Managing the groundwater reserves that supply our drinking water is a critical part of Busselton Water’s operations.
Most of our water comes from the Yarragadee aquifer, which is a major freshwater resource for the south west of Western Australia. It runs beneath the Swan Coastal Plain west of the Darling Scarp, from Geraldton to the south coast.
The aquifer is situated hundreds of metres below ground and is up to two kilometres deep. It stores about 1,000 cubic kilometres of water (one cubic kilometre = 1,000 GL). Formed during the Jurassic period, it is composed primarily of sandstone which is porous and poorly cemented creating spaces in the rock for groundwater reserves to accumulate.
Groundwater can remain in the aquifer for centuries – in some areas it has been in place for more than 30,000 years. It is brought to the surface by submersible pumps from nine bores across the Busselton Water licensed area. The water temperature when pumped out is around 35 degrees Celsius. We have successfully harnessed this natural heat energy and are using it to warm swimming pools at the Geographe Leisure Centre so our community can enjoy them all year round.
The groundwater aquifers are replenished by rainfall and our drying climate means we need to monitor them carefully to protect our future reserves and make sure that salt water from the ocean doesn’t find its way in.
Current models estimate the recharge rate is about 280 to 340 gigalitres per year. In comparison, the State Government licences Busselton Water to extract 7.6 gigalitres of groundwater from the Yarragadee aquifer and one gigalitre from the Leederville aquifer each year.