Freestone · Limestone · Primorska / Tolmin, SI

River Trebuščica

A clear stream cascading over limestone slabs beneath a stone arch bridge in the Srna gorge, Gorenja Trebuša.

The lower Trebuščica is a small limestone tributary running into the Soča, and one of the quiet places in RD Tolmin's water — the kind of stream you fish because you want to, not because someone told you it was good.

Poor · Marble Trout
F-Fly · 18-20
Poorlive now
Not the day for it
Low and clear — careful approach country. A morning for the obvious fish only.
90% confidence
What moved it
  • LevelDry recentlyNo gauge reading
  • Water temp22.6°C
  • ClarityClear
Today's fly
F-Fly
F-Fly18-20
Upstream dry, on top
Conditions on the water
Estimate
Level
Dry recently
No gauge reading
Water temp22.6°C
ClarityClear
Weather31°C
WindE 7 km/h
Pressure1015 hPa
Rain · recent0.0 mm
Rain · ahead2.3 mm

No gauge on this water — readings are regional estimates from weather, not a live gauge.

Water temperature for Marble Trout
Warm — slow
23°C est.ideal 8–13°C
0°14°28°
How to fish it · for Marble 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 22.6°C. This is the line where catch-and-release kills marble trout. Do not fish for them today.
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 3 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 2 with Pro.

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Evidence
ModelledModerate confidence

Modelled from regional ecology — no survey or occurrence data for this water 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
2
2
1
GrannomHatch
2
2
Evening SedgeHatch
2
3
3
3
2
Alpine RhithrogenaHatch
1
2
2
1
Large Dark OliveHatch
1
2
2
1

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

Ranked for today
Marble Trout fly box

Ultra-clear spring-fed rivers with large educated trout. Sight fishing, technical presentation, fine tippets. Euro-nymphing dominant subsurface method. Exceptional dry-fly windows during hatch periods. Gacka is the flagship water.

Permits & access
Permit required — see local rules.
  • Fishing licence + permit.
What's coming
Plan ahead
5-day outlook
Water here around 23°C. Nothing cooler within range — carry a thermometer.
Gallery · 2
  1. A clear stream cascading over limestone slabs beneath a stone arch bridge in the Srna gorge, Gorenja Trebuša.
    Srna gorge stream, Trebuščica valley
  2. Terrain map of the venue
    Terrain map
About this water

The lower Trebuščica is a small limestone tributary running into the Soča, and one of the quiet places in RD Tolmin's water — the kind of stream you fish because you want to, not because someone told you it was good. It carries genuine marble trout, which is the whole point: the upper 5.7 km above the fishable water is a breeding reserve, permanently closed, and that closure is the reason the fish below it are worth catching at all. Season runs 1 March to 20 October — earlier than most of the district, so don't assume the October dates that apply on the Soča apply here too. Barbless, C&R, and quiet feet.

  • River
  • Limestone
Water quality (WFD)
  • Ecology: Good
  • Chemical: Unknown
The full read · show the working · for Marble Trout · confidence 90%
How the 10 is built — score × weight = contribution
Temperature7 × 28%2.0
Flow45 × 22%9.9
Clarity95 × 18%17.1
Feeding Time55 × 13%7.2
Pressure80 × 7%5.6
Insect activity51 × 12%6.1
Limiting factor: Water temperature (22.6°C) is outside Marble Trout's preferred range (8–13°C)= 48
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
Cooler water — back toward the 8–13 °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 March → 20 October
  • Marble trout 1 April → 20 October
Related guides
Alpine Streamsmountain entomologyMarble TroutSoča systemEuro Nymphingsubsurface methods
Booking & contacts