Start Date
3-2-2021 10:20 AM
End Date
3-2-2021 11:25 AM
Abstract
Repeat topographic surveys are used for detecting changes in dynamic environments. The findings of repeat topographic surveys conducted on two landslides in the Tillamook State Forest of northwest Oregon are presented. Both landslides occurred on steep slopes with histories of industrial forestry. This study was conducted to measure the areas and volumes of erosion and deposition associated with each landslide. Baseline topographic data, captured prior to the landslides, was from free, publicly available lidar data from state-sponsored manned aircraft surveys. Data from after the landslides was collected using low-cost Unmanned Aerial Vehicles (UAVs) and processed using standard Structure from Motion (SfM) photogrammetry techniques to acquire topographic data. The UAV data acquisition and processing was cost and time effective and resulted in high resolution point-cloud and DEM data for subsequent volume analysis. The difference between the lidar and UAV datasets was used for cut/fill analysis to identify areas of erosion, deposition, and highlight impacts to the West Fork North Fork Wilson River floodplain and channel using open-source software. Documentation of the methods and 3D results visualizations of volumetric analysis are presented. Application of these economically approachable methods have value in geomorphology, fluvial geomorphology, and river restoration.
Subjects
Geology, GIS / modeling, Land/watershed management
Persistent Identifier
https://archives.pdx.edu/ds/psu/35469
Rights
© Copyright the author(s)
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Repeat Topographic Surveys Combining Lidar with UAV Structure from Motion Data for Change Detection of Two Landslides
Repeat topographic surveys are used for detecting changes in dynamic environments. The findings of repeat topographic surveys conducted on two landslides in the Tillamook State Forest of northwest Oregon are presented. Both landslides occurred on steep slopes with histories of industrial forestry. This study was conducted to measure the areas and volumes of erosion and deposition associated with each landslide. Baseline topographic data, captured prior to the landslides, was from free, publicly available lidar data from state-sponsored manned aircraft surveys. Data from after the landslides was collected using low-cost Unmanned Aerial Vehicles (UAVs) and processed using standard Structure from Motion (SfM) photogrammetry techniques to acquire topographic data. The UAV data acquisition and processing was cost and time effective and resulted in high resolution point-cloud and DEM data for subsequent volume analysis. The difference between the lidar and UAV datasets was used for cut/fill analysis to identify areas of erosion, deposition, and highlight impacts to the West Fork North Fork Wilson River floodplain and channel using open-source software. Documentation of the methods and 3D results visualizations of volumetric analysis are presented. Application of these economically approachable methods have value in geomorphology, fluvial geomorphology, and river restoration.