Field measurements of water depth from the American River near Fair Oaks, CA, October 19-21, 2020

Field measurements of water depth were acquired from a reach of the American River at Sailor Bar, near Fair Oaks, California, October 19-21, 2020, to support research on remote sensing of water depth from satellite images. The depth measurements included in this data release were obtained via two different methods: 1) By wading the shallow channel margins with RTK GPS receivers and measuring water surface elevations along the water's edge and bed elevations within the channel; depths were calculated by subtracting bed elevations from the nearest water surface elevation. 2) For the deeper areas representing most of the channel, depths were recorded along a series of cross-sections by a SonTek RiverSurveyor S5 acoustic Doppler current profiler (ADCP) and a SonarMite single beam echo sounder deployed from a boat. The spatial location of each measurement was obtained via Trimble R10 RTK GPS receivers. The map projection and datum for these data are UTM Zone 10 N and WGS84, respectively. The ADCP- and echo sounder-based depth measurements were cross-calibrated to one another using collocated observations from the two instruments and then combined with the wading measurements for the purposes of this data release, which consists of a comma-delimited (*.csv) text file with three columns: Easting_m, Northing_m, and Depth_m; the units of the spatial coordinates and the depths are meters. This ground-based depth data set was used to calibrate (i.e., train) models for inferring water depths from passive optical image data and to assess the accuracy of image-derived depth estimates.