Characterization of Field-Scale Water Balance Components at A Heterogeneous Prairie Field Site

English Abstract:

Understanding hydrological processes at different scales is essential for hydrological modeling, particularly in heterogeneous environments, such as the internally drained prairie basins, with high spatial variability in the snowpack and soil properties. A soil-weather monitoring system was installed at a pasture site in the Brightwater Creek sub-basin, near Saskatoon, Saskatchewan, Canada, to characterize field-scale water balance components during two continuous years with contrasting weather. In addition to traditional meteorological measurements, intensive transect surveys of snowpack, vadose zone soil water content and groundwater were conducted within the footprint of a flux tower (around 500 m). Through quantifying the field-scale water balance, some interesting results were found. During the snow accumulation period, snow redistribution happened at sub-field-scale and over-field-scale due to overcatch of patterned vegetation compared to surrounding stubble field. During the melt period, snowmelt and rainfall leads to surprisingly high infiltration into the vadose zone of glacial till. The features of spatiotemporal storage dynamics indicate existence of unique flow paths at the study site. These would of great interests for prairie hydrological modeling.