Bathymetric, topographic, and grain-size data were collected in April 2011 along a 27-mi (43.5 – km) reach of the Colorado River in Grand Canyon National Park, Arizona. The study reach begins at river mile 61.1, about 0.6 -mi (1 –km) above the confluence of the Colorado and Little Colorado Rivers and ends at river mile 88.1 at the upstream boundary of the Bright Angel Rapid (Phantom Ranch boat beach). Channel bathymetry was mapped using multibeam and singlebeam echosounders, subaerial topography was mapped using ground-based total-stations, and bed-sediment grain-size data were collected using an underwater digital microscope system. These data were combined to produce digital elevation models, spatially variable estimates of digital elevation model uncertainty, georeferenced grain-size data, and bed-sediment distribution maps. These data were created by the Southwest Biological Science Center, Grand Canyon Monitoring and Science Center as a component of a larger effort to monitor the status and trends of sand storage along the Colorado River in Grand Canyon National Park. This dataset is the hillshade generated from the 1-meter resolution digital elevation model (DEM_EGC_Apr2011.tif) associated with this data release.

Bathymetric, topographic, and grain-size data were collected in April 2011 along a 27-mi (43.5 – km) reach of the Colorado River in Grand Canyon National Park, Arizona. The study reach begins at river mile 61.1, about 0.6 -mi (1 –km) above the confluence of the Colorado and Little Colorado Rivers and ends at river mile 88.1 at the upstream boundary of the Bright Angel Rapid (Phantom Ranch boat beach). Channel bathymetry was mapped using multibeam and singlebeam echosounders, subaerial topography was mapped using ground-based total-stations, and bed-sediment grain-size data were collected using an underwater digital microscope system. These data were combined to produce digital elevation models, spatially variable estimates of digital elevation model uncertainty, georeferenced grain-size data, and bed-sediment distribution maps. These data were created by the Southwest Biological Science Center, Grand Canyon Monitoring and Science Center as a component of a larger effort to monitor the status and trends of sand storage along the Colorado River in Grand Canyon National Park. This dataset is a 1-meter resolution elevation uncertainty model generated by fuzzy inference system modeling associated from the 1-meter resolution digital elevation model (DEM_EGC_Apr2011.tif) associated with this data release.

Bathymetric, topographic, and grain-size data were collected in April 2011 along a 27-mi (43.5 – km) reach of the Colorado River in Grand Canyon National Park, Arizona. The study reach begins at river mile 61.1, about 0.6 -mi (1 –km) above the confluence of the Colorado and Little Colorado Rivers and ends at river mile 88.1 at the upstream boundary of the Bright Angel Rapid (Phantom Ranch boat beach). Channel bathymetry was mapped using multibeam and singlebeam echosounders, subaerial topography was mapped using ground-based total-stations, and bed-sediment grain-size data were collected using an underwater digital microscope system. These data were combined to produce digital elevation models, spatially variable estimates of digital elevation model uncertainty, georeferenced grain-size data, and bed-sediment distribution maps. These data were collected by the Southwest Biological Science Center, Grand Canyon Monitoring and Science Center as a component of a larger effort to monitor the status and trends of sand storage along the Colorado River in Grand Canyon National Park. This dataset is the bed sediment classification derived from multibeam sonar surveys.

These topographic/bathymetric digital elevation models (DEMs) were collected and compiled to characterize erosion and deposition in the Colorado River and in an adjacent zone of laterally recirculating flow (eddy) during both average flow conditions and during a controlled flood that occurred in March 2008. The objectives of the study were to measure changes sandbar morphology that occurred during changes in discharge associated with the controlled flood. These data were collected between February 6 and March 31, 2008 in a 1-mile study reach on the Colorado River within Grand Canyon National Park beginning 44.5 miles downstream from Lees Ferry, Arizona. These data were collected by the USGS Grand Canyon Monitoring and Research Center with cooperators from Northern Arizona University and funding provided by the Glen Canyon Dam Adaptive Management Program. All bathymetric data were collected with a multibeam sonar system (Reson Seabat 8124 sonar with TSS MAHRSS reference system for heave, pitch, roll, and heading). Topographic data were collected by conventional total station. These data can be used to study changes in channel morphology associated with changes in streamflow conditions.

These data were compiled to visualize the extent of Lake Powell at various elevation levels. These data represent water surface elevations for Lake Powell at levels critical to the operation of Glen Canyon Dam, at 5 foot intervals from the "Equalization Tier" ("Full Pool") to "Dead Pool", and at maximum and minimum elevations each water year throughout Glen Canyon Dam's operating history. These data were created for Lake Powell in Arizona and Utah. These data were created by the U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon Monitoring & Research Center by reclassifying "Modified topobathymetric elevation data for Lake Powell" (Jones and Root, 2021) at discrete elevation levels and converting them into vector format. These data can be used to visualize locations or resources in Lake Powell at various elevation levels as it continues to change.

