Supplementary data confirming the relationship between critical Shields stress, grain size and bed slope

This article presents new experimental data on threshold conditions for motion of coarse uniform sediments. The experiments were conducted with 2.8 mm gravel in a 7.5 m long by 0.3 m wide flume and included measurements of hydraulic characteristics and rate of bed particle movement for a range of flows at different bed slopes. A reference transport method was used to define the beginning of sediment motion. Results from experiments with glass balls (diameters 6 and 9 mm) and coarse uniform gravels (17.5 and 38.6 mm) conducted by other researchers were used as an additional independent data set. The experimental data confirm the recent finding that the critical Shields stress for motion of coarse uniform sediment varies with both grain size and bed slope. Copyright © 2007 John Wiley & Sons, Ltd.