Conventional orders of water streams on sites of braided channels

For conditions of the moderate and increased moistening of river basins it is shown that the treelike structure of water channels network causes gradual or spasmodic increase of the main river water runoff. There are violations of this regularity on sites of river and estuary branching. Processes of drain concentration are interrupted owing to channel bifurcation on rather short sites of river valleys. They become irreversible on sites of branched estuaries. Branching is characteristic for 17-35% of rivers extent of Northern Eurasia. On certain large rivers this morphody-namic type of the channel is up to 70% of their length. Research of water channels structure on branched sites of rivers is made. For this purpose information on 120 branched sites of 40 rivers of Russia, and on branching of river mouths in the South and the North of Russia is generalized. Possibility of formalization of water streams structure on sites of braided channels is studied. The concept of conventional orders for determination of the relative sizes of branches in channel and estuary forks is offered. The justification of determination method of branches conventional orders depending on their water content is given. It is established that information on the size of branchings conventional orders creates preconditions for their comparison by relative sizes, for determination of traction load runoff by parameters of ridges, for assessment of washout rate of concave banks of bends, for solutions of other applied and theoretical hydrologi-cal tasks. On this basis the criterion of similarity of dispersion conditions of river runoff on waterways on sites of braided channels is received and its ranges of change corresponding to weak, moderate, strong and exclusively strong variants of development of this process are specified. Processing of natural information showed that the size of similarity criterion changes in the range from 0.05 to 0.8 and depends on type of branching. More than 75% of single forks are characterized by weak dispersal of water runoff, complex single forks and systems of connected forks are distinguished by moderate dispersal of drain. Intense dispersal of water runoff is characteristic for inundated-channel forks of semi-mountain rivers, and also for parallel and branch forks of big plain streams. Research of channel branching functions leads to studying of transformation regularities making a river runoff on multichannel sites of rivers, a condition of marginal effect features studying in mouth areas of the rivers. The concept of conventional orders now is the only opportunity for the description of topological properties of water currents network on sites of channel and estuary branching, and the analysis of large-scale effects of material streams change within their limits.

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