South Boulder Creek (Gross Reservoir to Eldorado Springs)
South Boulder Creek (Gross Reservoir to Eldorado Springs) — Fishing Report for April 26, 2026
Quick Stats
Flow: 20 CFS | Trend: Falling | Fishability: Fair | Weather: Patchy fog, showers and thunderstorms likely, high 49°F
The Bite
Today is a weather story first and a fishing story second. Showers and thunderstorms are in the forecast for Sunday, which means your window on the water will be narrow and unpredictable. That said, the overcast, drizzly conditions between storm cells are exactly the kind of sky that triggers BWO activity on South Boulder Creek — this is the hatch that defines April on this stream, and the moody weather could actually work in your favor if you time it right.
Flows are sitting at 20 CFS and falling sharply after what appears to be a recent bump — likely a brief release from Gross Reservoir. At this level the creek is wading comfortably, and fish should be stacked in the slower water along seams and in tailouts. With a dry, low-snowpack water year in the basin — snowpack is running around 16% of normal — expect flows to stay modest and manageable through spring rather than blowing out. That's genuinely good news for this fishery.
The biggest risk today isn't the fishing — it's the lightning. Thunderstorms in the forecast are a hard stop. Plan to be off the water by early afternoon or whenever you see cells building, and keep an eye on the sky throughout your session. If you can catch a calm, overcast window between 1 and 4 PM, surface activity is plausible. Otherwise, nymphing through the morning is the safer and more consistent play.
What to Fish
- Juju Baetis #20-22 — dropper below a dry, or point fly in a tandem nymph rig; primary searching pattern
- RS2 (gray) #20-22 — excellent emerger during any BWO window; fish it in the film or just below
- Parachute Adams #18-20 — buoyant dry fly anchor for a dry-dropper setup; clip the dropper if fish start rising confidently
- Zebra Midge (black) #20-22 — reliable before the BWO hatch comes on, especially mid-morning
- Rainbow Warrior #18-20 — attractor nymph for the point position in a tandem rig; adds flash when visibility is slightly off
- Barr's Emerger (BWO) #20-22 — switch to this if you see fish sipping in the surface film during the hatch window
Tactics & Rigging
Start the morning with a tandem nymph rig: a Rainbow Warrior on point with a Juju Baetis or RS2 trailed 14–16 inches behind. Use 5X to 6X fluorocarbon tippet and a small indicator set to match the depth of the runs you're targeting — most of the productive water on South Boulder Creek is shallow enough that you won't need much. Focus on the slower water along current seams, the soft edges of riffles, and any deeper pockets behind structure.
If the sky stays overcast and the hatch comes on — typically somewhere between 1 and 4 PM — transition to a dry-dropper: a Parachute Adams as the anchor dry with an RS2 or Barr's Emerger dropped 14–18 inches below on 6X fluorocarbon. If fish are rising confidently and ignoring the nymph, clip the dropper and fish the dry alone. Keep your presentation drag-free through the slower water; these fish see enough pressure that a dragging fly will put them down fast.
Access & Logistics
Access is generally straightforward along this stretch, but trail conditions may be soft or muddy given recent precipitation and today's forecast. Wear waterproof wading boots and plan for slick approaches. Crowds should be light given the weather — one silver lining of a stormy Sunday. Verify current regulations with CPW before fishing, as rules on this section can change.
Stop by Estes Angler or Rocky Mountain Anglers for flies, local intel, and to support the shops that keep these fisheries healthy.
Looking Ahead
Monday brings more rain and snow showers with another chance of thunderstorms, and Tuesday looks like snow — a late-season system that could briefly bump flows or cloud the water. If conditions stabilize by mid-week, the BWO hatch should reassert itself and fishing could improve significantly heading into the Mother's Day caddis buildup.