right now.
The consequence of 218 CFS for wading: the edges are easier than they would be on a high release, but you’ll feel the current in the main run. Don’t wade out trying to reach what looks like “better” water 30 feet out — the deep edge of the current line is where the trout are. Wade deliberately, probe close, and trust that the fish in Pueblo tailwater are predictable about holding in depth and current.
Rigging for Midge and Emerger: The August Playbook
Top-water midge approach (dawn): Use a long, light leader — 9 to 10 feet of 4X to 5X mono, tapered down to 6X for the final 18 inches. Tie a #20 or #22 Black Beauty or Mercury Midge dry directly. Cast upstream of the seam, let it dead-drift, and set on any subtle take. On clear tailwater, you’ll see refusals. Mend to keep drag-free drift; on 218 CFS, the current is steady but not violent, so a single upstream mend halfway through the float usually does it.
Subsurface emerger rig (the workhorse): Use a two-fly setup. Tie a small anchor fly — a #18–20 Mercury Midge nymph or a Barr’s-style Copper John in olive — on your point. Drop 18 inches of 5X tippet, then tie a #20 or #22 RS2 emerger or olive caddis emerger on the dropper. Add a single small split shot just above the dropper, positioned to keep the rig skating along the bottom of the deep slots without hanging constantly. Use a dry-fly indicator (Thingamabobber or foam ball) set 3 to 4 feet up the leader.
Cast to the head of the slot, mend immediately to track the drift, and watch the indicator. The tailwater’s clear water means you see strikes clearly, but you also need delicate presentation. If the indicator twitches, set lightly — no hard strip-strikes. The emerger will hook most fish.
Afternoon caddis approach: Forget the indicator. Tie a #16–18 olive caddis dry on 4X, and fish the last productive hour as the light softens. Cast to seams and the inside of bends where slower water meets the current. If you want to fish an emerger, drop a #18 caddis pupa (tan Hare’s Ear or a simple pheasant-tail) on an 18-inch dropper of 5X below a foam strike indicator, set the depth to 2 to 3 feet, and work the slower side channels. Caddis on the Pueblo tailwater are more sporadic than midges, but they’re reliable in the evening window.
Water Temperature and Fish Welfare: The Non-Negotiable
Carry a thermometer. If the water hits the mid-60s°F, pack it in and fish again at dawn or dusk. The tailwater’s big browns and rainbows are cold-adapted, but August sun plus even 218 CFS of flow means the water will warm in the shallows and slower edges by late morning. Trout will migrate to the deepest, coolest holding water and stop feeding. You’re not being less aggressive; you’re being smart about when the water lets you fish productively.
If you’re there at dawn and the water is still cool (high 50s to low 60s), you’ve got a legitimate 4- to 5-hour window before the afternoon slow-down. Fish it hard, then let the afternoon go.
One More Thing: Check the Gauge Before You Drive
The Pueblo tailwater releases are dam-driven and volatile. 218 CFS is genuinely solid today, but the reading can swing dramatically. Check the flow chart on this page before you commit to the drive. If the trend is heading down or a big release is scheduled, that changes the rigging and the timing. Current flow matters; don’t assume it’ll hold.