Spring Fed · Limestone · Aragón, ES

Ríos Piedra, Mesa and upper Jalón (Calatayud / Monasterio de Piedra)

Miriela Rodríguez - CC BY-SA 3.0 es

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

Notify when prime

What moved it

LevelProxyvia Río Abión
Water temp8.3°C
ClarityClear

Today's fly

Grasshopper Pattern10-14

Proven pattern for this period

Rules at a glance

Public water
Licence required
Fly only

Live now

Conditions on the water

Proxy gauge

Trends shown where the gauge supports them

Level

Steady

Proxy

via Río Abión

Water temp

8.3°C

coldwarm

Clarity

Clear

Weather

21°C

Clear

Wind

N 8 km/h

calmblown out

Pressure

1026 hPa

lowhigh

Rain · recent

0.0 mm

dryspate risk

Rain · ahead

0.0 mm

dryspate risk

No gauge on this water — conditions are inferred from Río Abión. The trend transfers, the absolute level does not.

Water temperature for Brown Trout

Cool — slow

8°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

Good — water clarity is working for you, but river flow is the limiting factor today.

Likely species

Mayflies

Angler's CurseMost likelyLower confidenceNearest relative
#20–22 · Spinner
Go tiny: 20-22 spent spinner, single fly, long tippet.

Stoneflies

Autumn Needle FlyMost likelyLower confidenceNearest relative
#16–18 · Adult
Small slender stonefly of clean, cold riffles in autumn.

Gammarids

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

Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 6 active hatches hour by hour as a supporter.

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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 · October highlighted

Trout season

Brown Sedge

Small Spurwing

Freshwater Shrimp

Small Dark Olive

Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.

Ranked for today

Fly box · Brown Trout

Permits & access

Permit required — see local rules.

Aragón fishing licence required
Río Mesa is trout water from the Guadalajara border (Calmarza) down to the Z-453 bridge at the tunnel between Calmarza and Jaraba; the Hoces stretch below the tunnel to the Jaraba bottling plant is a catch-and-release free section
Río Piedra is trout water from source to the Jalón except La Tranquera and Abanto reservoirs, but the Monasterio de Piedra stretch (Argadiles bridge to Frailes bridge) is vedado all year
Trout season 21 March–15 October in the 2026 Aragón orden de vedas; confirm current rules before fishing.

What's coming

Plan ahead

5-day outlook

Gallery · 2

Terrain map

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

How the 67 is built — score × weight = contribution

Temperature70 × 28%19.6

Flow40 × 22%8.8

Clarity95 × 18%17.1

Feeding Time65 × 13%8.5

Pressure80 × 7%5.6

Insect activity59 × 12%7.1

Conditions total= 67

Can you trust it?

Water temperatureair-to-water estimateestimated

Level / flowproxy via Río Abiónproxy

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 troisième Saturday de March → 15 October
Aragón general C&R free-water dates (third Saturday of March, 2026-03-21, to 15 October) per the 2026 Orden de vedas. Iberian System tributaries of the Jalón — confirm the exact coto/free-water status per beat, since flows are highly seasonal and trout are only a legitimate target in salmonid-classified reaches. Dates added 2026-09-09; previously an unparseable placeholder.

Related guides

Booking & contacts

Spring Fed · Limestone · Aragón, ES

Ríos Piedra, Mesa and upper Jalón (Calatayud / Monasterio de Piedra)

Contributor photo

Miriela Rodríguez - CC BY-SA 3.0 es

Good · Brown Trout

Grasshopper Pattern · 10-14

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

Notify when prime

What moved it

LevelProxyvia Río Abión
Water temp8.3°C
ClarityClear

Today's fly

Grasshopper Pattern10-14

Proven pattern for this period

Conditions on the water

Proxy gauge

Level

Steady

Proxy

via Río Abión

Water temp8.3°C

ClarityClear

Weather21°C

WindN 8 km/h

Pressure1026 hPa

Rain · recent0.0 mm

Rain · ahead0.0 mm

No gauge on this water — conditions are inferred from Río Abión. The trend transfers, the absolute level does not.

Water temperature for Brown Trout

Cool — slow

8°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

Good — water clarity is working for you, but river flow is the limiting factor today.

Likely species

Mayflies

Angler's CurseMost likelyLower confidenceNearest relative
#20–22 · Spinner
Go tiny: 20-22 spent spinner, single fly, long tippet.

Stoneflies

Autumn Needle FlyMost likelyLower confidenceNearest relative
#16–18 · Adult
Small slender stonefly of clean, cold riffles in autumn.

Gammarids

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

Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 6 active hatches hour by hour as a supporter.

Start free trial

14-day free trial. Cancel anytime.

Sub-surface · on the nymphunder the surface

Hatch predictions

Supporters see the full sub-surface read.

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 · October highlighted

Trout season

Brown Sedge

Small Spurwing

Freshwater Shrimp

Small Dark Olive

Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.

Ranked for today

Fly box · Brown Trout

Permits & access

Permit required — see local rules.

Aragón fishing licence required
Río Mesa is trout water from the Guadalajara border (Calmarza) down to the Z-453 bridge at the tunnel between Calmarza and Jaraba; the Hoces stretch below the tunnel to the Jaraba bottling plant is a catch-and-release free section
Río Piedra is trout water from source to the Jalón except La Tranquera and Abanto reservoirs, but the Monasterio de Piedra stretch (Argadiles bridge to Frailes bridge) is vedado all year
Trout season 21 March–15 October in the 2026 Aragón orden de vedas; confirm current rules before fishing.

What's coming

Plan ahead

5-day outlook

Gallery · 2

Terrain map

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

How the 67 is built — score × weight = contribution

Temperature70 × 28%19.6

Flow40 × 22%8.8

Clarity95 × 18%17.1

Feeding Time65 × 13%8.5

Pressure80 × 7%5.6

Insect activity59 × 12%7.1

Conditions total= 67

Can you trust it?

Water temperatureair-to-water estimateestimated

Level / flowproxy via Río Abiónproxy

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 troisième Saturday de March → 15 October
Aragón general C&R free-water dates (third Saturday of March, 2026-03-21, to 15 October) per the 2026 Orden de vedas. Iberian System tributaries of the Jalón — confirm the exact coto/free-water status per beat, since flows are highly seasonal and trout are only a legitimate target in salmonid-classified reaches. Dates added 2026-09-09; previously an unparseable placeholder.

Booking & contacts