Abstract
A field investigation on sediment movement and beach evolution was performed in an alluvial system composed of the Same river and the Nakoso coast, Fukushima prefecture, which experienced significant beach erosion recently. Analyses on sand volume in the system revealed that the rate of decrease in sand on the beach is of the same order of the rate of accretion of sand in dam reservoirs and that the dredging of river bed near the rivermouth influenced nearby shoreline retreat. Sand movement processes were estimated from the distribution of mineral composition included in the sediment samples collected from the beach.
