Digital Elevation Model of Glen Canyon Prior to the Flooding of Lake Powell from Historic Topographic Surveys, Utah and Arizona

Development of a high-resolution digital elevation model (DEM) of the pre-Glen Canyon Dam topography in Glen Canyon National Recreation Area, Utah and Arizona was initiated to assist the U.S. Geological Survey (USGS) in its Lake Powell coring program in the fall of 2018 (https://www.usgs.gov/centers/ut-water/science/lake-powell-coring). Topographic surveys of Glen Canyon were commissioned by the Bureau of Reclamation during the planning stages for Lake Powell as part of the Colorado River Storage Project (S. 500, 1956). The Colorado River arm was surveyed by Alster and Associates, Inc. in 1958 and 1959 at a contour interval of 10-feet from the river surface at the future dam site through where the 3,750-foot contour crosses the channel (above Hite, UT). The San Juan River arm was surveyed by Fairchild Aerial Surveys, Inc. in 1947 at a contour interval of 20-feet from the confluence between the San Juan and Colorado Rivers through where the 4,100-foot contour crosses the channel (east of Mexican Hat, UT), though this DEM only includes topography up to 3,800 feet. Digitization of these contour maps into vector data was finalized in 2019 by the USGS Utah Water Science Center. The National Park Service, Glen Canyon National Recreation Area and the Bureau of Reclamation, and Glen Canyon Environmental Studies contributed in the digitization (c. 1999). The hydrologically corrected, 2-meter DEM was developed with the Topo to Raster tool in ArcMap (v. 10.6.1). These data are provided as-is and may be subject to revisions without warrant or consent.