Agisoft output report for structure-from-motion datasets for Fall Creek Lake, Oregon, during annual drawdown to streambed November 8, 2016

The Middle Fork Willamette River basin encompasses 3,548 square kilometers of western Oregon and drains to the mainstem Willamette River. Fall Creek basin encompasses 653 square kilometers and drains to the Middle Fork Willamette River. In cooperation with the U.S. Army Corps of Engineers, the U.S. Geological Survey evaluated geomorphic responses of downstream river corridors to annual drawdowns to streambed at Fall Creek Lake. This study of geomorphic change is focused on the major alluvial channel segments downstream of the U.S. Army Corps of Engineers’ dams on Fall Creek and the Middle Fork Willamette River, as well as the 736 hectare Fall Creek Lake. Reservoir erosion during streambed drawdown results in sediment delivery to downstream reaches. To better understand patterns and processes of reservoir erosion related to downstream geomorphic responses, detailed reservoir deposit mapping and change analyses are completed.
To support these analyses, aerial photographs were collected via unmanned aerial systems (UAS) on November 8 and November 9, 2016, and via Cessna aircraft (or manned aerial system; MAS) on November 10, 2016, to create 3-dimensional xyz point clouds, digital elevation models (DEMs), and orthophotographs of the Fall Creek Lake bottom during full reservoir drawdown using structure-from-motion (SfM) techniques. The November 8 model resulted in a ground resolution of 3.28 centimeters per pixel, average point density of 58.2 points per square meter, and DEM resolution of 13.1 centimeters per cell. The November 9 model resulted in a ground resolution on 2.86 centimeters per pixel, average point density of 76.6 points per square meter, and DEM resolution of 11.4 centimeters per cell. The model for the manned aerial system (MAS) flight on November 10 had a slightly lower ground resolution at 4.18 centimeters per pixel (for multiple altitudes), average point density of 35.8 points per square meter, and output DEM resolution of 16.7 centimeters per cell. Cell sizes were automatically generated by the software.
This documentation describes a pdf report generated by Agisoft PhotoScan Professional software describing project parameters, processing results, and accuracy assessment for point clouds, digital elevation models, and orthophotographs for datasets generated from aerial photographs of Fall Creek Lake, Oregon, acquired during annual drawdown to streambed on November 8, 2016. This dataset is part of a broader publication including aerial photographs, 3-dimensional xyz point clouds, DEMs, orthophotographs, model processing reports, ground control points, and dataset footprints for November 8-10, 2016.

Tags: aerial-images, aerial-photography, dam, drawdown, erosion, fall-creek, fall-creek-lake, fluvial-geomorphology, geomorphology, geoscientificinformation, geospatial-analysis, geospatial-datasets, imagerybasemapsearthcover, inlandwaters, jasper-oregon, lane-county, laz, middle-fork-willamette-river, oregon, orthoimagery, orthophotograph, photogrammetry, reservoir, sediment-transport, sfm, structure-from-motion, uas, unmanned-aerial-system, usgs-5dfd4d95e4b0b207aa00a144, winberry-creek
Organization: Department of the Interior