The 2016 Intensity–Frequency–Duration (IFD) design rainfalls are provided for use in conjuction with the 2016 edition of Australian Rainfall and Runoff (ARR2016)

The 2016 IFDs are:

  • based on a more extensive data base, with more than 30 years of additional rainfall data and data from extra rainfall stations;
  • more accurate estimates, combining contemporary statistical analysis and techniques with an expanded rainfall database; and
  • better estimates of the 2% and 1% annual exceedance probability IFDs than the interim 2013 IFDs.

While access to the ARR87 IFDs and 2013 IFDs will be maintained for a short period, use of these previous estimates should be limited to the guidance provided below.

2016 IFDs (new)

Should be used:

  • in conjuction with ARR2016
  • for new flood studies and flood assessments but must be used with the other ARR2016 design inputs
  • for sensitivity assessments of older studies and studies already underway


Should be used:

  • for old flood studies
  • to compare changes between 2016 IFDs and ARR87 IFDs
  • if adopting the ARR87 Probabilistic Rational Method


2013 IFDs (interim)


  • Should not be used.
  • Will be removed from web page early in 2017.

How were the new IFDs estimated?

How do the new IFDs compare to the AR&R87 IFDs?

New AR&R probability terminology

How do I incorporate climate change into the new IFDs?

Where can I find out more about the new IFDs?

More IFD questions and answers


Subscribe to email updates about IFD

Creative Commons By Attribution logo
Unless otherwise noted, all material on this page is licensed under the Creative Commons Attribution Australia Licence