Submitted to: ARS Workshop on Real World Infiltration
Publication Type: Proceedings
Publication Acceptance Date: 9/30/1996
Publication Date: N/A
Interpretive Summary: Seasonally frozen soil plays an important role in the hydrology in northern latitudes. In many areas, rain or snowmelt on seasonally frozen soil is the single leading cause of severe flooding and erosion, but most hydrologic models do not address the effects of soil freezing on infiltration. Efforts to predict frozen soil infiltration and runoff have had limited success, which is reflective of the current knowledge of frozen soil infiltration processes. Frozen soil processes lag considerably behind non-frozen processes due partly to the difficulty in quantifying and measuring water and ice conditions in frozen soil. An array of modeling approaches for describing infiltration into frozen soils is presented, and future directions for modeling infiltration into frozen soil is discussed. Incorporation of these modeling approaches into existing computer models of runoff and erosion promises better evaluation of flooding potential from seasonally frozen soils.
Technical Abstract: Infiltration of water into soils is the governing hydrologic process which partitions available precipitation into surface runoff, available soil moisture, and subsurface flow. The infiltration capacity of soils can have a large degree of temporal variability due to the poorly understood processes of shrinking/swelling, freezing/thawing, and grazing. A brief discussion of the effects these processes have on the temporal variability of infiltration is presented, and future research directions are proposed to better understand the impacts of these processes. Future research needs include: 1) Relating the shrinkage characteristic of soils to intrinsic soil properties and management practices; 2) Accurate characterization of the relationship between soil water content, ice content and frozen soil infiltrability, which may require better measurement and characterization of ice content and structure; and 3) Better definition of the factors controlling infiltration on rangelands and the tendency of grazing to influence these factors.