In this report
Low water, clear conditions, and the fall Baetis window—here’s what’s fishing
We’re at 69 CFS this week on Eleven Mile, and that’s materially below the typical 50–150 range for this canyon. It’s low even for a tailwater that doesn’t run huge, and it means the fish are concentrated, visible, and spooky. The upside: you’ll see them. The downside: they’ll see you first, and every step on that gravel will telegraph downstream. Water temperature sits at 62°F—safe for the fish, and actually a signal that fall’s arriving and the pre-spawn aggression in the browns is turning on. That’s the real story this week: work deliberately, stay low, and make longer casts from wider distances than you’d normally think necessary.
At this flow, wading is easy—maybe too easy, which trips up visiting anglers. The shallow margins and pocket water that normally require a careful footstep now feel like you could walk anywhere. Don’t. The fish have nowhere to hide; they’ve backed into the deeper slots and behind the slower water around mid-channel structure. That means most of your productive water is actually narrower than usual. The payoff is that when you do find a holding lie—a pocket behind a boulder, a deeper slot between the gravel bars, the tailout of a pool—the fish density there is high. One good cast in the right place beats ten casts across water that’s too fast or too open for trout to hold comfortably at this volume.
The Baetis window is arriving; small emergers and nymphs are the foundation
September brings the fall Baetis (BWO) hatch back to life on Colorado tailwaters after the summer lull. Expect these bugs in sizes #20–22, typically on overcast or grayer afternoons. At 69 CFS, that hatch window won’t move a ton of water by itself—midges remain the year-round backbone of Eleven Mile—but the Baetis will turn on aggressive fish, especially as the light softens toward late afternoon. The browns, in particular, respond to small mayfly activity this time of year with the intensity they show during spawn. They’re feeding hard because they’re burning calories before the breeding season arrives.
Your primary rig this week is a two-fly nymph setup: lead with a small midge emerger or Barr’s Midge pattern in black or mercury, sizes #22–24, and drop a #20 or #22 Baetis emerger (RS2, Flashback Baetis, or similar) 14 to 16 inches below it on 5X tippet. The emerger-on-emerger combo works because the Baetis are hatching just below the surface film, not fully submerged in the water column, and the slight lag in your drift will keep the point fly moving naturally behind the anchor fly. At 69 CFS, you don’t need heavy anchor flies; a standard Black Beauty or Mercury Midge with just a bead will move slowly enough to stay in the zone without hanging every other cast on the bottom.
If the light does gray out and you see actual Baetis on the water, switch to a small emerger pattern in the surface film: a #20 Flashback Baetis or a standard BWO emerger, fished alone on a 5X tippet with no weight. Let it drift into the film, and watch the takes—they’re often subtle at this size, so stay connected.
The rig for low-and-clear conditions on pocket water
Keep your indicator 3.5 to 4 feet above your point fly, set tight to the tippet on just a small split-shot or none at all. At 69 CFS, the water is not pushing; what little weight you need is just enough to let the flies sink slowly into the thin slots. Many anglers will want to add a single BB or split-shot 12 inches above the point fly and fish the emergers on a dead-drift, indicator-style, through the pockets and along the deeper margins. That’s the right call. Skip the heavy rigs; this water is too thin and clear for them, and you’ll snag constantly.
For the pocket water that defines Eleven Mile’s character—the broken, boulder-studded sections where the canyon walls press close and the current has carved small holding zones—approach from the side or from below whenever the sun is directly overhead. The light at this low flow makes the water transparent, and a trout in 3 feet of water can see a shadow on the bank 20 feet away. Wade slowly, keep your rod hand below the skyline, and cast long whenever you can. A 40-foot cast placed above a pocket you can see clearly will outfish a 20-foot cast ten times over.
The deeper pools, where the current slows and the bottom drops, are less dramatic this week because the reduced water volume hasn’t filled them the way a normal September flow would. But they’re still worth working the head and transition zones—anywhere the faster water slows as it enters the pool. Fish a tight-line nymph rig here (no indicator), keeping contact with the bottom and feeling for the rhythm of the drift. You’re looking for the slight tick or pause that means a fish has taken.
A note on fish welfare and the next few days
At 62°F, Eleven Mile’s trout are well within safe temperature range, and the canyon’s canyon’s tailwater regime (cold water from the dam’s depths) keeps thermal stress minimal year-round. That said, in September the days can still warm toward the afternoon, and water this low concentrates the fish. If you’re fishing late morning into early afternoon, be mindful of water temps if we get a sunny stretch—even a couple degrees can tip a stressed fish from feeding to listless. The cooler overcast days and the gray afternoons when the Baetis appear are ideal. Fish those windows hard.
The $11 day-use fee gets you access to the 3.8-mile Quality Water segment below the dam, and the road-parallel canyon access means you can work multiple sections without a massive hike. That’s a luxury on a tailwater. Use it: scout the water from your vehicle, park where it makes sense, and hit the sections that look most promising rather than committing to one hole. At this flow, mobility beats stubbornness.