Subsurface flow contributes considerably to river flow and plays an important role in river sediment loads. This research has been focused on investigation of soil properties and bankstream slope on seepage erosion. For this purpose a series of lysimeter experiments were performed for four different slopes of bankstream by varying the soil grain sizes. The obtained results indicate that Reynolds number in porous medium plays an effective role in depth of scour hole in noncohesive layer. It was observed that the time of beginning of sediment motion decreases with an increase in the soil grain size.