ASSESSMENT OF RIVER ENVIRONMENT BASED ON RIVERBED SEDIMENT IN THE FIRST CLASS RIVERS OF CHUGOKU DISTRICT

Abstract

A new assessment of river environment using the riverbed sediment is proposed in this study. Field observations for riverbed sediment, water quality and river plant were conducted at 4~12 points in the ten first-class rivers of Chugoku District.As a result, there isn't any significant correlation relationship among the water quality, the stable isotope ratios of nitrogen (δ¹⁵ N) in the sediments and in the river plant.However, δ¹⁵ N in the riverbed sediments have a clear relation with the amount of nitrogen load from the catchment which is estimated using GIS analysis. This result indicates that the δ¹⁵ N in the sediments can be an indicator of the river environment.