Chalk Stream · Chalk · Wiltshire, GB-ENG

River Bourne (Wiltshire)

The River Bourne chalk stream flowing through Idmiston near Salisbury, Wiltshire
Marginal · Brown Trout
CDC F-Fly · 18-20
Slow going — pick your moments
River steady at a fishable height. Slow going — pick your moments and do not force it.
45% confidence
limited data
What moved it
  • Level0.73 mLast reading 10h ago
  • Water temp17.6°C
  • ClarityVery colouredColouring up
Today's fly
CDC F-Fly
CDC F-Fly18-20
Upstream dry, on top
Conditions on the water
Live gauge
Level
Rising
0.73 m
Last reading 10h ago
Water temp17.6°C
ClarityVery coloured
Weather20°C
WindN 17 km/h
Pressure1018 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
18°C est.ideal 1016°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
Poor — barometric pressure is working for you, but water clarity is the limiting factor today.
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

See the full sub-surface read with Pro.

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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
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
Permits & access
Permit required — see local rules.
  • Private syndicate
  • Salisbury Estate offers limited access.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Gallery · 2
  1. The River Bourne chalk stream flowing through Idmiston near Salisbury, Wiltshire
    River Bourne at Idmiston, Wiltshire
  2. Terrain map of the venue
    Terrain map
The full read · show the working · for Brown Trout · confidence 45%
How the 30 is built — score × weight = contribution
Temperature64 × 28%17.9
Flow55 × 22%12.1
Clarity15 × 18%2.7
Feeding Time75 × 13%9.8
Pressure80 × 7%5.6
Insect activity55 × 12%6.6
Limiting factor: Water is very coloured — too coloured for Brown Trout= 55
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.
A drop and clear would lift the flow and clarity scores.
Directions
Seasons & zones
  • Trout 1 April30 September
Related guides
Casting instructors near here
Booking & contacts