STUDY ON EROSION CHARACTERISTICS AT EXPOSED RIVER BED ON MUDSTONE/ALLUVIAL COHESIVE SOIL LAYER IN LOWER REACHES OF THE KINUGAWA RIVER USING A HIGH-RESOLUTION SIDE SCAN IMAGING WITH BATHYMETRY

Abstract

Recently unprecedentedly rapid riverbed degradations are observed at several parts of exposed river channels on mudstone/alluvial cohesive soil layer in lower reaches of the Kinugawa River. This has induced various problems upon river management.

In this report, the erosion characteristics of exposed riverbed of mudstone/alluvial cohesive soil layers was studied to elucidate riverbed degradations mechanism at the exposed river channels. Existing periodic cross-sectional survey could not measure the surface topographical structure and substance of the riverbed, therefore a high-resolution side scan imaging bathymetry were applied to enable the measurement in this study.