Estimating urban flood risk - uncertainty in design criteria

M. Newby, S. W. Franks, C. J. White

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The design of urban stormwater infrastructure is generally performed assuming that climate is static. For engineering practitioners, stormwater infrastructure is designed using a peak flow method, such as the Rational Method as outlined in the Australian Rainfall and Runoff (AR&R) guidelines and estimates of design rainfall intensities. Changes to Australian rainfall intensity design criteria have been made through updated releases of the AR&R77, AR&R87 and the recent 2013 AR&R Intensity Frequency Distributions (IFDs). The primary focus of this study is to compare the three IFD sets from 51 locations Australia wide. Since the release of the AR&R77 IFDs, the duration and number of locations for rainfall data has increased and techniques for data analysis have changed. Updated terminology coinciding with the 2013 IFD release has also resulted in a practical change to the design rainfall. For example, infrastructure that is designed for a 1: 5 year ARI correlates with an 18.13 % AEP, however for practical purposes, hydraulic guidelines have been updated with the more intuitive 20 % AEP. The evaluation of design rainfall variation across Australia has indicated that the changes are dependent upon location, recurrence interval and rainfall duration. The changes to design rainfall IFDs are due to the application of differing data analysis techniques, the length and number of data sets and the change in terminology from ARI to AEP. Such changes mean that developed infrastructure has been designed to a range of different design criteria indicating the likely inadequacy of earlier developments to the current estimates of flood risk. In many cases, the under-design of infrastructure is greater than the expected impact of increased rainfall intensity under climate change scenarios.

LanguageEnglish
Pages3-7
Number of pages5
JournalIAHS-AISH Proceedings and Reports
Volume370
DOIs
Publication statusPublished - 11 Jun 2015

Fingerprint

Rain
precipitation intensity
infrastructure
rainfall
terminology
stormwater
Terminology
Uncertainty
recurrence interval
peak flow
Runoff
Climate change
distribution
runoff
hydraulics
Hydraulics
engineering
climate change
climate

Keywords

  • urban stormwater infrastructure
  • peak flow method
  • Austrailian rainfall and runoff guidelines
  • intensity frequency distribution
  • IFD
  • flood risk

Cite this

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abstract = "The design of urban stormwater infrastructure is generally performed assuming that climate is static. For engineering practitioners, stormwater infrastructure is designed using a peak flow method, such as the Rational Method as outlined in the Australian Rainfall and Runoff (AR&R) guidelines and estimates of design rainfall intensities. Changes to Australian rainfall intensity design criteria have been made through updated releases of the AR&R77, AR&R87 and the recent 2013 AR&R Intensity Frequency Distributions (IFDs). The primary focus of this study is to compare the three IFD sets from 51 locations Australia wide. Since the release of the AR&R77 IFDs, the duration and number of locations for rainfall data has increased and techniques for data analysis have changed. Updated terminology coinciding with the 2013 IFD release has also resulted in a practical change to the design rainfall. For example, infrastructure that is designed for a 1: 5 year ARI correlates with an 18.13 {\%} AEP, however for practical purposes, hydraulic guidelines have been updated with the more intuitive 20 {\%} AEP. The evaluation of design rainfall variation across Australia has indicated that the changes are dependent upon location, recurrence interval and rainfall duration. The changes to design rainfall IFDs are due to the application of differing data analysis techniques, the length and number of data sets and the change in terminology from ARI to AEP. Such changes mean that developed infrastructure has been designed to a range of different design criteria indicating the likely inadequacy of earlier developments to the current estimates of flood risk. In many cases, the under-design of infrastructure is greater than the expected impact of increased rainfall intensity under climate change scenarios.",
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Estimating urban flood risk - uncertainty in design criteria. / Newby, M.; Franks, S. W.; White, C. J.

In: IAHS-AISH Proceedings and Reports, Vol. 370, 11.06.2015, p. 3-7.

Research output: Contribution to journalArticle

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