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 stationary hydrophone systems were installed on April 23, 2019 at the above Catamount Bridge stationary hydrophone site (above Catamount Bridge site), and two were installed on April 24, 2019 at the Radium stationary hydrophone site (Radium site). These four systems recorded underwater sounds related to bed movement until all the stationary hydrophone systems were removed on August 26, 2019. The upstream location and downstream location at the Radium site were located on the right streambank 400 feet (ft) and 2,000 ft downstream from the Grand County Road 11 Bridge, respectively. The upstream location and downstream location at the above Catamount Bridge site were located on the right streambank 16,800 ft (3.2 miles) and 18,200 ft (3.4 miles) upstream from the Catamount Bridge, respectively. At each of the four monitoring reach locations (an upstream and downstream location at both sites), a stationary hydrophone system with two Aquarian H2a-XLR hydrophones and one recording computer was deployed. The stationary hydrophone systems were programmed to collect a 1-minute audio recording at 15-minute intervals, which is equivalent to the time stamp of the stage and streamflow data collected at the streamgages in the study area (USGS streamgage 09058000 Colorado River near Kremmling, Colo. and USGS streamgage 09060799 Colorado River at Catamount Bridge, Colo.). The audio data were recorded as 44.1 kilohertz, 16-bit stereo (2-channel) .wav files for 1 minute at 15-minute intervals. Debris was found on the hydrophones during each routine servicing, which caused nonsediment background noise in the recordings.