New data to improve flood modelling

Flood modelling across Australia will be more accurate than ever before, following the first major upgrade of the Australian Rainfall and Runoff (ARR) Guidelines in three decades.

Geoscience Australia and Engineers Australia worked over four years on the comprehensive upgrade, which is now complete and contains nearly 30 extra years of rainfall data from the Bureau of Meteorology.

Geoscience Australia’s Chief Executive Officer Dr Chris Pigram said while the Guidelines had been revised a number of times since they were first published in 1958, there had not been a substantial update since 1987. A review into a series of floods in the summer of 2010-11, including the January 2011 Brisbane floods, called for a complete upgrade to the Guidelines.

"With Engineers Australia, we’ve undertaken a complete revision of the Guidelines to ensure they are comprehensive with truly national coverage.

"For the first time, the Guidelines are completely based on Australian data. They include data from more than 30 years of observations from across the continent, including at least 100,000 storm events.

"It’s not just the data we’ve updated and improved, we have also made the Guidelines available for free online," said Dr Pigram.

Engineers and town planners use the ARR Guidelines to develop accurate and consistent flood studies and mapping across Australia; these are then used to design dams, stormwater drainage, improve floodplain management and assist land managers with soil conservation strategies.

Engineers Australia’s Chief Executive Officer Stephen Durkin said that engineers and town planners had been using the ARR Guidelines since they were first published by Engineers Australia over sixty years ago and that the comprehensive revision will be invaluable today and into the future.

"More accurate, consistent datasets and guidance means more accurate and consistent flood studies and mapping. This is not only good news for engineers and town planners, but for also for Australians living in areas with a flood risk," said Mr Durkin.

Ownership of the ARR Guidelines recently transferred from Engineers Australia to Geoscience Australia, the Australian Government’s trusted advisor on the nation’s geography and geology.

The upgrade of the ARR Guidelines was officially completed on 25 November 2016 following the inclusion of the Bureau of Meteorology’s new Intensity–Frequency–Duration (IFD) design rainfall estimates.

The Bureau of Meteorology’s Chief Executive Officer Dr Andrew Johnson said the new estimates include observations from over 10,000 rainfall gauging stations, including 2300 extra rainfall stations with nearly three decades of extra rainfall data.

"We’ve also used statistical analysis techniques that weren’t available 30 years ago.

"The new IFDs more accurately estimate rainfall intensity, frequency and duration in specific locations, which helps Australia to reduce the potential damaging impact of future floods," Dr Johnson said.

The ARR Guidelines are publicly available for free from arr.ga.gov.au.

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