Runoff Regime of Slopes in Continuous Permafrost Areas

The hydrological regime of slopes underlain by continuous permafrost is dictated by the seasonal differences in the supplies of water and energy. Based on a study at Resolute, N.W.T., three hydrological seasons are recognized. In winter, the ground freezes, snow accumulates, and most hydrological activities on the slopes are dormant. As energy supply increases in spring, snowmelt generates considerable runoff but frozen ground restricts subsurface water movement and surface flow prevails. Summer runoff declines as the slopes become snow-free and as evaporation increases. Rainfall is often of low magnitude though occasional storms of high intensity can rejuvenate surface flow.Spatial variation in slope runoff is conspicuous. Areas below deep snowpacks or at the base of concave slopes receive abundant water supply throughout most parts of the thaw season. Otherwise, the grounds become dry soon after the melt period. It is recommended that construction works in the High Arctic should not be carried out in spring when most slopes are saturated, and that areas with surface flow should be avoided in the summer season.