The US Geological Survey is offering a funding opportunity to a CESU partner for research on the classification of riverbed substrate for the Colorado River in Grand Canyon. Scientists at the U.S. Geological Survey’s (USGS) Southwest Biological Science Center, Grand Canyon Monitoring and Research Center (GCMRC) conduct a range of studies on the Colorado River in Grand Canyon that are used to inform U.S. Department of the Interior decisions about management of the Colorado River and Glen Canyon Dam. Many of those studies involve characterizing the riverbed and monitoring erosion and deposition of river sediments. These studies involve mapping river bathymetry with high-resolution multibeam sonar to develop detailed bathymetric maps of riverbed elevation. The acoustic backscatter that is simultaneously collected during these measurements may be used to map riverbed subtrate composition, but processing these data requires application of advanced machine learning methods. Methods and a workflow for processing these data have been developed by USGS scientists and cooperators over a period of many years. This opportunity seeks collaboration in adapting and applying the latest machine learning tools for riverbed substrate classification to existing datasets collected by GCMRC. This opportunity will also involve analysis of the resulting substrate classifications in relation to geomorphic characteristics of the Colorado River in Grand Canyon.