In 2019, the U.S. Geological Survey (USGS), in cooperation with the Upper Colorado River Wild and Scenic Stakeholder Group, studied the magnitude and recurrence interval of streamflow needed to initiate bed movement of gravel-sized and finer sediment in a segment of the Colorado River in Colorado to better understand sediment movement and its relation to flow regimes of the river. Bed movement occurred more frequently and at lower streamflows from State Bridge to Catamount Bridge compared to the study area upstream from State Bridge. Two independent and complementary lines of evidence were collected to detect incipient bed movement. Two stationary hydrophone systems were installed on April 23, 2019 at the above Catamount Bridge stationary hydrophone site, and two were installed on April 24, 2019 at the Radium stationary hydrophone site. These four systems recorded underwater sounds related to bed movement until all the stationary hydrophone systems were removed on August 26, 2019. Two longitudinal hydrophone profiles were carried out at different streamflows to collect underwater acoustic data using hydrophones throughout the study area on June 6-8, 2019 (June 6-8 longitudinal profile) and June 18-19, 2019 (June 18-19 longitudinal profile). The June 6-8 longitudinal profile began at the Pumphouse Recreation Area and ended at the Dotsero boat launch located at Dotsero, Colo. The June 18-19 longitudinal profile began at the Pumphouse Recreation Area and ended at the Catamount Bridge boat launch located at the USGS streamgage 09060799 Colorado River at Catamount Bridge, Colo. Pebble counts of coarse surface particles were performed in the wadeable areas adjacent to the stationary hydrophones to provide general estimates of the size of the material that could be mobilized and recorded near the hydrophones.