TEMPORAL AND SPATIAL VARIATION CHARACTERISTICS OF BRAIDED STREAMS

Temporal and spatial variation characteristics of braided streams between straight confining walls are studied by means of flume experiments and numerical simulations. Results are summarized as follows.(1) The number of streams produced in a straight channel depends on the width-depth ratio; the number of streams increases with the width-depth ratio.(2) The geometry of streams shows self-similar characteristics which suggests the possibility that the streams promote restoration of natural riverine ecosystem.(3) Small-scale bed geometry significantly affects the formation of large-scale bed geometry. In addition, stabilization mechanism of bars is discussed focusing on unsteadiness of flow and growth of vegetation. The results suggest that decrease of maximum water discharge promotes bar stabilization.