Stillwater · Old Red Sandstone · Wales / Brecon Beacons (Upper Usk)

Usk Reservoir

Usk Reservoir in Myddfai, Carmarthenshire, showing the open water body and surrounding landscape.
Contributor photo

Usk Reservoir

Dani - CC BY-SA 2.0

Usk Reservoir is the upland one — two hundred and eighty acres a few miles from the river Usk's source, set among forest and moorland in the Brecon Beacons National Park.

Fair · Rainbow
Diawl Bach · 12-14
Fairlive now
Good summer conditions for Usk Reservoir
Good wave on — drift country. A useful wave. Work the productive shore.
64% confidence
What moved it
  • WindW 9 km/hLight breeze
Today’s fly
Diawl Bach
Diawl Bach12-14
Washing-line, sub-surface
Conditions on the water
Live gauge
Wind
Light breeze
W 9 km/h
N
W
from the west
WaveRipple
Water temp—
Air temp12°C
CloudBroken
Pressure1022 hPa
Rain · recent0.0 mm

Some readings unavailable — check directly before fishing.

How to fish it · for rainbow
When
Current conditions suit Usk Reservoir well for summer tactics. The ripple should help fish move and feed more confidently.
Where
Start with Booby (8-10) on a fast strip on floating line or static on sinking. 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. In the ripple, a bushy searching dry (Hopper, Shipman's, Elk Hair Caddis) outperforms flush emergers — it stays visible and holds the surface tension.
The plan
Plan A

Start with Booby (8-10) on a fast strip on floating line or static on sinking. 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. In the ripple, a bushy searching dry (Hopper, Shipman's, Elk Hair Caddis) outperforms flush emergers — it stays visible and holds the surface tension.

Plan B

If the main plan stalls, drop to a size 14–16 midge — switch to a washing-line or suspender rig and change drift line before you change food group.

Watch for

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

Either bank or boat

Good ripple suits both bank and boat. Bank: work inflows, dam walls, and points. Boat: broadside drift covering wind lanes.

Through the year
0–3 scale · July highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Daphnia SwarmHatch
2
3
3
3
2
Daddy Long LegsHatch
2
3
2
Lake OliveHatch
2
3
3
3
3
3
2
Silverhorns & LonghornsHatch
1
2
2
2
1

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

Ranked for today
Rainbow fly box
Bays & launches · 1
Usk Reservoir — day ticket via Fishing PassportAccess varies
Remote upland reservoir near the source of the Usk — 280 acres of stocked rainbow and brown trout fishing with fly, spinner or worm permitted.
What's coming
Plan ahead
5-day outlook
Condition match
79%
Cloud70%
Wind100%
Temp60%

A good match for this venue — most conditions are close to what it fishes best in.

Other water nearby · 5
Llyn y Fan Fach
7.0 km
Brown trout
Llandyfan Trout Fishery
15 km
Rainbow trout · Brown trout
Afon Twrch
16 km
Brown trout
Llyn Brianne
17 km
Rainbow trout · Brown trout
Llyn Cwm Llwch
19 km
Brown trout
Gallery · 6
  1. Usk Reservoir in Myddfai, Carmarthenshire, showing the open water body and surrounding landscape.
    Usk Reservoir
  2. A broad view across the open water of Usk Reservoir with surrounding moorland and conifer plantations.
    View across Usk Reservoir
  3. Elevated view over Usk Reservoir looking northeast, the reservoir body with woodland on the far bank.
    View over the Usk Reservoir
  4. The shallow western end of Usk Reservoir with conifer and moorland shoreline reflected in calm water.
    Western end of Usk Reservoir
  5. The concrete dam wall at the eastern end of Usk Reservoir with the reservoir water behind the structure.
    Usk Reservoir Dam
  6. Terrain map of the venue
    Terrain map
About this water

Usk Reservoir is the upland one — two hundred and eighty acres a few miles from the river Usk's source, set among forest and moorland in the Brecon Beacons National Park. Fly, spinner and worm all permitted; the bag limits run to four or six fish, or a junior two-fish permit. Day tickets through the Fishing Passport. The setting feels properly remote: a long single road in and a stillness you don't get on the lower Taff waters. Best from late April once the water has warmed, with buzzers and beetle patterns through summer.

  • Reservoir
  • Old red sandstone
Why this score
  • Wind conditions (ripple) closely match what this water fishes best in.
  • Buzzer is in its seasonal window, boosting the chance of targeted feeding.
Related guides
Big Stillwater Playbookreservoir tacticsReservoir Entomologymatching the hatchThermal Layers & Troutreading depth and temperature
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