Where to Now for the Bushfire Inquiries?
The catastrophic bushfires of 2019/20 in eastern Australia are likely to be repeated with greater severity, as south-east Australia becomes hotter and drier, and dynamic fire propagation becomes more frequent. The various Bushfire Inquiries will, no doubt, recommend changes to fire-fighting, fuel reduction and building practices which have, in the past, been based on common steady-state forest fire behaviour. When bushfires become powerful enough to generate their own weather systems, however, little can be done to stop them.
The best solution is improved planning practice and bushfire design standards which take account of the latest bushfire behaviour research to locate new residential developments away from possibly indefensible locations, using a precautionary approach. As our cities grow, new suburbs on the urban fringe are increasingly built in areas where fire is an existential threat, as people optimistically choose to live near the bush, unaware of the increasing likelihood of extreme fires.
An example is the Ginninderry-Parkwood Development on the ACT/Yass shire boundary, between the Murrumbidgee River and Ginninderra Creek. This area has steep slopes to its north-west, an ideal site for dynamic bushfire propagation, resulting in wide-ranging ember attack driven by the north-westerly prevailing winds. This has been demonstrated by extreme bushfire behaviour expert, Professor Jason Sharples, and colleagues who, using modelling theory, found ember loads were 13-115 times higher in the Ginninderry area when compared with those for a known 2015 fire on the Mornington Peninsula where 32 houses were damaged all as a result of embers. In a geographic setting similar to Ginninderry, 100 structures were damaged in the Tathra fire of 2018. Ember attack or spotting is the main means of fire propagation in these cases.
The Ginninderry development complies with all current planning and bushfire regulations but these are likely to be inadequate for the bushfires of the future. If so, residents and firefighters may be unnecessarily endangered and the government might be held responsible, since the hazard was known when development was approved. Furthermore, where buffer zones are inadequate, demand by residents for more severe control burning on the steep slopes to protect housing from fires, or backburning in the event of a fire, would compromise the biodiversity values of the gorges of the Murrumbidgee and Ginninderra Creek and the associated fire-sensitive Black Cypress Pine forest, as well as threatened species like the Pale Pomaderris.
In cases like this, there is a conflict between revenue from land sales, the demand for housing blocks, and fire and environmental requirements. Consideration should be given to the extreme risks associated with dynamic fires near potential residential areas before rezoning occurs. Another significant consideration is the possibility that insurance companies will refuse to cover such areas or will make it too expensive to do so. In this situation, the burden will fall on the community as a whole, not on those who have benefited from the development.
Contact: Robyn Coghlan 6254 0487 / 0435 534 998