Freestone · Mixed · Alps / Savoie (Cœur de Savoie)

Gelon

Middle School Du Val Gelon venue image
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AAPPMA-managed tributary of the Isère at Valgelon–La Rochette.

Good · Brown Trout
Small Perdigón · 16-20
Goodlive now
A proper day on the water
Low and clear — careful approach country. Stay small, stay accurate.
75% confidence
What moved it
  • Level0.14 mLast reading 4h ago
  • Water temp17.2°C
  • ClarityClear
Today’s fly
Small Perdigón
Small Perdigón16-20
Euro-nymph
Conditions on the water
Live gauge
Level
Steady
0.14 m
Last reading 4h ago
Water temp17.2°C
ClarityClear
Weather20°C
WindNE 4 km/h
Pressure1021 hPa
Rain · recent1.0 mm
Rain · ahead26.3 mm

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

Water temperature for brown trout
Warm — slow
17°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
Good — water clarity is right today, though time of day could be better.
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 11 active hatches hour by hour with Pro.

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Evidence
Survey-backed · regionalModerate confidence

Backed by regional invertebrate surveys; no sampling on this exact reach 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
1
Grayling seasonSeason
1
2
2
2
1
GrannomHatch
2
2
Evening SedgeHatch
2
3
3
3
2
Alpine RhithrogenaHatch
1
2
2
1
Large Dark OliveHatch
1
2
2
1

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.
  • AAPPMA permits.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Isère (Combe de Savoie)
11 km
Brown trout · Grayling
Guiers
11 km
83
Brown trout · Grayling
Lac d'Aiguebelette
27 km
Brown trout · Char
Tarentaine
36 km
Brown trout · Grayling
Lac du Bourget
36 km
Brown trout · Char
Gallery · 1
  1. Terrain map of the venue
    Terrain map
About this water

AAPPMA-managed tributary of the Isère at Valgelon–La Rochette. Trout upstream, grayling in lower reaches. Alpine freestone on granite terrain. Spring through early autumn fishing. Mountain water with responsive character. Check local regulations for any restrictions or parcours requirements.

  • Mixed
Water quality (WFD)
  • Ecology: Moderate
  • Chemical: Unknown
What this classification means

WFD ecological status Good → Moderate corrected to EEA WISE 2022 (3rd RBMP) classification for waterbody FRDR10107 (was a stale earlier-cycle value). Source: EEA WISE SWB_SurfaceWaterBody (discodata.eea.europa.eu), verified 2026-06-18.

WFD classification · FRDR10107

The full read · show the working · for brown trout · confidence 75%
How the 75 is built — score × weight = contribution
Temperature72 × 28%20.2
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time50 × 13%6.5
Pressure80 × 7%5.6
Insect activity64 × 12%7.7
Conditions total= 75
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
The dawn and dusk windows score higher than the midday lull.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Trout2nd Saturday of March → 3rd Sunday of September
  • Grayling3rd Saturday of May → 3rd Sunday of September
Related guides
Grayling Playbookgrayling tacticsPyrenees PlaybookFrench riversEuro Nymphingsubsurface methods
Booking & contacts