Low and Warming: A Midge Week Below the Dam
The gauge is holding at 69 CFS—well below Eleven Mile’s typical 50–150 range, and a full 80 points south of the ideal dry-fly window of 150–250. At 61°F, the water temperature is still fishable, but this is a low-flow, warming-trend setup that demands respect and a shift in how you approach the canyon this week.
What this means on the ground: the river is concentrated. Every fish worth catching is in one of three places—deep slots, the current seams that stay oxygenated, or the soft water immediately downstream of structure where a midge emerger or small nymph can drift without a fight. Wading is easy; reading the water is harder because there’s less of it to hide in. The bright sun and low water will make trout touchy in the shallows and more inclined to hold tight against banks and under the canyon walls where the light doesn’t reach.
The 61-degree temperature is not an emergency yet, but it’s a signal. Fish are still feeding actively, but their metabolic window is starting to narrow as we move into early fall. A morning or late-afternoon session will be more productive than midday, when the water warms another degree or two in direct sun.
Midges Rule the Low-Flow Game
September on a tailwater always defaults to midges first, and at 69 CFS, the midge emerge is everything. Tricos are tapering as the month progresses—we’re past the peak—so don’t waste time on tiny #24 Trico patterns in the morning. Instead, focus on black and olive midges in the #20–24 range: Black Beauty nymphs, Mercury Midges, RS2 emergers, and zebra midges are your bread and butter all week.
Fall BWOs (#20–22) will show up on overcast afternoons if the clouds hold, but don’t count on a reliable window unless the sky genuinely darkens. With low flow, a single overcast hour can trigger a decent midge-to-baetis transition, but it’s brief and concentrated.
The pattern that matters most right now is a small emerger fished in the surface film. At 69 CFS, the current is slow enough that you can watch a #22 RS2 or Mercury Midge hang in the meniscus for a full two seconds before it drifts. That’s your strike window. Small dries—a #20 midge adult, a #18 Griffith’s Gnat—will work midmorning and again in the last hour before dark, but the emerger is more reliable all day long because the fish are still keyed on bugs in transition, not fully hatched adults.
How to Fish It: Tight-Line Below the Dam
With 69 CFS and the fish concentrated in seams and pocket water, forget the indicator setup. Tight-line nymphing will catch more fish because you’ll feel takes that an indicator rig would miss at this low flow. You need sensitivity, not bobber buoyancy.
Rig a #22 RS2 emerger as your point fly—this is your primary search tool. Tie a #20 black midge nymph or a small Barr’s Olive as your dropper, 16 to 18 inches up the leader using a standard surgeon’s knot. This combo covers the range of what’s emerging without forcing you to choose one or the other.
Split-shot placement matters in low water. Use a single BB split shot placed 12 inches above your top fly. This is enough weight to tick bottom in the 18-inch-deep runs without hanging constantly. In the deeper slots—places where the canyon wall creates a vertical drop or where the current has carved a pocket—add a second BB or consider a small tungsten bead on your dropper. The goal is to get the bottom fly ticking sediment without dead-drifting. Adjust on the water; if you’re hanging twice per dozen casts, drop the weight or move to shallower seams.
Use 4X tippet on the point and 5X on the dropper. At 69 CFS, you don’t need the fine stuff, and a slightly heavier tippet will turn these small flies over more efficiently on short casts—which is all you’ll make in the narrow, brushy sections of the canyon. The smaller flows mean you’re fishing close; precision matters more than distance.
Anchor your drift on the tight-line by keeping contact from the moment the fly hits the water. This is not full-contact nymphing; keep a slight bow in your line so you can feel the take without ripping the flies away. A sudden tick, a hesitation, or a sideways movement of your line means set the hook—no false casting, no wait-and-see.
Where the Fish Are This Week
Focus on water with current definition. In low flow, the difference between a feeding lie and dead water is stark. Prioritize: current seams where slower water meets the main flow; the soft edges just downstream of boulders where the pocket water slows; any slot against the canyon walls where the sun doesn’t reach and the water is cold enough to hold a holding fish. The shallow flats that might produce during higher flows are not worth the time right now.
The roadside-accessible pullouts and short walks will give you enough water to fish productively. You don’t need to commit to a long hike; fish the seams nearest the road first, work systematically downstream, and move to new water if you’re not seeing signs within 10 minutes.
One Welfare Note
At 69 CFS and 61 degrees, the fish are tolerable but not celebrating. Fish the early morning or the final two hours before dark when the water is coolest and the light is reduced. Midday sessions are possible, but if you hook and play a trout in full sun on shallow water, land it quickly and let it recover before you release it—these low conditions mean less dissolved oxygen and less thermal buffering. The canyon will be crowded on pleasant September afternoons; the early and late hours are yours.
The $11 entrance fee still applies. Check the flow chart on this page before you drive up; at 69 CFS, conditions are marginal but fishable. If the gauge drops below 50 CFS, you’ll be fighting dead water and stressed fish—save the trip for a better week.