Eleven Mile Canyon Hatch Report — June 6, 2026

We’re sitting at 248 CFS at Eleven Mile—a solid, fishable level that’s holding steady in that sweet spot where the canyon fishes with real purpose. This flow is high enough to oxygenate deeper runs and keep trout spread across multiple water types instead of crowding them into narrow slots, but low enough that you’re not fighting boot-sucking currents or dealing with the murky chop that comes with irrigation pulses. The water clarity is good. You’ll have room to work, and the fish should be confident.

What’s Hatching

Early June on the South Platte at Eleven Mile is all about Ephemerella genus mayflies—specifically the Pale Morning Dun (Ephemerella inermis) and its cousin the Pale Evening Dun (E. dorothea). You’ll see spinners as early as mid-morning and duns throughout the afternoon, peaking between 2:00 and 5:00 p.m. depending on cloud cover and water temperature.

Stock these patterns:

• PMD Dun: sizes 16–18, tied split-tail (Adams or Parachute Adams are standards, but also tie in pale yellow and cream variants)
• PMD Spinner: size 16–18, rusty dun body, clear or pale yellow wings
• Pale Yellow Comparadun: 16–18 (particularly effective on overcast days when duns sit longer on the water)

You’ll also see caddisfly activity—specifically Hydropsychidae (net-spinning caddis) in the 14–16 range. Greased-line fishing with an Elk Hair Caddis (tan or olive, size 14–16) works when you get picky midday risers. Don’t sleep on this option.

Subsurface, the nymphs doing the work are PMD nymphs (size 16–18, olive-brown bodies) and caddis larvae in olive and tan. If you’re not seeing consistent surface activity, these are your foundation patterns.

By late afternoon and into evening, caddis duns (Hydropsyche spp.) come off in waves—especially after 5:00 p.m. Have a few small Stimulators or Elk Hair Caddis in olive and tan, sizes 14–16.

Best Water This Week

Soft inside seams and near-bank runs

At 248 CFS, the softer water along inside bends and behind mid-stream obstructions is premium. Trout will be holding in the foam lines and in the slower current behind rocks, rather than tight to the bank. These are your dry-fly zones. The current is pushing enough that insects aren’t stalling, but the reduced velocity means fish can hold without expending max energy. Cast upstream, let your PMD or caddis drift naturally through the seam, and watch for head-and-shoulders rises. This is where you’ll spend 60% of your time.

Mid-column pocket water and boulder gardens

The riffle complexes—areas where the current breaks around larger stones and creates pockets of slightly slower water—fish exceptionally well at this flow. These zones hold fish actively feeding on nymphs. Wade deliberately through these sections with a three-fly nymph rig: anchor fly deep (a size 16 olive PMD nymph or a small tungsten caddis larva), then add a dropper 12–16 inches up, and another above that. Fish tight to the rocks. At this flow, you’re hitting the zone where fish are positioned to intercept drifting prey without having to hold in main current. Expect takes in 2–3 feet of water.

Deeper runs and tailouts

The run-off water at the bases of faster sections creates good seams between pushy current and slower water. Fish a tight-lined nymph rig here—lean into the depth with tungsten and let the current do the work. This is less glamorous than dry-fly water, but it produces. Trout will be stacked in the softer edge water, and they’ll take readily if you’re drifting clean.

Tactics

Leader Setup:

• 9-foot tapered leader, 3X butt
• For dries: taper to 5X for size 16–18 duns; 4X if you’re throwing caddis
• For nymphs: 3X main line to 2X anchor dropper, then 4X tag material for the upper flies

Tippet Size:

• 5X for dry flies (PMD duns, spinners)
• 4X for caddis dries and droppers
• Use 4X fluorocarbon for your nymph anchor; 5X for the upper droppers

Rigging Notes: If you’re dry-fly fishing, go long and light. A 12-foot leader or a 9-foot + 3 feet of 5X is ideal for this flow—it gives you better driftless and lets the fly move naturally. Mend aggressively. At 248 CFS, the current is pushing enough that you’ll get drag quickly if your mend timing is sloppy.

For nymphs, use a Czech nymph approach or a tight-line rig. Weight should be in the fly itself; avoid shot if you can. The water clarity means fish can see clumsy rigs.

Practical Notes

• Water temperature: Early morning temps are likely in the low 50s, so trout will be less aggressive until water warms through mid-morning. Plan your first two hours as reconnaissance; peak fishing is 10:00 a.m. onward.
• Access: Parking and wading at Eleven Mile can get crowded on weekends. Arrive early, or plan a weekday trip if the schedule allows.