Freestone · Limestone · Navarra, ES

Río Erro

A pristine Irati tributary in the eastern Pyrenean sector of Navarra, flowing through a compact limestone catchment with high elevation and steep gradients.

igorpatrice patta (NIGORAMUX)

Forecast · Today

Closed season

Out of season. Try elsewhere.

45% projected

Notify when prime

Today's fly

Black Gnat

Rules at a glance

Public water
Licence required

Forecast

Conditions on the water · Today

Live gauge

Trends shown where the gauge supports them

Level

Rising

0.16 m

Lifting fast

Water temp

16.4°C

coldwarm

Clarity

Unfishable

Colouring up

Weather

19°C

Showers

Wind

N 24 km/h

calmblown out

Pressure

1018 hPa

lowhigh

Rain · recent

14.2 mm

dryspate risk

Rain · ahead

3.3 mm

dryspate risk

The nearest gauge doesn't record temperatures, so we've estimated it — defer to the river keeper's advice.

Water temperature for Brown Trout

Warm — slow

16°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

Caddisflies

Net-spinning caddisMost likelyLower confidenceNearest relative
#12–14–16 · Pupa
Widespread riffle net-spinner; evening emergence.

Gammarids

Freshwater shrimpMost likelyLower confidenceNearest relative
#10–14 · Adult
No hatch? Dead-drift a shrimp deep — the year-round standby.

Hatch timeline · todayPeak at 12pm

12pm(now) — Heather Fly

Stage: Terrestrials on topApproach: Dry flyActivity: 56%

Also:Reed Smut44%Cinnamon Sedge25%

Peak emergence windowWeather boost10 food groups active

Peak activity at 12pm — Heather Fly (Heather Fly, Peak emergence window)

Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 4 guilds as a supporter.

Start free trial

14-day free trial. Cancel anytime.

Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Top prey shown — see all 2 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 · September highlighted

Trout season

Daddy Long Legs

Evening Sedge

Large Dark Olive

Iron Blue

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.

Gobierno de Navarra fishing licence required
Check the exact tramo and any daily-permit or coto-pass requirement for the named stretch before travel.

What's coming

Plan ahead

5-day outlook

Other water nearby · 5

Gallery · 1

Terrain map

About this water

A pristine Irati tributary in the eastern Pyrenean sector of Navarra, flowing through a compact limestone catchment with high elevation and steep gradients. Clear, cold alpine freestone with pocket water and short pools holding small to medium wild browns. Technical nymphing and dry fly essential — delicate presentation and careful wading. Limestone geology means rapid snowmelt rise and a fast return to base flow.

Limestone

Water quality (WFD)

Ecology: Good
Chemical: Unknown

What this classification means

WFD ecological status High → Good corrected to EEA WISE 2022 (3rd RBMP) classification for waterbody ES091MSPF698 (was a stale earlier-cycle value). Source: EEA WISE SWB_SurfaceWaterBody (discodata.eea.europa.eu), verified 2026-06-18.

WFD classification · ES091MSPF698

The full read · show the working · for Brown Trout · confidence 75%

How the 0 is built — score × weight = contribution

Temperature100 × 28%28.0

Flow80 × 22%17.6

Clarity95 × 18%17.1

Feeding Time45 × 13%5.9

Pressure80 × 7%5.6

Insect activity59 × 12%7.1

Conditions total= 81

Can you trust it?

Water temperatureair-to-water estimateestimated

Level / flowon-river gaugeobserved

Prey activitysurvey-backed invertebrate datasurvey

What would change the calculation

The dawn and dusk windows score higher than the midday lull.

Directions

Apple Maps Google Maps

Seasons & zones

Trout 1 May → 30 June
RSS Irati–Erro basin (2,728 permits in 2026). All catch-and-release. Extendable to 15 Jul by resolution. Daily basin permit required.

Related guides

Booking & contacts

Permits & access

Gobierno de Navarra — Permisos de Pesca
Navarran fishing licence and red trout card. Online via sede electrónica

Freestone · Limestone · Navarra, ES

Río Erro

Google Places

A pristine Irati tributary in the eastern Pyrenean sector of Navarra, flowing through a compact limestone catchment with high elevation and steep gradients.

Today · Closed season

Black Gnat

Forecast · Today

Closed season

Out of season. Try elsewhere.

45% projected

Notify when prime

Today's fly

Black Gnat

Conditions on the water · Today

Live gauge

Level

Rising

0.16 m

Lifting fast

Water temp16.4°C

ClarityUnfishable

Weather19°C

WindN 24 km/h

Pressure1018 hPa

Rain · recent14.2 mm

Rain · ahead3.3 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

Warm — slow

16°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

Caddisflies

Net-spinning caddisMost likelyLower confidenceNearest relative
#12–14–16 · Pupa
Widespread riffle net-spinner; evening emergence.

Gammarids

Freshwater shrimpMost likelyLower confidenceNearest relative
#10–14 · Adult
No hatch? Dead-drift a shrimp deep — the year-round standby.

Hatch timeline · todayPeak at 12pm

12pm(now) — Heather Fly

Stage: Terrestrials on topApproach: Dry flyActivity: 56%

Also:Reed Smut44%Cinnamon Sedge25%

Peak emergence windowWeather boost10 food groups active

Peak activity at 12pm — Heather Fly (Heather Fly, Peak emergence window)

Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 4 guilds as a supporter.

Start free trial

14-day free trial. Cancel anytime.

Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Top prey shown — see all 2 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 · September highlighted

Trout season

Daddy Long Legs

Evening Sedge

Large Dark Olive

Iron Blue

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.

Gobierno de Navarra fishing licence required
Check the exact tramo and any daily-permit or coto-pass requirement for the named stretch before travel.

What's coming

Plan ahead

5-day outlook

Other water nearby · 5

Bidasoa tributaries (Navarra side)

23 km

Brown trout · Sea trout

Gallery · 1

Terrain map

About this water

Limestone

Water quality (WFD)

Ecology: Good
Chemical: Unknown

What this classification means

WFD classification · ES091MSPF698

The full read · show the working · for Brown Trout · confidence 75%

How the 0 is built — score × weight = contribution

Temperature100 × 28%28.0

Flow80 × 22%17.6

Clarity95 × 18%17.1

Feeding Time45 × 13%5.9

Pressure80 × 7%5.6

Insect activity59 × 12%7.1

Conditions total= 81

Can you trust it?

Water temperatureair-to-water estimateestimated

Level / flowon-river gaugeobserved

Prey activitysurvey-backed invertebrate datasurvey

What would change the calculation

The dawn and dusk windows score higher than the midday lull.

Directions

Apple Maps Google Maps

Seasons & zones

Trout 1 May → 30 June
RSS Irati–Erro basin (2,728 permits in 2026). All catch-and-release. Extendable to 15 Jul by resolution. Daily basin permit required.

Booking & contacts

Permits & access

Gobierno de Navarra — Permisos de Pesca
Navarran fishing licence and red trout card. Online via sede electrónica