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| Home > Publications database > Temporal scaling laws for wetting and drying in variably saturated soils |
| Poster (After Call) | FZJ-2025-01331 |
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2024
Abstract: Natural systems often exhibit properties and temporal scalings of power law type due to their internal dynamics. These scaling laws facilitate a more generalized understanding and description of complex phenomena, offering valuable insights into the fundamental principles governing information transfer in natural systems. This study examines the process of constant vertical infiltration in a homogeneous subsurface with initially hydrostatic conditions and a free water table as a lower boundary condition. The research aims to enhance the understanding of time scales associated with variably saturated subsurface flow due to constant infiltration. In 1969, Philip introduced the characteristic time at which gravitational forces dominate over capillary forces in case of ponded infiltration. This time also helps determine the quasi-steady state of ponded infiltration. We introduce a scaling law that provides insights into quasi-steady state time scales for infiltration and drainage, beyond just ponded infiltration relaxing many of the assumptions in previous studies. Simulations were conducted using the variably saturated groundwater flow model ParFlow. In the simulations, the infiltration rate, water table depths, hydraulic conductivity, and respective soil texture parameters were perturbed systematically. Through dimensional analysis, new scaling relationships of infiltration and drainage time scales have been obtained. One relationship is based on the velocity of the pressure head response required to reach a quasi-steady state, while another is based on dimensionless ratios of the considered variables. The analyses allow us to estimate the order of magnitude of response times toward quasi-steady state conditions depending on the system's hydraulic characteristics and boundary conditions. Future research should expand the obtained results by considering initial conditions with varying moisture levels.
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