Karst · Limestone · Burgundy / Côte-d'Or

Armançon (Upper Trout Reach)

Armançon (Upper Trout Reach) — Armançon Nuits

The upper Armançon, before it becomes the broad canal-flanked river that runs across the Burgundy plain, is a Côte-d'Or trout stream of real quality.

Poor · Brown Trout
CDC Emerger · 16-18
New ruleReported 3 Aug 2026

Severe drought restrictions (alerte renforcée) in force

The Armançon amont zone (Dept 21) 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°37578

Temporary notices from official orders and recent fishery reports — they clear automatically once out of date.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 Loue
  • Water temp23.2°C
  • ClarityClear
Today's fly
CDC Emerger
CDC Emerger16-18
Dead-drift
Conditions on the water
Proxy gauge
Level
Steady
Proxy
via Loue
Water temp23.2°C
ClarityClear
Weather35°C
WindN 7 km/h
Pressure1020 hPa
Rain · recent0.0 mm
Rain · ahead1.2 mm

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

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 23.2°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 6 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
Grayling seasonSeason
1
2
2
2
2
2
2
1
Brown SedgeHatch
2
3
2
Freshwater ShrimpHatch
2
3
3
3
3
3
3
3
3
3
3
2
Blue Winged OliveHatch
2
3
3
3
3
2
Mayfly (Green Drake)Hatch
2
2

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 Montbard / Semur-en-Auxois
  • Standard 1ère catégorie.
What's coming
Plan ahead
5-day outlook
Water here around 23°C. Nothing cooler within range — carry a thermometer.
Gallery · 2
  1. Armançon (Upper Trout Reach) — Armançon Nuits
    Armançon Nuits
  2. Terrain map of the venue
    Terrain map
About this water

The upper Armançon, before it becomes the broad canal-flanked river that runs across the Burgundy plain, is a Côte-d'Or trout stream of real quality. It rises on the Jurassic limestone near Essarois, runs through Montbard and Semur-en-Auxois, and gathers water from a long series of spring feeders as it goes. The character is limestone throughout: clear water, weedy pool tails, slow seams, and wild brown trout that know exactly what a size 16 olive looks like and what it does not. Fish the upper and middle reaches for brown trout and the occasional grayling. The hatches are strong — Baetis through spring, grannom in April, BWO throughout, and reliable caddis from May — and the limestone buffering keeps the river in condition even through dry spells. The trout are selective in the slow glides and bolder in the faster runs below the bridges. Start small — size 16 or 18 on fine tippet — and expect the fish to inspect rather than grab. The upper Armançon rewards the kind of patient, careful fishing that people associate with English chalk streams, without any of the associated expense or fuss.

Hatches & food

In chalk-spring and karst trout systems, generally stable temperatures broaden olive and other mayfly activity from early spring into autumn, with strong evening caddis, steady subsurface scuds and buzzers where clear groundwater and weedbeds develop, and terrestrials from meadow and woodland banks rounding out the food calendar, depending on how fast each river drops and clears after rain.

  • Limestone
Water quality (WFD)
  • EcologyModerate
  • ChemicalGood
What this classification means

WFD chemical status Failing to achieve good → Good corrected to EEA WISE 2022 (3rd RBMP) classification for waterbody FRHR61C (was a stale earlier-cycle value). Source: EEA WISE SWB_SurfaceWaterBody (discodata.eea.europa.eu), verified 2026-06-18.

WFD classification · FRHR61C

The full read · show the working · for Brown Trout · confidence 90%
How the 2 is built — score × weight = contribution
Temperature1 × 28%0.3
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time60 × 13%7.8
Pressure80 × 7%5.6
Insect activity44 × 12%5.3
Limiting factor: Water temperature (23.2°C) is outside Brown Trout's preferred range (10–16°C)= 54
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowproxy via Loueproxy
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
  • Grayling 3rd Saturday of May31 December

    France national rule: grayling opens 3rd Saturday of May in all waters. In 2nd category waters, grayling remains open until 31 December. Departmental regulations may impose earlier closing dates. Always check the relevant département's 2026 arrêté préfectoral.

Related guides
Booking & contacts