Tailwater · Mixed · Montana, US

Kootenai River

Kootenai River — 18205 Lake Koocanusa
Tomorrow · Not the day for it
Czech Nymph
Forecast · Tomorrow
Not the day for it
Not much stacked in your favour today. Worth an hour if you are nearby, not worth the special trip.
45% projected
Today's fly
Czech Nymph
Czech Nymph
Conditions on the water · Tomorrow
Live gauge
Level
Rising
5.49 m
Lifting fast
Water temp11.0°C
ClarityUnfishable
Weather10°C
WindN 3 km/h
Pressure1009 hPa
Rain · recent0.0 mm
Rain · ahead0.0 mm

The nearest gauge doesn't record temperatures, so we've estimated it — defer to the river keeper's advice.

Water temperature for Rainbow Trout
Ideal
11°C est.ideal 10–18°C
0°14°28°

Typical for this reach at this time of year, fitted to the river's own record — not a reading of today's release. A change at the dam can move it several degrees within hours. It also warms as it runs away from the dam.

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.
Likely species
Hatch timeline · tomorrowPeak at 11h

12h(now) — Western Blue-Winged Olive

Stage: On emergersApproach: Emerger or dryActivity: 47%
Peak emergence window4 food groups active

Peak activity at 11h — Western Blue-Winged Olive (Western Blue-Winged Olive, Peak emergence window)

Sub-surface · on the nymphunder the surface

Hatch predictions

Supporters see the full sub-surface read.

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Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Top prey shown — see all 3 as a supporter.

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Evidence
Records-basedModerate confidence

Based on species-occurrence records, not local invertebrate surveys.

Through the year
0–3 scale · October 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
Fly box · Rainbow Trout
Permits & access
Permit required — see local rules.
  • Montana licence
  • Bull trout must not be targeted and must be released (federally threatened)
  • Fishability is set by the Libby Dam release, not the weather.
What's coming
Plan ahead
5-day outlook
Gallery · 2
  1. Kootenai River — 18205 Lake Koocanusa
    18205 Lake Koocanusa
  2. Terrain map of the venue
    Terrain map
Conservation note

Wild rainbow trout (including native redband lineage) are the headline. Native westslope cutthroat and federally threatened bull trout are also present: bull trout must not be targeted and must be released unharmed. The pack's 'cutthroat_trout' profile is a Phase 1 deliverable and there is no bull_trout scoring profile by design.

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

EPA ATTAINS assessment unit 'Kootenai River' (MT76D001_010), 2021 Integrated Report. Aquatic Life use: Not Supporting. Listed impairment causes: Temperature, Hydrologic Alteration. 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) · MT76D001_010

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 activity66 × 12%7.9
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
  • Trout 1 January → 31 December
Related guides
Booking & contacts