Hydrology of a small Canadian High Arctic basin during the snowmelt period

Abstract

Investigations were carried out in a small Canadian High Arctic basin to determine the influence of snowmelt on the hydrologic behaviour of the active layer and on basin discharge. The snowpack was characteristically thin but rapid melting in late June released a substantial amount of water to a thinly-thawed active layer, resulting in overland flow or standing water conditions. Owing to an uneven distribution of basin snow cover, the meltwater source area was highly variable both in time and in space, thus giving rise to different active layer hydrologic regimes in different parts of the basin. Slopes with a snowbank often had a high water table while the water table in the slopes bared of snow showed a gradual decline. Since streamflow represents a basinwide integration of these two active layer hydrologic regimes, there was a progressive reduction in daily peak flow accompanied by a prolonged lag time between daily discharge and snowmelt as the basin snow storage decreased. Spatially, inhomogeneity of snow cover also affected the downstream changes in discharge so that the ratio of discharge between two gauging stations depends on the relative magnitudes of snowmelt, evaporation and storage requirements of the two sub-basins. Rapid melting of an unevenly distributed Arctic snowpack therefore strongly influences the hydrologic behaviour of the active layer which in turn affects the streamflow regime.