Meandering probably develops because of imbalanced energy loss along a stream channel caused by water flow over pool sand riffles. The shallower parts that may break the surface are the riffles, which are characterized by by their shallowness, their symmetrical shape, their coarser bed material, and their being slightly wider then the pools. Pools are deeper portions of the river bed, they are associated with an asymmetrical portion and a finer river bed material. The same discharge of water has to get through the areas with larger (pool) and smaller (riffle) cross-sectional areas. Thus, the water velocity increases from pool to riffle. The meandering moves in two direction, they erode both laterally and migrate downstream. These two motions, and the increasing velocity, result in widening the stream’s valley and creating an extensive floodplain (the flat, low lying ground on either side of the stream channel that is inundated during periods of larger discharges. This picture is of my wife Jessica overlooking a meandering river.
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