Houses built in bushfire hotspots that met current Wildfire Management Overlay (WMO) standards were three times more likely to survive the Black Saturday fire conditions, according to a new University of Melbourne study.
And the planning overlay needs to be extended to a range of other bushfire risk areas, in which development is currently occurring without careful consideration of the associated risks, warns the study’s co-author, Dr Alan March.
In the fire footprint area, the rate of loss for WMO-referred houses was three times lower compared with houses within the WMO area not referred to the CFA and assessed according to WMO principles, March said.
“The clear association with significantly fewer house losses, and integration of a number of widely accepted practices including implementing defendable space to limit the impacts of radiant heat and ember attack and eradicate direct flame contact, suggests that the WMO is a highly effective planning tool for reducing house loss.”
The Wildfire Management Overlay - part of the Victoria Planning Provisions — is incorporated into many local government planning schemes. It seeks to ensure that applications to build in areas of identified high bushfire risk satisfy specified fire protection objectives, do not significantly increase threat to life or property and provides the minimum fire protection requirements to assist in protecting life and property from wildfire.
The study investigated five out of the many reported fire complexes in the February 2009 Victorian Bushfire event, including the Kilmore East - Murrindindi fire, the Churchill - Jeeralang fire, the Delburn fire, the Beechworth fire and the Bunyip fire.
The study found that within the five studied fire areas, 11.76 percent of WMO-referred dwellings were destroyed, compared with 38.06 percent of houses overall (includes WMO and non-WMO areas), and 40.3 percent house loss in the WMO areas for non-WMO referred houses.
March says that while the effectiveness of the WMO has come under question after more than 2,000 homes were lost during the Feb 2009 bushfires, results show that where the CFA assessed a planning application and imposed those overlay conditions on a new house, it tended to have a much higher survival rate.
The overlay has been “effective” in reducing house loss in bushfires, he said. “But the industry requires a broad approach embracing community education alongside a more consistent and integrated planning and building regulation system to fully harness the ability of mechanisms such as the WMO to reduce bushfire risks.”
