Coastal hazard overlay and Brisbane development

16 September 2018

Brisbane has experienced many floods since European settlement, with events in 1841, 1890, 1893, 1931, 1974, and most recently 2011. Floods are the most expensive natural disaster type in our country and it is reported the 2011 Brisbane event cost the country’s economy about $30 billion.

You can check your property’s flood risk with Brisbane City Council’s awareness map. The map will generate a Floodwise Property Report specific to your site which identifies current flood levels. However this does not deal with future flood levels and some properties within Brisbane will also be subject to the Coastal Hazard Overlay code.

More information on other types of flood risk can be found in our other article on flooding and what it means for development.

The State Planning Policy [SPP] has put natural hazards on the radar more than ever and requires Council to consider not only current flood risks but those anticipated in the future from climate change. In the case of Brisbane, this has brought about creation of the Coastal Hazard Overlay Code. Other coastal councils - like Moreton Bay Regional Council, Redland City Council, Logan City Council, and City of Gold Coast -  have the same obligation to satisfy the SPP requirements and some have specific codes whilst others do not.

The overall purpose of the code is to try and flood proof the city in low lying areas by requiring flood immunity based on the expected flood levels in the year 2100. Some of the low lying areas in Brisbane’s north included Nudgee, Northgate, Eagle Farm, Albion, Windsor, Wilston, Bowen Hills, and New Farm. To the east suburbs include Hemmant, Lytton, Murarrie, Tingalpa, Pinkenba, Balmoral, Hawthorne, and Bulimba. Vulnerable suburbs in the south are Wynnum, Manly, and Lota are included in the Coastal Hazard Overlay.

This overlay can have a significant impact on development as compliant with the current 100 year average recurrence interval [ARI] is inadequate. In bayside areas generally* the current 100y ARI for storm surge from Moreton Bay is RL2.5m AHD but increases to RL3.1m AHD in the year 2100. This can be difficult to achieve particularly when looking to extend an existing development.

The code applies to the assessment of development if:

  • accepted development subject to compliance with identified requirements, where acceptable outcomes of this code are identified requirements in a table of assessment for an overlay

  • assessable development where this code is an applicable code identified in the assessment benchmarks column of a table of assessment for an overlay

  • impact assessable development.

Land in the Coastal hazard overlay is identified on the Coastal hazard overlay map and is included in the following sub-categories:

  • Erosion prone area – coastal erosion sub-category and permanent inundation due to sea-level rise at 2100 sub-category;

  • Medium and high storm-tide inundation areas

  • Coastal management district areas.

Preparing a development application requires a current knowledge of all the relevant council codes specific to the site. A town planner can help you navigate through the planning process and confirm what codes do, or do not, apply to your site.

Contact us to discuss the approvals your project will likely require via or call 1300 017 540. We offer free desktop reviews, so get in touch!

*Flood levels for any development site need to be confirmed as these can vary.

Disclaimer: While every effort has been made to provide accurate information, Consult Planning does not guarantee that this blog article is free from errors or omissions or is suitable for your intended use.