Chalk · Normandy / Seine-Maritime (Dieppe area), FR

Arques

Arques terrain map

The Arques is a quiet Normandy chalk stream near Dieppe that holds a genuine sea trout run alongside its resident brown trout and grayling — 28 declared sea trout in 2024, which places it ahead of several more famous French migratory rivers.

Marginal · Brown Trout
Sedge du Soir · 12-16
Marginallive now
Slow going — pick your moments
River temperature is the limiting factor today, not the flow. Fish dawn or dusk if you go at all, and handle everything with extra care.
80% confidence
What moved it
  • Flow0.5 m³/sLast reading 19h ago
  • Water temp19.9°C
  • ClarityClear
Today's fly
Sedge du Soir
Sedge du Soir12-16
Upstream dry
Conditions on the water
Live gauge
Flow
Steady
0.5 m³/s
Last reading 19h ago
Water temp19.9°C
ClarityClear
Weather22°C
WindNW 6 km/h
Pressure1016 hPa
Rain · recent0.0 mm
Rain · ahead0.2 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
20°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 chalk-stream stretches around Dieppe. The Arques is intimate water; read each lie.
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 19.9°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Hatch timeline · todayPeak at 6pm

Hatch predictions

Today's headline hatch shown — see all 11 active hatches hour by hour with Pro.

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Sub-surface · on the nymphunder the surface

Hatch predictions

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Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 3 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
Sea trout runRun
1
2
2
2
2
2
1
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

Classic French chalkstream fishing. Gin-clear, weed-rich, slow to moderate flow. Dry fly and sight nymphing dominate. Stronger sedge hatches than English equivalents. French tradition favours flush-sitting dries (comparaduns, CDC patterns) and upstream presentation.

Permits & access
Permit required — see local rules.
  • AAPPMA permits
  • Private estate water on sections.
What's coming
Plan ahead
5-day outlook
Water here around 20°C. Nothing cooler within range — carry a thermometer.
About this water

The Arques is a quiet Normandy chalk stream near Dieppe that holds a genuine sea trout run alongside its resident brown trout and grayling — 28 declared sea trout in 2024, which places it ahead of several more famous French migratory rivers. The chalk character gives it stable, clear water and prolific invertebrate life. Small olives and evening sedges sustain selective dry-fly fishing for brown trout through the season. Sea trout enter from the estuary and run on spate water, providing a secondary but credible target from summer through autumn.

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.

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

WFD classification · FRHR166

The full read · show the working · for Brown Trout · confidence 80%
How the 28 is built — score × weight = contribution
Temperature26 × 28%7.3
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time55 × 13%7.2
Pressure80 × 7%5.6
Insect activity66 × 12%7.9
Conditions total= 63
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
  • Sea trout 25 April → 25 October
  • 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.

Sea trout: Open (2026) — Credible secondary sea trout river. 28 declared rod catches in 2024 — better than many historic glamour rivers.

Related guides
Chalkstream Playbookchalk stream tacticsGrayling Playbookgrayling tacticsPyrenees PlaybookFrench rivers
Booking & contacts