A dusty red soil farm with a corrugated iron windmill pumping in the middle of it is a classic image of Australian folklore. But what the windmill is pumping — groundwater — remains a tumultuous issue in Australia water management; particularly in light of the new draft Murray Darling Basin Plan.
The use of groundwater is “a major determiner in Australia’s future when it comes to water”, according to Professor Craig Simmons, director of the National Centre for Groundwater Research and Training. Simmons is one of several world groundwater experts meeting in Sydney for a three day conference this week.
Groundwater is exactly what it says it is, water that lays under the ground and can usually only be accessed by pumping. But this isn’t any old water, it’s water in underground storage facilities that have filled up over thousands of years. These days it makes up about 20% of the world’s drinking water and 30% of Australia’s total water use.
Groundwater was raised as a key problem with the latest Murray-Darling Basin Plan guide in a 25-page report released by the Wentworth Group of Concerned Scientists last week, where they noted the issue of groundwater over-allocation and the lack of research conducted on what impact increased groundwater extraction will have in the basin.
Currently around 1744 gigalitres of groundwater are extracted from the Murray-Darling Basin per year. The 2010 guide to the draft plan recommended a decrease in that usage by 160 gigalitres. In contrast the new draft plan calls for an increase in groundwater usage by an additional 2,760 gigalitres per year, taking it to a total of 4,340 gigalitres of groundwater being extracted from the Basin. But there’s been no reason given for the “major u-turn” in groundwater policy from the 2010 guide, says Simmons.
“The lack of justification for such large changes to groundwater extraction levels raises serious concerns about the groundwater extraction levels in the draft Basin Plan and the decision to not include an analysis of groundwater reductions in the surface water model,” said the Wentworth Group in its report released last week.
Simmons agreed with the criticisms raised by the Wentworth Group, declaring “it’s absolutely clear that the Wentworth Group has got it right, they’re spot on in their analysis of that document.”
For Simmons, the groundwater changes without scientific justification raise “real issues around trust, confidence and transparency” in the Murray Darling Basin Plan and Authority.
“It really does beg the question about our confidence in the project and its ability to deliver ultimately what it needs to, and that is a healthy, working river system,” added Simmons.
In Australia groundwater is mainly used for irrigation, agriculture, mining (including coal seam gas) and drinking water in regional areas. “We’ve got to husband the groundwater resource with great care if and when we need them,” said Simmons, noting the huge social, economic and environmental demands on it.
Professor Robert Glennon from the University of Arizona and author of Unquenchable: America’s Water Crisis and What To Do About It explained that in 1965 eight billion gallons of groundwater were pumped per day in the United States. In 2005 (the most recent time period available for groundwater data in the US) that figure had grown to 80 billion gallons a day. Half of the United States is reliant on groundwater for drinking.
Since it has to be pumped up from below the ground, it’s extremely difficult to be sure of exactly how much water is available in aquifers, meaning ground water is ripe for misuse.
There’s a growing awareness amongst Australian governments and authorities of the importance of groundwater, with most allocations requiring groundwater extractions and usage to be licensed. But one of the biggest issues is compliance, says Simmons. “We think illegal use is probably rampant but can we get data on that? No.”
Problem is, although it takes thousands — even millions — of years for groundwater aquifers to collect fully, humans are using the groundwater in just a few decades. By pumping away the water for human usage, it’s impacting on the rivers, wetlands and springs that would usually receive the water. Until people understand the finite quality of groundwater — and the importance of it, we’re likely to overuse it, says Glennon: “Humans … have an infinite ability to deny reality.”
After publishing this story the Murray Darling Basin Authority contacted Crikey (and left a comment below) and pointed us in the direction of this groundwater fact sheet on their website. Although it was first written in November, it was updated yesterday to reflect some of the current debate over the new groundwater targets.
It notes that the proposed groundwater sustainable diversion limits (SDLs) is approximately 0.1% of the basin’s total groundwater. How did it come to the 4,340 (4,339.6 to be precise) number?
“In deciding the groundwater SDL number, we looked at the amount of water that is ‘recharged’ (i.e., naturally replenished) to each aquifer. We then looked at the long-term ability of water to be taken from the aquifer, groundwater-dependent ecosystems, groundwater flowing to surface water and groundwater quality and used all of that information to assess the level of risk involved in taking groundwater. Based on this, we chose to make only a proportion of the total recharge available for use — that proportion is the SDL.”
The MDBA also explained how they developed their plan based on state government information:
“In developing the groundwater sections of the draft plan, we’ve been working with the state governments. The states gave us updated information on current levels of groundwater entitlements, stock and domestic use of groundwater and SDL area boundaries. We’ve also received a lot of monitoring information from the states during the development of the draft. The states also provided science about new groundwater models, recharge estimates for a number of areas and the varying connectivity between surface and groundwater.”
For more information head over to its site.