A flood search system is in place to provide designated flood levels.
A flood level search report can be obtained for a property. It summarises available flood information for a property. This includes:
- like estimated designated flood level (for determining floor levels). The City requires residential habitable floor levels to be at or above the height of the combined defined flood level, with minimum freeboard (300 millimetres) as prescribed in the Flood Overlay Code of the City Plan and the Building Regulation 2006. Freeboard associated with other land use types can be found in the City Plan Flood Overlay Code.
- ground level at the centre of the property.
The search does not show the flood extent.
We recommend owners engage a licensed surveyor to determine accurate property and floor levels.
What does a flood search report include?
The outcome of a flood search is the Designated Flood Level. Results are in metres AHD (Australian Height Datum). As a general guide, 0.0 metres AHD is close to the mean sea level. So, 1.5 metres AHD is approximately equal to 1.5 metres above Mean Sea Level. The Designated Flood Level reflects the impact of a rain event that has a minimum one per cent chance of occurrence in any given year (1% AEP) coinciding with a storm-tide for most areas.
Flood search results refer to riverine or regional flooding only. Results do not cover local (flash) flooding. Regional flooding is caused by long duration rainfall over a whole catchment or number of catchments.
As an example, a flood the size of a 100-year ARI has one chance in 100 (1%) of occurring in any one year. There is no guarantee:
- when such a flood will occur
- that it won't be much larger
- that it will only occur once in any year.
If your property is not below the Designated Flood Level, your property may be still affected by extremely rare flood events.