Indicative plans showing the approximate 3.0m datum and land for those sections of Hobart’s urban watercourse modelled by Council to date as being prone to flooding at the 1% AEP level of risk are available for viewing below.
Please note that Council has only modelled some sections of the Hobart Rivulet, New Town Rivulet and Sandy Bay Rivulet.
Storm Surge and Flood Prone Areas
Storm Surge Prone Land has been defined as all land below 3m on the Australian Height Datum [Tasmania AHD83]. Note that 0.0 metres AHD83 approximates the mean sea level in Tasmania in 1972.
The 3m AHD83 datum is based on a report by Sharples (2006) Indicative Mapping of Tasmanian Coastal Vulnerability to Climate Change and Sea-Level Rise: Explanatory Report (2nd Ed)”. The maximum 1% Annual Exceedance Probability (AEP) for 2100 is 1.943 m above AHD83 in the Hobart Region. A 1.0m freeboard is then added to account for wind and ocean swell generated waves. This totals 2.934m; rounded up to 3m.
#Annual Exceedance Probability (AEP) means the likelihood of occurrence of a flood of a given size or larger in any one year, usually expressed as a percentage. For example, if a peak flood discharge of 100 cubic metres per second has an AEP of 1 percent, there is a 1 percent probability (approximately equivalent to an average recurrence interval of 100 years) of a peak flood discharge of 100 cubic metres per second or larger occurring in any one year. Note however that the AEP of a flood event gives no indication of when a flood of that size will occur next.
If are contemplating the development of land that is close to any watercourse (including one not yet modeled and mapped by Council) and think it may be at risk then you should seek advice from Council officers on (03) 6238 2900.