Fact sheet 14. Flood planning provisions

 

Public notification - subject to change

Brisbane - development of a city built on a floodplain

Brisbane is a thriving, world-class city, enjoyed for its subtropical climate. Like many cities around the world, for largely historical reasons, parts of Brisbane have been built on a floodplain, which makes flooding a natural part of our environment.

We will never be able to eliminate flooding in Brisbane but we can be a city that copes well with flooding and meet those challenges through planning for future development.

There is potential to shape our city in a way that adapts to flooding and increases our capacity to live with flooding. This involves smart land use planning and smart building design - the draft new City Plan applies both of these elements.

Brisbane's flood types

River flooding is caused when widespread, prolonged rain falls over the Brisbane River catchment area - causing high flows of water to rise and flow over our river's banks. River flooding downstream can occur days after the rain has stopped.

Creek flooding is caused by heavy rainfall in the local catchments. It often flows quickly and can cause flash flooding within an hour of areas around creeks and waterways.

Local overland flow flooding is water that runs across the ground after heavy rain, and occurs very quickly. This is the most common type of flooding in our city.

Storm tide flooding is caused when wind from a storm pushes the ocean towards land causing higher than normal sea levels. The risk from storm tide or storm surge is increased during times of high tidal flooding and affects low-lying areas close to tidal waterways and shores.

What we learnt from the January 2011 flood

The 2011 flood highlighted the importance of improving our ability to recover from disasters. It also emphasised the importance of adapting to and managing flooding effectively.

Following the 2011 flood, Council implemented emergency town planning rules to guide development in suburbs affected by flooding (through the Temporary Local Planning Instrument 01/11 and 01/12) which included the following:

  • setting floor levels in homes and apartments above either the 2011 flood level or the defined Brisbane River flood level, whichever is the higher
  • allowing houses in flood-prone areas to be built higher than standard buildings to protect homes from flooding

Following feedback from the community, council has now adopted these requirements into the draft new City Plan.

A new approach to flood risk management

In 2012 Council released Brisbane's FloodSmart Future Strategy 2012-2031. This document demonstrates how our city has an integrated plan to respond to its flood risk. It takes an integrated approach to managing flood risk through a co-ordinated mix of flood mitigation infrastructure, flood awareness and information, flood emergency management, land use planning and development control.

Urban planning is one of the most effective means of addressing flooding, but these planning rules can only apply to new development. The planning provisions, through the flood overlay code in the draft new City Plan, will ensure that future development contributes to creating a safe and flood-resilient city in the future.

The flood overlay code is part of the draft new City Plan and categorises flood susceptibility into five areas - describing how future development might be affected by flooding.

The flood overlay code delivers a balanced outcome which recognises the need for new development but which deals with protecting the safety of the community and minimising property impacts from flooding - while not imposing unnecessary costs on builders and developers. This is achieved by providing clear guidance for any future development in flood affected areas.

This flood overlay code will help business and industry to invest with confidence, knowing suitable development is properly located. It will enable business and industry to better understand the risk affecting their property when planning and designing for any future development.

New flood overlay code regulations

Council's planning regulations have always included planning provisions to manage flood risk. Over time our understanding of flood risk has increased and the flood overlay code is another example of how Council manages new development in Brisbane.

The flood overlay code will guide the future development of sites at risk of flooding with newly defined Flood Planning Areas (FPAs) shown on flood overlay maps. These regulations will only apply to new developments (including extensions, rebuilds and expansions).

If you are planning to renovate or build, Council recommends you engage a professional to undertake a thorough assessment of all flood risks specific to your property. These regulations will not apply to existing buildings. These are flood planning provisions to manage flood risk for any future and new development in our city.

The flood overlay code in the new draft City Plan does not change the zoning of properties in response to the January 2011 flood, or any other flood event.

Future growth and development in the city will be guided by the following planning principles:

  • locate new growth areas where there are minimal flood constraints
  • locate land-uses to be consistent with the nature and degree of natural hazards
  • recognises that land in a floodplain is an important community, economic and environmental resource
  • ensure that where a flood hazard is able to  be mitigated, new development is designed, sited and constructed to protect the safety and amenity of users

Flood Planning Areas (FPAs)

Council has developed five Flood Planning Areas (FPAs) for Brisbane River and creek flooding to guide future building and development in flood prone areas. There is one FPA for local overland flow flooding. Storm tide flooding is mapped separately.

Improvements in flood modelling have increased our understanding of how floods behave, giving us better tools to guide future land use planning. We can tailor regulations to mitigate the flood risks property owners could face and avoid building critical infrastructure where the risk of flooding is higher. The FPAs are designed to advise the susceptibility of flooding. Susceptibility is a combination of frequency of flooding, the flood depth and the speed at which the water is travelling.

Development regulations are tailored to each FPA. Planning controls are higher in areas when flood susceptibility is more frequent, and/or to a higher depth and/or in fast flowing water. For example, FPA1 would be subject to the highest development assessment requirements for any future development within that area.

Council has produced maps that show each of the five FPAs. FPAs are not expected to change over time but new versions of the maps will be produced if better information becomes available through flood modelling.

Flood Planning Area Description What does the code mean for development
1 FPA1
Flooding is very likely and/or there may be very deep and/or very fast moving water
Any new development would be subject to the highest development assessment requirements. This area is generally best suited to environmental and recreation uses
2 FPA2
Flooding is likely and there may be deep and/or fast moving water
New development may be subject to additional development requirements to address flood impacts - such as being high-set with specialised stronger building design
3 FPA3
Flooding is likely and there may be deep and/or moderate-fast moving water
New development may be built in this area but may need modifications such as houses being built on stumps
4 FPA4
Flooding is likely and there may be shallow and/or slow moving water
New development that can mitigate flood impacts with slight building modifications may be allowed to be built in this area - such as meeting minimum floor heights
5 FPA5
There is no recent history of flooding but there is potential for flooding
No flood overlay code requirements apply to houses. New development such as essential community services like hospitals may be built in this area - by meeting minimum floor heights
Local Overland Flow Water may rise quickly and move with speed but will recede quickly Minimum standards for floor heights apply to houses. Other development will be designed to not increase flooding impacts on neighbouring properties

Current flood provisions

For more information on Council's current flood planning provisions view the Brisbane City Plan 2014 or view Council's FloodWise Property Reports.

More information

For more information on the draft new city plan, you can:

  • contact Council on 07 3403 8888
  • email the project team
  • find us on Facebook and Twitter

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Disclaimer: The content of this information page deals with technical matters in a summary way only and have been prepared to assist the reader to understand the draft new City Plan. Please refer to the draft new City Plan for further detail.

07 August 2014