by Chris McCormack
- Devastating droughts are nothing new in Australia
- Fish-kills as we have seen recently, however, are new
- Production along Murray-Darling worth $19.4 billion a year
- Some of the dead fish could have been up to 60 years old
Was the recent mass fish-kill in the Menindee Lakes along the Darling River the result of drought or poor water policy in the Murray-Darling Basin?
The mainstream media would have us believe that every drought is now the result of man’s burning of fossil fuels causing “dangerous climate change”. Meanwhile, the Greens are blaming a lack of “environmental flows” for causing the fish-kill.
In reality, a check of Australian history shows that devastating droughts have been with us since time immemorial, however, mass fish-kills of this scale have not been seen before. Furthermore, poor water management in compliance with the Murray-Darling Basin Plan (MDBP) can be blamed for the mass-fish kill.
Australia has always been, in the words of Dorothea Mackellar’s immortal poem, “a land … of droughts and flooding rains”. A paper by a group of researchers studying tree ring and coral records looked at the incidence of drought in eastern Australia over the last 500 years. They found that the 1791–92 drought was one of the worst in half a millennium and that the five most extreme single years of drought occurred before 1900, with none after.
The Federation Drought (1895–1903) saw Bourke in western New South Wales record an average temperature of 44 degrees for three weeks in 1896, with four consecutive days over 48 degrees and 160 people dying of heat and disease. By the end of the drought, nearly half (54 million) of the nations’ 106 million sheep had died.
Prior to the building of the Hume Dam and weirs and locks along the Murray River between 1922 and 1939, the river’s ebb and flow largely depended on recent precipitation (or the lack thereof) upstream, meaning the river could be reduced to a trickle during long dry periods.
The building of these water storages meant that water was not wasted in flood events or sent out to sea but able to be regulated and used for agricultural production 12 months a year. This has contributed to the gross value of agricultural production in The Basinof $19.4 billion ($7.1 billion from irrigation), comprising 50 per cent of Australia’s irrigated produce, according to the Murray Darling Basin Authority in 2016.
The Menindee Lakes system, dammed by a weir constructed on the Darling River near Menindee in 1960, holds 1730 gigalitres of water, equivalent to 3½ Sydney harbours. The MDBA manages the water in the lakes when they hold in excess of 640GL and until the volume drops below 480GL, triggering NSW government control.
In January, Maryanne Slattery and Roderick Campbell from The Australia Institute produced a discussion paper, “A fish kill QandA: Questions, answers and dead fish the Menindee Lakes”. They maintain that Murray Darling Basin Authority practice is to drain the lakes to minimise evaporation. In late 2016 and 2017, the Menindee Lakes were drained of 819GL, almost two Sydney harbour’s worth. In 2017–18, 952GL were discharged over the barrages at Lake Alexandrina, South Australia, and out to sea.
One wonders, why is emptying the lakes to reduce evaporation a MDBP priority? The Menindee Lakes Water Saving Project aims to “[deliver] on [the] NSW Government’s commitment to the Murray Darling Basin Plan to adjust the sustainable diversion limit by reducing evaporative losses … and achieve environmental outcomes for the southern Murray Darling Basin”.
So, a bureaucratic decision had been made to comply with “water savings” of the MDBP, which is not only having a detrimental effect upon the residents and agricultural producers around Menindee but would have led to the mass fish-kill. Water normally held in the lakes would have enabled the fish to swim to more oxygenated waters when the decaying blue-green algae caused an oxygen deficiency in the dwindling Darling River.
Wakool River Association chairman John Lolicato said that some of the dead fish could have been up to 60 years old and that this shows that water extraction from the Darling for irrigation alone could not have been the culprit as fish had been able to survive in the river for the last 60 years. The difference in recent times was that a decision to drain the Menindee Lakes had been made, jeopardising the breeding habitat of many fish species in the Darling.
Mr Lolicato also pointed to the result of over-watering from the MDBP in his area. “During drought it is not uncommon to have a few fish deaths. But looking back over 100 years of records, which is backed up by anecdotal evidence, there were never any major recordings of massive native fish kills until 2009 [after the 2007 Water Act was introduced].
“Since then, there have been four major hypoxic blackwater events in the Edward/Wakool River systems, of which two spread throughout the Murray and Murrumbidgee River systems, killing hundreds of thousands of native fish on each occasion.”
Other MDBP “water savings” measures that the NSW Government is undertaking include the construction of the Wentworth-Broken Hill pipeline, which will redirect water from the Murray River to Broken Hill. It is due for completion in April. This will replace the Menindee Lakes as Broken Hill’s main water supply; which may strengthen the MDBA’s case to drain the lakes continually, which will destroy the tourism drawcard of the lakes, result in more mass fish-kills and decimate local agricultural production.
Contrary to the Greens’ contention that higher “environmental” flows would have prevented the fish-kill, it seems the MDBA’s obsession with emptying the Menindee Lakes in order to push more water to the Southern Basin to “help the environment”, combined with low flows from the drought, enabled the perfect circumstances for an unprecedented mass fish-kill.
