CARP REMOVAL AT RIVER MURRAY LOCK ANDWEIRSLOCK AND WEIRS

Brenton Erdmann

About the Murray‐Darling Basin

• Area: covers 1 061 469 km2 equivalent to469 km2, equivalent to 14% of Australia’s landmass or Francelandmass or France and Spain combined

• Australia’s largest river systemsystem

About the Murray‐Darling Basiny g

D li Ri 2 740• Darling River at 2,740 km is Australia’s longest riverlongest river

• Murray River is 2 530k l2,530km long

• Basin extends over 75% NSW, 60% Victoria, 14% Qld, 7% SA 100% ACTSA, 100% ACT

The River Murray System

Menindee LakesSA Responsibility Menindee Lakes

Lake VictoriaSnowy Mountains

Hume Dam

yScheme

Lock and Weirs

L L k

Dartmouth Reservoir

Lower Lakes

MDBC Native Fish Strategy

• Native fish populations p pnow 10% of pre‐European stocks.

• Restore to 60% in 50 yrs.

• 13 objectives.

• Objective 5 ‐ Provide adequate passage for native fish.native fish.

• Objective 8 ‐Manage j gInvasive species.

MDBA Sea to Hume Fish Passage Program

N ti Fi h St t Obj ti 5Native Fish Strategy Objective 5 ‐Provide adequate passage for native fish.

• $55m program to restore fish passage to 2,255 km of the p g ,River Murray from the Sea to Hume Dam by constructing fishways at 13 barriers.fishways at 13 barriers.

• Fishways constructed at Murray Mouth Barrages and Lock andMouth Barrages and Lock and Weirs 1 – 11 and 15

DESIGN CONSIDERATIONS

• The fishways were designed• The fishways were designed to pass native fish from 65 mm up to Murray Cod with amm up to Murray Cod with a length of 1100 mm.

Unspecked Hardyheadp y

Golden Perch or Callop

Murray Cod

DESIGN CONSIDERATIONS

• A 1:32 slope vertical slot fi h l dfishway was selected.

• Later fishways were changedLater fishways were changed to 1:20 slope vertical slope for large fish plus a fish lockfor large fish plus a fish lock for small fish.

TYPICAL VERTICAL SLOT FISHWAY

MDBA Sea to Hume Fish Passage Program

Native Fish Strategy Objective 8 M I i i‐Manage Invasive species

• Carp accumulate in large• Carp accumulate in large numbers, especially below Lock and Weir No 1.

CARP SEPARATION

• Alan Williams, a Lockman from Torrumbarry, observed that carp jump when they meet a barrier but native fish don’tcarp jump when they meet a barrier but native fish don t.

• He built the first carpHe built the first carp separation cage based on this observation and installed it atobservation and installed it at Torrumbarry Weir.

• The original Williams carp separation cage has goneseparation cage has gone through various modifications and is now installed at Lock 1and is now installed at Lock 1, 3 and 10.

LOCK AND WEIR No. 1

LOCK 1 CARP SEPARATION CAGE

Vertical Bar Mesh TrapFlow

Exit Channel

Weir Pool

Holding Cage

Mesh Trap

Weir Pool

Holding Cage

ol

FlowDirection

Weir Pool

Holding Cage

Weir Pool

Interchange Flow Direction

Weir Pool

Wei

r PooDocking

Holding Cage

Carp Chute

Jumping A

Carp Chute

Jumping AreaArea

Cone Trap

p g

Cone TrapFishway

Exit Channel

FishwayCone Trap

Entry to Exit Channel

Fish Movement

LOCK 1 CARP SEPARATION CAGE

LOCK 1 CARP SEPARATION CAGE

FISH HANDLING – lifting holding cage

FISH HANDLING – emptying cage

FISH HANDLING – into the freezer

FISH HANDLING – packed for transport

FISH HANDLING – loading truck

CLOSING COMMENTSCLOSING COMMENTS•Expect to remove approximately 90 tonnes of carp inExpect to remove approximately 90 tonnes of carp in August to December period

•Majority of fish are large pre spawned females•Majority of fish are large pre‐spawned females

•Proven effective in separating migrating carp from native fish

•Negligible amount of native fish caught in carp holdingNegligible amount of native fish caught in carp holding cages

C b d t d t th i t t•Can be adapted to other river structures•Represents the only ongoing carp control practice in the Murray‐Darling Basin