Influence of seasonally frozen soil properties on infiltration rates: based on field data

The presence of seasonal ground frost can markedly modify infiltration processes and runoff generation, yet its hydrological impacts remain inconsistently described. The literature alternately reports enhanced, uncertain, or negligible effects of frozen soils on runoff and infiltration. Few studies rely on direct field measurements of infiltration under frozen conditions, and none have directly linked infiltration rates to measured soil ice content. Expanding field observations across contrasting soil types is therefore necessary to better constrain winter hydrological behavior. Quantifying infiltration capacity under frozen conditions remains challenging, as soil freezing renders many standard measurement techniques ineffective. Yet such data are essential to understand the links between infiltration rates, soil ice content, and other frozen ground properties. We conducted field measurements using double-ring infiltrometers in a clayey agricultural field and a sandy clearing to quantify infiltration under both frozen and unfrozen conditions. A combination of in situ sensors and soil sampling was used to characterize soil ice and liquid water content, frost depth, and soil temperature. The resulting field observations reveal pronounced variability in infiltration rates under frozen conditions at both sites, with substantially greater variability in the clay-rich soil. Moreover, the relationships between infiltration rates and frozen soil properties—including frost depth, thermal state, and water and ice content—were found to depend strongly on soil composition.