Can Stream Rating Curves be Modeled from Large-Scale, Low-Resolution Airborne Laser Scanning Data?

Wednesday, 17 December 2014: 2:55 PM
Steve W Lyon1, Marcus Nathanson2, Norris Lam2, Helen E Dahlke3, Martin Rutzinger4,5, Jason W Kean6 and Hjalmar Laudon7, (1)Stockholm University, Physical Geography & Quaternary Geology, Stockholm, Sweden, (2)Stockholm University, Stockholm, Sweden, (3)University of California Davis, Davis, CA, United States, (4)Austrian Academy of Sciences, 4Institute for Interdisciplinary Mountain Research, Graz, Austria, (5)University of Innsbruck, Institute of Geography, Innsbruck, Austria, (6)USGS, Denver, CO, United States, (7)SLU Swedish University of Agricultural Sciences Umeå, Umeå, Sweden
This study explores the potential of using large-scale, low-resolution airborne laser scanning (ALS) derived elevation data to model stream rating curves. Rating curves, which allow the functional translation of stream water depth into discharge making them integral to water resource monitoring efforts, were modeled using a physics-based approach that captures basic geometric measurements to establish flow resistance due to implicit channel roughness. We tested synthetically thinned high-resolution airborne laser scanning data (topographic LiDAR data) as a proxy for low-resolution data at a point density equivalent to that obtained within most national-scale ALS strategies. Our results show that the errors incurred due to the effect of low-resolution versus high-resolution ALS data were less than those due to flow measurement and curve fitting uncertainties or uncertainty pertaining to vegetation densities. As such, although there still are some scale and technical limitations to consider, it appears theoretically possible to generate rating curves for any point in a river network from airborne laser scanning data of the resolution anticipated within national-scale ALS schemes. This would greatly enhance our ability to monitor streamflow globally by simplifying the effort required.