Longitudinal Hydrophone Profile Data on the Upper Colorado River, Colorado, June 18 to 19, 2019

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 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 and June 18-19, 2019 (June 18-19 longitudinal profile). 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. For the June 18-19 longitudinal profile, a mobile hydrophone system, consisting of two H2a-XLR hydrophones (Aquarian Audio, 2013) and a recording system, was attached to a 16-foot Hyside inflatable raft and mounted about 1 foot below the water line (one on the port side of the raft and the second the starboard side of the raft).