Channel Mapping of the Colorado River in Grand Canyon National Park, Arizona - April 2019, river miles 30 to 88

Bathymetric, topographic, and grain-size data were collected in April 2019 along a 58.6 mile (94.3 kilometer) reach of the Colorado River in Grand Canyon National Park, Arizona. The study reach begins at river mile 30, about 2.5 miles above South Canyon, and ends at river mile 88 at the upstream boundary of the Bright Angel Rapid (Phantom Ranch boat beach). This reach spans two previously surveyed reaches that we term Lower Marble Canyon (LMC) and Eastern Grand Canyon (EGC). This data release splits the 2019 surveys into two separate DEMs to match the previous surveys, even though they were collected in one campaign. Channel bathymetry was mapped using multibeam echosounders, subaerial topography was mapped using ground-based total-stations. These data were combined to produce digital elevation models. 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.