Freestone · Limestone · Castilla y León, ES

Upper Río Duero

El río Duero, cerca de su nacimiento en Duruelo de la Sierra, Soria

The upper Duero navigates beautiful limestone plateau country above Soria — 40 km of clear water and productive brown trout habitat.

Today · Closed season
Frenchie
Forecast · Today
Closed season
Out of season. Try elsewhere.
55% projected
Today's fly
Frenchie
Frenchie
Conditions on the water · Today
Live gauge
Level
Steady
0.65 m
Dropping in the last 6h
Water temp4.2°C
ClarityClear
Weather8°C
WindN 31 km/h
Pressure1017 hPa
Rain · recent46.1 mm
Rain · ahead1.7 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
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.
Likely species
Gammarids
Hatch timeline · todayQuiet day

Low insect activity predicted today

Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 3 guilds as a supporter.

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 · 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 Revinuesa
7.0 km
0
Brown trout
Río Abión
17 km
0
Brown trout
Río Arlanza
29 km
0
Brown trout
Río Ucero
35 km
0
Brown trout
Embalse de la Cuerda del Pozo
3.0 km
Carp · Barbel
Gallery · 2
  1. El río Duero, cerca de su nacimiento en Duruelo de la Sierra, Soria
  2. Terrain map of the venue
    Terrain map
About this water

Classic high-altitude freestone fishing with excellent insect diversity and selectively rising fish. Strong limestone mayfly hatches (Baetis in spring, Ephemerella in early summer) support consistent dry-fly opportunity. Evening spinner falls from May onwards reward technical work.

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

WFD ecological status Moderate → Bad corrected to EEA WISE 2022 (3rd RBMP) classification for waterbody ES020MSPF000000306 (was a stale earlier-cycle value). Source: EEA WISE SWB_SurfaceWaterBody (discodata.eea.europa.eu), verified 2026-06-18.

WFD classification · ES020MSPF000000306

The full read · show the working · for Brown Trout · confidence 55%
How the 0 is built — score × weight = contribution
Temperature14 × 28%3.9
Flow48 × 22%10.6
Clarity15 × 18%2.7
Feeding Time40 × 13%5.2
Pressure80 × 7%5.6
Insect activity32 × 12%3.8
Limiting factor: Water temperature (4.2°C) is outside Brown Trout's preferred range (10–16°C)= 32
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.
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 Last Sunday of March → 31 July
Related guides
Pyrenees PlaybookSpanish riversEuro Nymphingsubsurface methods
Booking & contacts
At a glance

Upper Río Duero is a freestone river in Castilla y León, Spain. Its recorded elevation is about 1,110 m above sea level and the catchment geology is limestone. The river is described as roughly 40 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 bad. Nearby waters in our listings include Embalse de la Cuerda del Pozo at 3.0 km, Río Revinuesa at 7.0 km and Río Abión at 17 km.