AGL's two year irrigation trial in Gloucester will end this month. Just how that end has come about, and how (un)successful it has been, depends like so many things on who is doing the talking.
"We've been really happy with the results from the Tiedmans Irrigation Program and as we only have a very small volume of produced water left, we made the decision not to apply for an extension of the program. The decision was made not to extend the program beyond April 30 after careful consideration."" John Ross, AGL's hydrogeology manager, said.
Over the period of two years, more than 50 megalitres of produced water from its gas exploration activities were blended with freshwater to irrigate crops including lucerne, triticale and forage sorghum, and an area of improved pasture.
Mr Ross cited no impact to adjacent surface water resources or underlying groundwater, and no adverse impacts to soils and fodder, which he said had been proven to be suitable as supplementary feed for cattle and sheep.
By comparison the Environment Protection Authority (EPA) also reviewed the data from the irrigation trial. Although not responsible for monitoring the trial, which had been approved by the Division of Resources and Energy (DRE), the program is reflected in the EPA's Environmental Protection Licence held by AGL for its coal seam gas activities in Gloucester.
"The EPA analysed data from the irrigation trial and was concerned about the levels of salt and metals - the presence of these made the long term viability of the program unsustainable," a spokesperson for the EPA said.
Based on this review the EPA told AGL and the DRE it would not support a continuation of the trial. AGL has since announced it would not to seek approval to extend the irrigation trial.
"This decision has clearly been forced upon AGL because the EPA had made it clear that they were unhappy with it," David Hare-Scott, the deputy chairman of CSG protest group Groundswell Gloucester, said.
No longer able to irrigate with produced water after April, AGL said the remainder of the water would stay in one of the holding ponds at their Tiedmans property, and be treated by reverse osmosis when the water treatment plant was built as part of Stage 1 of the Gloucester Gas Project.
"AGL should not now be permitted to continue storing its produced water in ponds as they would amount to evaporation ponds which are banned in NSW," Mr Hare-Scott said.
Manning beef farmer and economist Bruce Robertson said he has long been concerned that the trial was a cheap way of disposing of heavy metal salts on the river flat at Gloucester.
"This is in our water catchment and these salts will leach out over time. Silage was also cut from these contaminated paddocks. AGL had wanted to do 10 such irrigation schemes up and down the valley," he said.
Greens mining spokesman Jeremy Buckingham said it was obvious salt and heavy metals were going to build up in the soil over time.
"If this method of disposing of wastewater has failed with only a few exploration wells, then how will AGL dispose of the toxic water from over 100 production wells?" Mr Buckingham asked.
The EPA stressed that whilst no long term effects had yet been found, with the irrigation trial slightly uphill from the waterways, leaching had always been a concern. A spokesperson said the EPA would closely analyse AGL's final report and all other monitoring data to work with the DRE to determine whether any further action, such as site remediation, would be necessary.