DISCHARGE AND SEDIMENT-LOAD CHARACTERISTICS OF THE HILDA ROCK-GLACIER STREAM, CANADIAN ROCKY MOUNTAINS, ALBERTA

Abstract

Water discharge and sediment load characteristics of the Hilda rock-glacier stream are described for portions of the 1985 and 1986 ablation seasons. Covering an area of 1.5 km2, the Hilda rock glacier yields a relatively consistent flow, generally low in suspended sediments and relatively high in total dissolved solids during the ablation season. The seasonal hydrograph shows decreasing discharge and suspended sediment load and increasing dissolved loads through the ablation season as snowmelt water sources are depleted. Superimposed on this is a diurnal hydrograph showing that daily peaks in discharge lag several hours behind daily temperature maxima. Rain events produce hydrograph anomalies and act to flush sediment, elevating suspended loads, while diluting dissolved loads. These data suggest that rock-glacier hydrological systems are more responsive to short-term and transient meteorological conditions than previously suggested in the literature. Nonetheless, the data indicate that the Hilda rock glacier is more conservative in both water and sediment yield than glacier systems of comparable size and in the same environment.