In this report
Flow Is Below Par — Adjust Your Expectations
At 103 CFS, Eleven Mile is running well below its typical 50–150 CFS range and significantly short of the 150–250 CFS sweet zone where dry-fly fishing really opens up. This matters here more than it would on a bigger water. At this level, the canyon’s pocket water is still fishable, but the pools flatten out and compress. Wading is easy—almost too easy, which means you’ll spook fish faster if you’re not deliberate about your approach. The main current slots that normally hold steady fish on the drop become thin and sluggish. Expect the trout to be tighter to structure and more reactive to vibration.
Temperature is also a real concern this week. Low flow means slower water movement and less thermal turnover; July sun on a narrow canyon means the water will warm as it sits in the pools, especially in the afternoon. Check the water temperature at the dam entrance before you commit to a full day—if it’s nudging above 65°F, you’re entering fish-stress territory. The canyon’s tailwater advantage (stable, cold release from the reservoir) disappears fast when flow drops this far. If temps are high, fish the first light window hard (dawn through mid-morning), then take a long midday break and return for the last hour or two when the sun clears the rim.
Tricos and Midges — Small and Early
The primary hatch right now is the Trico spinner fall, and on a low-flow week like this, it becomes even more important. These #22–24 mayflies emerge in the pre-dawn dark and mate by mid-to-late morning, spinning back down to the water in dense clusters. At 103 CFS, the current is slow enough that the spinners hang in the water column longer instead of getting swept away, making them concentrate and linger in the flatter pools. Hit the water early and be ready to fish spent-wing patterns—a #24 Trico spinner in traditional gray or a Rusty Spinner in #22 if visibility is low—from first light through about 10 a.m. Fish the lower, slower sections where the current spreads across pool flats; the trout will key on the spinners there because the food is presented slowly and densely.
Midges remain the workhorse year-round. At this flow, a #20–22 Black Beauty or Mercury Midge fished as your point fly (dropped underneath a small dry or an indicator) will pick up steady fish all day, especially in the deeper pockets and around any structure that breaks the current. Don’t overthink midge selection—the fish aren’t fussy when the water is low and the hatches are sparse.
PMDs (#16–18) are still present in small numbers, but they’re secondary this week. If you see a few emergers or duns in mid-to-late morning, a #18 PMD emerger fished tight to the bottom in the deeper slots can produce, but don’t build your day around it.
Caddis and terrestrials (ants, beetles) will appear in the evening warmth, but at this flow, they’re bonus, not the plan. An ant or small beetle pattern (#16–18) late in the day might surprise a large brown, but the trout are already keyed on small prey.
How to Fish It This Week
Your setup needs to match both the low flow and the dominance of small emergent mayflies and midges.
Nymph-and-dropper in the morning (dawn through mid-morning): Rig a #20 midge or #18 PMD emerger as your point fly, 18–20 inches below a larger, heavier anchor (a #14 Barr’s Olive or a small stone). Use a single split shot placed 8 inches above the point fly. Fish this tight-line or with a small indicator set 3.5 to 4 feet above the point—at this flow, tight-line feels more natural and gives you better contact with slow-moving fish. Target the depth where the pockets narrow and deepen; at 103 CFS, this might be only 2.5 to 3.5 feet in the slots. Make short casts across the current and let the rig drift without much mend. The current is too slow to generate natural dead-drift tension, so you’ll need to feel for the take.
Dry-and-dropper for the spinner fall (dawn to 10 a.m.): Use a small dry (a #22 Trico spinner or a #18 PMD dry as your indicator) with a #22–24 emerger or additional spinner pattern hung 18 inches below it. Fish this in the flatter pools where the spinners will land. Cast to the edges of slow current and let it float. At this flow, the drag window is wider—the water moves slowly enough that your dry will float naturally longer before the line tension kills it. Don’t set hard; these are tiny flies and light-bite fish. Let the emerger do most of the work; the dry is mainly a visual signal and a strike indicator.
Afternoon midge focus (10 a.m. onward, or after a midday break if temps are high): Return to your nymph rig or switch to a small dry midge pattern (#20–22) fished solo over the pockets. Midge activity continues all day, and at a slow, low flow, even a small dry will sit long enough for a trout to rise deliberately. If you see risers, cover them. If not, work the deeper pockets with a tight-line rig and a small emerger.
Tippet and line: Use 5X for the nymphs and 6X for the dries—the water is clear and low, and at this flow, the fish have time to inspect. Thin tippet helps with turnover and natural drift. Your leader should be 9 to 10 feet for nymphing, 7.5 to 8 feet for dry work.
Where to focus: The pocket water immediately below the dam tailrace is always productive, but at low flow, it will be less dramatic—still, those rocks and current breaks are where the fish concentrate. Work through it slowly. The flatter sections between pockets, normally overlooked, are worth fishing now because the spinners will hang there during the morning fall. Don’t skip the deeper slots on bends; at 103 CFS, they’re still the most reliable holding water.
Logistics and Stewardship
The $11 vehicle entrance fee applies—this is a U.S. Forest Service (Pike-San Isabel National Forest) day-use site, not covered by a Colorado State Parks pass. Plan on it.
The canyon road parallels the river and gives you excellent access from the vehicle; you don’t need a long hike to good water. That’s Eleven Mile’s gift and its challenge. The proximity means you can fish multiple sections easily, but it also means other anglers can find fish quickly. Fish early and avoid midday if the water is warm.
Keep the trout in the water. At 103 CFS and peak July heat, these fish are working hard to stay cool and fed. Barbless hooks, quick releases, and zero unnecessary air time are not optional—they’re your stewardship responsibility on a low-flow tailwater in midsummer.