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