Coal seam gas extraction is "irreversibly" affecting the state's prime agricultural land and there will be "incalculably great" remediation costs when the industry is phased out, a new report says.
The paper, published last month by a group of scientists in the Proceedings of the Royal Society of Queensland, says CSG mining in the Surat and Bowen Basins has created permanent subsidence, depleted groundwater and eroded landholders' rights.
One of the authors, University of Queensland agricultural scientist Dr Peter Dart, said considerable subsidence or sinking had occurred across the Surat Basin over the past 10 years.
"It disturbs the flow of gravity-fed irrigation water and the management of flood waters and is irreversible," Dr Dart said.
For the work, Dr Dart was joined by Griffith University adjunct professor Dr Geoff Edwards, who is a former Queensland Department of Mines and Energy (now the Department of Resources) principal policy officer, Environmental Defenders Office managing lawyer Revel Pointon, and retired UQ Seismograph Stations senior observer Colin Lynam.
Concerns about groundwater, government
Gas is extracted from more than 13,000 wells in the Surat Cumulative Management Area in southern Queensland, with the four major companies involved given the go ahead by the state and federal governments to expand this to a predicted 22,000 wells.
The gas is held naturally in small layers of coal, sealed in by water pressure trapped by the depth of rock strata and sediment above the coal seams.
This water needs to be pumped out to release the CSG from the coal.
Dr Dart said currently about 54GL of water were extracted per year from the Walloon Coal Seam aquifers, equivalent to about 40 per cent of the volume extracted from all the aquifers in the region, used by farmers for irrigation and municipal drinking supply.
"The issue is the acknowledged depletion caused by the CSG mining to groundwater storage aquifers in the GAB on which the agriculture, springs and ecosystems depend," he said.
Dr Dart and his co-authors have also been critical of the government, accusing the state of avoiding its duties.
"The prevailing self-regulation, lack of baseline assessment and inadequate monitoring of the mining processes and causal effects is an abrogation of government responsibility and the precautionary principle ...," he said.
He said as the industry geared up for more CSG wells, there was "precious little time" to protect agricultural land.
Resources Council 'acknowledges concerns'
Queensland Resources Council chief executive Ian Macfarlane said the council acknowledged concerns about subsidence risk in relation to the CSG industry on the Darling Downs.
"The use, extraction and treatment of groundwater is a sensitive issue in irrigated black soil country, which is why the industry is spending millions of dollars working with independent and well-respected government scientists to measure soil movements in the region," he said.
Mr Macfarlane said the CSG industry was focussed on understanding the science around working with highly productive cracking and swelling vertosol soils, so companies could "harmoniously coexist" with agricultural businesses, families and communities "for mutual, long-term benefit".
"The ongoing involvement of local farmers in subsidence research programs is essential to this process and is much appreciated. Their contribution is helping shape practical and enduring solutions that will work for individual farms, the region and industry."
Government promotes 'co-existence'
The Department of Resources did not address the criticisms directly, but did say agriculture and resources were multi-billion-dollar industries that supported thousands of jobs and helped underpin Queensland's economy and regional communities.
"Queensland's resources framework promotes the coexistence of landholders, regional communities, and industry, manages environmental impacts and maximises benefits for all Queenslander," a spokesperson said.
Growers say they're feeling the effects
In July, Dalby area farmers Zena and Garry Ronnfeldt spoke to Queensland Country Life about subsidence on their property.
They have seven Arrow Energy CSG wells on their boundary and five wells on their property, which they say caused subsidence and prevented them from planting 120ha of wheat this year.
At the time, Arrow Energy CEO Cecile Wake said the company had thoroughly investigated the claims and provided extensive LiDAR and historical satellite data, which demonstrated that the depressions of concern were not caused by coal seam gas activities.
The independent GasFields Commission is currently reviewing the potential implications of CSG-induced subsidence.