The diagram illustrates the way the water supply system currently works in Australia and how the system will be changed in the future.
Overall, although both systems use the dam as a water supply, the present system returns both storm and waste water directly or indirectly to the river, whereas the future system plans to recycle both forms of water.
The current water supply system shows that water is stored in a dam before being transferred to a city to be used by households, shops and factories. From the city, storm water is directed straight into the river, by contrast waste water is sent to a water treatment plant to be processed. After the waste water is treated, it is safe to be released into the river.
Regarding the future water supply system, water will be brought from the dam for the same uses as in the present. However, both the storm water and waste water from the city are to be directed to the water treatment plant for processing after which they will both be recycled for use in the city. It is planned that no water will be released back into the river.
