非定常流中のウォッシュロードの堆積とそれに伴う川幅縮小過程

抄録

Stable channel is realized through the process of (1) channel widening caused by a bank erosion, and (2) channel narrowing by a sediment deposition on a bank. The mechanics of the latter process is studied in the present paper. The deposited sediment in natural rivers is reported to be a very fine sand or silt transported as washload. So an idealized flume experiment together with a numerical computation were conducted in a steady or unsteady flow over a gravel bed with a fine sediment as washload. As a result, the deposition occurs around a water margin without any effect of vegitation by a significant amount in an unsteady flow but by an extremely small amount in a steay flow.