Tailwater · Limestone · Texas

Guadalupe River — below Canyon Lake

The Guadalupe River flowing past a limestone bank with green Hill Country woodland on the far shore, Texas.

The Guadalupe below Canyon Lake is the strangest trout river in this whole app — a Hill Country limestone river in central Texas that grows rainbow trout only because Canyon Lake Dam dumps cold water out of its depths into the summer heat.

Good · Rainbow Trout
Sparkle Dun · 14-18
Goodlive now
A proper day on the water
River high but settled. Match the colour and fish the seams.
75% confidence
What moved it
  • Level1.34 m
  • Water temp10.3°C
  • ClarityClear
Today's fly
SD
Sparkle Dun14-18
High-confidence seasonal pick
Conditions on the water
Live gauge
Level
Steady
1.34 m
Water temp10.3°C
ClarityClear
Weather28°C
WindSE 15 km/h
Pressure1014 hPa
Rain · recent0.0 mm
Rain · ahead0.0 mm

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

Water temperature for Rainbow Trout
Ideal
10°C est.ideal 1018°C
0°14°28°
How to fish it · for Rainbow 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
Good — water temperature is working for you, but time of day is the limiting factor today.
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
Rainbow Trout fly box
Local fly shops: ReelFly
Permits & access
Permit required — see local rules.
  • Texas licence required
  • Special harvest/gear regulations apply on the GRTU lease and TPWD special-reg reaches — verify the current reach rules before you fish.
What's coming
Plan ahead
5-day outlook
Gallery · 2
  1. The Guadalupe River flowing past a limestone bank with green Hill Country woodland on the far shore, Texas.
    Calm, clear water of the Guadalupe River lined with Hill Country limestone and cypress near New Braunfels, Texas.
  2. Terrain map of the venue
    Terrain map
About this water

The Guadalupe below Canyon Lake is the strangest trout river in this whole app — a Hill Country limestone river in central Texas that grows rainbow trout only because Canyon Lake Dam dumps cold water out of its depths into the summer heat. It's the southernmost trout fishery in the country, kept alive by Texas Parks and Wildlife stocking and the Guadalupe River chapter of Trout Unlimited, who lease private reaches and run special regulations to hold a year-round fishery. Fish the cold water close to the dam, especially in summer; the further downstream you go, the warmer it gets and the shorter the trout's welcome.

Under the surface

The Guadalupe below Canyon Lake is the southernmost trout fishery in the United States, which is a sentence that requires a dam to be true — the cold bottom release out of Canyon Reservoir keeps a stretch of Hill Country river cold enough for rainbows and the occasional holdover brown to survive the Texas heat, at least for a while. It runs through the limestone canyon country northwest of San Antonio, clear and green over a bed of limestone cobble, ledge and the bald cypress roots that line every Hill Country river, the flow entirely dependent on what the dam lets out. It's a tailwater novelty and a genuinely fun one — stocked heavily, fished hard, prone to crowds and tubers in summer — but the lower releases hold over fish and the limestone gives it real character. Wading is comfortable on firm rock. It is trout fishing where trout shouldn't be, and Texans love it all the more for that.

Wading: Release dependent flow, summer crowds

  • Limestone
  • Partly confined
  • Pool riffle
Water quality · US Clean Water Act
  • Aquatic lifeSupporting
What this classification means

EPA ATTAINS assessment unit 'Guadalupe River Below Canyon Dam' (TX-1812_03), 2024 Integrated Report. Aquatic Life use: Fully Supporting. 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) · TX-1812_03

The full read · show the working · for Rainbow Trout · confidence 75%
How the 79 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time40 × 13%5.2
Pressure75 × 7%5.3
Insect activity63 × 12%7.6
Conditions total= 79
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
Seasons & zones
  • Trout1 January31 December
Related guides
Booking & contacts