Freestone · Mixed · Alps / Savoie (Haute Maurienne)

Arc

Arc venue image
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Major Savoyard alpine river in Haute Maurienne.

Prime · Brown Trout
Small Perdigón · 16-20
Primelive now
About as good as it gets
River high but settled. Coloured water — fish bigger and deeper, confident takes down the seams.
75% confidence
What moved it
  • Level1.43 mDropping in the last 6h
  • Water temp14.9°C
  • ClarityClear
Today’s fly
Small Perdigón
Small Perdigón16-20
Euro-nymph
Conditions on the water
Live gauge
Level
Steady
1.43 m
Dropping in the last 6h
Water temp14.9°C
ClarityClear
Weather15°C
WindSW 1 km/h
Pressure1024 hPa
Rain · recent73.9 mm
Rain · ahead10.6 mm

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

Water temperature for brown trout
Ideal
15°C est.ideal 10–16°C
0°14°28°
How to fish it · for brown trout
When
Through the open trout season — late spring through autumn. The Arc is glacial-fed from Haute Maurienne; fishes once meltwater eases.
Where
Pool tails and pocket water through the Maurienne valley. Glacial Alpine freestone — clear cold water, intimate scale.
Method
Upstream dry to risers; dry-dropper through the riffles. The water reads clear — long leader, fine tippet. Move slowly, cast accurately.
Kit
9 ft #4 — French freestone default. Floating line, 12 ft leader to 4 to 5 lb fluoro. Studded boots.
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 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.
  • Savoie AAPPMA permits.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Arc (Bessans reach)
< 1 km
Brown trout · Grayling
Plan d'Aval
16 km
Brown trout
Tarentaine
19 km
Brown trout · Grayling
Lac du Mont-Cenis
23 km
Brown trout · Char
Isère (Combe de Savoie)
45 km
35
Brown trout · Grayling
Gallery · 1
  1. Terrain map of the venue
    Terrain map
About this water

Major Savoyard alpine river in Haute Maurienne. 7 km no-kill fly-fishing course with barbless-hook requirement. Snowmelt-dominated — May–June best when melt provides volume and insect life emerges. Technical pocket-water fishing in high-alpine terrain on granite freestone. Wild trout in pristine conditions. Check Savoie AAPPMA for permits and regulations.

  • Mixed
Water quality (WFD)
  • Ecology: Good
  • Chemical: Unknown

WFD classification · FRDR361A

The full read · show the working · for brown trout · confidence 75%
How the 80 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time45 × 13%5.9
Pressure80 × 7%5.6
Insect activity51 × 12%6.1
Conditions total= 80
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