Evaluation of the Impact of Transpiration Flux in Thermo-Hydraulic Numerical Analyses

Vegetation cover influences slope stability through coupled soil-atmosphere processes, commonly described within the Soil-Vegetation-Atmosphere (SVA) interaction framework. In this context, evapotranspiration (ET) plays a key role in the surface energy and water balances, lowering pore-water pressures and reducing susceptibility to rainfall-induced landslides. A physically consistent representation of ET fluxes in numerical models is therefore essential for the reliable assessment of equilibrium conditions and for the conservative design of Nature-Based Solutions (NBS), which are increasingly recognized as effective and sustainable strategies for landslide mitigation. Since ET depends on evolving vegetation characteristics as well as soil thermo-hydraulic states, its computation must be fully integrated into the governing equations of the finite elements, FE, formulation. This work utilizes the FE code Code_Bright, recently extended with a subroutine for ET computation based on a physically based resistance scheme derived from atmospheric science. The preliminary results presented herein highlight the importance of explicitly integrating transpiration flux computations into thermo-hydraulic, TH, modelling. This approach is essential to achieve more realistic predictions of the soil TH response, particularly within the rooted zone.