During periods of drought, secure, large volume water storage facilities are a valuable asset to industries and groups with high water consumption requirements. Storage of harvested water in natural aquifers offers this potential in many locations around the world.
In this project a fractured rock aquifer, located at the Kingswood Golf Club in outer metropolitan Melbourne, was tapped with a pilot bore and 1.9 million litres of harvested storm water was successfully injected and recovered. The club now aims to extend the use of this aquifer to store up to 25 million litres of stormwater to augment their irrigation water supply in periods of low rainfall.
Experience gained from the CSIRO led project at neighbouring Rossdale Golf Club, where aquifer storage was investigated, was valuable in obtaining a bore construction licence and EPA permit to trial inject and recover up to 5 ML of stormwater for this pilot storage program. A survey for a suitable drilling site was then conducted.
Once the drill site was selected, bore drilling was followed by a geophysical logging of the resulting pilot hole which extended to a depth of 114 meters. This provided access to the underlying fractured rock aquifer. The pilot hole diameter was widened via a reaming operation and the bore walls cased in concrete to a depth of 109 meters.
Trial injection of storm water showed that injection and recovery rates of above 10 litre per second were possible. Water recovered from the aquifer during this trial had levels of total dissolved solids up to 1800 parts per million. Both contamination levels and flow rates are compatible with the intended use for the recovered water in golf course landscape irrigation.
The pilot program showed that it was possible to store up to 1.9 ML of storm water in the fractured rock aquifer beneath the Kingswood Golf Course and to recover this water at a sufficient rate and quality to make an effective contribution to the irrigation and maintenance of the golf course landscape.
Future work is required to establish that the storage volume can be extended to the 25 ML target and to verify that the aquifer will continue to store and return water with satisfactory quality and flow rates. Water losses during storage are a significant risk to the project. Establishing that losses are at acceptable levels is an important key to success.
This will involve groundwater modelling, risk analysis and preparation of an application for an EPA operating licence.
As the storage target is an order of magnitude larger in volume than the pilot program, design, installation and commissioning of equipment to furnish the aquifer storage and recovery facility with sufficient capacity remain as tasks to be completed.
The results of this project will be available as reference material to water industry professionals, the golf industry and other interested community associations.