In cooperation with the U.S. Army Corps of Engineers (USACE), the U.S. Geological Survey (USGS) surveyed ground control points and coordinated aerial photograph acquisition of Hills Creek Lake, a multi-purpose reservoir in western Oregon impounded by the 92-meter ([m]; 302-foot [ft]) tall Hills Creek Dam. Aerial photographs were acquired by the Civil Air Patrol (CAP) on December 20, 2023 and December 28, 2023 when water levels were at 443 and 441 m (1453 ft and 1448 ft; National Geodetic Vertical Datum of 1929 [NGVD 29]) elevation, respectively, about 10 m above typical annual “low pool” or minimum pool for flood risk management operations. Photographs were acquired at about the same altitude with a WaldoAir XCAM Ultra 50 camera mounted on a Cessna aircraft and captured the entire reservoir area as defined by full pool (or maximum conservation pool elevation), including major tributaries entering the reservoir such as the Middle Fork Willamette River and Hills Creek, upstream of Hills Creek Dam. Dam operations at the 1,107-hectare (2735-acre) Hills Creek Lake, located about 19 kilometers upstream of the confluence of the Middle Fork Willamette River and the head of Lookout Point Lake, along with other hydrogeomorphic conditions, result in a diverse array of geomorphic processes and landforms within the reservoir. To document reservoir floor geomorphology, the USGS applied structure-from-motion (SfM) techniques to these aerial photographs, following the workflow outlined in Over and others (2021), and generated three-dimensional xyz point clouds, digital surface models (DSMs), and orthomosaics of Hills Creek Lake.
This data release includes ground control points, dataset footprints, original aerial photographs, point clouds, DSMs, and orthomosaics of Hills Creek Lake with varying aerial extents and resolutions that were developed from imagery acquired December of 2023: (1) the December 20 model (HillsCreekLake_20231220) covered the entire reservoir area with an average point density of 27.6 points per square meter, DSM resolution of 19 centimeters per pixel, and orthomosaic ground resolution of 9.52 centimeters per pixel; (2) the December 28 model (HillsCreekLake_20231228) covered the entire reservoir area, excluding a portion of the Larison Creek arm, with an average point density of 29.8 points per square meter, DSM resolution of 18.3 centimeters per pixel, and orthomosaic ground resolution of 9.15 centimeters per pixel. All DSMs and orthomosaics are formatted as Cloud Optimized GeoTIFFs (COGs) for enhanced web visualization (GDAL, 2024).
This documentation describes an orthomosaic of Hills Creek Lake, Oregon, generated from SfM techniques using aerial photographs acquired on December 28, 2023.
References:
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Geospatial Data Abstraction Library [GDAL], 2024, COG -- Cloud Optimized GeoTIFF generator: GDAL, webpage, accessed August 11, 2025, at https://gdal.org/drivers/raster/cog.html#raster-cog.
Over, J.R., Ritchie, A.C., Kranenburg, C.J., Brown, J.A., Buscombe, D., Noble, T., Sherwood, C.R., Warrick, J.A., and Wernette, P.A., 2021, Processing coastal imagery with Agisoft Metashape Professional Edition, version 1.6—Structure from motion workflow documentation: U.S. Geological Survey Open-File Report 2021–1039, 46 p., https://doi.org/10.3133/ofr20211039.
Schwid, M.F., Keith, M.K., and Overstreet, B.T., 2025, High-resolution orthoimagery and digital surface models of Fern Ridge Lake, Oregon, during annual low pool, January and February, 2023: U.S. Geological Survey data release, https://doi.org/10.5066/P1Q5K657.
