In this report
46 CFS in July: Fish the Margins, Not the Clock
The Pueblo tailwater is running 46 cubic feet per second right now. That’s extremely low for summer, and it changes everything about how you fish this water this week.
To be direct: this is a fish-welfare situation. At 46 CFS in midsummer, the thin water warms fast under direct sun. Midday air temps will push surface temps into the mid-60s°F quickly, and in a low, narrow channel, that stress spreads fast. Carry a thermometer. Stop targeting trout when the water hits 65°F—that’s not a suggestion, it’s the threshold where these fish shift into survival mode. Plan to fish hard from first light until mid-morning, and again in the final hour or two before dark. The middle of the day is a loss.
The low flow also means every riffle flattens and every current seam compresses. Holding water concentrates in the deepest slots and the shadiest lies under the banks. Fish will be spooky. You need to fish it accordingly.
What to Actually Do with This Flow
At 46 CFS, wading is easier than it will be in a healthy summer release, but easier is not the point—accuracy is. The trout aren’t scattered across broad flats; they’re locked into deep pockets and undercut banks where the current keeps moving and the temperature stays lowest.
Fish the deep slots first. These are the narrow trenches where the main current has carved down; they’ll be 3–5 feet of water in a ribbon maybe 6–8 feet wide. Use a 6X or 7X tippet—the water is gin-clear at this flow, and spooky fish demand fine leader. Rig a tight-line nymph setup: a #20 black beauty or mercury midge as your point fly, weighted or unweighted depending on depth, with a #18 PMD emerger or RS2 hung 18–20 inches above it on a dropper. Add one split shot about 12 inches above the point fly. This setup lets you tick bottom without overdoing weight, and it delivers two presentations at once—the midge for immediate takes, the emerger for fish that key on the slower drift just off the substrate.
Cast up and across at a 45-degree angle, mend once to get slack out of the line, then follow your indicator or tight-line feel as the rig drifts through. Don’t fish fast. Let it breathe. At 46 CFS, there’s no race; the trout have nowhere to go, and they’ll inspect a properly drifted nymph.
Skip the thin, sunlit flats entirely. Anything shallower than 2 feet in direct sun is a waste of time at this flow. The water temp there is already climbing.
Bank edges and undercuts are premium. If the right bank has overhanging willows or undercut earth, that’s a trout’s air-conditioning unit. Wade carefully—these seams are tight, and a careless approach will blow everything out. Work from below, casting slightly upstream into the shade and letting the rig swing and drift through the underhang. Use the same tight-line nymph rig. A trout under a bank has confidence; it won’t chase far, so precision is everything.
What’s Hatching
July on this tailwater runs on its own schedule, dictated by dam releases and cold water, not by the freestone upstream. Expect midge hatches to be the backbone—they’re always on at Pueblo, and in low summer water, the trout become utterly focused on them. Fish #20–24 black beauties, mercury midges, and zebra midges dead-drift in the film and just below it.
PMDs (#16–18) are still around, though not as dominant as they were in June. They’ll show in late afternoon; tie a few emergers and a couple of drys in case you see risers, but don’t expect a full-blown spinner fall at this flow and temp. The trout are too stressed to cherry-pick drys.
Caddis will show in the evening—#14–16 tan and gray patterns. If you’re here at dusk and the water temp has dropped a couple of degrees, there’s a window for a caddis dry or a soft-hackle fished in the current seams. Early success with a caddis often means you’ve timed the cooldown and the hatch overlap perfectly.
Terrestrials (small ants and beetles, #16–18) can work on warm afternoons if you find shaded bank edges or overhanging cover. Ants especially can trigger opportunistic feeding in tight lies.
Before You Drive Down
Check the flow chart on this page before you leave. 46 CFS is a real number today, but this tailwater swings violently day to day—summer releases are unpredictable, and what you read now may shift 40 or 60 CFS up or down by tomorrow. A spike to 120+ CFS changes the wading completely and redistributes the fish. A drop to 30 CFS or lower makes the water dangerously warm and the fish nearly unfishable by midday.
If you’re driving from a distance, that check is worth the two minutes.
Bring a thermometer and use it. In July at 46 CFS, it’s not a luxury—it’s the responsible call for the fish. And if the water hits 65°F by mid-morning, don’t fight it. Fish dawn and dusk, or pick another day.
This is still the Pueblo tailwater—world-class big browns and rainbows, year-round access, special-regulation water. But right now, low summer flow asks you to be precise and thoughtful. Fish the deep, shaded water. Use small, realistic flies and fine tippet. Keep the trout safe. It pays back.