Design Rainfalls

Design flood support

Hundreds of millions of dollars are spent annually on hydraulic structures in Australia, ranging from small drains and culverts to bridges and large dams used for town water supply and irrigation.

Rainfall intensity, frequency and duration data plays an integral part in the design of these structures and the Bureau is undertaking a major revision of the information it provides in this domain.

The Bureau currently provides design rainfall data in the form of:

  • Intensity–Frequency–Duration (IFD) information, which is used in the design of gutters, culverts, bridges and stormwater drains
  • Probable Maximum Precipitation (PMP) estimates for the design of large dams and for use in floodplain management.

2016 IFD information NEW

The Bureau of Meteorology released the new IFD design rainfall estimates in 2016. The new 2016 IFD estimates represent the completion of the eight-year IFD Revision Project and replace the interim 2013 IFD estimates.

The 2016 IFDs are based on a more extensive database, with more than 30 years’ additional rainfall data and data from 2300 extra rainfall stations. By combining contemporary statistical analysis and techniques with this expanded rainfall database, the 2016 IFDs provide more accurate design rainfall estimates for Australia. In addition, the 2016 IFDs provide better estimates of the 2% and 1% annual exceedance probability IFDs than the interim 2013 IFDs.

The 2016 IFDs should be used in conjunction the other design inputs contained in the 2016 edition of Australian Rainfall and Runoff (ARR2016).

Access the new 2016 IFDs.

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