In this report
100 CFS: Low for August, but fishable if you adjust
We’re running at 100 CFS on the canyon right now—well below this water’s typical 50–150 band and considerably short of the 150–250 sweet zone where Eleven Mile fishes easiest. That said, don’t write off the week. A hundred on this tailwater isn’t crisis water; it’s just tighter, spookier, and requires you to think smaller and move slower than you might on a normal August day.
The real consequence here is twofold. First, the fish are concentrated hard into the deeper slots and tail-outs—there’s less water to hide in, and they know it. Second, the slower current means water temps will climb through the day, especially in the afternoons when the direct sun hits the canyon walls. If you’re targeting this stretch, prioritize morning sessions, work the deeper pockets deliberately, and don’t linger in the shallower runs where warmed water and spooky fish make for a grinding afternoon.
Midges rule; Tricos are secondary
August on this tailwater is still midge season, full stop. Midges—Black Beauty, Mercury Midge, zebra midge, and RS2 emergers in #20–24—are going to move more fish than anything else, and they’ll do it at this low flow when the trout are locked into holding lies.
The other primary play is Trico spinners in the mornings, especially in the first light and for an hour or so after. You’ll see the spinners (tiny, #20–24) coming down in scattered clusters rather than the dense blanket you’d see on a freestone. That’s a tailwater thing—the dam buffers the hatch intensity, and emergence gets strung out. Focus on the first hour post-sunrise; after that, the spinners thin out fast.
PMDs (#16–18) are still present on warmer afternoons, and terrestrials—particularly ants and small beetles in #16–18—will draw strikes on days with real sun intensity. But if you’re not catching fish on midges and Trico spinners, you’re probably not catching fish. Everything else is sauce.
Caddis will show in the evenings, but at 100 CFS, the action is typically quiet and sporadic. If you’re here for a dry-fly evening, bring caddis (#14–16), but go in knowing it’s a secondary play compared to the morning midge and Trico window.
Rigging for low, clear water
At this flow, depth is everything and presentation is unforgiving. Here’s how to rig:
Your primary setup: Start with a heavier midge anchor—something like a Barr’s Black Beauty #22 or a mercury midge—tied to 4X or 5X tippet. Drop a split shot about 18 inches above it, or use a small tungsten bead-head RS2 emerger as your point fly if you want to fish slightly shallower. Add a smaller dropper off the bend of that anchor—a #24 zebra midge or a tiny Trico emerger—at about 12–14 inches. This two-fly rig gives you depth options and the chance to fish different sizes without rerigging.
Indicator or tight-line: At 100 CFS, I lean tight-line with a small indicator if you’re new to contact nymphing. A small yarn indicator lets you hold depth while tracking the drift, which matters when your margin for error is thin. If you’re running dry dropper, use a small Trico or RS2 emerger (#22–24) as your point fly, suspended 14–18 inches below a Trico dun or PMD dry in #18. The dry gives you a visual reference and occasionally draws a rise; the nymph does 90% of the work.
Tippet and why it matters: 5X for the main leader to the first fly. The canyon is clear, and at 100 CFS, the fish will turn on heavier material. If you’re going two flies, use 5X for the first ten inches, then step down to 6X for the dropper. Yes, 6X is a liability in terms of abrasion on the rough bottom, but it’s the only way the drifts look natural when the water is this thin and the light is this good.
Where to spend your time
Forget the wide, slow flats—they’re too thin and too exposed at this flow. Your water is the deeper pockets and runs where the current has cut a defined channel. Look for:
- Slot water below minor drops: These hold fish hard when the flow is low. A two- to three-foot-deep run with a defined current seam is money. Get downstream and fish up into it, letting your nymphs tick the bottom as they drift through.
- Tail-outs of pools: The trout use these as a funnel. A quarter-turn below a deeper pool, where the water narrows slightly and current stacks fish tightly, is prime. Work it methodically—you won’t have many fish there, but the ones that are will eat if you drift drag-free.
- The deeper slots along the canyon walls: The road parallels the river closely for miles, and on reaches where the canyon pinches and forces water into a defined channel, that’s where the trout stacked up when flow dropped. These are hard to access from the roadside pullouts sometimes, but if you can reach them, fish them first.
Avoid the wide shallows and the gentler gradient sections. They’ll look dead at 100 CFS, and they probably are.
One logistics note: water temps and timing
At this flow and this time of year, water temps climb into the 60s and low 70s by midday—stressful for the trout, especially in the shallow sections. Plan to fish the morning, take a break from about 11 a.m. to 3 p.m., and return for a modest evening session if the Tricos or caddis are genuinely on. Don’t grind it out in the heat expecting a rise.
The $11 day-use fee gets you access; spend it on a solid morning and an early evening, and you’ll have a better day than fighting low, warm water all afternoon.