EFFECT OF GRAVEL BAR SHAPE AND SUBSTRATE STRUCTURE ON THE DISTRIBUTION CHARACTERISTIC AND STABILITY OF VEGETATION AREA

Abstract

The mainstream during flood concentrates specific place in river channel, due to the shape of gravel bars. Thus we consider the bar shape is an important factor to influence the stability of gravel bar and the vegetation on it. We selected Kinu River and Asa River as our target rivers. By conducting field measurement and analyzing aerial photograph and periodic vegetation observation data, we got results as follow. 1. The difference of river scale effects morphology transition of braided channel. The large scale river like Kinu River transit to low model numbers braided channel, but small scale river like Asa River transit to alternate bars. 2. Low model numbers braided channel creates more stable vegetation area on gravel bars 3. Inducing mainstream to flow on gravel bars is an efficient way to disturb stable vegetation area which in the relatively high location.