Teacher background information
Our water sources
Water in WA comes from three major sources: surface water, groundwater and desalination. Surface water is obtained from dams on rivers and groundwater is obtained from large natural underground storages called aquifers. In the Perth metropolitan area and in a few other places throughout the state, desalinated seawater is also used for scheme water supply. Rainwater tanks supply small volumes of water to some households.
Integrated Water Supply Scheme
The Perth metropolitan area is supplied by the Integrated Water Supply Scheme (IWSS), which also supplies Mandurah, Pinjarra, Harvey, Waroona, Binningup, Myalup, Yarloop and towns serviced by the Goldfields Pipeline.
It is called an integrated scheme because water is drawn from an integrated network of dams, groundwater and seawater sources. In some northern metropolitan areas, water supplied is from groundwater sources alone, while in other areas of Perth the supply may be from dams or a mixture of sources.
Dams servicing the metropolitan area include Canning, Serpentine, North and South Dandalup, Wungong, Victoria, Bickley and Churchmans Brook. Mundaring Weir provides water to towns along the Goldfields Pipeline, to agricultural districts and at times to Perth.
Other major dams throughout WA include Harris Dam, which supplies water to 32 towns in the Great Southern region and Harding Dam near Roebourne, which supplies towns in the West Pilbara region including Karratha.
Groundwater is water that occupies the spaces between particles of soil (sand, silt and clay) or rock beneath the earth’s surface. The source of groundwater is rain, which infiltrates the soil. Groundwater moves quickly through sandy soils and reaches the water table. As a result, large volumes of groundwater can often be pumped from wells (bores) sunk in sandy soils.
The Perth Seawater Desalination Plant has been producing fresh drinking water since 2007 at a capacity of 45 billion litres a year. Located in the Kwinana industrial area on the coast south of Perth, the plant supplies desalinated water to the IWSS.
A second seawater desalination plant located in Binningup in the South West began operating in 2013, and supplies up to 100 billion litres of fresh drinking water to Perth a year.
Today, the two desalination plants combined provide almost half of Perth’s water needs.