Living with drought

Melbourne Water

• What is drought?
• History of drought in and around Melbourne
• Where our water comes from
• Managing our water for the long term
• Towards a sustainable future
• El Niño
• Climate change and global warming
• Melbourne Water's Living With Drought Booklet

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Where our water comes from

Melbourne is one of only about five cities in the world that has protected, wilderness catchments.

Most of the city's water comes from these uninhabited catchments high up in the Yarra Ranges. The catchments, which cover more than 157,000 hectares of national parks or State forests, are closed to human activity to protect water quality and public health.

The forests catch, hold and filter rainwater as it flows across land into streams and then reservoirs. Deep soils and shaded understorey enable reliable streamflow, which helps accumulate water for storages. These storages provide security of supply for drought.

About half of Melbourne's water supply catchment area is covered in mountain ash, which are among the world's largest hardwood trees. Some 90 per cent of Melbourne's water comes from ash-type forests.

Studies by Melbourne Water and the Cooperative Research Centre for Catchment Hydrology have found that these forests reach their maximum water yield after 120 years or more following a minimum yield at about 30 years. That is why Melbourne Water places so much emphasis on protecting the catchments from fire. The risk of fire is higher during severe drought periods when the catchments are dry.

The city's water supply is largely unfiltered, with only a small amount of chlorine added to ensure its purity.

Melbourne Water has nine major reservoirs that currently supply Melbourne (not including Tarago). Water is stored for long periods - up to years in some reservoirs - to help purification. Only then is the water delivered to Melbourne Water's customers: the metropolitan retail water companies, Western Water and Gippsland Water. Water is also released from the Thomson Dam for Southern Rural Water's irrigators.

These metropolitan retail water companies - City West Water, South East Water and Yarra Valley Water - transport about 500,000 million litres a year of fresh water (and provide sewage services) to more than three million people in homes and businesses in greater Melbourne.