Seed entrainment

Hello! I am working on a problem to resolve the balance

of forces on a seed (very small and disc shape) that is being

'captured' on the stream bank. The density of the seed is less than

water thus it is buoyant (making the problem different than sediment

deposition theory). I am assuming that the water is receding and the

capture of the seed is the result of friction forces overcoming the

pull force of the water. Would it be better to resolve this by thiking in

terms of Net force= driving force/resisting force or solving the shear forces?

Also, would surface tension or drag forces have to be considered?

Any thoughts would be greatly appreciate or literature suggestions!