Karst · Limestone · Burgundy / Côte-d'Or, FR

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.

Tomorrow · Not the day for it
Coch-y-bonddu
New ruleReported 3 Aug 2026

Severe drought restrictions (alerte renforcée) in force

VigiEau lists this venue's surface-water zone (Armançon amont, dépt 21) at alerte renforcée, under an official préfectoral drought arrêté. Fishing is not itself banned by it, but water levels are low — go gently on stressed fish.

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Temporary notices from official orders and recent fishery reports — they clear automatically once out of date.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.

Forecast · Tomorrow
Not the day for it
Not much stacked in your favour today. Worth an hour if you are nearby, not worth the special trip.
80% projected
Today's fly
Coch-y-bonddu
Coch-y-bonddu
Conditions on the water · Tomorrow
Proxy gauge
Level
Rising
Proxy
via Loue
Water temp17.4°C
ClarityVery coloured
Weather21°C
WindN 22 km/h
Pressure1018 hPa
Rain · recent0.1 mm
Rain · ahead33.9 mm

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

Water temperature for Grayling
Warm — slow
17°C est.ideal 4–14°C
0°14°28°
How to fish it · for Grayling
When
Midday window — grayling feed best from late morning into early afternoon.
Where
Work runs and glides — grayling shoal in the bottom third of the water column.
Method
Tight-line nymph the bottom third with weighted patterns.
Kit
10 ft #3 rod, floating line, long leader to 4 lb fluoro for nymphs.
Why this works
Water at 17.4°C — above the grayling caution line (17°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Likely species
Hatch timeline · tomorrowPeak at 5pm

12pm(now) — Reed Smut

Stage: On emergersApproach: Emerger or dryActivity: 31%
Peak emergence window6 food groups active

Peak activity at 5pm — Summer River Midge (Summer River Midge, 10 food groups active)

Sub-surface · on the nymphunder the surface

Hatch predictions

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

Start free trial

14-day free trial. Cancel anytime.

Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Top prey shown — see all 4 as a supporter.

Start free trial

14-day free trial. Cancel anytime.

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
2
2
2
1
Freshwater ShrimpHatch
2
3
3
3
3
3
3
3
3
3
3
2
Brown SedgeHatch
2
3
3
3
2
Small SpurwingHatch
2
3
3
3
2
Small Dark OliveHatch
2
3
3
3
2

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

Ranked for today
Grayling 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.

Small Perdigón
Small Perdigón
Hook 14–18 · Fly
in season · matches water height
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 17°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)
  • Ecology: Moderate
  • Chemical: Good
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 Grayling · confidence 80%
How the 16 is built — score × weight = contribution
Temperature8 × 28%2.2
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time20 × 13%2.6
Pressure80 × 7%5.6
Insect activity72 × 12%8.6
Limiting factor: Water temperature (17.4°C) is outside Grayling's preferred range (4–14°C)= 52
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 4–14 °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 March → 3rd Sunday of September
  • Grayling 3rd Saturday of May → 31 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