Water Supply Catchments
- Where does Melbourne's water come from?
- Protecting our catchments
- Some facts about the creation of new dams.
Where does Melbourne's water come from?
Melbourne's drinking water is highly regarded by the community. Most of our water comes from uninhabited mountain ash forests high up in the Yarra Ranges east of Melbourne, and more than 157,000 hectares has been reserved for the primary purpose of harvesting water. These water supply catchments have been closed to the public for more than 100 years. Some of them are now National Parks managed by Melbourne Water and Parks Victoria.
Melbourne is one of only about five cities in the world that has such protected catchments.
Some 90% of Melbourne's water comes from these native forests, which catch, hold and filter rainwater as it flows across land into streams and then reservoirs. Every time you turn on your tap, the water you use has come from one of these reservoirs, which also provide security of supply for times of drought.
Melbourne's water supply system is based on the principle that it is better to start with the highest quality source water than having to treat it to reach required standards.
Protecting the catchments
Safeguarding Melbourne's water supply catchments to ensure the highest quality source water is a priority for Melbourne Water.
Bushfires, erosion and unauthorised public entry are the main risks that we manage to ensure our pristine source water is protected.
Bushfires leave soot and ash, which can be washed from the catchments into the reservoirs. Fires can also destroy the mountain ash trees that cover about half the catchment areas. Firefighters are on call over Summer to try to ensure that any fires that occur do not take hold.
Melbourne Water invests about $1 million a year on fire prevention and suppression to protect the security and quality of our water supplies.
Melbourne Water also pays particular attention to roads in the catchments to ensure appropriate drainage is constructed and maintained to minimise erosion and sediment flowing into the water.
We also restrict public access to the catchments to minimise the risk of humanborne disease and chemical contaminants entering our water supply system. The system of protected catchments provides a significant barrier against contamination of the water supply by Cryptosporidium, Giardia and other parasites.
In recent years, we have increased security for the catchments and our water supply assets by upgrading signage and security systems. Our security team patrols the water supply catchments regularly.
Some facts about the creation of new dams
New dams do not create any new water. They simply take it from somewhere else - either from farmers who currently rely on it or from the environment. However, upgrading and improving dam and pipeline infrastructure is an important way to increase water security.
If a new dam were built for Melbourne, it would need to be filled with water that is currently used by rural and regional communities and the environment. Such a dam would take water from rivers that are already stressed. This would not only harm the habitat of our native plants, fish and animals, but also threaten our waterways, tourism and recreation industry.
In June 2007, the Victorian State Government announced a new plan to provide water security for Victoria's growing population and economy by diversifying and boosting water supplies, networking the State's water resources in a Victorian Water Grid and enabling a rapid and flexible response to changing future water needs.
The plan included the announcement of $4.9 billion of projects to secure Melbourne and Victoria's water supplies for the long term, including:
- A 150 billion litre desalination plant to provide water for Melbourne, Geelong, Westernport and Wonthaggi;
- A major irrigation upgrade in the Food Bowl in Northern Victoria to deliver water savings to be shared equally between irrigators, the environment, and Melbourne; and
- A major expansion of the Victorian Water Grid with pipelines to connect Melbourne's water system with the desalination plant and Northern irrigation upgrades, connect Geelong to Melbourne's supplies, and connect Hamilton to the Grampians Wimmera Mallee System.
These projects will deliver a 50 per cent boost to Melbourne's water supply within five years and allow water to be moved where it's needed most.