Australian Rainfall and Runoff is the industry guide to flood estimation. It provides important advice in developing an understanding of flood behaviour.
In July 2016, a significant update of techniques and base information in Australian Rainfall and Runoff (ARR) was released, to replace earlier versions.
The NSW Office of Environment and Heritage (OEH) has developed this guide to assist councils to transition to ARR2016 when managing their flood risk through the development and implementation of floodplain risk management plans using the process outlined in the Manual.
This guide provides some advice on ARR2016 and on techniques, approaches and data that take precedence over ARR2016 in New South Wales. The use of local techniques, approaches and data is consistent with Book 1 Chapter 1 of ARR2016, which states: '...where circumstances warrant, designers have a duty to use other procedures and design information more appropriate for their design flood problem.'
This guide does not remove the need for flood practitioners to fulfil their professional responsibilities to consider ARR2016 in depth. This includes ensuring that studies use techniques, approaches and data that are relevant to the context of the study, are fit for purpose for the location, and that results are reasonable in consideration of flood history.
This guide is supported by ARR 2016 Case Study – Urban and ARR 2016 Case Study – Rural. It is informed by the Review of ARR Design Inputs for NSW, the Revised 2016 Design Rainfall Investigations into the need for and Derivation of Local Techniques and the Review of Australian Rainfall and Runoff Design Inputs for NSW, which provide advice to support the guide.