Could gulf run-off irrigate the rest of Australia?
VICTORIAN Rex McIntosh recently sailed around the top of Australia. And he saw floodwaters washing away to the ocean. He believes an economic salvation could be found for Queensland if that water was captured and used productively.
We need to transfer the massive amounts of rainwater that pelt the Gulf of Carpentaria basin to the southern states of Australia.
The Gulf run-off is about 62,000 GL per year. That's the largest catchment run-off in Australia. Except for some small dams new Mt Isa, all this water currently wastes into the ocean and represents a huge financial loss to the driest continent on earth.
About half the run-off would be lost to seepage and evaporation, but the other half could be captured and used to irrigate food crops. But there is not sufficient flat arable land in the Gulf to utilise that volume of water for irrigation.
As well, the Gulf climate is too tropical to grow most food crops. Tropical farming ventures have been tried before, but pests and plant disease have overwhelmed those ventures.
And it's not an easy life trying to work farms up there - Burketown cemetery is full of graves of hopeful Victorian farmers who perished last century.
If we dammed, there would be destruction of some environmental features. However, on the positive side, the huge amounts of freshwater would be a benefit to human life, wildlife, birdlife, and to fish and crayfish.
If we dammed the 20 major Gulf Rivers we could store about 30,000GL of water. Dams are necessary because the catchment flow is seasonal and monsoonal. Some storage may be possible by reclaiming part of the Gulf near Normanton.
We would then release the stored water (generating hydroelectric power), which would run down each water course until collected by a coastal canal.
This canal design is quite challenging because it must be near the coastline to control the catchment water, but not so close as to ever get contaminated by sea water surges such as cyclone may cause. Each rive estuary would have to change from saltwater environment to a freshwater one.
Each estuary would need pumps to cause the canal water to flow to near Normanton.
Pump 40,000ML per day via Norman or Staaten River, plus a stepped channel with pumps and rising pipelines until discharge on to the Gregory Range. If the water is risen to 340m above sea level it will flow over the Gulf Divide into the Lake Eyre Basin.
Run the water in a huge open channel along the western side of the Great Divide for the whole length of the Lake Eyre Basin, to a point near Tambo and near to the Grey Range Divide. The water would need to be stored and raised in elevation at some places-perhaps Lake Galilee and Loch Nagar and maybe others.
Pump the water up 100m to run over the Grey Range into Langlo River. The Langlo River channel would need to be deepened and made wider to accommodate the flow. This excavation may need to be extended down the Warrego River to the Darling River near Bourke. Electricity could be generated along this waterway as water falls into the Darling River.
Queensland has the greatest scope for using its share of the saved water, before it reaches the Langlo. NSW has huge potential to bring into profitable production the flood plains of the Darling. Victoria may not get Gulf water, but could profit by using its own Murray River water which would no longer be needed in South Australia.
While it is the geometry of the land that makes this scheme possible it is only the will of the people and their elected representatives who can make it happen.
If it happens, this scheme would probably be the biggest ever undertaken in Australia and would not have a small price tag.
The huge boost to farming production would certainly pay for it in the foreseeable future for young farmers. It would probably at least double the potential maximum population of Australia.