Concerns over water wastage

The Observer 12/10/2010

12th October 2010
“WHEN most of the county is in drought, why is water being used as a waste product,” Surat Basin Friends of the Earth environmental campaigner Drew Hutton said.

And it would seem he has a point as Santos (GLNG) and BG Group (QCLNG) have acknowledged that the emerging coal-seam gas (CSG) industry will affect underground water levels.

The revelation comes on the eve of the Federal Environment Minister’s environment approval of Santos and BG’s liquefied natural gas (LNG) plants on Curtis Island set for October 22.

Concerns centre on the projects’ impacts on groundwater levels of the Great Artesian Basin, with the sinking of 12,000 wells across some of Queensland’s best agricultural land.

Mr Hutton said he was amazed at the lack of concern about this by both the companies and the State Government.

“A recent study by hydrologist John Hillier for Central Downs Irrigators found that the Walloon coal measures from which the methane is extracted along with the water (usually briny) is linked with the Condamine Alluvium which is the main aquifer used by irrigators along the Condamine flood plain,” Mr Hutton said.

“If the Walloon coal measures are de-pressurised by the removal of masses of water then this is likely to set up a dynamic which places the whole alluvium in jeopardy.
“New bores might not be an option and we will have lost much of the productivity of this fertile area.”

BG and Santos have stated the groundwater impacts will be “small but manageable” and they will offer “make-good measures” should the groundwater table drop.

Annual volumes of CSG water for the Santos GLNG project may potentially equate to 18,250 ML per annum in the first 10 years, and 10,950 ML per annum for the subsequent 10 years.

Coal Seam Gas water typically contains significant concentrations of salts, has a high sodium adsorption ratio and may contain other contaminants (e.g. hydrocarbons) that have the potential to cause environmental harm if released to land or waters through inappropriate management.

Santos said up to 180ML a day of water produced from the coal seam could lead to changed pressure gradients in the groundwater, lowering the water table.

The Co-ordinator-General’s evaluation report for GLNG’s environmental impact statement says the CSG water management strategies presented were not comprehensive enough to determine they were adequate in preventing environmental impacts, and the following analysis indicates the areas of concern to DERM and other agencies.

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