Landform evolution modelling using transitional soil moisture content-modifying factors for erodibility

Authors: Livsey, D; Eadie, J; Garneau, P; Aguilera Pettinelli, E Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_repo/2615_93

Cite As:
Livsey, D, Eadie, J, Garneau, P & Aguilera Pettinelli, E 2026, 'Landform evolution modelling using transitional soil moisture content-modifying factors for erodibility', in AB Fourie, G Boggs, J Heyes & M Tibbett (eds), Mine Closure 2026: Proceedings of the 19th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 1-8, https://doi.org/10.36487/ACG_repo/2615_93



Abstract:
In this study, the long-term stability of a closure landform was evaluated in a landform evolution model (LEM) that permits soil erodibility parameters to change with soil moisture. Recent advances in soil mechanics indicate soil erodibility is a function of soil moisture and may increase by up to a thousandfold as soils dry. Therefore, including soil moisture erodibility feedback in LEMs is especially important for evaluating longterm closure stability under climate change, as warming climates are expected to result in a long-term decrease in soil moisture. For the analysis, mean annual erosion rates from a 30 m-tall by 500 m-square plateau with 1V:3H side slopes were computed from a LEM using meteorological data from Central Queensland, Australia, and published soil erodibility measurements. Including soil moisture-erodibility feedback increased mean annual erosion rates by more than tenfold as compared to the LEM run assuming constant soil erodibility. Additional soil erosion measurements from closure structures at various soil moisture conditions are needed as the soil erodibility data utilised results from laboratory-compacted soils. That said, an increase in erosion rates following drying of soils is consistent with many field-based studies of erodibility. Accounting for the soil moisture erodibility feedback in LEM predictions is important because LEMs are especially sensitive to soil erodibility-related parameters (i.e. soil detachment rate and critical shear stress). Furthermore, the dependency of erodibility on soil moisture is important to note in subtropical climates where significant wetting and drying of mechanically placed soils can result in the degradation of soil structure and increases in soil erodibility with time. Results of this work indicate that wetting and drying of closure landform soils may reduce the long-term stability of closure landforms, especially for climates expected to warm into the coming decades. Establishing vegetation cover is expected to stabilise mechanically placed soils from degradation caused by wetting and drying cycles. Furthermore, since soil erodibility is strongly affected by soil moisture and changes in vegetation cover, accounting for these changes in LEMs may be needed to assess the long-term stability of closure landforms more accurately under climate change.

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