Freestone · Mixed · Alps / Savoie (Haute Maurienne), FR

Arc

Arc à Saint-Michel-de-Maurienne dans l'après-midi (juillet 2022) 2

Major Savoyard alpine river in Haute Maurienne.

Poor · Brown Trout
Hare's Ear Nymph · 14-16
Closed season
Out of season. Try elsewhere.
Closed — confidence not applicable today.
What moved it
  • Level0.47 mLast reading 10h ago
  • Water temp11.4°C
  • ClarityClear
Today's fly
Hare's Ear Nymph
Hare's Ear Nymph14-16
Upstream
Conditions on the water
Live gauge
Level
Steady
0.47 m
Last reading 10h ago
Water temp11.4°C
ClarityClear
Weather11°C
WindSE 6 km/h
Pressure1029 hPa
Rain · recent0.0 mm
Rain · ahead6.2 mm

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

Water temperature for Brown Trout
Ideal
11°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.
Likely species
Caddisflies
Hatch timeline · todayPeak at 6am

Hatch predictions

Today's headline hatch shown — see all 12 active hatches hour by hour as a supporter.

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Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 4 guilds as a supporter.

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Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Supporters see what else is on the menu.

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Evidence
Survey-backed · regionalHigh confidence

Backed by regional invertebrate surveys; no sampling on this exact reach yet.

Through the year
0–3 scale · September 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
Evening SedgeHatch
2
3
3
3
2
Alpine RhithrogenaHatch
1
2
2
1
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
2
2
2
2
2
2
1

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

Ranked for today
Brown Trout fly box

French nymph-first water. Fast current, technical presentation, weighted nymphs and emergers, with dry flies when fish rise.

Permits & access
Permit required — see local rules.
  • Savoie AAPPMA permits.
What's coming
Plan ahead
5-day outlook
Fishing better nearby · 5
Dora Baltea (No-Kill, Chambave-Verrayes)
58 km
30
Brown trout · Marble trout · Grayling
Arc
< 1 km
Brown trout · Grayling
Lac du Mont-Cenis
11 km
Brown trout · Char
Plan d'Aval
23 km
Brown trout
Ayasse
59 km
Rainbow trout
Gallery · 2
  1. Arc à Saint-Michel-de-Maurienne dans l'après-midi (juillet 2022) 2
  2. 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.

Hatches & food

In true Alpine headwaters, trout feeding is squeezed into a short high-summer slot, with mountain olives and other mayflies following snowmelt, daytime stoneflies over rough, bouldery water, evening caddis on the warmest settled nights, and small buzzers keeping fish interested before, between and after the main up-wing and caddis hatches.

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

WFD classification · FRDR361A

The full read · show the working · for Brown Trout · confidence 90%
How the 0 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time70 × 13%9.1
Pressure80 × 7%5.6
Insect activity59 × 12%7.1
Conditions total= 84
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Trout 2nd Saturday of March → 3rd Sunday of September
  • Grayling 3rd Saturday of May → 3rd Sunday of September

    France national rule: grayling opens 3rd Saturday of May in all waters. In 1st category (salmonid) rivers, grayling closes with the trout season on the 3rd Sunday of September. Departmental regulations may impose additional restrictions. Always check the relevant département's 2026 arrêté préfectoral.

Related guides
Grayling Playbookgrayling tacticsPyrenees PlaybookFrench riversEuro Nymphingsubsurface methods
Booking & contacts