Hydrology of a prairie slough

A three year study was carried out at a prairie slough to determine the hydrological processes occurring in the wetland and its surrounding uplands. On the upland slopes, snow accumulation was highly uneven, giving rise to spatial variations in infiltration and overland flow during melt. Rainfall distribution was more uniform but much of it was lost to evaporation, leaving minor amounts to groundwater recharge or runoff to the slough. The slough comprises a pond and its fringing non-flooded wetlands, the areal extents of which changed during the season as the pond expanded and contracted. Slough storage was rapidly replenished by the snow and ice melt in the slough and by the meltwater input through overland flow from the uplands. During summer, rainfall was the main source of water supply to the experimental slough, and evaporation exceeded water yield to the groundwater system. Water balance allows a contrast of hydrological conditions between years, with the drier years producing storage deficit for the slough, and wet summers producing a surplus.