Intensity–Frequency–Duration

The 2016 Intensity–Frequency–Duration (IFD) design rainfalls are provided for use in conjuction 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 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

AR&R87 IFDs

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

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