MCMASTER RIVER AND ARCTIC HYDROLOGY

This paper provides a synopsis of research on arctic hydrology conducted in the catchment of the McMaster River, a river in the Canadian High Arctic that bears the name of our University. In snow hydrology, we found that terrain strongly affects the redistribution of the snow cover, and the weather stations sometimes register only half or one-third of the snow measured in their nearby areas. Snowmelt is dominated by radiation energy input and by sensible heat flux when the snow cover becomes patchy. Coldness of the snow leads to refreezing of the meltwater to form ice lenses, the most prominent being basal ice formed at the snow-ground boundary. Infiltration of meltwater into frozen ground depends on the soil materials but is limited compared with total melt. Much of the melt-water then runs off on slopes. Surface flow diminishes when thawing of the active layer above the permafrost enlarges the water storage capacity. Between the active layer and the atmosphere, vertical exchanges occur through such processes as evaporation and rainfall infiltration. Stream-flow regime reflects the dual control of snow and permafrost hydrology, yielding high flows during the melt season, followed by summer flows influenced by active layer processes. [Key words: snow cover, snowmelt, permafrost, arctic hydrology.]