階段状河床波上における流砂機構

Abstract

Step-pool bed forms are usual in mountain streams and play an important role in sedimenttransport phenomena. The present study discusses the transporting process of sediment particleson a step-pool system. In additions, theoretical, experimental discussions are made on the de-sruption condition of bed with step-pool system as well as on sediment transports in formative, deformative processes of such a bed form.A mathematical model which calculates the sediment transport rate in time and space isdeveloped, using an idea such as coverage rate or storage rate by sediment particles to be trans-ported on the armoured bed of step-pool system. The results simulated by the model agree wellwith those from flume experiments.The stable step-pool bed form begins to deform and the destruction occurs as soon as alargest particle composing the step sets in motion. A method to predict the critical dischargeabove which the destruction occurs is proposed. The critical discharges calculated by the methodare compared well with data from flume experiments.