The devastation caused by large, intense bushfires on communities, forests and farms is well-known. It is a focus for the media every time there is a fire. What is less well-known is the damage from wildfire to our water catchments. The 2005 Perth Hills bushfire is a good example. This fire had a major adverse effect on the catchment of the Mundaring Weir and was a major threat to water quality. But what was learned from that event? Apparently very little, since staff have retired and corporate memory has been lost. Few people know about the huge job involved in keeping Mundaring Weir operational after the fire.
Two key reservoirs feeding Perth urgently require bushfire protection- Wungong and Canning. These store ‘excess’ water produced by the desalination plant at Kwinana and are used to supply the system at times of peak demand. However they are not secure.
The catchments have not been well managed and carry heavy fuel loads. A wildfire followed by a summer downpour would be disastrous as ash and silt washed into the dam would disrupt the effectiveness of chlorination treatment, essential for maintaining water quality. The threat is growing year by year, with seemingly little effort from the government to protect these key water supplies. The Water Corporation and the forest manager (DBCA) need to work urgently to reduce the fire hazard surrounding these water bodies. A modest financial contribution by the Corporation to increase the annual level of prescribed burning would greatly assist.
Responsible land management is about identifying threats and then taking action to minimise potential damage. The threat of damage to Perth’s water supplies from large, high intensity wildfires is well-known …. but at the moment not enough is being done to prevent or mitigate this potential disaster.