Rural Catchment Modelling: Application in Ungauged Catchments

Maloney, Joshua (2020) Rural Catchment Modelling: Application in Ungauged Catchments. [USQ Project]

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Analysis of ungauged catchments is a challenging endeavour with large degrees of uncertainty. The uncertainty stems from the lack of accurate inputs for modelling. Various efforts have been made to improve the availability of this information mainly through regionalisation of parameters. Several studies have been carried out on model specific parameters such as the Kc and m values for the RORB model however, loss parameters are still being properly developed. Loss parameters for ungauged catchments can only be sourced from ARR Datahub or from a specific regionalisation of nearby catchments for which initial loss and continuing loss variables have been derived.

This report investigated the use of unchanged loss parameters from nearby catchments and the use of ARR Datahub values obtained for the specific catchment. Four catchments were chosen with a pair in QLD and a pair in NSW. Each pair was similar in size, shape and proximity. The loss parameters were input into a simple DRAINS and RORBWin model for each catchment using default and ARR2019 recommended settings elsewhere. Model outputs of design storm AEP’s were compared to FFA data for those sites. Results suggest that using neighbour site derived loss values provides a better approximation of actual loss values than the ARR Datahub source and should be used in preference for flood modelling. ARR Datahub values tended to underestimate flows making it unsuitable for flood modelling but may be applicable to water balance and reservoir storage estimations.

The average of the four catchments suggested the neighbouring loss values were a better approximation of site loss values however one site dramatically underestimated flows. Further study including refinement of the site FFA for that exception and including a much larger sample size is required to strengthen claims.

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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: 20 Aug 2021 01:11
Last Modified: 26 Jun 2023 04:13

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