How are we meeting Sydney’s water needs?

Managing supply

Image of the Hawkesbury-Nepean River flooding

We are preparing for future rainfall and flood events by identifying Sydney Water assets that could be flooded and the possible impacts. Photo courtesy of Hawkesbury City Council.

Heavy rainfall in February/March 2012 means we will go into summer with high water storage levels.

The rainfall washed a lot of debris and nutrients into the raw water in the dams. This meant our water treatment plants had to work harder to filter the water. This is something that has not happened for a decade or more because we had been in drought.

We engaged researchers from around Australia and overseas to look at how we can better manage this in the future. The researchers are testing different approaches we can use to treat the water under these sorts of conditions.

Preparing for future rainfall and flood events is also important. We are sourcing flood modelling information from councils so we can identify Sydney Water assets that could be flooded and the possible impacts. Once this work is finished, we can put preventative measures in place to minimise flood impacts.

We also ran an exercise with NSW Heath, Sydney Catchment Authority and other government agencies to look at how we would respond to a major flood event. We learnt that we need to have a backup communications system in place, work closely with emergency services and be an active part of the long-term community recovery process.

As a result of the rainfall and rising dam levels, we reduced the water supply from the desalination plant in February 2012 to 45 million litres a day. This is the lowest amount the plant can practically produce without switching it off.

As the desalination plant was still in its proving period, it was essential that we ran the plant at a lower capacity so we could fully test it. The proving period ended in June 2012.

Before the February rainfall, we recognised the need to lower production at the plant in December 2011 after dam storage levels in Sydney reached 80%. We made a decision to reduce the water supplied from the plant to 90 million litres a day at that time.

The NSW Government’s 2010 Metropolitan Water Plan outlines the operating rules for the plant. It states that if dam levels reach 80% the desalination plant will be switched off and not restart again until the levels fall below 70%. As the dam levels are currently above 80%, the plant has been switched off.

Recycling and water efficiency are also part of the NSW Government’s plan.

Over the past decade, we achieved big gains in water savings. We are now changing our approach to water efficiency and recycling. We remain committed to:

  • meeting regulatory requirements

  • researching new opportunities to provide services that customers value

  • promoting water efficiency

  • operating recycled water schemes and encouraging water recycling by businesses where it is cost-effective.