Karst Spring · Limestone · Karlovac County / Risnjak NP, HR

Kupa (Risnjak National Park)

Kupa (Risnjak National Park) — IMG 20180713 163857(fixed)
Marginal · Brown Trout
CDC Emerger · 16-20
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
  • LevelProxyvia River Kolpa
  • Water temp20.2°C
  • ClarityVery colouredColouring up
Today's fly
CDC Emerger
CDC Emerger16-20
Proven pattern for this period
Conditions on the water
Proxy gauge
Level
Rising
Proxy
via River Kolpa
Water temp20.2°C
ClarityVery coloured
Weather12°C
WindNE 12 km/h
Pressure1018 hPa
Rain · recent0.0 mm
Rain · ahead4.4 mm

No gauge on this water — conditions are inferred from River Kolpa. The trend transfers, the absolute level does not.

Water temperature for Brown Trout
Warm — slow
20°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
Water at 20.2°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Hatch timeline · todayQuiet day

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Beyond the hatch · worth watchingambient prey

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Through the year
0–3 scale · August highlighted
J
F
M
A
M
J
J
A
S
O
N
D
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.
  • Croatian freshwater fishing licence required
  • Risnjak NP permit required for the source area
  • Check Croatian Angling Federation for beat permits.
What's coming
Plan ahead
5-day outlook
Cooler water nearby · 2
Water here around 20°C — probably warm enough to stress Brown Trout . These are likely cooler.
Gallery · 2
  1. Kupa (Risnjak National Park) — IMG 20180713 163857(fixed)
    IMG 20180713 163857(fixed)
  2. Terrain map of the venue
    Terrain map
The full read · show the working · for Brown Trout · confidence 80%
How the 26 is built — score × weight = contribution
Temperature23 × 28%6.4
Flow30 × 22%6.6
Clarity15 × 18%2.7
Feeding Time40 × 13%5.2
Pressure80 × 7%5.6
Insect activity14 × 12%1.7
Limiting factor: Water is very coloured — too coloured for Brown Trout= 28
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowproxy via River Kolpaproxy
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.
Related guides
Booking & contacts