Freestone · Limestone · Haute-Savoie

Fillière

A clear rocky-bedded stream, the Filliere river, flowing between bare winter trees near Les Ollieres, Haute-Savoie, France.

The Fillière feeds the Fier from the Bornes massif and carries enough limestone character to behave like a miniature Jura stream — clear, cold, and stubbornly selective.

Poor · Brown Trout
Small Perdigón · 16-20
New ruleReported 1 Aug 2026

Severe drought restrictions (alerte renforcée) in force

The Fier zone (Dept 74) is at alerte renforcée — the second-highest French drought tier — under a préfectoral arrêté. Fishing itself is not named as prohibited, but water is severely restricted and flows are likely very low; fish with care and check locally.

Arrêté préfectoral n°37507

Temporary notices from official orders and recent fishery reports — they clear automatically once out of date. Always confirm locally before travelling.

Poorlive now
Not the day for it
River temperature is the limiting factor today, not the flow. This is not the day to push it. Check the thermal advice above before you head out.
90% confidence
What moved it
  • Level0.09 mLast reading 23h ago
  • Water temp22.8°C
  • ClarityClear
Today's fly
Small Perdigón
Small Perdigón16-20
Euro-nymph
Conditions on the water
Live gauge
Level
Steady
0.09 m
Last reading 23h ago
Water temp22.8°C
ClarityClear
Weather32°C
WindN 9 km/h
Pressure1021 hPa
Rain · recent0.0 mm
Rain · ahead2.1 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
Warm — slow
23°C est.ideal 1016°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
Water at 22.8°C. This is the line where catch-and-release kills brown trout. Do not fish for them 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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Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 2 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 · August highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
2
2
1
Alpine RhithrogenaHatch
2
3
3
2
Sculpin / Baitfish (Rivers)Hatch
2
3
3
3
3
3
3
3
2
March BrownHatch
2
3
2
Large StoneflyHatch
2
3
2

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.

What's coming
Plan ahead
5-day outlook
Water here around 23°C. Nothing cooler within range — carry a thermometer.
Gallery · 2
  1. A clear rocky-bedded stream, the Filliere river, flowing between bare winter trees near Les Ollieres, Haute-Savoie, France.
    La Filliere @ Les Ollieres
  2. Terrain map of the venue
    Terrain map
About this water

The Fillière feeds the Fier from the Bornes massif and carries enough limestone character to behave like a miniature Jura stream — clear, cold, and stubbornly selective. It's not long and it's not big, and the pools are short enough that you'll fish the whole river in a morning if you move quickly and know what you're doing. The trout are wild, small, and educated; they've seen the hatches come and go for their entire lives and they are not easily persuaded. Match the olive, drop it on the cushion above the fish, and try not to false-cast over the pool. The canopy is tight in places — a 7ft 3-weight is the right rod. Spring and early summer are the moment. By August the flow thins and the fish retreat under the cut-banks where you can't reach them.

  • Limestone
Water quality (WFD)
  • EcologyGood
  • ChemicalGood

WFD classification · FRDR537

The full read · show the working · for Brown Trout · confidence 90%
How the 4 is built — score × weight = contribution
Temperature2 × 28%0.6
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time55 × 13%7.2
Pressure80 × 7%5.6
Insect activity61 × 12%7.3
Limiting factor: Water temperature (22.8°C) is outside Brown Trout's preferred range (10–16°C)= 55
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
Cooler water — back toward the 10–16 °C ideal band — would lift the score and ease welfare.
The dawn and dusk windows score higher than the midday lull.
Directions
Seasons & zones
  • Trout 2nd Saturday of March3rd Sunday of September
Related guides
Booking & contacts
Clubs & associations