bedforms

In hydrology, forms such as ripples and hollows moulded on a river bed by a flow of water. Bedforms range in size from ripples in the sand, a few centimetres apart, to ‘dunes’ tens of metres in length.

Bedforms appear to develop further as stream power increases. Initially, the bed is flat; the plane bed. With an increasing discharge, small ripples form and develop into dunes. There follows a transitional zone with a plane bed again. With further increases in discharge, standing waves are set up in the water, creating dunes and anti-dunes. Additionally, the pattern of bedforms has an effect upon the river flow.