High-resolution orthoimagery and digital surface model of Blue River Lake, Oregon, December, 2023

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 Blue River Lake, located on Blue River about 2.5 kilometers upstream of the confluence of the Blue River and the McKenzie River in western Oregon. Blue River Lake is a multi-purpose reservoir impounded by both the 82-meter ([m]; 270-foot [ft]) tall Blue River Dam and the smaller Saddle Dam along the Blue River. Aerial photographs were acquired by the Civil Air Patrol (CAP) in December 2023 when water levels were at an elevation of 360 m (1,179 ft; National Geodetic Vertical Datum of 1929 [NGVD29]), near typical annual “low pool” or minimum-conservation pool for flood-risk management operations. Photographs were acquired at a single 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, 383 m [1,257 ft]), and the lower reaches of major rivers entering the reservoir including Blue River, Quartz Creek, and North Fork Quartz Creek, as well as other smaller tributaries. The USGS applied structure-from-motion (SfM) techniques to these aerial photographs, following the workflow outlined in Over and others (2021) and used for similar datasets (Schwid and others, 2025) to generate a three-dimensional xyz point cloud, digital surface model (DSM), and orthomosaic of Blue River Lake. 
 
This documentation describes the aerial photographs acquired by the Civil Air Patrol on December 20, 2023, a CSV file containing ground control point locations surveyed on December 4, 2024, that were used to spatially register SfM datasets, a high-resolution point cloud, DSM, and orthomosaic generated from SfM techniques using the aerial photographs, and a polygon shapefile including the footprint (spatial coverage) of the DSM and orthomosaic.

 
References:
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., accessed March 11, 2026, at 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, accessed March 11, 2026, at https://doi.org/10.5066/P1Q5K657