QUANTIFYING SEDIMENT INTENSITY FROM THE NISQUALLY GLACIER AND NONGLACIAL SOURCES TO THE NISQUALLY RIVER, MOUNT RAINIER NATIONAL PARK

Alpine glaciers are sensitive to minor climate fluctuations. Recent global warming trends have resulted in rapid retreats of many of the world’s alpine glaciers. Nonglacial processes rapidly erode the newly exposed surfaces and lead to significant changes in local river valleys. Quantifying contemporary nonglacial processes and comparing them to rates of contribution from the glacier terminus is a critical first-step to predicting the effects of this sediment transport on future earth surface process and landscape development changes, which are fundamental prerequisites to better management of future water resources. Airborne and terrestrial laser scanning data are used to produce repeat, high-resolution topographic surveys to quantify intra-annual sources, sinks, and pathways of the hillslope-channel coupling. GIS analyses from high-resolution digital terrain models are used to measure the intensity and patterns of sediment transport, from the glacier terminus, slopes composed of till from lateral moraines, slopes where colluvial processes dominate, and areas where a combination lateral moraines and colluvial slopes exist, to the Nisqually River. Our findings show significant transport from the glacier terminus directly to the channel, while areas adjacent to lateral moraines and/or colluvial slopes show evidence of sediment transport from steeper side slopes and subsequent storage on high terraces. These terrace locations are short-term sinks where sediment can be transported during future outburst floods.