Chalk · Normandy / Seine-Maritime (Coastal chalk stream), FR

Durdent

A historic stone watermill with a large wooden waterwheel, with the Durdent River flowing past in the foreground.

Small Normandy chalk stream with quiet character and consistent flow.

Today · About as good as it gets
Czech Nymph
Forecast · Today
About as good as it gets
On the feed top to bottom — start on the rises with a dry, drop a nymph if they stay down.
90% projected
Today's fly
Czech Nymph
Czech Nymph
Conditions on the water · Today
Live gauge
Level
Falling
0.26 m
Dropping after lift
Water temp10.9°C
ClaritySlightly coloured
Weather5°C
WindN 15 km/h
Pressure1016 hPa
Rain · recent0.8 mm
Rain · ahead11.4 mm

The nearest gauge doesn't record temperatures, so we've estimated it — defer to the river keeper's advice.

Water temperature for Grayling
Ideal
11°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
Good — water temperature is working for you, but time of day is the limiting factor today.
Likely species
Stoneflies
Hatch timeline · todayPeak at 6pm

12pm(now) — Autumn Olive

Stage: On emergersApproach: Emerger or dryActivity: 44%
Also:Autumn Needle Fly30%Black Midge21%
Peak emergence window5 food groups active

Peak activity at 6pm — Caperer (Caperer, 4 food groups active)

Sub-surface · on the nymphunder the surface

Hatch predictions

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

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14-day free trial. Cancel anytime.

Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Top prey shown — see all 3 as a supporter.

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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 · November 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
Mayfly (Green Drake)Hatch
2
2
Brown SedgeHatch
2
3
3
3
2
Small SpurwingHatch
2
3
3
3
2

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

Ranked for today
Grayling 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.

Small Perdigón
Small Perdigón
Hook 14–18 · Fly
in season
Permits & access
Permit required — see local rules.
  • AAPPMA permits.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Saâne
27 km
75
Brown trout · Grayling
Scie
35 km
Brown trout · Grayling
Arques
36 km
82
Brown trout · Grayling · Sea trout
Paradis Aquatique
48 km
Rainbow trout
Yères
51 km
77
Brown trout · Grayling
Gallery · 2
  1. A historic stone watermill with a large wooden waterwheel, with the Durdent River flowing past in the foreground.
    Vieux moulin/Old Mill, Normandy-France
  2. Terrain map of the venue
    Terrain map
About this water

Wild brown trout and grayling respond to seasonal insect patterns. Clear water, stable temperature typical of chalk geology. Small flies required: olives and ephemeralids (16–18), sedges (14–16) in evening. Presentation matters more than fly choice. Some stretches private. Check access with local club.

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: Good
  • Chemical: Unknown

WFD classification · FRHR171

The full read · show the working · for Grayling · confidence 55%
How the 75 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time10 × 13%1.3
Pressure80 × 7%5.6
Insect activity56 × 12%6.7
Conditions total= 75
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
The dawn and dusk windows score higher than the midday lull.
Directions
Apple MapsGoogle Maps
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
Chalkstream Playbookchalk stream tacticsGrayling Playbookgrayling tacticsPyrenees PlaybookFrench rivers
Booking & contacts
At a glance

Durdent is a chalk stream in Normandy / Seine-Maritime (Coastal chalk stream), France. Its recorded elevation is about 7 m above sea level and the catchment geology is chalk. The river is described as roughly 23 km long. Our data lists brown trout and grayling here. The trout season is recorded as running from 2nd Saturday of March to 3rd Sunday of September. The grayling season is recorded as running from 3rd Saturday of May to 31 December. Best window recorded for anglers: March–October. Core methods listed: Dry fly; nymphing. Level and flow data for this water is linked from 1 gauge. Its Water Framework Directive ecological status is recorded as good. Access is recorded as day tickets through the local AAPPMA (angling association). Nearby waters in our listings include Saâne at 27 km, Scie at 35 km and Arques at 36 km.