Comparison of the Practical Application of ARR1987 and ARR2016 for Urban Stormwater Catchments in Bundaberg

Fulton, David (2018) Comparison of the Practical Application of ARR1987 and ARR2016 for Urban Stormwater Catchments in Bundaberg. [USQ Project]


Australia’s national guidelines for flood estimation are documented within a manual called Australian Rainfall and Runoff (ARR). The latest version of the document, Australian Rainfall and Runoff 2016 (ARR2016), contains new data and recommendations relating to stormwater design in urban areas. The design impact associated with switching from the previous version of Australian Rainfall and Runoff (ARR1987) to ARR2016 is relatively unknown to the engineering industry. However, this impact is of interest to Bundaberg Regional Council and other engineering consultants. This research project undertakes a comparison of ARR1987 and ARR2016, focusing on the peak design discharge from several urban catchments within the Bundaberg region.

This research project focuses on the three major updates within ARR2016 which are likely to influence the peak design discharge: updated Intensity-Frequency-Duration (IFD) data, rainfall temporal patterns and new climate change recommendations. Six sites of investigation were selected from around the Bundaberg region. A comparison of the peak design discharge was achieved by independently applying the data and recommendations from both ARR2016 and ARR1987 for each site, utilising the runoff routing software package XPRAFTS. The model for each site was prepared in accordance with the current Bundaberg Regional Council Planning Scheme, Queensland Urban Drainage Manual and standard design practice to simulate a typical design scenario.

The results produced within this research project for the six sites demonstrate minimal differences in peak design discharge calculated using the approaches described by ARR1987 and ARR2016, despite ARR2016 rainfall depths that are approximately 15-30% greater than those included in ARR1987. This is primarily a result of the temporal pattern structures and selection criteria for the design temporal pattern recommended within ARR2016. However, the results also demonstrate that consistently higher peak design discharges are observed when the ARR2016 rainfall depths are further increased to allow for climate change considerations as described in ARR2016.

Observations of this research project indicate that the difference between peak design discharges is likely to be larger for sites with steeper catchments where the critical storm duration is reduced. It was also confirmed that there is minimal difference between the mean and median peak discharges in almost all scenarios.

This research project offers a positive outcome for Bundaberg Regional Council in that the immunity of existing infrastructure designed based on peak discharges can be assumed to be relatively unchanged by adopting the new guidelines. Industry stakeholders can have confidence that designs undertaken using the current ARR2016 guidelines will not be dissimilar to the ARR1987 equivalent designs and that existing infrastructure will allow for a continuity of drainage outcomes from past to present.

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Item Type: USQ Project
Item Status: Live Archive
Faculty/School / Institute/Centre: Historic - Faculty of Health, Engineering and Sciences - School of Civil Engineering and Surveying (1 Jul 2013 - 31 Dec 2021)
Supervisors: Alam, Md Jahangir; Chowdhury, Rezaul
Qualification: Bachelor of Engineering (Honours) (Civil)
Date Deposited: 15 Sep 2021 05:57
Last Modified: 29 Jun 2023 01:34

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