Chalk Stream · Chalk · Dorset

River Allen (Dorset)

Photo of River Allen (Dorset)

The Allen is a tributary of the Stour running through the Crichel Estate in Dorset — a small chalk stream of exceptional water quality and habitat, with classic ranunculus, gravel runs, and stable flows.

Marginal · Brown Trout
CDC F-Fly · 18-20
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
  • Level0.44 mLast reading 8h ago
  • Water temp20.4°C
  • ClarityClear
Today's fly
CDC F-Fly
CDC F-Fly18-20
Upstream dry, on top
Conditions on the water
Live gauge
Level
Steady
0.44 m
Last reading 8h ago
Water temp20.4°C
ClarityClear
Weather30°C
WindS 15 km/h
Pressure1020 hPa
Rain · recent0.0 mm
Rain · ahead0.0 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
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 20.4°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 8 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 · regionalHigh 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
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

The heartland of English dry fly fishing. Upstream dry fly and emerger presentation dominates. Nymphing restricted or discouraged on many beats. Gin-clear alkaline water, prolific weed growth, educated wild brown trout. Precise imitation and delicate presentation are paramount.

Permits & access
Permit required — see local rules.
  • Private — Crichel Estate covers upper
  • Day tickets limited.
What's coming
Plan ahead
5-day outlook
Cooler water nearby · 1
Water here around 20°C — probably warm enough to stress Brown Trout . These are likely cooler.
Damerham Trout Fisheries
14 km
~20°C
Rainbow trout · Brown trout
Gallery · 2
  1. Photo of River Allen (Dorset)
    River Allen (Dorset) — image via Wikipedia (River Allen, Dorset)
  2. Terrain map of the venue
    Terrain map
About this water

The Allen is a tributary of the Stour running through the Crichel Estate in Dorset — a small chalk stream of exceptional water quality and habitat, with classic ranunculus, gravel runs, and stable flows. Crichel House manages most of the upper-river beats; lower river around Wimborne Minster has limited day-ticket access. Wild brown trout, technical chalk-stream conditions on a smaller scale than the Hampshire chalks.

  • Chalk
The full read · show the working · for Brown Trout · confidence 80%
How the 25 is built — score × weight = contribution
Temperature20 × 28%5.6
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time65 × 13%8.5
Pressure80 × 7%5.6
Insect activity65 × 12%7.8
Limiting factor: Water temperature (20.4°C) is outside Brown Trout's preferred range (10–16°C)= 62
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
  • Trout 1 April → 30 September
Related guides
Chalkstream Playbookchalk stream tacticsTrout Near Londonaccess guideEuro Nymphingsubsurface methods
Casting instructors near here
Booking & contacts