Dear Velusamy Gobinath, 

That depends largely on what kind of erosion you are interested in. If you are speaking about a sand bed, I assume slope of the bed, water flow and water depth will be the most important parameters that explains your erosion over time. Especially if you are going to use it in a model, the required parameters should be given/asked by that model.

If you mean surface erosion the main parameter is the critical shear stress (Shileld's formulation) expressed through the critical flow velocity. But also, size distribution and grain shape are of interrest.

Dear Velusamy Gobinath, 

As it was explained by Mr Jeroen ;I think the slope, the flow and the depth of the water are the most important parameters.

Grain size; Grain shape - rounded or irregular & sharp edges; slope of the river bed; depth & velocity of the river water are the factors which control the erosion of sand bed.

In Addition to the answers already presented, I would recommend you to refer to one of the plenty number of the books on sediment trasnport to have an idea of fundamental processes on the Sediment Transport. There you will find also topics on armouring effect, ripples and dunes and so on.

One useful book might be :

García, M.H. (Editor-in-Chief), Manual of Engineering Practice 110, “Sedimentation Engineering,” Environmental and Water Resources Institute (EWRI), American Society of Civil Engineers (ASCE), 2008, 1150p.

Dear Velusamy

I think the physical properties of the filtration media plays a significant role in this type of studies along with what Mr. Bemanar mentioned

Best regards and good luck with your study

Not only a slope of the bed, water flow , water depth and also a strength of riparian is also one the parameters.