Estimation of peak flow in Queensland using Quantile Regression Technique and ARR 2019

Walker, Samuel (2019) Estimation of peak flow in Queensland using Quantile Regression Technique and ARR 2019. [USQ Project]

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Design flood estimation for small and medium sized catchments is required for the design of culverts, small to medium sized bridges, causeways and other engineering projects. Currently, the most widely used approaches within Australia include the Rational Method, the Quantile Regression Technique (QRT) and the Regional Flood Frequency Estimation (RFFE). Unfortunately, these techniques have been found to produce unreliable and inconsistent results for various reasons.

Empirical models (QRT, for example) are correlated to a particular set of data, they require updates when more data or improved methods are available. Australian Rainfall and Runoff has published 2019 version superseding the industry standard 1987 version. In addition, 1987 rainfall intensityfrequency-duration tables are also out-of-date and will no longer be available as of June 2020, replaced by 2016 version. The aim of this project is to update and improve overall performance of the QRT method presented by Palmen and Weeks (2011), utilising the latest 2016 rainfall intensities and new ARR 2019 procedures. Catchments are limited to smaller than 1000km2 in area.

The project involved reviewing the quality of some rating curves with the aid of two-dimensional hydraulic models. Flood frequency analysis at each gauge produced discharge quantiles which were correlated by regression with catchment area and 2016 design rainfall intensities. A variety of standard frequency-durations of rainfall intensity was tested to find the best performing. The final model was compared to common methods in the industry, including those mentioned above, frequency analysis results and gauge data.

The result of this investigation is a set of six two-parameter equations for each design probability; 50%, 20%, 10%, 5%, 2%, and 1% AEP events, requiring only readily accessible catchment areas and design rainfall intensities to quickly and reliably obtain design flood estimates. The model was found to have similar performance to RFFE and so provides and alternative method. It may be used to validate larger and more complex hydrologic models and is particularly suited for planning, preliminary design and use when little information is known or available.

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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: Chowdhury, Rezaul
Qualification: Bachelor of Engineering (Honours) (Civil)
Date Deposited: 16 Aug 2021 04:43
Last Modified: 27 Jun 2023 04:11

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