The 2016 Intensity–Frequency–Duration (IFD) design rainfalls are provided for use in conjunction with the 2016 edition of Australian Rainfall and Runoff (ARR2016) http://arr.ga.gov.au/arr-guideline
The 2016 IFDs:
- are based on a more extensive database, with more than 30 years of additional rainfall data and data from extra rainfall stations;
- are more accurate estimates, combining contemporary statistical analysis and techniques;
- have an increased probability range from 12 exceedances per year to 1-in-2000 annual exceedance probability;
- provide better estimates of the 2% and 1% annual exceedance probability IFDs than the interim 2013 IFDs.
While access to the ARR87 IFDs will be maintained for a short period, use of these previous estimates should be limited to the guidance provided below.