Chalk · Normandy / Seine-Maritime (Arques headwaters)

Béthune / Eaulne

Béthune / Eaulne terrain map
Terrain map

The Béthune and the Eaulne are the two headwater rivers that join at Arques-la-Bataille to form the Arques proper, and each of them on its own is worth a day's fishing.

Poor · Brown Trout
Spent Spinner · 16-20
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
  • LevelDry recentlyNo gauge reading
  • Water temp22.0°C
  • ClarityClear
Today’s fly
Spent Spinner
Spent Spinner16-20
Upstream dry
Conditions on the water
Estimate
Level
Dry recently
No gauge reading
Water temp22.0°C
ClarityClear
Weather21°C
WindNE 18 km/h
Pressure1018 hPa
Rain · recent0.2 mm
Rain · ahead0.3 mm

No gauge on this water — readings are regional estimates from weather, not a live gauge.

Water temperature for brown trout
Warm — slow
22°C est.ideal 10–16°C
0°14°28°
How to fish it · for brown trout
When
Through the open trout season. Iron Blue and CDC grannom in April; olives through May; sedges through summer evenings.
Where
Pool tails and weeded glides through the Seine-Maritime chalk-stream stretches. Intimate water — read each lie carefully.
Method
Upstream dry to spotted rising fish; long fine leader. The water reads clear — careful approach matters more than fly choice. Move slowly upstream, cast accurately, accept the result.
Kit
9 ft #4 — French karst-stream default. Floating line, 14 ft leader to 4 lb fluoro. Polarising glasses non-negotiable.
Why this works
⛔ Water at 22°C. This is the line where catch-and-release kills brown trout. Do not fish for them today.
Hatch timeline · todayQuiet day

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Sub-surface · on the nymphunder the surface

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Beyond the hatch · worth watchingambient prey

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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 · July 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
Permits & access
Permit required — see local rules.
  • AAPPMA du Pays de Bray and local AAPPMAs share the beats on both rivers
  • Fly-only parcours on several stretches
  • Check current rules before fishing.
What's coming
Plan ahead
5-day outlook
Water here around 22°C. Nothing cooler within range — carry a thermometer.
About this water

The Béthune and the Eaulne are the two headwater rivers that join at Arques-la-Bataille to form the Arques proper, and each of them on its own is worth a day's fishing. The Béthune runs down from Neufchâtel-en-Bray through Bellencombre and Saint-Saëns, a proper chalk stream with cold stable water and a wild brown trout population throughout — nothing large, but honest and consistent. The Eaulne is shorter and quieter, rising near Londinières and running parallel to the Béthune before they meet. Both rivers get occasional sea trout running up from the Arques in autumn, and both hold grayling in the steadier pools. Olives from March, mayfly in the second half of May, summer caddis. AAPPMA beats through most of the fishable length. If you've fished the Arques itself and want to trace the river back to its sources, this is where it comes from.

  • Chalk
Water quality (WFD)
  • Ecology: Moderate
  • Chemical: Unknown

WFD classification · FRHR163

The full read · show the working · for brown trout · confidence 90%
How the 12 is built — score × weight = contribution
Temperature6 × 28%1.7
Flow60 × 22%13.2
Clarity95 × 18%17.1
Feeding Time40 × 13%5.2
Pressure80 × 7%5.6
Insect activity55 × 12%6.6
Limiting factor: Water temperature (22°C) is outside Brown Trout's preferred range (10–16°C)= 49
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
Apple MapsGoogle Maps
Seasons & zones
  • Trout2nd Saturday of March → 3rd Sunday of September
  • Grayling3rd 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.

Sea trout: Variable seasonal (2026)

Related guides
Chalkstream Playbookchalk stream tacticsGrayling Playbookgrayling tacticsPyrenees PlaybookFrench rivers
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