Freestone · Granite · Castilla y León

Río Eresma

Río Eresma terrain map
Terrain map

The Eresma rises in the Sierra de Guadarrama at Valsaín — the upper river through La Granja and into Segovia city is genuine wild-trout water, with strong granite-headwater character and excellent clarity.

Good · Brown Trout
Klinkhammer · 14-18
Goodlive now
A proper day on the water
River steady at a fishable height. A proper day for it. Work the seams with an upstream nymph, switch to the dry when they show.
75% confidence
What moved it
  • Level0.55 mLast reading 3h ago
  • Water temp17.8°C
  • ClarityClear
Today’s fly
Klinkhammer
Klinkhammer14-18
High-confidence seasonal pick
Conditions on the water
Live gauge
Level
Steady
0.55 m
Last reading 3h ago
Water temp17.8°C
ClarityClear
Weather19°C
WindE 8 km/h
Pressure1023 hPa
Rain · recent0.0 mm
Rain · ahead0.0 mm

Live readings — water temperature is an estimate where the gauge does not record it.

Water temperature for brown trout
Warm — slow
18°C est.ideal 10–16°C
0°14°28°
How to fish it · for brown trout
When
Through the Castilla y León trout season — 3rd Sunday of March to 31 July. Spring olives April through May; summer sedges in evening hours; sin muerte stretches extend through autumn.
Where
Pool tails, riffle heads, and the seams behind boulders through the Segovian beats. The Eresma runs from the Sierra de Guadarrama through clear granite pocket water.
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.
Why this works
Good — water clarity is working for you, but time of day is the limiting factor today.
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 8 active hatches hour by hour with Pro.

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Evidence
Records-basedModerate confidence

Based on species-occurrence records, not local invertebrate surveys.

Through the year
0–3 scale · July highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
1
Large Dark OliveHatch
1
2
2
1
Blue Winged OliveHatch
1
2
2
2
2
1
Autumn OliveHatch
1
2
1
GrannomHatch
1
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 licence required
  • The Valsaín–La Granja stretch is the wild-trout identity of the river; lower city/agricultural beats follow different (often stocked) management
  • Match the tramo to your goal before booking.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Río Lozoya (cotos & tramos)
14 km
Brown trout
Upper Río Manzanares (La Pedriza)
16 km
Brown trout
Río Moros
23 km
Brown trout
Molino de la Horcajada (Lozoya coto)
26 km
Brown trout
Río Cega
31 km
30
Brown trout
About this water

The Eresma rises in the Sierra de Guadarrama at Valsaín — the upper river through La Granja and into Segovia city is genuine wild-trout water, with strong granite-headwater character and excellent clarity. Lower reaches downstream of Segovia city become more mixed: stocked beats, urban influence, and warmer summer flow mean the Eresma's fly-fishing identity sits firmly in the upper basin around Valsaín / La Granja, not in the broader river.

  • Granite
The full read · show the working · for brown trout · confidence 75%
How the 70 is built — score × weight = contribution
Temperature60 × 28%16.8
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time40 × 13%5.2
Pressure80 × 7%5.6
Insect activity62 × 12%7.4
Conditions total= 70
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 10–16 °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
  • TroutLast Sunday of March → 31 July
Related guides
Pyrenees PlaybookSpanish riversEuro Nymphingsubsurface methods
Booking & contacts