The diagram shows the water supply system in Australia at the present time and how it will change in the future.
Overall, the future system is more efficient because water will be recycled and reused. In the present system, some water goes into the river, while in the future almost all water will be treated and sent back to the city.
At present, pure water comes from the dam or storage and is supplied to the city, including households, shops and factories. After being used, some wastewater is sent to the water treatment plant. However, the treated wastewater is discharged into the river. In addition, storm water from the city also flows directly into the river without being treated.
In the future, the dam will still provide clean water to the city in the same way. However, the wastewater from the city will be sent to the water treatment plant, where it will be cleaned. After treatment, the water will be pumped back to the city for reuse. Furthermore, storm water will also be directed to the treatment plant instead of flowing into the river. As a result, the river will receive much less water from the city than it does at present.