Provenance & quality
Data were collected to provide information on spatial patterns of dune migration rates and associated flow characteristics, at locations on the South Saskatchewan River, Canada. Dune migration rates were measured using repeat aerial imagery with flight lines completed on a grid pattern with 80% lateral and longitudinal overlap between images. Orthomosaics were constructed from these images using the SfM program Pix4D (https://pix4d.com/). Multiple flights were flown at 1 hour intervals (maximum of five epochs in a day) to allow tracking of bedforms. Image Ground Sampling Distance (GSD) was typically 0.025–0.03 m. Bedform crests were digitised in individual images, and average dune migration rates were calculated from the mean migration distance between image pairs, divided by the time between image collection. Data were collected on 12th June 2017.
Water depth and velocity data were collected using a Sontek M9 acoustic Doppler current profiler (aDcp) mounted on a small zodiac boat. The position of the aDcp was recorded using a RTK dGPS system. Velocities are calculated relative to the instrument head and are corrected using the dGPS calculated boat speed and heading. The aDcp data were collected in pulse coherent mode, averaging 7 pings per second, and were averaged to 1 Hz to improve the signal-to-noise ratio. The M9 uses 9 transducers at frequencies between 0.5 and 3.0 MHz. Data were collected along cross-sections of the river that extended between both banks and were aligned approximately perpendicular to the downstream flow direction.