First fill of a soil aquifer treatment
basin near Alice Springs.
Photo courtesy of Power Water Corp, NT
As the nation grapples with the need for greater water security a new report suggests that Australia should investigate the potential of managing its hidden assets, aquifers, as a prospective supply and management option for drinking or non-drinking uses.
The Managed Aquifer Recharge Waterlines report, released by the National Water Commission in February, provides information on managed aquifer recharge (MAR), alongside other alternatives, to help decision makers, water utilities and the broader community consider the potential benefits offered by MAR.
Releasing the report, National Water Commissioner Mr Chris Davis said, "at a time when we need to look to new ways to secure our water supplies, managed aquifer recharge (MAR) is an increasingly valuable option within our water supply portfolio."
“Aquifers are naturally occurring dams sitting below cities, regional communities and rural areas and can provide a wide range of significant benefits, including economic,” says lead author Dr Peter Dillon from CSIRO.
MAR involves the active managed recharge of water to underground aquifers for subsequent recovery and use or environmental benefit offering effective storage for recycled water and storm water.
“The costs of MAR, being one third to one half that of sea water desalination, should make water suppliers sit up and take notice,” Dr Dillon says.
At a time when a diversified portfolio of water supply measures is needed, MAR is an increasingly valuable option, already contributing 45 gigalitres to annual irrigation supplies and seven gigalitres to urban water supplies in Australia in 2008.
There is widely acknowledged potential for more extensive application of this process, which can be employed at varying scales and complexities, from backyard infiltration and recovery systems to large-scale augmentation of drinking supplies.
The report, prepared for the National Water Commission by CSIRO through its Water for a Healthy Country Flagship, explains MAR as a technology that can deliver a range of benefits to help communities meet the water challenges facing Australia.
MAR can be used for urban and rural irrigation and industrial purposes. It can be used to prevent seawater intrusion or provide environmental benefit, and is even being trialled for future potable use in some Australian cities.
“One of the features of this report is we take account of the natural treatment processes that occur in aquifers, which is another small economic benefit,” Dr Dillon says. “This passive treatment to make water safe has wider applications globally.”
MAR projects, especially those in urban areas, can have objectives and benefits over and above the provision of additional water supply. These can include:
- improved waterway health and ecosystem protection
- flood alleviation and reduced pollution loads
- more urban greenspace, water views and increased land value
- reduced asset management costs for storm water and storage infrastructure (because water can be injected in one place, stored, and taken out at another location)
- reduced land-use requirements compared to dams
- reduced evaporation losses
- water quality treatment benefits, potentially avoiding the need for additional treatments.
Existing MAR schemes have proven to be a cost-effective water supply measure in comparison to other supply options, and can form a useful component in a portfolio of options for securing water supplies.
Not all areas lend themselves to the establishment of a MAR scheme and the introduction of a MAR scheme should always be considered in light of existing legislation, planning rules and environmental conditions.
Dr Dillon says the key message for urban planners from the report is the need to dedicate land for water harvesting and injection into aquifers.
“Water supplies like these are not possible unless urban planners have taken water harvesting opportunities into account when planning new areas,” he says.
Publication of this Waterlines report, funded by the National Water Commission under the Australian Government's Raising National Water Standards Program, follows the May 2008 release of the Australian Guidelines for Water Recycling - Managed Aquifer Recharge draft for public consultation.
Fact sheets and more information:
Peter Dillon, CSIRO Land and Water