Formation, Evolution and Morphology of Floodplains of Rivers with a Branched Channel

The floodplains of branched rivers are diverse, but the fundamental mechanism of their formation is similar. The formation of branches is associated with the division of the river stream into several flows and the formation of mid-channel sediment bars in the accumulation zones between the dynamic axes of the flow, which, when drying out in low water, are fixed by vegetation and turn into elementary floodplain islands. The channels between the elementary islands become shallow and drift over time; a consolidated island massif appears, which, when one of the river branches dies off, joins the shore. The former islands become wide elevations with a relatively flat surface, and the channels become hollows of various sizes. The morphological appearance of floodplains of rivers with branched channels is diverse, since the relief and linear dimensions of its elements, the number and characteristics of former channels and branches between islands, and the landscape structure depend on the structure and morphology of the branches, their transformations, the water runoff and hydrological regime of the river, and anthropogenic influences. The article examines the morphology, formation and evolution of floodplains in the valleys of branched rivers, and characterizes their main types.