The original Australian Rainfall and Runoff (ARR – 2016) climate change guidance recommended increasing rainfall design events (rainfall intensity) in the typical range of 10-20% to allow for the impact of climate change to the year 2100. This guidance assumed the increase was not a function of event AEP or duration, but only a function of location and the representative concentration pathway (RCP).
The latest ARR climate change guidance, based on the latest IPCC research, has radically changed this previous advice. As well as recognising that current climate is already impacted by climate change, the latest advice also recognises the impacts are significantly greater than previously thought and are now dependent on storm duration. Shorter duration storms (<1 hour duration) are particularly impacted.
The first part of this presentation will outline the background to the changes to the ARR guidance and what the implications are for design floods in Queensland. This will tap into an extensive testing database of over 400 catchments in Queensland and NSW and an online tool that will let users understand the change in risk.
The second part of the presentation will then consider the implications of these changes to the design of drainage systems of linear infrastructure in the light of TMR’s Engineering Policy 170. Both TMR’s policy and engineering responses may need significant amendment to accommodate the latest ARR guidance.
