Fire has been a major influence in shaping the Australian environment. Over millions of years, the continent has progressively dried out. Modern development adjacent to bushland means Council must assess risks and carry out strategies to lessen potential impacts on humans, livestock and property.
The bushfire risk rating for an area or property is calculated by determining the likelihood and the consequence of a bushfire igniting and spreading. It includes information on past fire history (including arson), the vegetation type, slope and proximity of assets to flammable vegetation.
The behaviour of fire in the Australian bush has been extensively studied and described. Here is a brief summary of some of the main factors that influence how a fire will behave:
- The types of plants will influence how intense a fire is. Find a fresh eucalypt leaf and hold it up to the light. You will be able to see that it is covered in tiny dots. These are the oil glands. Many Australian plants have volatile oils in their leaves - the eucalypts, boronias and tea trees.
- Fire will travel much faster up a slope than along flat land or downhill. This means that houses and other infrastructure at the top of a slope are at higher risk from bushfire.
- The aspect (direction that the land is facing) will also influence the intensity of a fire. Slopes that face north and west are hotter and drier than those that face south and east. This means that they will tend to have drier and more flammable vegetation growing on them.
- The ambient temperature and humidity will determine how intense a fire is. Bushfires are uncommon on cold winter days, and are easier to control on humid days. A hot, dry day (anything over 28 degrees Celsius) means that a bushfire can be difficult to control.
What is bushfire risk mitigation?
In developed areas, the only one of these things that can be controlled is the vegetation. Mitigation strategies that may be implemented include:
- Asset protection zones (APZ): A defined area of vegetation that is substantially modified to reduce the fuel load and potential for high intensity fire
- Strategic fire advantage zones (SFAZ): A defined area of vegetation with reduced fuel loads
- Hazard reduction burning, and
- The establishment and maintenance of a fire trail network
All mitigation strategies have to be assessed for their environmental impacts, and there are strict guidelines for their implementation.
Part V of the Environmental Planning and Assessment Act 1979 outlines the requirements of environmental assessment for public authorities.
In terms of bushfire hazard reduction activities, such as modifying vegetation and prescribed burning, the Bushfire Environmental Assessment Code 2006 provides a streamlined process for environmental assessment.
Central Coast Council works to lessen the impact of fires by:
- Maintaining about 47 kilometres of Asset Protection Zones (buffer zones) to minimise fire risk adjacent to Council land.
- Maintaining fire trails on Council land
- Conducting hazard reduction burns, planned and carried out with the NSW Rural Fire Service and Fire and Rescue NSW.
- Providing bushfire information in areas identified as being at risk
- Implementing development controls to minimise the impact of bushfires on new development and additions in bush fire prone areas.
Preparing for a bushfire
Anyone living on the interface with a bushland area needs to understand the potential bushfire risk to their property, and how to reduce that risk.
In most Fire Weather Conditions (excluding catastrophic), the only plant communities that are unlikely to burn are rainforests. If there is a wild fire nearby, burning embers (firebrands) will be swept high into the air, and can then fall many kilometres ahead of the fire.
All houses in bushfire prone areas need to be prepared. If you live in one of these areas, you need to be FireWise, and know how to protect your home and family.
Understanding the terms 'bushfire prone' and 'bushfire risk'
Your property could be in a bushfire prone area, which will impact on the requirements for new buildings, building additions or redevelopment.
However, being in a bushfire prone area does not necessarily mean that you are at significant risk from bushfire, or that council will be doing mitigation works adjacent to your property.