Cross-Section Geometry at Two Bridges over the Gunnison River in Western Colorado, 2016-17

This dataset contains cross-section surveys of the Gunnison River at Colorado Department of Transportation bridges I-04-K and I-03-A, western Colorado, 2016-17. The surveys were performed using a combination of: Trimble R8 Real-Time Kinematic Global Navigation Satellite System (RTK-GNSS) receiver, a USGS bridge crane with sounding weights, and optical levels. During surveys performed in 2016, a base was established at each bridge using the RTK-GNSS equipment. Subsequent surveys of channel geometry were performed using optical levels for ground surface observations above the water line and sounding weights for streambed observations below the water line, referenced to the base established in 2016. Streambed elevations were interpolated at 10 foot intervals between the measured points for both bridges because measured elevations were not always obtained at the exact same stationing from 2016 to 2017. Additionally, streambed elevations were interpolated at 5 foot intervals for stations within 20 feet of either side of the monitored piers. Stationing and elevation data are presented in the .CSV files, with one file for each bridge. Discussion of these data is presented in Henneberg (2018) USGS Scientific Investigations Report, Real-Time Streambed Scour Monitoring at Two Bridges over the Gunnison River in Western Colorado, 2016-17." These data were collected in cooperation with the Colorado Department of Transportation.