Freestone · Granite · Morvan / Nièvre

Yonne (Upper, Morvan Headwaters)

Yonne (Upper, Morvan Headwaters) — Le pont Boffrand-Hupeau - Joigny

The upper Yonne, before the Pannesière and Chaumeçon reservoirs and long before the broad navigable river of tourist Burgundy, is a proper Morvan trout stream.

Poor · Brown Trout
CDC Emerger · 16-18
New ruleReported 7 Aug 2026

Severe drought restrictions (crise) in force

The ARROUX MORVAN zone (Dept 71) is at crise — 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°37613

Temporary notices from official orders and recent fishery reports — they clear automatically once out of date.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
  • LevelProxyvia Sioule
  • Water temp23.6°C
  • ClarityClear
Today's fly
CDC Emerger
CDC Emerger16-18
Dead-drift
Conditions on the water
Proxy gauge
Level
Steady
Proxy
via Sioule
Water temp23.6°C
ClarityClear
Weather35°C
WindSE 10 km/h
Pressure1020 hPa
Rain · recent0.0 mm
Rain · ahead3.3 mm

No gauge on this water — conditions are inferred from Sioule. The trend transfers, the absolute level does not.

Water temperature for Brown Trout
Warm — slow
24°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 23.6°C. This is the line where catch-and-release kills brown trout. Do not fish for them today.
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
Large Dark OliveHatch
1
2
2
1
Blue Winged OliveHatch
1
2
2
2
2
1
Autumn OliveHatch
1
2
1
GrannomHatch
1
1

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

Ranked for today
Brown Trout fly box

More balanced than the mountain-river pack. French nymphing still matters, but there is more room for dries, spiders and general searching flies.

Permits & access
Permit required — see local rules.
  • AAPPMA Château-Chinon / Fédération Nièvre
  • Standard 1ère catégorie.
What's coming
Plan ahead
5-day outlook
Water here around 24°C. Nothing cooler within range — carry a thermometer.
Gallery · 2
  1. Yonne (Upper, Morvan Headwaters) — Le pont Boffrand-Hupeau - Joigny
    Le pont Boffrand-Hupeau - Joigny
  2. Terrain map of the venue
    Terrain map
About this water

The upper Yonne, before the Pannesière and Chaumeçon reservoirs and long before the broad navigable river of tourist Burgundy, is a proper Morvan trout stream. It rises in the Mont Preneley bogs at the heart of the granite massif and runs down through the high Morvan woods towards Château-Chinon. The first thirty kilometres are small, cold, and stony — real wild trout country that happens to share its name with a river everyone thinks they already know. Fish it slowly. The Baetis are good from late March onwards, the caddis build from May, and the stoneflies in the rough water are worth imitating through spring. The trout are wild and small-to-medium — six to ten inches is the working average, with the odd surprise in the deeper pool-tails that you did not expect. Upper Morvan water runs cold until May, so the season starts slowly. Nymph in April, shift to dry fly once the first march browns show, and do not expect a river that looks anything like the Yonne of the schoolbook maps. This is a different animal altogether — honest, quiet, and almost entirely unpublicised.

  • Granite
Water quality (WFD)
  • EcologyHigh
  • ChemicalFailing to achieve good
What this classification means

WFD ecological status Good → High and chemical status Good → Failing to achieve good corrected to EEA WISE 2022 (3rd RBMP) classification for waterbody FRHR42A (was a stale earlier-cycle value). Source: EEA WISE SWB_SurfaceWaterBody (discodata.eea.europa.eu), verified 2026-06-18.

WFD classification · FRHR42A

The full read · show the working · for Brown Trout · confidence 90%
How the 0 is built — score × weight = contribution
Temperature0 × 28%0.0
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time60 × 13%7.8
Pressure80 × 7%5.6
Insect activity46 × 12%5.5
Limiting factor: Water temperature (23.6°C) is outside Brown Trout's preferred range (10–16°C)= 54
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowproxy via Siouleproxy
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