SAND MOVEMENT AND LONG-TERM BEACH EVOLUTION IN A FLUVIAL SYSTEM COMPOSED OF THE SAMEGAWA RIVER AND THE NAKOSO COAST.

A field investigation on sediment movement and beach evolution was performed in a fluvial system composed of the Samegawa River and the Nakoso coast, which experienced significant beach erosion recently. Analyses of regional sand volume in the system revealed that the rate of decrease in nearshore sand on the beach is of the same order as the rate of accumulation of sand in dam reservoirs. Dredging of the riverbed near the river mouth also influenced nearby shoreline retreat. Long-term changes in sand movement processes were estimated from the distribution of mineral composition included in the sediment samples collected in a wide area. [ABSTRACT FROM AUTHOR]