Chalk Stream · Chalk · Wiltshire, GB-ENG

River Bourne (Wiltshire)

The River Bourne chalk stream flowing through Idmiston near Salisbury, Wiltshire

The Wiltshire Bourne (Hampshire Avon tributary, distinct from the Hampshire Bourne) runs through Salisbury Plain country from Tidworth past Salisbury to join the Avon.

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
  • Level0.02 mLifting fast
  • Water temp19.9°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
0.02 m
Lifting fast
Water temp19.9°C
ClarityVery coloured
Weather24°C
WindW 9 km/h
Pressure1017 hPa
Rain · recent0.0 mm
Rain · ahead2.3 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 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 8 active hatches hour by hour with Pro.

Start free trial

14-day free trial. Cancel anytime.

Sub-surface · on the nymphunder the surface

Hatch predictions

See the full sub-surface read with Pro.

Start free trial

14-day free trial. Cancel anytime.

Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 3 with Pro.

Start free trial

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 · 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
Large Cinnamon SedgeHatch
2
3
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

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 syndicate
  • Salisbury Estate offers limited access.
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.
Avon Springs
8.0 km
~19°C
Brown trout · Rainbow trout
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
About this water

The Wiltshire Bourne (Hampshire Avon tributary, distinct from the Hampshire Bourne) runs through Salisbury Plain country from Tidworth past Salisbury to join the Avon. Classic Wessex chalk stream — stable flows, technical clear water, wild brown trout. Mostly private syndicate water but the Salisbury area sometimes offers limited day tickets via Salisbury Estate or local clubs.

  • Chalk
The full read · show the working · for Brown Trout · confidence 80%
How the 28 is built — score × weight = contribution
Temperature26 × 28%7.3
Flow55 × 22%12.1
Clarity15 × 18%2.7
Feeding Time60 × 13%7.8
Pressure80 × 7%5.6
Insect activity52 × 12%6.2
Limiting factor: Water is very coloured — too coloured for Brown Trout= 42
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.
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