This App can calculate the threshold when erosion will occur in a river or the hopper of a dredger, given certain circumstances.
Furthermore it can also calculate the minimal grain size a particle must have to stay on the sand bed.
In the calculation the Soulsby and Whitehouse erosion line is presented in a Shields Parker diagram with the various thresholds for suspension, deposition and a flat bed.
The diagram is plotted for the different flow conditions so results can be directly interpreted from the graph.