A direct analysis of flood interval probability using approximately 100-year stream flow datasets

Brodie, Ian M. and Khan, Shahjahan (2016) A direct analysis of flood interval probability using approximately 100-year stream flow datasets. Hydrological Sciences Journal, 61 (12). pp. 2213-2225. ISSN 0262-6667

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Abstract

Series of observed flood intervals, defined as the time intervals between successive flood peaks over a threshold, were extracted directly from eleven approximately 100-year streamflow datasets from Queensland, Australia. A range of discharge thresholds were analysed that correspond to approximately 3.7 months to 6.3 year return periods. Flood interval histograms at South East Queensland gauges were consistently unimodal whereas those of the North and Central Queensland sites were often multimodal. The exponential probability distribution (pd) is often used to describe interval exceedance probabilities, but fitting utilizing the Anderson Darling statistic found little evidence that it is the most suitable. The fatigue life pd dominated sub-year return periods (<1 year), often transitioning to a log Pearson 3 pd at above-year return periods. Fatigue life pd is used in analysis of the life time to structural failure when a threshold is exceeded and this paper demonstrates its relevance also to the elapsed time between above-threshold floods. At most sites, the interval medians were substantially less than the means for sub-year return periods. Statistically the median is a better measure of central tendency of skewed distributions but the mean is generally used in practice to describe the classical concept of flood return period.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Submitted version deposited in accordance with the copyright policy of the publisher.
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Agricultural, Computational and Environmental Sciences
Date Deposited: 23 Feb 2016 05:42
Last Modified: 03 May 2017 00:31
Uncontrolled Keywords: flood frequency analysis; design discharges; partial series, peaks over threshold, annual series, flood interval, return period, probability distribution, nonparametric test
Fields of Research : 09 Engineering > 0907 Environmental Engineering > 090702 Environmental Engineering Modelling
01 Mathematical Sciences > 0104 Statistics > 010405 Statistical Theory
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970101 Expanding Knowledge in the Mathematical Sciences
D Environment > 96 Environment > 9609 Land and Water Management > 960999 Land and Water Management of Environments not elsewhere classified
Identification Number or DOI: 10.1080/02626667.2015.1099790
URI: http://eprints.usq.edu.au/id/eprint/28415

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