The National Water Commission has stated that coal seam gas mining risks having 'significant, long-term and adverse impacts' on water resources and called for caution in its implementation. Some of the threats identified by the NWC include depressurisation and contamination of aquifers, land subsidence, reduction of surface flows in connected systems, management challenges surrounding large volumes of waste water, alterations of water quality and impacts on the health of wetlands and rivers.
Australia Pacific LNG have approval to discharge up to 20 million litres of treated coal seam gas wastewater each day into the Condamine River. Even after treatment, tests show that this water includes chemicals such as boron, silver, chlorine, copper, cyanide and zinc at concentrations that would be toxic to aquatic organisms.
In late May 2012, the Condamine River was found bubbling 'like a spa bath' near the Queensland country town of Chinchilla. A gas metre registered high levels of methane coming from the river. The bubbling was occurring in an area where coal seam gas wells are located in close proximity to the River. Whilst the gas company concerned, Origin Energy, blithely described the bubbling as a 'natural' phenomenon, landholders in the area have never heard of or encountered gas leakages on this scale previously, and Dr Gavin Mudd from Monash University School of Engineering stated that it was feasible that de-watering of the coal seam had enabled methane gas to escape to the surface.
Evidence of methane migration as a result of coal seam gas mining has also been provided by a local landholder who has been able to set his water bore on fire after drilling took place nearby, and an old coal exploration drillhole at Daandine, near Dalby, which has recently caught fire after coal seam gas mining in the vicinity. There is also a large body of evidence indicating that methane migration is a relatively frequent occurrence near unconventional gasfields in America.