Aldinga Managed Aquifer Recharge Scheme | South Australia

This pioneering Managed Aquifer Recharge (MAR) project lead the way in Australia for storing treated urban wastewater below ground. Designed and constructed under the leadership of HydroPlan, the trial for the Aldinga Managed Aquifer Recharge Scheme was extended to provide a valuable source of water to local irrigators, while significantly reducing the volume of pollutants released out to sea.

Managed Aquifer Recharge (MAR) schemes store water in underground aquifers, providing a cost-effective opportunity to improve water security. MAR also supports ecological health by recharging over-used aquifers and – as water is stored below the ground – reduces evaporation loses and the presence of algae and mosquitoes.

Following our involvement in CSIRO trials for treatment options, HydroPlan was engaged to design a system comprising two wells that could be expanded to six with a storage capacity of 400 megalitres. To accelerate initial operation of the scheme, our design included the use of a low-pressure, self-regulating gravity injection arrangement until down-hole sensors and aquifer pressure regulation was possible. A central control and monitoring facility was established at Willunga Basin Water’s existing pump station, reducing potential safety hazards, and allowing the system to be powered by a single generator until mains power was connected.

After commissioning, HydroPlan was retained to operate the network for several injection/abstraction cycles to monitor salinity and recovery efficiencies, and to ensure the efficient delivery of water to irrigators – especially important as the scheme was launched towards the end of the Millennium Drought. During operation of the system, HydroPlan developed a dedicated website to capture technical data, which was made available to stakeholders, regulators, and scientists.

Aldinga Managed Aquifer Recharge Scheme provides a valuable lifeline for local irrigators by storing water during winter for access during summer. During the first ten years of operation, 2,000 megalitres of water was injected and recovered from the recharge scheme, reducing the amount of wastewater that would otherwise have been released into the sea. Studies have calculated that this has resulted in a reduction of 30 tonnes of nitrogen and 10 tonnes of suspended soils discharged into the Gulf of St Vincent – a significant contribution to the protection of marine environments and biodiversity.

Sources: CSIRO, Ozwater