High-resolution orthoimagery and digital surface model of Detroit 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 Detroit Lake, located on the North Santiam River about 85 kilometers upstream its confluence with the Willamette River in western Oregon. Detroit Lake is a multi-purpose reservoir impounded by the 141-meter ([m]; 463-foot [ft]) tall Detroit Dam along the North Santiam River. Aerial photographs were acquired by the Civil Air Patrol (CAP) in December 2023 when water levels were about 45 ft above typical annual “low pool” or minimum-conservation pool, a target elevation of 434 m (1,425 ft; National Geodetic Vertical Datum of 1929 [NGVD29]) 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, 477 m [1,564 ft]) and also included the uppermost 2 kilometers (km) of Big Cliff Reservoir, immediately downstream of Detroit Lake. The aerial photograph coverage also encompassed the lower reaches of major rivers entering the reservoir, including the North Santiam River and the Breitenbush River 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 Detroit Lake.
 
This documentation describes the aerial photographs acquired by the Civil Air Patrol on December 17 and 18, 2023, a CSV file containing ground control point locations surveyed in December of 2024 that were used to spatially register SfM datasets, a high-resolution point cloud (LAZ file), 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