Freestone · Limestone · Castilla y León, ES

Río Carrión

Río Carrión — Velilla desde Compuerto

The Carrión flows through limestone uplands creating a classic freestone river — clear water and consistent insect productivity supporting unusually large brown trout (many exceeding three pounds).

Poor · Brown Trout
Pheasant Tail Nymph · 14–18
Closed season
Out of season. Try elsewhere.
Closed — confidence not applicable today.
What moved it
  • Level0.42 mLast reading 6h ago
  • Water temp4.3°C
  • ClarityClear
Today's fly
Pheasant Tail Nymph
Pheasant Tail Nymph14–18
High-confidence seasonal pick
Conditions on the water
Live gauge
Level
Steady
0.42 m
Last reading 6h ago
Water temp4.3°C
ClarityClear
Weather8°C
WindW 13 km/h
Pressure1013 hPa
Rain · recent23.0 mm
Rain · ahead13.6 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
Cool — slow
4°C est.ideal 10–16°C
0°14°28°
How to fish it · for Brown Trout
When
Through the Castilla y León trout season. Spring olives April through May; summer evenings; small dark flies into autumn close.
Where
Pool tails and the seams behind boulders through the Palencia valley. The Carrión runs cool Cantabrian-fed water through the upper beats.
Method
Upstream dry to risers; dry-dropper through the riffles. The water reads clear — long leader, fine tippet, careful approach.
Kit
9 ft #4 — Castilian default. Floating line, 12 ft leader to 4 lb fluoro. Studded boots — granite cobble runs slick.
Likely species
Gammarids
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 4 active hatches hour by hour as a supporter.

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Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 2 guilds as a supporter.

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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 · November highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
1
Evening SedgeHatch
2
3
3
3
2
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
2
2
2
2
2
2
1
Blue Winged OliveHatch
1
2
2
2
2
1

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.
  • Castilla y León fishing licence required
  • Many premium trout waters use the Junta's tramo-based management system, including EDE sections, so check the exact section and current rules before travel.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Río Cardaño
19 km
0
Brown trout
Río Yuso
21 km
0
Brown trout
Río Remolina
24 km
0
Brown trout
Embalse de Camporredondo
12 km
Brown trout
Embalse de Riaño
25 km
Brown trout
Gallery · 2
  1. Río Carrión — Velilla desde Compuerto
    Velilla desde Compuerto
  2. Terrain map of the venue
    Terrain map
About this water

Designated Coto Intensivo sections near Guardo enforce selective management and fly-only regulations protecting these fish. Stable limestone hatches (Baetis rhodani, Ephemerella notata, small olives) run April–July. A river where size and quality reward careful presentation.

  • Limestone
Water quality (WFD)
  • Ecology: Poor
  • Chemical: Unknown
What this classification means

WFD ecological status Moderate → Poor corrected to EEA WISE 2022 (3rd RBMP) classification for waterbody ES020MSPF000000130 (was a stale earlier-cycle value). Source: EEA WISE SWB_SurfaceWaterBody (discodata.eea.europa.eu), verified 2026-06-18.

WFD classification · ES020MSPF000000130

The full read · show the working · for Brown Trout · confidence 55%
How the 0 is built — score × weight = contribution
Temperature15 × 28%4.2
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time65 × 13%8.5
Pressure80 × 7%5.6
Insect activity38 × 12%4.6
Limiting factor: Water temperature (4.3°C) is outside Brown Trout's preferred range (10–16°C)= 58
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
Warmer water — toward the 10–16 °C ideal band — would lift the temperature score.
The dawn and dusk windows score higher than the midday lull.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Trout Last Sunday of March → 31 July
Related guides
Pyrenees PlaybookSpanish riversEuro Nymphingsubsurface methods
Booking & contacts
At a glance

Río Carrión is a freestone river in Castilla y León, Spain. Its recorded elevation is about 1,091 m above sea level and the catchment geology is limestone. The river is described as roughly 85 km long. The species listed for this water is brown trout. The trout season is recorded as running from Last Sunday of March to 31 July. Best window recorded for anglers: March–July (season); best dry fly May–June. Core methods listed: dry fly; nymph; streamer or wet fly on larger reaches. Level and flow data for this water is linked from 1 gauge. Its Water Framework Directive ecological status is recorded as poor. Nearby waters in our listings include Embalse de Camporredondo at 12 km, Río Cardaño at 19 km and Río Yuso at 21 km.