Sample answer
The diagrams illustrate how the water supply system in Australia works at the present time and possible changes of this system in the future. Overall, the primary modification is related to the use of recycled water in the city.
As can be seen from the current water supply system, pure 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, whereas waste water is sent to the water treatment plant to be processed. After the waste water is treated, it is safe to be released into the river.
Turning to the future water supply system, it is clear that the storage of pure water in the dam and the uses of it in the city remain unchanged. 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 back for usage in the city. It is planned that no water will be released into the river.
Nguồn: Ms Liz IELTS