Trico spinners and terrestrials take over CO's tailwaters

What's biting

What's next

No temperature reading came through with this morning's gauge pull, and there's no fresh precipitation or wind data in this cycle, so the near-term outlook leans on flow trend and seasonal pattern rather than a hard forecast — check local forecast before heading out and plan around the numbers you see streamside.

At 249 cfs, the gauge is sitting in a range that typically supports easy wading and good drift control on tailwater runs, but Pat Dorsey Fly Fishing (CO) has been warning that 2026 ranks among Colorado's driest years on record, alongside 1975-78, 2002, 2012, 2018 and 2020. If that pattern holds through the next few weeks, expect flows to keep sliding lower rather than spiking, which usually concentrates fish into deeper runs and pools as water drops and warms through the afternoon. Anglers should plan around early mornings and evenings as the safer windows once daytime heat builds, both to protect fish handled in warmer water and to fish the bug windows that matter most this time of year.

Two hatch windows should keep firming up over the next several days. Gink and Gasoline's account of the South Platte's trico spinner falls describes a classic July pattern: dense morning hatches that pile up in the surface film and trigger some of the most technical dry-fly fishing of the season, best fished early before the day heats up and the spinners disperse. Trout Unlimited's current TROUT Tip on pink terrestrials points to the other half of the summer program — as ants, beetles and hoppers start getting blown or knocked into the current, fish key on them as an easy meal, which should only get more productive as banks dry out further into summer.

For tactics, AvidMax Blog (CO)'s recent tying features are a useful read on what's working right now: small midge emergers like their Chocolate Foam Back and Titan Tube Midge for low, clear tailwater flows, and a jig-style tungsten nymph like the Jigged CDC PT Tungsten for Euro-nymphing faster runs. That combination — small midges and technical nymphs in the morning, terrestrials and trico spinners as the day warms — is a reasonable plan for the coming days if the current flow and dry pattern hold. Anyone planning a trip should still check current state regulations and any flow- or temperature-based fishing restrictions before heading out, since low-water years can bring added caution around handling fish in warmer water.

Context

Pat Dorsey Fly Fishing (CO) gives the clearest comparative signal in this data set: writing about Colorado's water-year history, the shop lists 1975-78, 2002, 2012, 2018 and 2020 as the state's notable low-water years and says many climate-watchers consider 2026 the worst on record for Colorado's snowpack-fed rivers. If that framing holds, a summer 2026 flow reading in the mid-200 cfs range on a South Platte or Arkansas tailwater gauge is consistent with a below-average water year rather than an anomaly for this one date.

Seasonally, early-to-mid July on Colorado's front-range tailwaters typically means the spring runoff pulse has faded and rivers have settled into their summer baseline — clearer water, more consistent day-to-day flows, and a hatch calendar leaning on midges, PMDs, caddis and the trico spinner falls that Gink and Gasoline specifically calls out on the South Platte. Terrestrial activity, as Trout Unlimited's current tip notes, typically ramps up through July and August as the season's insects mature, which tracks with what these feeds describe.

Beyond the drought framing and general seasonal hatch timing, this data set doesn't include a same-week or same-month prior-year comparison for the South Platte and Arkansas tailwaters specifically, so it isn't possible to say with confidence whether this week's numbers are running ahead of, behind, or on pace with a typical mid-July for these exact stretches. Treat the drought context as the most reliable historical signal available right now.