Issue |
E3S Web of Conf.
Volume 382, 2023
8th International Conference on Unsaturated Soils (UNSAT 2023)
|
|
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Article Number | 20003 | |
Number of page(s) | 6 | |
Section | Multi Phase Media and Multi Physical Coupling - Part II | |
DOI | https://doi.org/10.1051/e3sconf/202338220003 | |
Published online | 24 April 2023 |
Physically-based reduction function to model unsaturated flow associated with plant transpiration
Department of Civil and Environmental Engineering, University of Strathclyde, Glasgow, UK
* Corresponding author: eve.roberts-self@strath.ac.uk
Vegetation plays an important ‘hydrological’ role in stabilising geostructures. Soil water is extracted by the roots due to transpiration, this increases soil suction and, hence, soil shear strength. Transpiration occurs in two different regimes, energy-limited and the water-limited regimes respectively. These two regimes are reflected in the two branches of the transpiration reduction function used to model the hydraulic boundary conditions for vegetated ground. The water-limited branch accounts for the reduced transmissivity of the soil-root system when the degree of saturation and, hence, the hydraulic conductivity declines. The water-limited branch of existing reduction functions (e.g., Feddes function) is defined in purely phenomenological fashion with parameters that have no clear link with the complex interaction between soil hydraulic properties and root architecture. A paradigm shift can be achieved through physically-based reduction functions. These require analytical closed-form solutions of radial water flow at the soil-root interface that, in turn require introducing simplifying assumptions, i.e., steady-state flow and a simplified hydraulic conductivity function. This paper explores the implications of these assumptions by i) benchmarking the water-limited branch of the reduction function derived analytically against the one derived numerically for more realistic hydraulic behaviour and ii) assessing the steady-state assumption.
© The Authors, published by EDP Sciences, 2023
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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