SMH - Ben Cubby - 12.11.2011
Protecting the water wealth of the Great Artesian Basin is the latest challenge for the coal seam gas industry, writes Ben Cubby.
Beneath the bone-dry surface of inland Australia, west of the Great Dividing Range, a vast body of water is slowly flowing towards the sea.
The basin has existed in its current form for millions of years, but one of the biggest tests to its existence will come in the next decade. Beneath the layers of water lie some of the world’s most extensive coal seams. Just as the sandstone aquifers contain water, so the coal seams contain methane.
But the real impact on the basin is likely to come from the cumulative, long-term effects of large-scale drilling and pumping. The National Water Commission says the potential water impacts of the coal seam gas boom are not well understood, but are likely to have adverse effects on other water users.
”Extracting large volumes of low-quality water will impact on connected surface and groundwater systems, some of which may already be fully or over-allocated, including the Great Artesian Basin and Murray-Darling Basin,” its latest advice on the matter says.
Drilling of the 40,000 planned wells could have a series of consequences, it says. These include changing pressures in underground aquifers so that potable water mingles with unusable water, fouling bores, reduced flows in rivers and land could subside ”over large areas, affecting surface water systems, ecosystems, irrigation and grazing lands.”
The water commission, a government agency, is reluctant to be seen as partisan in the coal seam gas debate, but last month it expressed doubt about the long-term effects of the gas boom.
”The commission is concerned that CSG development represents a substantial risk to sustainable water management given the combination of material uncertainty about water impacts, the significance of potential impacts, and the long time period over which they may emerge and continue to have effect,” it says.
The commission’s statements carry weight within and without the coal seam gas industry, and the companies are finding themselves increasingly distracted by a mammoth and expensive public relations effort.
”Five years ago nobody cared what you did – you could turn up and drill a hole and do a frack and nobody cared about it,” the chairman of the Australian Petroleum Production and Exploration Association, Eric Streitberg, told an industry conference on Tuesday.