Coastal hazard area maps methodology
The maps are based on the most recent LiDAR and digital elevation modelling data, which has a vertical accuracy of plus or minus 15 cm or better.
The coastal hazard area mapping method has re-sampled the LiDAR data to a five-metre digital elevation model (DEM) to enable its use at a regional scale, and corrected the surface to the highest astronomical tide level recorded at the nearest tide gauge. The mapping method has been validated by an independent coastal engineering consultant; following the re-sampling, data accuracy has been verified by a quality assurance process.
How are the coastal hazard maps generated?
The coastal hazard maps have been prepared using:
- high resolution digital aerial photography of the coast
- digital elevation data (LiDAR) applied through a DEM process that generated high resolution and accurate land-level information covering more than 60,000 square kilometres of the state’s coastline
- storm tide statistics contained within a report prepared by James Cook University Marine Modelling Unit: Hardy T.A., Mason L. and Astorquia A. (2004b) Queensland climate change and community vulnerability to tropical cyclones – ocean hazards assessment – stage 3: the frequency of surge plus tide during tropical cyclones for selected open coast locations along the Queensland east coast
- existing erosion prone area information
- estimates of recession due to the morphological response of sandy coasts to a sea-level increase.
How are the coastal hazard area maps different from similar maps which are already available?
Coastal hazard area maps may be compared with the climate change sea-level rise maps released by the Australian Government (OzCoasts Australian online coastal information website) or storm-tide inundation maps released by local governments.
The Australian Government maps show only sea-level rise areas based on three sea-level rise scenarios to the year 2100. The Queensland coastal hazard area maps show coastal risk factors including indicative erosion prone areas, default storm-tide inundation areas, and projected sea-level rise of 0.8m from the present day.
Local council storm-tide inundation maps (which may be available on local council websites) are generally intended for present day emergency management purposes, such as evacuation, rather than for future planning or development assessment purposes. These evacuation maps show land contours as a means of indicating potential water inundation depths from storms or cyclones. On the other hand, the coastal hazard area maps delineate an area of land at risk of inundation from a single ‘defined’ storm-tide event and use a default water level for the event as a broad estimate of the 1% (or one-in-100) annual return probability.
The default depths are 1.5m above highest astronomical tide for South East Queensland, and 2.0m above highest astronomical tide for the rest of Queensland.
What if I disagree with the mapping?
To verify the coastal hazard risks in a particular lot, you can submit either of the following as part of the development application process.
- A storm-tide inundation study prepared for a local government area
- Report by a Registered Professional Engineer of Queensland (RPEQ) complying with the methodology outlined in the Coastal Hazard Technical Guide (PDF, 348KB).
Further information
For general enquiries, phone 13 QGOV (13 74 68), 9am–5pm, Monday to Friday; or email coastal.support@des.qld.gov.au.