Keith Williams sets up the Reigl VZ-1000 for scanning with the resulting scan overlaid on the image. (Photo/Danica Roth; Scan overlay, Keith Williams) 
Keith Williams mounts a GPS receiver onto a TLS target for georeferencing of the scans, as snow starts to fall. (Photo/Danica Roth) 
Recently burned study site with slopes of interest (center of photo). (Photo/Keith Williams, UNAVCO) 
Danica Roth nails reflective targets to trees that the scanner will use as tiepoints to align each new scan position. (Photo/Keith Williams, UNAVCO)
Overview
Terrestrial laser scanning (TLS) was used in project support of researchers from the University of Oregon refining sediment transport models in steep terrain. TLS yielded measurement densities of greater than one point per centimeter, enabling researchers to image tree throws, or the cavities left behind by a tree’s roots when the tree is upended. Aerial LiDAR previously collected in the region yielded a point density of only 8 points per meter, too low a resolution for the researchers to extract these small-scale terrain changes and thus study their effects on sediment transport.
Significance
The lack of accurate sediment transport models in steeplands has hampered progress on a wide range of topics in geomorphology, land management and hazard mitigation. Sediment transport on hillslopes is currently most often viewed and modeled using a single, very simplified local hillslope characteristic, such as slope. This project aims to account for nonlocal sediment transport along these slopes, as the nonlocal approach accounts for sediment transport across further distances. These nonlocal processes can be from tree throws, burrowing animals, and fire-induced ravel. Two distinct study areas were scanned for this project, the first a well-established forest, and the second a recently burned area.
Challenges
TLS allowed the resolution needed to address the research questions, but required careful site selection, as well as some clearing of vegetation to allow the laser to resolve to the ground surface. Due to the nature of the burned site, two individual slope faces were collected simultaneously in the scans while the heavily vegetated area required two separate sites to collect differing slopes.
Project information
- Principal Investigators: Danica Roth, University of Oregon
- UNAVCO Staff: Keith Williams
- Dates: February 21-28, 2017
- Location(s): Oregon Coast Range
- Funding Source(s): NSF-EAR: Geomorphology and Land Use Dynamics: EAR-1420898
- Map of Triangle Lake, Oregon
Related links
Written by:
- Keith Williams
- Posted: 30 March 2017
- Last updated: 17 June 2021
- Tags: project highlights, TLS
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