Acoustic, Spatial, and Sediment Size Data Collected on the Upper Colorado River to Estimate the Flushing Flows, Colorado, 2019

In 2019, the U.S. Geological Survey, in cooperation with the Upper Colorado River Wild and Scenic Stakeholder Group, studied the magnitude and frequency of streamflow needed to initiate bedload transport of gravel-sized and finer sediment on the Colorado River to maintain spawning habitat for fish and maintain substrate and interstitial spaces for benthic macroinvertebrates. Bedload transport occurs more frequently and at lower streamflows downstream from State Bridge compared to the study area upstream from State Bridge. Two independent, yet complementary, lines of evidence were collected to determine the presence of bedload transport. Two stationary hydrophone systems were installed on April 23, 2019 at the above Catamount Bridge site and two others on April 24, 2019 at the Radium site. These four systems monitored bedload transport until all the stationary hydrophone systems were removed on August 26, 2019. These provided continuous temporal data on the presence of bedload transport at four stationary locations. Two longitudinal profiles were carried out at different streamflows which collected hydrophone data 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, CO. The June 18-19 longitudinal profile began at the Pumphouse Recreation Area and ended at the Catamount Bridge boat launch which is at the Catamount streamgage.