MERGE: modelling erosion resistance for gully erosion – a process-based model of erosion from an idealised linear gully
M. E. Roberts
A Australian Rivers Institute, Griffith University, Kessels Road, Nathan, Qld Australia. Email: m.roberts2@griffith.edu.au
B School of Mathematics and Statistics, University of Melbourne, Vic. Australia.
Soil Research 58(6) 576-591 https://doi.org/10.1071/SR20027
Submitted: 29 January 2020 Accepted: 5 June 2020 Published: 23 July 2020
Abstract
Gullies are responsible for as much as 40% of the accelerated erosion impacting the Great Barrier Reef lagoon. Consequently, to protect the reef from the impacts of poor water quality associated with eroded sediment, the remediation of gullied landscapes is important. The geographic location and geomorphic characteristics of gullies affects their erosion characteristics and the extent to which eroded sediments may be transported to the reef. Existing models of gully erosion are predominantly empirical in nature, and are poorly suited to represent the potential benefits of different interventions in the data scarce environment that exists. The Queensland Government, through the Queensland Water Modelling Network, identified the development of process-based models of gully erosion as necessary to support efforts to protect the reef. MERGE (modelling erosion resistance for gully erosion) was developed to address this need. MERGE exhibits the expected characteristics for gully erosion including achieving a steady concentration under constant conditions, the development of a depositional layer, as well as first flush effects and hysteresis in the dynamic case. Analytical steady-state solutions are found to be excellent approximations to the full dynamic solutions. The suitability of the model to represent interventions is demonstrated for the example cases of porous check dams and improved ground cover.
Additional keywords: mathematical modelling, remediation, rill.
References
Arcement GJ Jr, Schneider VR (1989) Guide for selecting Manning’s roughness coefficients for natural channels and flood plains. U.S. Geological Survey Water-Supply Paper 2339. Prepared in cooperation with U.S. Department of Transport, Federal Highway Administration.Brooks AP, Spencer J, Doriean N, Pietsch TJ, Hacker J (2018) A comparison of methods for measuring water quality improvements from gully rehabilitation in Great Barrier Reef catchments. In ‘Proceedings of the 9th Australian Stream Management Conference’ (Hobart, Australia), pp. 1–8.
Fukuoka S, Tabata K (2019) Derivation of the index governing the seepage flow and dynamic similarity condition of levee failures due to seepage flow. In ‘River Basin Management X, volume 234’ (Eds. Mambretti S, Melgarejo J) pp. 63–70. (WIT Press: Southampton, UK)
Garzon-Garcia A, Burton J, Franklin HM, Moody PW, De Hayr RW, Burford MA (2018) Indicators of phytoplankton response to particulate nutrient bioavailability in fresh and marine waters of the Great Barrier Reef. The Science of the Total Environment 636, 1416–1427.
| Indicators of phytoplankton response to particulate nutrient bioavailability in fresh and marine waters of the Great Barrier Reef.Crossref | GoogleScholarGoogle Scholar | 29913602PubMed |
Great Barrier Reef Marine Park Authority (2019) Great Barrier Reef Outlook Report 2019. Available at http://hdl.handle.net/11017/3474 [verified 26 June 2020].
Hairsine PB (1988) A physically based model of the erosion of cohesive soils. PhD Thesis, Griffith University, Australia.
Hairsine PB, Rose CW (1992a) Modeling water erosion due to overland flow using physical principles: 1. Sheet flow. Water Resources Research 28, 237–243.
| Modeling water erosion due to overland flow using physical principles: 1. Sheet flow.Crossref | GoogleScholarGoogle Scholar |
Hairsine PB, Rose CW (1992b) Modeling water erosion due to overland flow using physical principles: 2. Rill flow. Water Resources Research 28, 245–250.
| Modeling water erosion due to overland flow using physical principles: 2. Rill flow.Crossref | GoogleScholarGoogle Scholar |
Hairsine PB, Moran CJ, Rose CW (1992) Recent developments regarding the influence of soil surface characteristics on overland flow and erosion. Australian Journal of Soil Research 30, 249–264.
| Recent developments regarding the influence of soil surface characteristics on overland flow and erosion.Crossref | GoogleScholarGoogle Scholar |
Prosser IP (2018) Improving how gully erosion and river sediment transport processes are represented in Queensland catchment models. Available at https://science.des.qld.gov.au/__data/assets/pdf_file/0030/80787/qwmn-gully-erosion-processes-report.pdf [verified 6 July 2020]
Roberts ME (2019) The erosion of an ideal gully under steady state conditions. In ‘23rd International Conference on Modelling and Simulation’ (Canberra, Australia). Available at https://mssanz.org.au/modsim2019/G1/roberts.pdf [verified 6 July 2020]
Rose CW, Yu B, Ward DP, Saxton NE, Olley JM, Tews EK (2014) The erosive growth of hillside gullies. Earth Surface Processes and Landforms 39, 1989–2001.
| The erosive growth of hillside gullies.Crossref | GoogleScholarGoogle Scholar |
Rose CW, Shellberg JG, Brooks AP (2015) Modelling suspended sediment concentration and load in a transport-limited alluvial gully in northern Queensland, Australia. Earth Surface Processes and Landforms 40, 1291–1303.
| Modelling suspended sediment concentration and load in a transport-limited alluvial gully in northern Queensland, Australia.Crossref | GoogleScholarGoogle Scholar |
Schiesser WE (1991) ‘The numerical method of lines: integration of partial differential equations.’ (Academic Press)
Waterhouse J, Schaffelke B, Bartley R, Eberhard R, Brodie J, Star M, Thorburn P, Rolfe J, Ronan M, Taylor B, Kroon F (2017) 2017 Scientific consensus statement. Available at https://www.reefplan.qld.gov.au/about/assets/2017-scientific-consensus-statement-summary.pdf [verified 26 June 2020].
Wilkinson S, Henderson A, Chen Y (2008) SedNet User Guide, 2.0 edition. Available at https://toolkit.ewater.org.au/Tools/SedNet/documentation [verified 26 June 2020].
Wilkinson S, Hairsine P, Brooks A, Bartley R, Hawdon A, Pietsch T, Shepherd B, Austin J (2019) ‘Gully and stream bank toolbox. A technical guide for the Reef Trust Gully and Stream Bank Erosion Control Program.’ 2nd edn. (Commonwealth of Australia)
Wooldridge SA (2017) Preventable fine sediment export from the Burdekin River catchment reduces coastal seagrass abundance and increases dugong mortality within the Townsville region of the Great Barrier Reef, Australia. Marine Pollution Bulletin 114, 671–678.
| Preventable fine sediment export from the Burdekin River catchment reduces coastal seagrass abundance and increases dugong mortality within the Townsville region of the Great Barrier Reef, Australia.Crossref | GoogleScholarGoogle Scholar | 27780581PubMed |
