Freestone · Schist · Cévennes / Lozère-Ardèche

Chassezac

Chassezac — No need for HDR
Marginal · Brown Trout
CDC Emerger · 16-18
New ruleReported 7 Aug 2026

Severe drought restrictions (alerte renforcée) in force

The Cèze amont (de source à la confluence Tave jusqu'à la confluence avec la Claysse, ruisseau de la Clays) zone (Dept 30) is at alerte renforcée — the second-highest French drought tier — under a préfectoral arrêté. Fishing itself is not named as prohibited, but water is severely restricted and flows are likely very low; fish with care and check locally.

Arrêté préfectoral n°37649 ↗

Temporary notices from official orders and recent fishery reports — they clear automatically once out of date. Always confirm locally before travelling.

Marginallive now
Slow going — pick your moments
River temperature is the limiting factor today, not the flow. Fish dawn or dusk if you go at all, and handle everything with extra care.
80% confidence
What moved it
  • LevelProxyvia Loire (Upper)
  • Water temp20.1°C
  • ClarityClear
Today's fly
CDC Emerger
CDC Emerger16-18
Dead-drift
Conditions on the water
Proxy gauge
Level
Steady
Proxy
via Loire (Upper)
Water temp20.1°C
ClarityClear
Weather23°C
WindW 4 km/h
Pressure1018 hPa
Rain · recent0.0 mm
Rain · ahead2.1 mm

No gauge on this water — conditions are inferred from Loire (Upper). The trend transfers, the absolute level does not.

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
Through the open trout season. Spring olives April through May; sedges through summer evenings.
Where
Pool tails and pocket water through the Lozère-Ardèche valley. Cévennes freestone — clear water, fast pockets.
Method
Upstream dry to risers; dry-dropper through the riffles. The water reads clear — long leader, fine tippet. Move slowly, cast accurately.
Kit
9 ft #4 — French freestone default. Floating line, 12 ft leader to 4 to 5 lb fluoro. Studded boots.
Why this works
Water at 20.1°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 6am

Hatch predictions

Today's headline hatch shown — see all 3 active hatches hour by hour with Pro.

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Sub-surface · on the nymphunder the surface

Hatch predictions

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Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 2 with Pro.

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Evidence
Survey-backed · regionalModerate confidence

Backed by regional invertebrate surveys; no sampling on this exact reach yet.

Through the year
0–3 scale · August highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
2
2
1
GrannomHatch
2
2
Evening SedgeHatch
2
3
3
3
2
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
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.
  • AAPPMA Lozère / Ardèche
  • 1ère catégorie
  • Zones de réserve à truite sauvage sur le cours amont.
What's coming
Plan ahead
5-day outlook
Cooler water nearby · 1
Water here around 20°C — probably warm enough to stress Brown Trout . These are likely cooler.
Allier (Upper, Langogne–Langeac)
33 km
~18°C
Brown trout · Grayling
Gallery · 2
  1. Chassezac — No need for HDR
    No need for HDR
  2. Terrain map of the venue
    Terrain map
Water quality (WFD)
  • Ecology: Good
  • Chemical: Unknown
What this classification means

WFD ecological status Moderate → Good corrected to EEA WISE 2022 (3rd RBMP) classification for waterbody FRDR413C (was a stale earlier-cycle value). Source: EEA WISE SWB_SurfaceWaterBody (discodata.eea.europa.eu), verified 2026-06-18.

WFD classification · FRDR413C

The full read · show the working · for Brown Trout · confidence 80%
How the 27 is built — score × weight = contribution
Temperature24 × 28%6.7
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time70 × 13%9.1
Pressure80 × 7%5.6
Insect activity65 × 12%7.8
Limiting factor: Water temperature (20.1°C) is outside Brown Trout's preferred range (10–16°C)= 64
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowproxy via Loire (Upper)proxy
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 2nd Saturday of March → 3rd Sunday of September
Related guides
Pyrenees PlaybookFrench riversEuro Nymphingsubsurface methods
Booking & contacts