Tailwater · Mixed · Colorado

Big Thompson River (canyon, below Lake Estes)

The Big Thompson River flowing over cobblestones through pines and aspens, Colorado.

The Big Thompson is the Front Range canyon fix below Estes Park — a tailwater-fed stream running down Highway 34 toward Loveland, holding wild and stocked browns and rainbows in tight, technical pocket water.

Prime · Brown Trout
Sparkle Dun · 14-18
Primelive now
About as good as it gets
River dropping into shape after a lift. The kind of afternoon you remember — a weighted nymph through the clearing seams, the dry as it settles.
90% confidence
What moved it
  • Level0.43 mDropping after lift
  • Water temp10.3°C
  • ClarityClear
Today's fly
SD
Sparkle Dun14-18
High-confidence seasonal pick
Conditions on the water
Live gauge
Level
Steady
0.43 m
Dropping after lift
Water temp10.3°C
ClarityClear
Weather30°C
WindSE 15 km/h
Pressure1013 hPa
Rain · recent0.0 mm
Rain · ahead1.7 mm

Live readings — water temperature is an estimate where the gauge does not record it.

Water temperature for Brown Trout
Ideal
10°C est.ideal 10–16°C
0°14°28°
How to fish it · for Brown Trout
When
Nymphing can work through most of the day.
Where
Cover mixed depths.
Method
Start with tight-line nymphs and adjust if fish rise or drift higher.
Kit
9 ft #4 rod, floating line, 12 ft tapered leader to 4–5 lb fluoro tippet.
Why this works
Excellent — water temperature is right today, though time of day could be better.
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 3 active hatches hour by hour with Pro.

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Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 3 guilds with Pro.

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Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 3 with Pro.

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Evidence
ModelledModerate confidence

Modelled from regional ecology — no survey or occurrence data for this water yet.

Through the year
0–3 scale · July highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
2
2
2
2
2
2
2
1
Western Blue-Winged OliveHatch
2
3
3
3
3
3
3
3
2
Pale Morning DunHatch
2
3
3
2
TricoHatch
2
3
2
Black MidgeHatch
2
3
3
3
3
3
3
3
3
3
3
2

Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.

Ranked for today
Brown Trout fly box
Permits & access
Permit required — see local rules.
  • Colorado licence
  • Wild Trout catch-and-release flies/lures section in the canyon — verify CPW rules
  • Roadside access throughout the canyon.
What's coming
Plan ahead
5-day outlook
Other water nearby · 3
St. Vrain Creek (Lyons)
22 km
Brown trout · Rainbow trout
Cache la Poudre River
28 km
Brown trout · Rainbow trout
Boulder Creek (Boulder Canyon)
46 km
4
Brown trout · Rainbow trout
Gallery · 3
  1. Venue photo
  2. The Big Thompson River flowing over cobblestones through pines and aspens, Colorado.
    Listening While the River Runs - Big Thompson River
  3. Terrain map of the venue
    Terrain map
About this water

The Big Thompson is the Front Range canyon fix below Estes Park — a tailwater-fed stream running down Highway 34 toward Loveland, holding wild and stocked browns and rainbows in tight, technical pocket water. The catch-and-release Wild Trout section in the canyon is the real prize: small flies, careful wading, and fish that have been educated by every Denver and Loveland angler who ever pulled over. Flow comes off Lake Estes and the Colorado-Big Thompson plumbing, so it's release-driven, fishes through the winter, and makes a reliable quick-hit when the high country's shut.

  • Mixed
Water quality · US Clean Water Act
  • Aquatic life: Impaired
What this classification means

EPA ATTAINS assessment unit 'Big Thompson River, mainstem' (COSPBT02_F), 2024 Integrated Report. Aquatic Life use: Not Supporting. Listed impairment causes: Metals Other Than Mercury. This is a Clean Water Act assessment-unit classification (the US analogue of WFD), not a live reading.

Status is for the Clean Water Act assessment unit covering this reach.

EPA ATTAINS (Clean Water Act) · COSPBT02_F

The full read · show the working · for Brown Trout · confidence 90%
How the 83 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time55 × 13%7.2
Pressure80 × 7%5.6
Insect activity63 × 12%7.6
Conditions total= 83
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
The dawn and dusk windows score higher than the midday lull.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Trout1 January → 31 December
Related guides
Euro Nymphingsubsurface methods
Booking & contacts