Laboratory data of bed topography, grain size, water depth and flow velocity along alternate bars

Experiments performed in a 24-meter-long flume with fixed straight and fixed banks, with erodible bed composed by a mixture of sediments. In each experiment, water discharge Q is kept fixed. Sediment supply is adjusted to maintain overall equilibrium with the initial channel slope S=1%. All data refer to the final equilibrium state.

Two experimental series:

• MW40: channel width W=40 cm, mean grain size 1.22 mm
• MW60: channel width W=60 cm, mean grain size 1.29 mm

Five types of products (geotiff format, spatial resolution 0.5x0.5 mm):

• Ortophotos (RGB), obtained from Structure-from-Motion photogrammetry
• Elevation model (DEM) [m], obtained from Structure-from-Motion photogrammetry
• Grain size maps (d50) [mm], obtained from image analysis
• Water depth maps (depth) [m], obtained from 2-D shallow water simulations
• Shear stress maps (tau) [Pa], obtained from 2-D shallow water simulations
• Water velocity field (velocity) [m/s], obtained from 2-D shallow water simulations

File "Grain_size_samples.csv" contains data on the 24 sediment samples used to calibrate the method for automated grain size extraction from images.

For details see: Redolfi, M., Ragno, N., Welber, M., & Bertoldi, W. (2025). Grain size sorting and steady bars formation in straight channels - Part 1. Laboratory experiments. Journal of Geophysical Research: Earth Surface (submitted).

The laboratory experiments were supported by the project GLORI, funded by the Autonomous Province of Bolzano-Bozen. We thank Francesco Boeri, Michele Portogallo and the staff of the Hydraulic Laboratory for their help in the execution of the experiments.