Why groundwater remains misunderstood — and undervalued
Groundwater plays a crucial role in ensuring water security around Australia, but mediating the impact on the environment of extraction for drinking water, irrigation and industry is an issue that requires more attention and understanding.
The theme of this year’s World Water Day is "Groundwater: making the invisible visible". Held on 22 March, the day will draw attention to the need to increase groundwater literacy and continue efforts to understand and manage this resource sustainably.
National Centre for Groundwater Research and Training Director Peter Cook, who will present a talk on the importance of groundwater in Australia on World Water Day, said that despite the crucial role groundwater plays in our communities, industries and environments, the resource is still largely misunderstood.
“Groundwater supplies most of our water over most parts of Australia. It’s mostly used for irrigation, but there are also large users for industry, mining, and domestic and rural supply in many areas,” he said.
“But increasing groundwater literacy has always been tricky. People understand rivers; they can see them and know how they work. But there seems also to be an assumption that groundwater is an infinite supply. It’s not though, and there are consequences of using it.
“There is much less of an understanding around groundwater in the community, but also in industry. People can’t see it; they can’t see the connections or how it behaves. There is a big need to try to improve people's understanding and the visibility of this important resource.”
While the traditional approach to groundwater management has typically prioritised human needs and applications, Cook said there is now a much stronger understanding of the impact that extraction has on the environment.
“Traditionally, we’ve managed groundwater principally for our own needs. Our main goal was making sure it wasn't going to run out — that there would be plenty of groundwater moving into the future for our own purposes,” he said.
“About 50 years ago, we started to realise that the environment is also an important groundwater user. Trees in some dry areas, where it’s not raining, have their root systems down in the groundwater.
“A lot of our rivers flow all year, even when it's not raining, because groundwater is flowing into them. And people are familiar with springs, which are clearly groundwater-fed.”
Following this realisation, there has been a struggle to strike the right balance in terms of managing groundwater to ensure there is enough left for environmental use, Cook said.
“This has proven to be a real challenge. In the last 20 years, there has been a real push to try to manage groundwater for the environment. But, it’s a hard balance, and we haven't always been very successful,” he said.
“The real difficulty is that the environment uses the top of the aquifer. Trees have their roots in it, but they are taking water from the top of the system. So, if we extract groundwater and drop the water level, the trees can’t access it anymore.
“If we pump and the groundwater level declines below the base of the river, the groundwater won’t be flowing into the river anymore.”
Cook said that while there can be huge amounts of groundwater in a system, if the environment only uses the top, extraction practices will still affect environmental use.
“It’s like having two people drinking from the same glass, one with a long straw and one with a short straw. At some point, the person with the short straw is going to lose access to the water in the glass, regardless of how deep it is,” he said.
“Intent in terms of trying to ensure there is enough water for the environment has been good, but the reality of how groundwater has been managed has not always worked well.”
New ways forward
In order to improve outcomes for the environment, Cook said there is a big need to try new ways of managing groundwater resources, which requires the adoption and implementation of new research in the field.
“We’ve been trying to allocate water for the environment, but it hasn’t really been working. We need to rethink the way we have been trying to manage groundwater,” he said.
“One of the difficulties we have is getting some of the research done into groundwater systems adopted. We need to get better at linking research to industry and community.
“Research can develop a whole bunch of new approaches, but if they aren’t being used, there’s not much point.
“We are getting better at this, but there is still a lack of understanding of the methods we use to understand this resource. In some areas of groundwater management, we are still doing things in the same way we did in the 1950s.”
Cook said there has certainly been a lot of effort put into managed aquifer recharge, but that addressing the problem will require more than one solution.
“Managed aquifer recharge tends to be done for urban supplies, where there is the available capital investment to set up these schemes, and it’s largely a water security solution for cities and towns,” he said.
“While water reuse and managed aquifer recharge is certainly a good way to go in terms of trying to reduce over-extraction from groundwater systems, there is nothing that will be the ultimate solution to the issue.
“Rather, we need to continue to rethink our usual water allocation practices and use the research we have available to work towards a more balanced solution.”