Freestone · Schist · Otago, NZ

Clutha / Mata-Au

Clutha / Mata-Au — On the Clutha River at Albert Town

The Clutha / Mata-Au is the big stable giant of the South Island — New Zealand's largest river by flow, lake-fed from Wānaka and Hāwea and held by the Clyde and Roxburgh dams, so it runs big and clear where rain-fed rivers blow out.

Today · About as good as it gets
Stonefly Nymph
Forecast · Today
About as good as it gets
On the feed top to bottom — start on the rises with a dry, drop a nymph if they stay down.
90% projected
Today's fly
Stonefly Nymph
Stonefly Nymph
Conditions on the water · Today
Live gauge
Flow
Steady
880.5 cumecs
Last reading 7h ago
Water temp11.2°C
ClarityClear
Weather11°C
WindN 10 km/h
Pressure1020 hPa
Rain · recent3.4 mm
Rain · ahead1.6 mm

The nearest gauge doesn't record temperatures, so we've estimated it — defer to the river keeper's advice.

How these readings are sourced

Weather-only: no live gauge wired. Lake-fed and dam-regulated — flow is governed by lake levels and hydro operation, not recent rain. Watch for sudden dam-driven level changes.

Water temperature for Brown Trout
Ideal
11°C est.ideal 1016°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
Excellent water temperature is right today, though insect activity could be better.
Hatch timeline · todayPeak at 11am

12pm(now) NZ Green Stonefly

Stage: Creeping nymphsApproach: Heavy nymphActivity: 92%
Also:Deleatidium / NZ Mayfly Dun51%Reed Smut40%
Peak emergence window5 food groups active

Peak activity at 11amNZ Green Stonefly (NZ Green Stonefly, Peak emergence window)

Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 2 guilds as a supporter.

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Evidence
Records-basedModerate confidence

Based on species-occurrence records, not local invertebrate surveys.

Through the year
0–3 scale · September highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Deleatidium / NZ Mayfly DunHatch
3
3
3
3
2
2
3
3
3
Burrowing Mayfly / Green MayflyHatch
3
2
2
Caddis / SedgeHatch
3
3
3
2
2
3
Cased Caddis / CreeperHatch
3
3
3
2
2
3
3

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.
  • Otago Fish & Game region — a Fish & Game licence is required
  • Beware dam-controlled flow changes
  • Check the current Anglers Notice
  • Check Clean Dry (didymo present).
What's coming
Plan ahead
5-day outlook
Gallery · 2
  1. Clutha / Mata-Au — On the Clutha River at Albert Town
    On the Clutha River at Albert Town
  2. Terrain map of the venue
    Terrain map
About this water

The Clutha / Mata-Au is the big stable giant of the South Island — New Zealand's largest river by flow, lake-fed from Wānaka and Hāwea and held by the Clyde and Roxburgh dams, so it runs big and clear where rain-fed rivers blow out. It holds large brown and rainbow trout, fished from the wadeable margins, the side-braids and the slower edges rather than the heavy main flow. A powerful river to be respected; its size and regulation make it a reliable option when others are out.

Under the surface

New Zealand's largest river by volume, the Clutha / Mata-Au pours green and powerful out of Lakes Wānaka and Hāwea and drives through the schist gorges and orchards of Central Otago to the Pacific. Lake-fed and dam-held, it runs big and stable where lesser rivers rise and fall, its margins and side-braids holding large brown and rainbow trout.

Wading: Very powerful big river current, dam controlled level changes — wade margins only, great care

Hatches & food

Fish & Game describe the lower river's invertebrate community as predominantly mayflies and caddis — mayfly hatches run midday into late afternoon across the open season, with an evening caddis rise particularly strong in early summer; exact monthly boundaries are an interpretation rather than a stated hatch calendar.

  • River
  • Schist
  • Partly confined
  • Large river
  • Glide
The full read · show the working · for Brown Trout · confidence 75%
How the 84 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time75 × 13%9.8
Pressure80 × 7%5.6
Insect activity49 × 12%5.9
Conditions total= 84
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
Directions
Seasons & zones
  • Trout year-round (most reaches)year-round

    Otago Fish & Game licence required. Dam-controlled flows — safety note. Legal status: guidance_not_permission.

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