Streamflow

The streamflow data shown represents all dams that supply the Integrated Water Supply Scheme (IWSS), our largest scheme providing water for Perth, Goldfields and Agricultural Region and some parts of the Great Southern Region. This includes figures from both Stirling and Samson Brook dams. 

Did you know?

More rain doesn't always mean more water in our dams. We need steady, soaking rain, which is becoming less common in the shoulder seasons. Our soil and plants soak up much of the rain they need after dry spells, resulting in reduced streamflow even when rainfall is above average.

The graph below shows the current total for this month and shows how much water has flowed into the dams so far this month.

Please note: The Streamflow data provides the monthly streamflow totals for all Integrated Water Supply Scheme (IWSS) dams and is updated each Thursday. The data is not real-time and should not be considered accurate until after 5pm each Thursday. 

Our water overview

* Average monthly rainfall (for the period 1876 - 2016).
Dam volumes, rainfall and water use data is updated every working day, streamflow is updated weekly.

How climate change is impacting our water sources

Water sources for our largest scheme, the Integrated Water Supply Scheme (IWSS) which supplies Perth, the Goldfields and Agricultural Region and some parts of the South West have changed dramatically. Water for the IWSS is now comprised of a combination of sources, including desalinated seawater, groundwater, groundwater replenishment and streamflow into dams.

Traditionally, Perth relied heavily on streamflow into our dams as a water source, but declining streamflow has meant dams now play a bigger role as storage reservoirs. The water in our dams is no longer just made up of inflows from rain. Groundwater and desalinated water are stored in these dams during periods of low demand so it is available when it is most needed in the hotter months.

How Perth's water sources have changed