Morphological diversity of channel patterns of braided rivers

Abstract

The paper presents the description of main channel types of braided rivers distinguished in the channel pattern classification produced in the Moscow State University. It is shown that the diversity of braided channels is determined by various conditions of their formation, different degree of channel stability and other factors. This diversity is defined by the number, size and shape of islands, formation of islands in channel arms, composing bifurcations of the 2nd and 3rd orders, presence of floodplain branches (floodplain multi-channel), symmetry or asymmetry of braided reaches themselves, development of the bends of the branches, water discharge of the branches and distribution of runoff over them in different phases of water regime, high- and low-water years, etc. Also braided channel reaches occur when cut-off meanders are formed (incomplete meandering). On the largest rivers there are braided reaches which are characterized by the development of branches in different parts of the river valley bottom and differing in their channel and even water regime. Certain features are typical for braided reaches of wide-floodplain or incised channels, for rivers with a one-sided floodplain. As a result single, conjugated, floodplain, parallel branches, one-sided, alternate one-sided braided reaches can be either simple (for example, single or parts of conjugated formed by one island) or complex, and the latter are represented by several varieties. The identification of various morphological types, subtypes and varieties of braided channel reaches is directly connected and determines the methods of channel processes management in water economy and water transport development of rivers, construction of communications through rivers, etc.