Researchers from the National Centre for Groundwater Research and Training, based at Flinders University, have identified very low chances of problems with groundwater contamination due to fracking, but a very high likelihood of some kind of incident at the surface where unconventional gas is produced.
Unconventional gas production — such as coal seam gas and shale gas — is a highly contentious issue, with concerns that groundwater contamination could be among many possible impacts. However, just because something is possible does not mean it is probable, and it is quantifying the probability of impacts on water resources that presents an interesting and important scientific challenge.
The Flinders researchers sought to quantify the likelihood of surface water and groundwater contamination, and shallow aquifer depletion from unconventional gas developments. They compiled several hundred global scientific comparisons — from Australia, North America and Europe — between the likelihood of impacts to surface and groundwater sources from producing shale gas, tight gas and coal seam gas.
“Our work synthesises global literature and fundamental scientific understanding to quantify the probability of impacts on water resources occurring,” said study co-author Professor Craig Simmons.
The results, published in the journal Groundwater, show that spills at the surface can and do happen everywhere that gas production from unconventional reservoirs occur, and that production processes require human vigilance for the prevention and mitigation. The researchers note that more attention is needed to bring the probability of surface spills down.
The researchers believe the likelihood of something bad happening underground is much lower than the general public may tend to believe, having examined a wide range of possibilities. However, they warn that this risk will be quite variable, depending on how deep the gas is and what the geology between that gas and the potable water above it looks like.
Source: Sustainability Matters