SUSPENDED SEDIMENT CONCENTRATIONS AND EROSION RATES ON MOUNT RAINIER, WASHINGTON

Tracking suspended sediment concentrations in glacial meltwater has important implications for erosion rates, and for downstream channel capacity. In order to characterize suspended sediment transport on Mount Rainier, Washington, samples were collected from meltwater streams of five glaciers: Carbon, Tahoma, Emmons, Nisqually, and Winthrop. Samples were taken at the estimated maximum and minimum discharge times during the diurnal cycle, as close to the terminus as possible. Results from 2012-2014 indicate that most often, more sediment is transported during the maximum discharge time. Evidence of this is seen at Carbon glacier which yielded a greater than 50% increase in sediment transported between minimum and maximum discharge times; a 24-hour sampling period at Emmons glacier revealed a 130% increase. An interannual study of Emmons and Carbon glaciers indicate that a significantly larger amount of sediment was transported in 2013 compared to 2012. Future work will include integrating 2014 data into the interannual study, as well as completing simultaneous sampling at Nisqually glacier to examine potential downstream sediment deposition. Archived weather data will also be utilized to examine how weather affects sediment concentrations. Ultimately, data obtained between 2012 and 2014 will help characterize variation between glacial valleys on Mount Rainier, including erosion rates and sediment transport.