Dual‐permeability modeling of preferential flow and snowmelt partitioning in frozen soils

Abstract

The infiltrability of frozen soils modulates the partitioning of snowmelt between infiltration and runoff in cold regions. Preferential flow in macropores may enhance infiltration, but flow dynamics in frozen soil are complicated by soil heat transfer processes. We developed a dual-permeability model that considers the interacting effects of freeze-thaw and preferential flow on infiltration and runoff generation in structured soils. This formulation was incorporated into the fully integrated groundwatersurface water model HydroGeoSphere, to represent water-ice phase change in macropores such that porewater freezing is governed by macropore-matrix heat exchange. Model performance was evaluated against laboratory experiments and synthetic test cases designed to examine the effects of preferential flow on snowmelt partitioning between infiltration, runoff, and drainage. Simulations were able to reproduce experimental observations of rapid infiltration and drainage behavior due to macropores very well, and approximated soil thaw to an acceptable degree. Simulation of measured data highlighted the importance of macropore hydraulic conductivity, as well as macropore-matrix heat and water transfer, on controlling preferential flow dynamics. Test cases replicated a range of snowmelt partitioning behavior commonly observed in frozen soils, including subsurface conditions that produce rapid infiltration and deeper drainage, the contrast between limited vs. unlimited infiltration responses to snowmelt, and the temporal evolution of runoff generation. This study demonstrates the important influence that water freezing along preferential flowpaths can have on infiltrability and runoff characteristics in frozen soils and provides a physically based description of this mechanism that links infiltration behavior to hydraulic and thermal properties of structured soils.

Simulating preferential flow and snowmelt partitioning in seasonally frozen hillslopes

“…Simulations here agree with previous 1‐D modeling studies (Larsbo et al, 2019; Mohammed et al, 2021) which showed that a dual‐permeability approach can reproduce the dynamics of preferential flow in frozen soils. This formulation allows relatively large amounts and rates of infiltration, by incorporating the effects of macropores on enhancing frozen soil hydraulic conductivity and infiltrability (Demand et al, 2019; Watanabe & Kugisaki, 2017).…”

Quantifying hydrologic pathway and source connectivity dynamics in tile drainage: Implications for phosphorus concentrations

“…Nevertheless, infiltrated meltwater may freeze due to matrix-macropore heat and water transfer, and the frozen water can block the macropore pathway, and consequently reduce infiltration of Vadose Zone Journal F I G U R E 4 (a) Time series of data including 30-min tile flow (mm) and 15-min specific conductance (SC, μS cm −1 ). Two events are highlighted at different times of year including (b) fall and (c) summer event water (Demand et al, 2019;Mohammed et al, 2021;Stadler et al, 1997;Watanabe & Kugisaki, 2017). Cumulatively, these seasonal environmental factors in precipitation and soil dynamics are likely drivers of short time to peaks in spring and summer and longer time to peaks in fall and winter.…”

“…Conversely, during winter, a large amount of infiltration can occur via preferential flow because under partially saturated conditions a considerable portion of macropores remain air filled (Granger et al., 1984; Mohammed et al., 2018; Pittman et al., 2020; Stadler et al., 2000). Nevertheless, infiltrated meltwater may freeze due to matrix–macropore heat and water transfer, and the frozen water can block the macropore pathway, and consequently reduce infiltration of event water (Demand et al., 2019; Mohammed et al., 2021; Stadler et al., 1997; Watanabe & Kugisaki, 2017). Cumulatively, these seasonal environmental factors in precipitation and soil dynamics are likely drivers of short time to peaks in spring and summer and longer time to peaks in fall and winter.…”

A new seasonal frozen soil water-thermal coupled migration model and its numerical simulation

“…Lei Zhidong et al [ 7 ] considered that the Richards equation only considered the effect of water migration and phase transition, but not the effect of heat conduction. However, the other scholars [ 9 – 16 ] considered the heat conduction and phase change latent heat, but did not consider the water migration. On the basis of these two equations, Lei Zhidong et al [ 7 ] put forward the coupled water and heat transfer equation of frozen soil, which considered the factors of soil water transfer, heat conduction, water phase change latent heat and so on.…”

“…Literatures [ 12 – 14 ] considered it crucial to identify modeling schemes for macropore-matrix interactions and permeate water refreezing, discussed the necessity to study the effects of macropore flow and soil freeze-thaw interactions, the need to integrate these concepts into a framework of coupled hydrothermal transfer, then they proposed a conceptual model for freezing unsaturated flow in macropore soils that assumed two interacting domains (macropore and matrix) with different water and heat transfer mechanisms. Existing problems were [ 12 , 15 , 16 ]: the detailed understanding of macropore flow mechanism in permafrost, and how it changes with different soil thermal conditions were still uncertain in these proposed models, so it was necessary to further develop the existing macropore flow description and various scale modeling methods. New modeling approached that test these concepts and quantify these dynamics can address the rate of water flow in frozen micropore soils and investigate the conditions that allow water to bypass the freezing zone, or cause water to freeze in the macropores in the opposite way.…”