MODELLING SNOWMELT INFILTRATION PROCESSES IN SEASONALLY FROZEN GROUND

Abstract

In cold regions, freezing and thawing of the soil governs soil hydraulic properties that shape the surface and subsurface hydrological processes. The partitioning of snowmelt into infiltration and runoff has important implications for integrated water resource management and flood risk. However, there is an inadequate representation of the snowmelt infiltration into frozen soils in most land-surface and hydrological models, creating the need for improved models and methods. In this research, we test the Frozen Soil Infiltration Model, FroSIn, which is a novel algorithm for infiltration into the frozen soils. The model is applied in a simple configuration to reproduce observations from field sites in the Canadian prairies, specifically St Denis and Brightwater Creek in Saskatchewan, Canada. We demonstrate the limitations of conventional approaches to simulate infiltration in frozen soils, which systematically over-predict runoff and under predict infiltration. The findings show that FroSIn enables models to predict more reasonable infiltration volumes in frozen soils, and also better represent how infiltration-runoff partitioning is impacted by antecedent soil water content.