Stillwater · Alluvial · Isère / Nord-Isère (Trept)

Domaine des 3 Lacs du Soleil

Fairlive now

Good summer conditions for Domaine des 3 Lacs du Soleil

Useful ripple, fishable wave. Worth a session if the wind holds.

60% confidence

What moved it

WindSW 5 km/hCalm

Today’s fly

Medium nymphs14–16

Search the runs and pockets, dead-drift near the bottom.

Rules at a glance

Day tickets

Live now

Conditions on the water

Live gauge

Trends shown where the gauge supports them

Wind

Calm

SW 5 km/h

from the south-west

Wave

Ripple

glasstoo rough

Water temp

—

No reading

Air temp

21°C

coldhot

Cloud

Clear

Pressure

1018 hPa

lowhigh

Rain · recent

0.0 mm

drywet

Some readings unavailable — check directly before fishing.

How to fish it · for rainbow

When

March–May and September–October

Where

Start with Medium nymphs (12-14) on a As per local method. Rainbows respond to more active retrieves — try short strips between pauses. If that does not produce, switch depth or speed before changing the pattern entirely.

The plan

Plan A

Plan B

Fish early and late, try deeper during the heat of the day with a fast-sinking line.

Watch for

Evening tends to be the best period in summer — stay late if you can for a sedge or spinner fall.

Bank

Bank fishing near inflows, dam walls, and weed beds. Move to find feeding fish.

Through the year

0–3 scale · July highlighted

Black Midge

Reservoir Buzzer

Lake Olive

Silverhorns & Longhorns

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

Ranked for today

Rainbow fly box

Medium nymphsTop

14–16 · Nymph

Search the runs and pockets, dead-drift near the bottom.

dries

12–16 · Fly

A dependable searching pattern for these waters.

buzzers

10–14 · Buzzer

Static or slow on a long leader — the staple stillwater chironomid.

streamers

8–10 · Streamer

Strip it for fish chasing fry or in coloured water.

Permits & access

Permit required — see local rules.

Commercial fly-only on the Grand Lac (the other lakes are bait/coarse only)
Day tickets required
Black bass and perch no-kill.

What's coming

Plan ahead

5-day outlook

Condition match

66%

Cloud25%

Wind100%

Temp60%

A reasonable day here, though cloud isn't quite in the sweet spot.

Other water nearby · 5

About this water

The Domaine des 3 Lacs du Soleil is a private three-lake complex at Trept in the Nord-Isère, about an hour from Lyon, and the Grand Lac is the fly-only reservoir — the other two waters are for bait and coarse fishing and are not what a fly angler comes here for. The Grand Lac is stocked with rainbow trout as the main target, with perch and black bass both present and both managed as no-kill, which is the sort of mature policy that used to be unheard of in French commercial fisheries and is now slowly becoming standard at the better venues. The water is alluvial and warms up in summer more than an upland reservoir does, so the early season (March–May) and the autumn shoulder (September–October) are the productive windows. This is the closest serious fly-only commercial fishery to Lyon and it functions as the Rhône-Alpes equivalent of Coyolles: your reliable weekend casting venue when the rivers are out of shape.