Abstract
Dynamic characteristics of braided streams formed on beds with non -uniform sediment are discussed by means of numerical analysis. Results are summarized as follows.(1) Sedime nt particles are exchanged to fine ones in dry bed regions and coarse in streams, respectively, under steady flow conditions, whereas, under unsteady flow conditions, mean diameter in trough increases in the rising stage of water discharge and decreases in the falling stage.(2) If the frequency with which water covers bars decreases by reducing peak flood discharge, vegetation growth will be promoted. Furthermore, vegetation suppresses the development of small streams and grows large streams.(3) If huge amount of sediment is excavated artificially, number of streams will decrease with eroding bed in main streams.
