Freestone · Mixed · Navarra, ES

Río Arga

Río Arga — Puente la Reina

Navarra's principal river, an Ebro tributary flowing south through Pamplona.

Today · Closed season
Black Gnat
Forecast · Today
Closed season
Out of season. Try elsewhere.
80% projected
Today's fly
Black Gnat
Black Gnat
Conditions on the water · Today
Live gauge
Level
Rising
1.07 m
Lifting fast
Water temp19.8°C
ClarityUnfishable
Weather21°C
WindN 21 km/h
Pressure1018 hPa
Rain · recent4.3 mm
Rain · ahead0.0 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
20°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.
Why this works
Water at 20.4°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Hatch timeline · todayPeak at 12pm

12pm(now) — Heather Fly

Stage: Terrestrials on topApproach: Dry flyActivity: 60%
Also:Black Gnat36%
Peak emergence windowWeather boost6 food groups active

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

Sub-surface · on the nymphunder the surface

Hatch predictions

Supporters see the full sub-surface read.

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Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Top prey shown — see all 2 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 · September highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
1
Daddy Long LegsHatch
2
3
2
Evening SedgeHatch
2
3
3
3
2
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
2
2
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.
  • Gobierno de Navarra fishing licence required
  • Use the exact tramo and daily-permit structure for the section you plan to fish rather than assuming one simple Arga rule.
What's coming
Plan ahead
5-day outlook
Water here around 20°C. Nothing cooler within range — carry a thermometer.
Gallery · 2
  1. Río Arga — Puente la Reina
    Puente la Reina
  2. Terrain map of the venue
    Terrain map
About this water

Navarra's principal river, an Ebro tributary flowing south through Pamplona. The Arga rises in the western Pyrenees and joins the Aragón before reaching the Ebro (Mediterranean drainage — no Atlantic salmon access). Limestone and granite headwaters transition to sandstone near the city. Productive brown trout water with pool-and-run structure. Dry fly and nymphing for summer trout in clear upper reaches; water turns brownish during spates.

  • Mixed
Water quality (WFD)
  • Ecology: Moderate
  • Chemical: Unknown

WFD classification · ES091MSPF546

The full read · show the working · for Brown Trout · confidence 80%
How the 0 is built — score × weight = contribution
Temperature9 × 28%2.5
Flow60 × 22%13.2
Clarity95 × 18%17.1
Feeding Time70 × 13%9.1
Pressure80 × 7%5.6
Insect activity62 × 12%7.4
Limiting factor: Water temperature (20.4°C) is outside Brown Trout's preferred range (10–16°C)= 55
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
Cooler water — back toward the 10–16 °C ideal band — would lift the score and ease welfare.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Trout 1 May → 30 June

    RSS Arga–Ultzama basin (922 permits in 2026). All catch-and-release. Extendable to 15 Jul by resolution. Daily basin permit required. Tramo-specific rules apply — check the official web app for stretch-level status.

Related guides
Fly Fishing Near Pamplonafeatured in this city guidePyrenees PlaybookSpanish riversEuro Nymphingsubsurface methods
Booking & contacts