SEDIMENT TRANSPORT IN HOT WEATHER CREEK, ELLESMERE ISLAND, NWT, CANADA, 1990-1991

Streamflow and sediment concentrations in Hot Weather Creek (basin area 155 km2) and a small sub-basin (''Heather Creek,'' 6 kM2) were monitored throughout the 1991 thaw season (25 May-23 August). Suspended sediment concentrations peaked 4 h prior to maximum discharge in the snowmelt period (1870 mg L-1) while the greatest solute concentration (derived from specific conductance) occurred at the beginning of a late-summer rain event (500 mg L-1). Simple logarithmic and composite polynomial rating curves were used to develop estimates of hourly suspended sediment and solute loads for four periods of the runoff season. Bedload was not measured. Neglecting the latter, suspended sediment accounted for between 47 and 51% of the material transported in Hot Weather Creek and between 35 and 42% in Heather Creek. Gross sediment yields in 1991 were 3.5 to 3.7 t km-2 for Hot Weather Creek and 2.8 to 3.1 t km-2 for Heather Creek. Hindcasting using the same rating curves produced an estimated yield of 22 to 56 t km-2 for Hot Weather Creek in 1990, due to higher peak discharges and greater overall runoff as a consequence of deeper snow in the basin. Suspended sediment removal was very much more important than solution in 1990 and constituted 79 to 92% of the sediment delivered. The two basins have the lowest runoff values published for catchments in the Canadian Arctic Archipelago. Solute yields were similar to results obtained from other nonglaciated basins in this region while suspended sediment yields were similar in 1990, but much lower in 1991.