Australia's groundwater management challenge
Up to a third of the water Australia consumes is groundwater, but management of this precious subterranean resource faces many challenges: fragmented regulation, a lack of planning and threats from mining.
The only source of water in many communities, groundwater also underpins vast amounts of agriculture and is responsible for billions of dollars in economic value each year. But when it comes to regulation and planning, it has been consistently overshadowed by more visible sources of water.
With some exceptions, most regions of Australia have been significantly increasing their reliance on groundwater in recent decades. In the past 10 years, meanwhile, the body of research around groundwater has grown substantially, fuelling a greater understanding of the elaborate complexities of the system, as well as calls from scientists urging governments to step forward and start planning for sustainable groundwater use on a national scale.
“If you can’t measure it, you can’t manage it” has been a touchstone of the water industry since the Millennium Drought, and the approach to groundwater is no different. A major driver of improving knowledge in this sector was the National Groundwater Action Plan (NGAP).
“One of the critical NGAP results was an improvement of the access to data and collaboration between government and industry on collating national groundwater data,” CSIRO Experimental Scientist Andrew Taylor said.
Jurisdictional groundwater data across Australia is now available thanks to the Bureau of Meteorology’s National Groundwater Information System and the Australian Groundwater Explorer.
However, we remain a long way from gaining a complete understanding of the complexities of and relationships between all of the country’s various aquifer systems, Taylor said.
“Not all groundwater systems in the country are equally characterised, and such knowledge is critical to support regional development,” he said.
“There is a need for improved understanding of the landscape and hydrogeological settings of Australia’s groundwater systems. This influences our knowledge on the groundwater balance: recharge to and discharge from aquifers, and surface and groundwater interaction.
“Better understanding and quantifying the interconnection between groundwater systems in large geological basins with shallow groundwater is critical, particularly for the sustainable development of the resource sectors.”
In some regions, there is poor measurement and regulation of groundwater extraction. Jacobs Principal Hydrogeologist Dr Richard Evans said there was lax enforcement of illegal pumping in some jurisdictions.
“We need to get serious about enforcing laws surrounding people who have illegal bores or who are illegally pumping,” he said.
“Currently, there are few implications. If people want water, they just go and pump groundwater. It’s illegal use but they don’t worry about it because the compliance process is weak in some jurisdictions.”
To University of New South Wales Associate Professor and Connected Waters Initiative Research Centre Member Bryce Kelly, part of the problem is a lack of precision in monitoring groundwater extraction.
“Measurements of stock and domestic use in many areas is just guesswork,” he said.
Out of mine
Kelly also called for better monitoring networks around coal mines, as well as oil and gas projects.
“Why is it that we have hundreds of groundwater monitoring locations assessing irrigation impacts in the Namoi Catchment but only six coal seam gas (CSG) monitoring wells initially planned to monitor the Pilliga coal seam gas developments?” he said.
“We need all catchment water balance models in the public domain so that others can explore conceptual and calibration issues with the models.”
He’s not the only one concerned, with the Australian Water Association’s 2016 Australian Water Outlook finding that more than half of Australia’s water professionals are concerned about the possible impacts of the extraction of unconventional gases – such as coal seam, shale and tight – could have on water supplies, with community concern even higher.
Almost two-thirds of water professionals also thought water trigger legislation should cover all unconventional gas extraction, while just 13% thought there was adequate scientific information on the impacts of unconventional gas on water.
However, some recent strides have been made in the field, with a recent CSIRO study shedding light on how to reinject large volumes of water produced by CSG extraction without compromising water quality.
Experiments on re-injection at Reedy Creek and Condabri – both in Queensland’s Surat Basin, where CSG extraction produces an average of 70GL of water annually – found that stripping oxygen from treated CSG water prior to reinjecting it could prevent the mobilisation of harmful chemicals such as arsenic.
Since 2015, more than 10 GL of treated CSG water have been reinjected into the area’s aquifer, currently making it Australia’s largest treated water reinjection scheme and causing the first rise in nearby groundwater levels recorded in decades.
That title is unlikely to last for long however, with WA’s Water Corporation’s Groundwater Replenishment Scheme ramping up. The first stage is expected to annually pump up to 14GL of recycled water into Perth’s aquifers, the source of almost half its potable supply. Once the second stage of the scheme is in place in coming years, that total could double to 28GL.
Many hope the high-profile project will awaken other regions to the potential offered by managed aquifer recharge, described by UNSW researcher and CWIRC member Dr Wendy Timms as a much smarter way to store water than shallow, evaporative dams. However, she said the challenge lies in a lack of incentive or pricing signal to actively manage recharge to balance the use of groundwater.
“Despite Australia leading world practice in water management, some cross-jurisdictional and cross-disciplinary challenges remain,” she said.
“For example, seepage losses from a surface water model often do not match gains in a groundwater model, and a groundwater model with horizontal outflow should match horizontal inflows to a groundwater model in the adjacent catchment area, even if crossing jurisdictions.”
Australia’s hydrogeology makes this a vital concern, with the Great Artesian Basin, for example, spanning Queensland, New South Wales, South Australia and the Northern Territory. Groundwater policy at present is managed at the state level, but groundwater researchers urge that a national policy is desperately needed to ensure the asset is managed sustainably.
“Our current policy is largely managing the status quo,” said Jacobs’ Dr Richard Evans. “Aquifers around the world are treated as a huge asset, but we generally don’t see them as an asset in Australia – we only think about the water itself.
“The question then becomes: What is the national policy for how that will be handled? There isn’t such a thing. There are plenty of policy documents written, but there is no national vision on how we’ll get there. Our knowledge base has improved greatly, but our policy base has not moved forward as much as our science.
“It’s all about realising we have this great natural asset. We can use it much more to our advantage, but unfortunately people don’t yet understand the value of it.”
First published in Current magazine February 2017.