Thousands of miles of polyethylene pipe are helping drought-proof vast tracts of the Australian outback and preserve a precious water source.
The Great Artesian Basin (GAB) is an underground reservoir beneath 22 percent of Australia. It spans 656,000 square miles under arid and semi-arid parts of the states of Queensland, New South Wales and South Australia and the Northern Territory.
It was discovered in 1878 when water poured from a shallow bore sunk near the GAB perimeter and since then graziers — people who raise cattle — and rural townships have sunk thousands of bores to access the water. But many are still free flowing, so most of the water is wasted.
Fifth-generation western Queensland grazier John Seccombe, who owns a 64,000 acre cattle property, Kenya Station, near the Queensland outback town of Longreach, is the architect of a massive scheme to cap the bores and lay PE pipe to transport water for livestock around rural properties.
No one is certain how many bores exist. Seccombe told Plastics News an initial estimate was 3,700 across the GAB, but “I'm skeptical of the numbers.”
Seccombe has 85 miles of PE pipe crisscrossing Kenya Station, replacing open drains where up to 95 percent of the water is lost through evaporation and seepage. He has no idea how many thousands of miles of pipe have now been installed across the GAB, but said in a phone interview from his remote property: “I'd be very wealthy if I'd been selling the pipe.”
Seccombe, as a pioneer of capping and piping, paid personally for the work on Kenya Station, but was instrumental in getting Australia's Federal Government and the state and territorial governments to jointly form the GAB Sustainability Initiative (GABSI) in 1999. It wasn't easy to convince governments, which license access to GAB water, that his plan would work and funding has often been under threat.
GABSI shares 40 percent to 60 percent of the cost of capping and piping with landowners. Seccombe says GABSI has contributed about A$300 million (US$217 million) to the A$500 million (US$362 million) spent since GABSI's launch.
Applications for the latest round of funding in Queensland have just closed.
The Queensland Government says 676 bores have been rehabilitated so far and 8,700 miles of bore drains replaced with PE piping, saving an estimated 199,000 megaliters of water annually.
Knowledge on how to lay PE pipe has advanced enormously since Seccombe started experimenting in the late 1980s. Pipe quality has improved, too. Initially PE piping was clear and went brittle quickly.
Today's black PE piping is more flexible and stronger, but still needs to be buried deep enough to avoid getting damaged. Seccombe says piping cannot be laid in the heat of the day, otherwise it shrinks and the joints leak when it's buried.
Environmental body GAB Protection Group Inc. says the equivalent volume of Sydney Harbor, 500,000 megaliters, of GAB water is wasted every year.