With all that rain in NSW people are again saying
“Grafton floodwaters would save Murray-Darling—build the Clarence Scheme!”
Are some of the old ideas gaining currency? I was fascinated by the following;
The Bradfield Water Schemes – for ‘nouveaux’ engineers like yours truly – get their name from the Sydney Harbour Bridge architect John Bradfield’s 70 year old scheme to divert North Queensland rivers to the Warrego and Thompson rivers and into the Murray-Darling system – a way to irrigate dry areas and supply water to urban centres as far away as Adelaide. The late Richard Pratt was willing to help fund a Bradfield scheme to save the Murray-Darling Basin.
The Clarence River Scheme from the early 1920s would divert the waters of the upper Clarence and Nymboida Rivers over the Great Dividing Range into the Dumaresq River, and on into the Macintyre, Barwon, and Darling Rivers, before flowing into the Murray River near Mildura, and on down to South Australia.
The arguments against these ‘dreams’ seem to be horrendous costs, political ‘challenges’ and lack of water.
“We have to be very careful about building gold-plated infrastructure, and then finding we have no water to put through it” says Dr Kelvin Montagu, knowledge manager for the Cooperative Research Centre for Irrigation Futures.
Matt Cawood writing for Farm Online reports that Sydney-based Terry Bowring is the latest to come up with a water transfer scheme. He believes it is the only answer to today’s water scarcity issues and says
“Victoria and South Australia are in deep trouble, and may be in deeper trouble in years to come…There’s talk of taking agriculture north to the rain, but that’s full of problems.”
Terry has proposed that
“about 4,000 gigalitres (GL)—slightly under the long-term average storage capacity of the Murray storages—be siphoned off the Burdekin and adjacent rivers and sent 1,500 km south in lined canals to about Bourke.
From Bourke, subsidiary pipelines or canals would take water past the evaporation pans of Menindee Lakes and dump it into the Darling, to be take south by gravity.
Other subsidiary lines would feed Brisbane and Sydney, and any irrigation areas that the market deemed viable would run from the canal.
According to Mr Bowring, an average of about 11,600 GL a year currently flows out to sea from the Burdekin River. His extraction plan would take about a third of that, although some could be taken from other rivers.
Rough costings on a pipeline to carry water across the main 1500 km section of the scheme came to about $32 billion—prohibitively expensive.
Mr Bowring then looked at canals lined with concrete or synthetic linings, a technology he has seen at work in the United States, and came up with around $5.6 billion to get water from the Burdekin to Bourke.
He suggests that the canal route be sited to take advantage of existing and proposed gas pipelines, which could deliver the energy needed to shift such huge volumes of water.
In order to average out seasonal flows, Mr Bowring’s proposal suggests that excess water should be stored in “fractured rock aquifers” such as the huge Gilbert River Aquifer in north Queensland.
Using a system to hold water over the fractured rock zone would allow water to enter the aquifer at a seepage rate of a couple of metres a day, he claims. Once underground, it is stored indefinitely away from evaporation.
“So long as you keep very good records about what you’ve put in, there should be no argument about what you can extract,” he said.
Mr Bowring and his supporters have submitted rough proposals to the Victorian Government, the Federal Senate, and concrete industry majors in the hope of getting funds for a full feasibility study.
“Australia has to think about, debate, and make decisions about its long term future,” he said.
“The way we value, allocate and manage water will have major impact on the quality of our future.”
You can contact Terry Bowring by email email@example.com
Will we see a community discussion about such schemes, guided by science?