Bushfires in Catchments
Most of Melbourne's water comes from within 160,000 hectares of uninhabited, forested catchments north-east of Melbourne. It's critical that we protect these native forests from fire.
Our fire fighting role
Melbourne Water firefighters training for another bushfire season
We're responsible for 'first-attack' response to fires in the catchments. Using fire towers, lightning trackers and (new for 09-10) a 'spotter chopper', we detect fires early and work to put them out before they take hold. In the event of a major fire, we work with the Department of Sustainability and Environment and the Country Fire Authority to fight them.
A key focus this season is protecting the Upper Yarra and Thomson catchments, which hold the majority of Melbourne's water supply and were largely untouched by Black Saturday.
The February 2009 bushfires burned through much of the smaller catchments O'Shannassy, Maroondah and Tarago catchments. While they are recovering well, these catchments are now less of fire risk than Upper Yarra and Thomson.
Protecting the catchments
Each year we commit resources to prepare and respond to bushfires. Here's how:
Closed catchments
Most of the catchments are off-limits to the public. This reduces the risk of fires starting in the first place.
Early warning and detection
Fire tower in the Upper Yarra catchment
Lightning tracker - Lightning can start fires, so we use the Department of Sustainability and Environment's tracking tool to locate lightning strikes.
Fire towers - Help us spot fires when they start and put them out before they take hold. Our 4 towers are part of a network with the Department of Sustainability and Environment and Country Fire Authority towers.
Regular patrols - Fire fighters patrol our catchments during fire season.
Fire breaks and access roads
Areas cleared of ground cover vegetation (up to 30 metres wide). Fire breaks are designed to stop the spread of fire. Many double as service roads and fire tracks.
1,860 kilometres of access roads assist quick and safe fire fighting.
Fire breaks established during the 2006/07 Great Divide Fire were critical in keeping fire out of the Thomson and Upper Yarra catchments. Department of Sustainability and Environment is currently creating 500 kilometres of fire breaks to help protect Melbourne's catchments, in addition to the 126km of firebreaks we currently maintain.
More on strategic fire breaks
Fire fighters
We have more than 30 permanent accredited fire fighters based near water catchment areas year round. During fire season, more than 100 trained fire fighters on standby.
Water bombing helicopter releases water over a fire
Fire Equipment
- 1 fire-bombing helicopter with a 1,400 litre capacity
- 1 'spotter chopper' to improve fire detection (new for 09/10 season)
- 6 bulldozers (incl. 1 new large bulldozer for 09/10 season)
- 5 large (3,200 litre capacity) fire fighting units
- 2 medium (1,000 litre capacity) fire fighting units (new for 09/10 fire season)
- 18 small fire fighting units with 400 litre capacity.
- 40 water tanks (22,000 litres each) are strategically located in the catchments to provide easy access to water for fire fighting.
In the event of fire...
There are ways we can safeguard the quality of Melbourne's drinking water supply if there was a major bushfire in the catchments.
Our 10 water storage reservoirs are spread over a wide area and we can transfer water between them. If bushfire affects one (like Thomson or Upper Yarra), we can rely on supply from the others (like Silvan, Cardinia and Sugarloaf) for the period of weeks or months that it might take for the water quality to return to normal.
Longer-term impacts of bushfire are harder to manage. Forests recovering from fire need a lot of water and that would reduce the runoff available for reservoirs.
Some estimates say it can take more than a century after a bushfire for the catchments to return to normal. That's why we work hard to protect them.
Brief history of bushfire in catchments
1939 - 129,000 hectares of our catchments burnt including Maroondah, O'Shannassy, Upper Yarra and Thomson.
1982/83 - 17,000 hectares burnt (5,000 ha in Wallaby Creek Catchment in late November and 12,000 ha in the February Ash Wednesday fires at Starvation, McMahons, Upper Yarra and O'Shannassy catchments).
2006/07 - Major summer bushfires came close to entering the Thomson and Upper Yarra catchments but were stopped by efforts of fire fighters and fire breaks.
February 2009 - Devastating bushfires damaged about 30% of Melbourne's water supply catchments to some degree. Most of this was in the O'Shannassy and Maroondah catchments. Billions of litres of water was moved to Cardinia Reservoir, away from the bushfire zone, as a safeguard. Water supply to as unaffected.