DETERMINATION OF INFILTRATION CHARACTERISTICS OF A FROZEN PALOUSE SILT LOAM SOIL UNDER SIMULATED RAINFALL

Better understanding of the frozen ground runoff-infiltration relationship is needed to accurately partition the applied rainfall and snowmelt into runoff and infiltration volumes. This study utilized the Palouse rainfall simulator to provide the necessary rainfall for infiltration studies on frozen soil. To provide for a wider range of soil moisture content, a one meter square soil sample was frozen in a laboratory and infiltration runs were made on this sample. Intensities of rainfall utilized ranged from 12.2 mm/hr to 23.6 mm/hr. Soil moisture contents ranged from 14.3 percent to 45.1 percent. Frost depths observed ranged from 0 to 180 mm.; Final infiltration rates calculated for the various runs indicated that when dry soil was frozen, the infiltration capacity was actually enhanced. When the soil was frozen at high moisture content the infiltration capacity was decreased.; The Green and Ampt infiltration equation was applied to data collected in this study. This equation could be used for prediction of infiltration rates for a frozen Palouse silt loam soil with a soil moisture content less than 30 percent.