In this report
248 CFS: Right at the Upper Edge of Ideal
The flow chart is showing 248 CFS as we head into this week — and that’s a reading that lands squarely in the premium band for Eleven Mile. This canyon does not fish the same way as the broader South Platte tailwater downstream; it’s tighter, pocket-heavy, and built for lower flows. At 248, you’re seeing the river rise just enough to open up the deeper slots and transition zones without pushing into the hard-wading territory that kicks in above 300. For this specific water, this is textbook early-summer timing.
What that means practically: the fish are still holding in defined, reachable lanes. The faster seams along the old railway-bed canyon walls are pushing enough current to keep insects drifting cleanly, and the pocket water — which is the character signature of this stretch — is oxygenated and active. Wading is manageable if you respect the current and move deliberately. The water temp on a tailwater below reservoir discharge sits cool even in early June, but at this flow you’re not dealing with the thermally shocked cold-shock conditions that often arrive when flow drops into the low 50s CFS range; you’re in a window where the fish feed with reasonable confidence rather than suspicion.
PMD Emergers and the Midge Foundation
June means Pale Morning Duns, and Eleven Mile is no exception. The peak emergence typically hits late morning through early afternoon — roughly 10 a.m. to 2 p.m., depending on cloud cover and the specific day. You’ll see the naturals in the #16–18 range, mostly emergers and dun, with a genuine dry-fly window if the clouds break. But on this canyon, the way you fish them matters more than on a wider, slower tailwater.
The midges — black, zebra, RS2 emerger patterns in #20–24 — are your bread-and-butter, all day, every day. They’re what the fish are keyed on before the mayflies show and what they return to afterward. On a flow like 248, with pocket water that concentrates drifts and fish, a midge is often the most effective anchor. The trout here are not in a mood for slop; they’re selective because the current lane is defined and any fly that drifts outside it gets ignored or eats water.
Caddis will appear in the evenings (#14–16), but that’s not the story this week — PMD and midge are. Don’t waste morning water chasing evening patterns.
The Rig: Midge Anchor, PMD Dropper
Here’s the setup that works on Eleven Mile at 248 CFS:
Start with a small midge — RS2 emerger or black Beauty in #22 or #24 — as your point fly. Tie 18 to 24 inches of 5X fluorocarbon above it. Attach a #16 or #18 PMD emerger (not a dry; an emerger) as your dropper, setting it 12 to 18 inches up the tippet from the midge. This keeps both flies in the feeding zone and lets you respond to whatever the fish prefer on any given drift.
Add split shot — two small bb-sized shot is usually enough — positioned 12 to 15 inches above the PMD. This keeps the midge ticking the bottom of the deeper slots without dragging the emerger under, and it gives you the sensitivity to feel when you’re in the pocket rather than overshooting into dead water.
Use an indicator only if you’re fishing the deeper, slower pools that run alongside the canyon wall — and there are a few. Most of the time on this water, tight-line nymphing gives you better drift control and hook-up response in the faster seams. The canyon geometry means you’re rarely far from the current tongue; you can see the line and feel the pressure without a bobber.
Tippet: 5X for the main strand, 6X for the dropper if you want to break off the PMD cleanly and preserve the midge during a tangle. The pocket water doesn’t demand the ultra-light stuff, but 6X gives you a tiny edge on spookiness when the water is this clear and the current is defined.
Water Types: Pocket First, Pools Second
Eleven Mile is pocket water. The canyon’s narrow profile, the old railway grade that the road follows, and the history of the water create fast, broken current and defined holding lanes. This week, prioritize:
Fast seams along the near bank — wherever the current accelerates along the canyon’s rocky shoulders. These lanes are only 3 to 6 feet wide, but they’re where the emergers stack up. Cast slightly upstream and across, let the midge and PMD settle on the drop, and work them with a slack-line drift. You’ll feel the strike. Most of your fish will come here.
Transition zones where the pocket slows — these are often 15 to 25 feet below a main current break. The fish move into these softer zones to feed without fighting the push. Strip-set or tighten immediately when the line pauses; the strikes are often subtle because the fish aren’t fighting current.
The few slower pools — typically found where the canyon widens slightly or where a side drainage flattens the grade. At 248 CFS, these still run active enough that fish won’t be tucked into the deepest slots; they’re in the edges, holding along drop-offs. A small indicator and a dead drift through these zones accounts for maybe 20 percent of your day, but on a warm afternoon when the pocket water slows, these softer lies can be productive.
Skip the flat runs. Eleven Mile doesn’t have many, and the ones that exist don’t hold fish like the pocket does. Your time is better spent covering the broken water.
Access and Stewardship Notes
The entrance fee is $11 per vehicle — that’s a US Forest Service fee at the gate, separate from any Colorado Parks pass. The Quality Waters section (artificial-flies-and-lures-only, catch-and-release) runs 3.8 miles from the dam downstream to the Wagon Tongue Gulch Road bridge. The road is pullout-friendly and close to the water, which means parking and access are straightforward, but it also means the canyon can get moderately busy on a good-weather weekend. If you’re going to be here, bring your entrance fee in cash and plan to get on the water early in the week if you want solitude.
Water temperature in early June on this tailwater sits in the high 40s to low 50s Fahrenheit — cold enough that the fish are not thermally stressed, but cool enough that they hold feeding lanes with confidence. At 248 CFS, there’s no fish-welfare concern driving the week.
The Forecast
This is a strong week to be on the water. The flow is in the sweet zone for this specific canyon, the PMD emergence is beginning to build, and the pocket water is set up to give you defined, readable lies. Tie small, drift clean, and give the seams their due.