South Platte Below Chatfield Reservoir

South Platte Below Chatfield — Fishing Report for April 27, 2026

Quick Stats

Flow: 88 CFS | Trend: Rising | Fishability: Good | Weather: Overcast with afternoon rain showers and thunderstorms, high 59°F

The Bite

Overcast skies, cool temps, and a decent chance of afternoon showers — this is the setup BWO fishers dream about. April is the premier dry fly month on this stretch, and today's cloud cover should trigger surface activity earlier and hold it longer than a bluebird day would. Look for fish to start showing in the slower tailouts and along softer current seams by early afternoon, with the best window likely running from 1 PM until the thunderstorms push through. If the storms arrive early, that surface activity may compress — keep an eye on the sky and be ready to pivot.

Flows are sitting at 88 CFS and nudging upward — about 10% above the 10-day average. Chatfield's dam buffers the worst of any turbidity, but with rain in the forecast through Wednesday, expect the river to color slightly by mid-week. Today it should be fishing clear enough for dries. Water temps aren't available from the gauge, but seasonal patterns suggest somewhere in the mid-to-upper 40s°F — enough to get fish active and feeding aggressively. It's also worth noting that this is a dry year across the basin, with snowpack well below normal. That means runoff will be lighter and shorter than usual, which is actually good news for anglers — fewer blowout days and a longer fishable window through May.

This section draws crowds, and a Monday with good BWO conditions won't be quiet. Walk. The water a half-mile or more from any parking area fishes noticeably better — not because the fish are different, but because they haven't been lined up and spooked since 7 AM.

What to Fish

• CDC BWO Emerger #18–20 — Fish this in the film during the hatch; natural presentation in the slower water where fish are sipping
• Parachute BWO #18–20 — Easier to track than the CDC pattern; good choice when fish are rising confidently
• Sparkle Dun (olive) #18–20 — Effective when fish are keying on emergers just below or in the surface film
• RS2 #20–22 — Pre-hatch nymph; fish it on a drag-free drift through seams before surface activity picks up
• Scud (orange/pink) #16 — All-day subsurface option; reliable when nothing is happening on top
• San Juan Worm (red) #14 — Worth adding as a point fly if the rain muddies things up this afternoon

Tactics & Rigging

Before the hatch gets going — say, before noon — rig a two-nymph setup with a San Juan Worm or weighted Scud on point and an RS2 or small Pheasant Tail trailed 12–15 inches above on a tag. Fish the deeper slots and current seams with a natural drift. Once fish start showing on top, simplify: switch to a single CDC Emerger or Parachute BWO on 5X or 6X fluorocarbon with a long leader (9–12 feet). If you want to cover both levels during the hatch transition, rig a dry-dropper with the Parachute BWO as the anchor dry and a size 20 RS2 dropped 14–18 inches below — the dry floats, the nymph hangs in the film, and you're covered either way.

Target the soft water: tailouts, inside bends, and the slack lanes along current edges. Fish in this section are less selective than the Gold Medal water upstream, but clear flows and heavy pressure mean presentation still matters. Mend early, keep your drift clean, and approach rising fish from downstream.

Access & Logistics

Parking areas along the Platte River Greenway fill early on good hatch days. The water closest to the lots sees the most pressure — plan to walk. Trail conditions should be fine, though afternoon storms may make the return muddy. New Zealand mudsnails have been documented in this drainage; clean, drain, and dry all waders, boots, and nets before and after every trip. Verify current regulations with CPW before fishing — stocking schedules and any urban corridor rules can change.

Stop by Trouts Fly Fishing or Sportsman's Warehouse (Littleton) for flies, local intel, and to support the shops that keep this fishery on the radar.

Looking Ahead

Rain is in the forecast through Wednesday, which may push flows up slightly and add a touch of color — nothing Chatfield can't manage, but worth checking the gauge before you head out mid-week. The Mother's Day Caddis hatch is building and should start showing more consistently over the next two weeks, so keep an Elk Hair Caddis or Caddis Pupa in the box.