The modelling of the extent and impact of flooding is now possible to unprecedented levels of accuracy, thanks to the recent update of the Australian Rainfall and Runoff (ARR 2016) guidelines.

Now in its fourth edition, ARR 2016 is the first to be entirely based on Australian data, analysing 100,000 storm events and an additional thirty years of data to better reflect Australia’s variable landscape. Based on rainfall and stream flow data, case studies and computer modelling, ARR 2016 will be used by engineers, flood practitioners and policy makers to understand how much rainfall to expect and where to expect the water to go once it hits the ground.

“ARR 2016 represents a significant improvement in best practice for flood modelling,” said Mark Babister, Chair of the ARR Technical Committee and past Chair of Engineers Australia’s National Committee on Water Engineering. “Since the last edition of the ARR in 1987, estimation methods have improved significantly and more complex models have been developed, allowing engineers to provide a more robust estimate of flood risk.”

“While most people remember the extreme flooding events in major centres that have happened in the last few years, ARR 2016 is equally important to understanding the effects of dryer weather events such as El Niño, particularly as climate change induced extreme weather becomes more common.

“ARR 2016 represents the first inclusion of climate change guidelines, drawing on the most recent climate science from CSIRO, the Bureau of Meteorology and the IPCC Fifth Assessment. However, despite this improvement, Australia will need to make major research investment into how climate change will affect extreme rainfall and flooding to refine these further.”

The 2016 Australian Rainfall and Runoff guidelines were published by Engineers Australia with funding from the Australian Government, and are freely available at www.arr.org.au.