Abstract
Field survey and numerical simulation of the river flow near the habitat of Anaphalis Margaritacea community established on a gravel bar in mid reach of Ibogawa River in Hyogo Prefecture, Japan, have been conducted in order to study the characteristics of the morphological and hydraulic characteristics associated with maintenance mechanism of communities of this rare species that is indicative of well-balanced riparian environment. The riffle around a sharp bend with well-developed gravel bar appears the most important factor required of the maintenance of the community. Large boulders on the outer bank and low vegetation upstream and inner bank are found to be additional features that appear to help moderate the bed shear stress at the locations of the habitat during heavy floods of long recurrence frequency.