The horizontal accuracy assessment dataset consists of spatial coordinate and elevation values of “hard points” identified in each digital surface model (DSM) dataset and their spatial location data from the geodetic control network maintained by the U.S. Geological Survey (USGS), Grand Canyon Monitoring and Research Center (GCMRC). Surveyed “hard points” represent stationary natural features, such as corners of large boulders, that are visible in aerial imagery and elevation datasets and are in the geodetic control network maintained by the USGS, GCMRC. The vertical accuracy assessment dataset consists of pixel elevation values extracted from the DSM and digital elevation model (DEM) datasets for 926 “control points”. Surveyed "control points" represent survey marks and benchmarks in the geodetic control network maintained by the USGS, GCMRC. Each “hard point” and control point is denoted by a unique identifier from the Grand Canyon survey control network database maintained by the USGS, GCMRC. All point location are denoted by the distance upstream or downstream along the river channel from Lees Ferry, AZ. The temporal extent of the data is for the years 2002, 2009, 2013, and 2021, and the spatial extent is for the segment of the Colorado River riparian corridor from Glen Canyon Dam downstream to Pearce Ferry, AZ.

The 2021 Digital Elevation Model (DEM) dataset consists of single band rasters at 1-meter pixel resolution that were generated to orthorectify four band ortho imagery acquisition, and to support development of additional GIS products. Each pixel represents the elevation of the ground surface at that point expressed as NAD83(2011) ellipsoid height. A Digital Surface Model (DSM) was generated by automatic correlation of stereoscopic imagery collected from approximately 8,000 ft to 11,000 ft above mean sea level at 20-cm resolution with one Leica ADS100 digital push-broom multi-spectral sensor on each of two aircraft May 29, 2021 – June 4, 2021. The DEM was generated by removing the aboveground features from the DSM by filtering process. Data were collected during a period of low steady river flow of approximately 8,000 cubic feet per second released from Glen Canyon Dam. The data are for the segment of the Colorado River corridor from Glen Canyon Dam downstream to Pearce Ferry, AZ.

These datasets consist of four, 1-meter spatial resolution digital surface models (DSMs) that were generated to orthorectify airborne multispectral imagery acquired in 2002, 2009, 2013, and 2021 for the Colorado River in Grand Canyon in Arizona, USA. These datasets also consist of a 1-meter spatial resolution digital elevation model (DEM) that was generated from the 2021 DSM. The DSMs and DEM were also produced to support development of additional GIS products. Elevation values are expressed as ellipsoid heights. These datasets also include accuracy assessments that were performed to show the limitations of estimating elevation from the DSMs and DEM pixels locations on the landscape. Data were acquired during periods of low steady Colorado River flow of approximately 8,000 cubic feet per second released from Glen Canyon Dam.

The 2002 Digital Surface Model (DSM) dataset consists of single band rasters at 1-meter pixel resolution that were generated to orthorectify a four band ortho imagery acquisition, and to support development of additional GIS products. Each pixel represents the elevation of the surface at that point expressed as NAD83 ellipsoid height. The DSM is a reflective surface DSM which provides elevation data on open ground (e.g. bare soil, rocks, and water), as well as aboveground terrain features including buildings, trees, and vegetation that cover otherwise open ground. The Digital Surface Model (DSM) was generated by automatic correlation of stereoscopic imagery collected from a flight altitude of approximately 17,000 feet above river level (approximately 18,000 to 21,000 feet above mean sea level) at 22-cm resolution with a HRSC-AX push-broom sensor May 24 through June 5, 2002. Data were collected during a period of low steady flow of approximately 8,000 cubic feet per second released from Glen Canyon Dam. The data are for the segment of the Colorado River riparian corridor from Glen Canyon Dam downstream to Pearce Ferry, AZ.

The dataset is a digital elevation model (DEM), in GeoTiff format, of the bathymetric surface of Blue Mountain Lake, Arkansas, within the extent of pool elevation 420 feet (ft) above the North American Vertical Datum of 1988 (NAVD88). The DEM was derived from a terrain dataset created by merging bare earth point data from an aerial LiDAR survey conducted in December 2010 for the U.S. Army Corps of Engineers (USACE), Little Rock District, with point data from a bathymetric survey conducted in May 2017 by the Lower Mississippi-Gulf Water Science Center of the U.S. Geological Survey (USGS) using methodology similar to that described by Wilson and Richards (2006).