Using repeat lidar to estimate sediment transport in a steep stream
Article first published online: 26 MAR 2014
©2014. American Geophysical Union. All Rights Reserved.
Journal of Geophysical Research: Earth Surface
Volume 119, Issue 3, pages 621–643, March 2014
How to Cite
2014), Using repeat lidar to estimate sediment transport in a steep stream, J. Geophys. Res. Earth Surf., 119, 621–643, doi:10.1002/2013JF002933., and (
- Issue published online: 15 APR 2014
- Article first published online: 26 MAR 2014
- Accepted manuscript online: 13 FEB 2014 08:56AM EST
- Manuscript Accepted: 7 FEB 2014
- Manuscript Received: 25 JUL 2013
- sediment transport;
- morphologic budgeting;
- Mt. Rainier
Sediment fluxes in steep mountain streams remain difficult to quantify, despite their importance in geomorphology, ecology, and hazard analysis. In this work, aerial lidar surveys, acquired in 2002, 2008, and 2012, are used to quantify such fluxes in Tahoma Creek, a proglacial stream on Mount Rainier, Washington. As these surveys encompass all coarse sediment sources in the basin, we are able to translate geomorphic change into total bed material transport volumes for the time steps between surveys. By assuming that the relationship between daily sediment transport and daily mean discharge is of the form Qs=a(Q−Qc)b, our two observed total loads and estimates of daily mean discharge allow us to numerically solve for values of a and b to create a bed material sediment rating curve. Comparisons of our transport estimates with sediment deposition in a downstream reservoir indicate that our transport estimates and derived rating curve are reasonable. The method we present thus represents a plausible means of estimating transport rates in energetic settings or during extreme events, applicable whenever at least two cumulative sediment loads and the driving hydrology are known. We use these results to assess the performance of several bed load transport equations. The equations generally overpredict transport at low to moderate flows but significantly underpredict transport rates during an extreme event. Using a critical shear stress value appropriate for steep streams improves agreement at lower flows, whereas a shear-partitioning technique accounting for form drag losses significantly underpredicts transport at all flows.