Suspended sediment flux downstream of the retreating Castle Creek Glacier, Cariboo Mountains, British Columbia.

Glaciers are a major erosive force that increase sediment load to the downstream fluvial system. The Castle Creek Glacier, British Columbia has retreated ~1.0 km in the past 70 years. The dynamics of suspended sediment concentration (SSC) and streamflow (Q) were monitored independently at six sites within its proglacial zone over a 60 day period from July to September, 2011. The time-series were divided into hydrologic days and the SSC response to hydro-meteorological conditions was categorized using principal component analysis (PCA) and cluster analysis (CA). Suspended sediment load (SSL) was computed and summarized for the categories. During the 2011 study period, c. 60% of the total SSL was derived from the glacial stream and sediment deposits proximal to the terminus of the glacier during storm' events, that contribution drops to 40% as contribution from diffuse and point sources of sediment within the meltwater channel and proglacial zone increase. While storm' events accounted for just 3% of the field season, SSL was 500% higher than the seasonal average, and c. 20% of the total SSL was generated in that time. --Leaf ii.