The District's climate and natural landscape can create natural hazards such as heatwaves, bushfire, flooding, storms, coastal inundation and erosion. Climate change will exacerbate these natural hazards. While planning for resilience has traditionally focused on responses to natural hazards and climate change, it is increasingly being used to consider a wider range of social and economic shocks and stresses.
Effective planning can reduce the exposure to natural and urban hazards, and build resilience to shocks and stresses. Growth and change needs to consider exposure at a local level, and when making decisions about growth and considering cumulative impacts, at district and regional levels.
State agencies and councils use a range of policies and tools to reduce risks from natural and urban hazards. Centralised and coordinated collection of data on hazards, particularly on how infrastructure is exposed to hazards, will help embed resilience in land use planning and infrastructure planning.
Natural and urban hazards
The climate, vegetation, topography and pattern of development in the District mean that bushfire and flooding will continue to be hazards. Placing development in hazardous areas or increasing the density of development in areas with limited evacuation options increases risk to people and property.
All local government areas in the North District are exposed to some flood threat, whether from major rivers or local overland flow. The Floodplain Development Manual 2005 provides councils with policy directions and tools for managing exposure to flooding. Some coastal areas of the District are at risk of coastal erosion and inundation, and sea-level rise such as Collaroy. Potential sea-level rise associated with climate change could also lead to saltwater intrusion into freshwater ecosystems and damage coastal open space and infrastructure.
Past and present urban development and activities can also create urban hazards such as noise, air pollution and soil contamination. Compared to many cities around the world, Greater Sydney enjoys excellent air quality, which enhances its reputation as a sustainable and liveable city. However, the combined effect of air circulation patterns in the Sydney Basin, local topography, and proximity to different sources of air pollution such as wood-fire smoke, can lead to localised air quality issues.
Transport movements along major roads and rail corridors generate noise and are a source of air pollution. The degree of noise or air pollution can be related to the volume of traffic and the level of truck and bus movements. The design of new buildings and public open space can help reduce exposure to noise and air pollution along busy road and rail corridors. Public transport, walking and cycling, as well as hybrid and electric cars, provide opportunities to reduce air pollution. The NSW Government has recently strengthened regulation of ventilation outlets in motorway tunnels, which will also help reduce air pollution.
Soil and groundwater contamination is another urban hazard which will require careful management as the District grows, and land uses change. This is particularly important when planning for more sensitive land uses such as schools, open space and low-density residential neighbourhoods, in areas with the potential for pre-existing contamination. State Environmental Planning Policy No. 55 - Remediation of Land and its associated guidelines manage the rezoning and development of contaminated land.
Greater Sydney, particularly its rural land, is at risk from biosecurity hazards such as pests and diseases that could threaten agriculture, the environment and community safety. Biodiversity hazards are being managed by the NSW Government through the Greater Sydney Peri Urban Biosecurity Program.
In planning for future growth, consideration of natural hazards and their cumulative impacts includes avoiding growth and development in areas exposed to natural hazards, and limiting growth in existing communities that are exposed and vulnerable to natural hazards. In exceptional circumstances, there may be a need to reduce the number of people and amount of property that are vulnerable to natural hazards, through managed retreat of development.
The impact of extreme heat on communities and infrastructure networks can also be significant. More highly developed parts of the District can be exposed to extreme heat as a result of the urban heat island effect. Increasing tree canopy cover is important to help reduce those impacts. The State Heatwave Sub Plan, which is within the NSW State Emergency Management Plan, details the control and coordination arrangements across State and local governments for the preparation for, response to, and immediate recovery from a heatwave.
Current guidelines and planning controls also focus on minimising hazards and pollution by:
- using buffers to limit exposure to hazardous and offensive industries, noise and odour
- designing neighbourhoods and buildings that minimise exposure to noise and air pollution in the vicinity of busy rail lines and roads, including freight networks
- cooling the landscape by retaining water and protecting, enhancing and extending the urban tree canopy to mitigate the urban heat island effect.
Minimising interfaces with hazardous areas can reduce risks. Clearing vegetation around developments on bushfire-prone land can help reduce risks from bushfire, but must be balanced with protecting bushland, and its ecological processes and systems. Planning on bushfire prone land should consider risks and include hazard protection measures within the developable area. The Rural Fire Service requires new developments to comply with the provisions of Planning for Bush Fire Protection 2006.
Adapting to climate change
The most significant natural hazards and acute shocks that affect the North District include bushfire, severe storms and coastal erosion and inundation, which can also impact coastal lagoons and streams. These natural phenomena will be exacerbated by climate change.
The draft Coastal Management Manual sets out approaches to address sea level rise and the resilience of coastal assets, while CoastAdapt collates tools to support adaptation to coastal climate change and sea-level rise.
Air temperatures in Greater Sydney are expected to increase due to climate change and increasing urbanisation. With projected increases in heatwaves and the number of extreme temperature days, taking action to cool the city, in conjunction with supporting the community to adapt to a changing climate, is increasingly important. Increasing tree canopy cover will help reduce those impacts.
Figure 23 shows different levels of vulnerability to heatwaves. Areas are ranked by their combined level socioeconomic disadvantage and exposure to heat during a heatwave, and Figure 24 shows land surface temperatures during heatwave conditions. Figure 25 shows tree canopy cover as at 2011.
The way neighbourhoods and buildings are planned and designed can help communities adapt and be more resilient to extreme heat. Increased tree canopy and green groundcover, will help minimise these effects.
Retaining more water in the landscape and integrating waterways in the design of new communities will help create a greener and cool city. Water-play features and connections with water will become essential elements of urban areas while green walls, green roofs and initiatives such as rain gardens will help cool urban environments.
Building design and building materials can also mitigate the urban heat island effect. Cooler building materials, including lighter-coloured roofs, lighter-coloured paving and more permeable paving can be highly effective.
Shocks and stresses
Councils across the North District are participating in the 100 Resilient Cities initiative and considering ways to respond to shocks and stresses that could strengthen community resilience.
The Australian Government has released Australia's Strategy for Protecting Crowded Places from Terrorism, which provides a framework for making public places safer and more resilient. This strategy is accompanied by tools which councils and building owners and managers can use to implement protective measure that will strengthen community resilience.