In this report
107 CFS and 56°F: Low Summer Water, But the Timing Could Save the Week
The live gauge is reading 107 CFS this morning, and that number carries real weight on a tailwater that swings as violently as the Pueblo stretch does. For summer context: anything below 70 CFS on this water is LOW, and 107 sits just above that threshold—which means you’re in a genuinely marginal window. The water temperature at 56°F is excellent and still within safe holding range, but flows this thin in August will warm fast under afternoon sun. The consequence is not wading difficulty or a “spooky” fishery (you’ll see plenty of water)—it’s that the trout have nowhere to spread out, and every fish worth targeting will be stacked in the deep slots and runs where current breaks and temperature gradients hold. Thin water also means fish see everything, and they’re not forgiving of sloppy casts or thick tippets.
Before you drive down: check the flow chart on this page. Releases from Pueblo Dam are volatile in summer, and the reading could shift 30–40 CFS in either direction while you’re loading the truck. A bump to 150–200 CFS changes everything about how you fish this stretch. A drop below 50 CFS makes the afternoon heat a genuine welfare concern and justifies waiting for dawn or dusk. Take two minutes to verify where things actually stand.
Midge Anchors in the Morning; Tricos and Caddis in Transition
August on a Colorado tailwater means the season’s primary hatches are still in play, but the window has narrowed. Midges remain the day-in, day-out backbone—they’ll hatch all morning and through the afternoon on low, cold tailwater flows. Start with a #22–24 black midge emerger or RS2, fished tight to the bottom in the deepest slots. This is not a visual game; you’re fishing subsurface, and a small black nymph in gin-clear water needs weight and a short leader to get down and stay there.
Trico spinner falls (those tiny #20–24 mayflies) can light up the water in early morning, typically first light through mid-morning, but they’re weather-dependent and not guaranteed this week. If you’re on the water at dawn and see small pale spinners on the water or in the air, switch to a #20–24 Trico spinner (cream, olive, or tan) and fish the slow, flat holding water along the banks where the current dies. They’re dry-fly work if conditions align, but the fall is brief—an hour, sometimes less.
Caddis in the evening (around dusk) will bring stronger, more aggressive rises than you’ll see midday. Fish a #16–18 tan or olive caddis dry (or soft-hackle emerger) on a slightly heavier leader (5X) to handle a potential fast take. The evening window on low flows is often the best bite of the day because water temps are dropping back into the 50s, and trout become less inhibited about chasing. You’ll get more refusals at midday; you’ll get actual eats at dusk.
Terrestrials—ants and beetles especially—are worth a small fly box slot. A #16–18 black ant or beetle cast to the shallower edges and overhanging willows in the early morning or late afternoon can draw strikes that midge imitations won’t. Don’t overfish them, but don’t ignore them either.
The Rigging That Works at 107 CFS
With flows this low, fish are concentrated and hypersensitive. Here’s the actual tackle setup:
Point fly + dropper combo: Start with a #22–24 black midge or RS2 emerger as your anchor (the heavier fly that gets you to the bottom), and hang a #20–24 PMD emerger or lighter midge 18 inches up the line on a short dropper (8–10 inches of tippet, 6X). This gives you a two-fly presentation in a thin, clear water situation—the bottom fly is your depth tool; the top fly is where half your takes will come from. Both should be nymphs at midday.
Weight and split shot: Add one or two small split shot 12–14 inches above the point fly, just enough to kiss bottom in the 3–5 foot depths where fish are holding. You’re not trying to load weight; you want just enough to maintain contact with structure without getting snagged on every drift. On water this low, precision beats force.
Tippet: 6X for midge-and-dropper work; 5X if you’re fishing caddis dries or slightly heavier nymphs in the evening. 7X is overkill even on gin-clear tailwater at this flow—it doesn’t improve your hookup rate on small flies, and it costs you when a decent brown actually eats.
Presentation method: Fish tight-line or with a small indicator, depending on your preference. Tight-line gives you better feel and is less visible in clear water; an indicator is easier to read and hold depth in faster pockets. At 107 CFS, both work. Focus on the seams where current bends around deeper ledges, the soft water immediately behind small rocks, and the slots along the banks where the current slows.
Where to Actually Fish This Week
Skip the thin, sunlit flats. They’ll be warm and bare of fish by 10 a.m. Fish the deep runs and slots—any place where the current has carved a darker, deeper channel and you can see the water actually moving. On low flows like these, trout are not spread across the channel; they’re in the deepest, coolest part, and nowhere else matters. Spend your time in those slots, drifting your midge rig tight to the bottom, moving only 20–30 feet at a time before repositioning.
The slower inside bends and pocket water along the banks are gold in the evening when water temperature drops and caddis are active. These areas fish best in the last two hours of usable light.
One Hard Truth: Fish the Thermal Window
With water temperature at 56°F and air temperature likely to climb into the 80s by midday, fish hard from first light until 10 a.m., then stop targeting trout. By noon, water temp could easily climb into the low 60s°F on a low-flow day, and pushing trout when they’re above their comfort zone stresses the fish and burns through your ethical stake in this water. A thermometer (a simple digital one, $20) is not optional this week—clip it to your vest and check every 30 minutes. When water temperature hits 64°F, put the rods down and come back at 6 p.m. when flows and temps stabilize. This is a Gold Medal fishery built on browns and rainbows that rely on the dam-controlled cold water to survive summer. Respect that, and the river will be there in September when flows stabilize and temperatures drop.
Fish dawn and dusk. Skip the middle of the day. That’s the week ahead.