The disposition of water that is released as snow melts in agricultural fields is of considerable importance with respect to flooding, solute transport, and recharge of soil moisture depleted during the previous growing season. We have made a broad range of measurements during the snowmelt season for several years at the University of Minnesota Agricultural Experiment Station in Rosemount, MN. In level portions of untilled fields the contribution of snowmelt to soil moisture recharge is generally small (less than 20% of overwinter liquid equivalent precipitation). Evaporation is also not a large sink for water from the snowpack, again accounting for less than 20% of the overwinter precipitation. Most of the water released during snowmelt finds its way to low points within the field, resulting in the formation of large ephemeral ponds, which can form within a day to depths approaching 1 m. Infiltration is often almost as rapid, despite the presence of a frozen layer in the soil below. We will discuss the mechanisms contributing both to the formation and the disappearance of these ponds.

John M. Baker
Dept. of Soil, Water, & Climate
University of Minnesota
439 Borlaug Hall
1991 Upper Buford Circle
St. Paul, MN  55108
Phone: (612) 625-4249
FAX: (612) 625-2208
email: jbaker@soils.umn.edu