Entire catchment and buffer zone approaches to modeling linkage between river water quality and land cover - A case study of Yamaguchi Prefecture, Japan

This study investigated the linkages between river water quality and land use in river catchments in Yamaguchi Prefecture, the western Japan, in order to examine the effect of land use changes of both entire catchment and buffer zone on river water quality. Dissolved Oxygen (DO), pH, Biological Oxygen Demand (BOD), Suspended Solids (SS), Escherichia coli, Total Nitrogen (TN) and Total Phosphor-us (TP) were considered as river water quality indicators. Satellite images were applied to generating the land use map. Multiple regression model was applied to linking the changes in the river water quality with the land uses in both entire catchment area and buffer zone. The results indicate that the integrative application of land use data from the entire catchment and the buffer zone could give rise to more robust model to predict the concentrations of Suspended Solids (r(2)=0.88) and Total Nitrogen (r(2)=0.90), rather than models which separately considered land use data in catchment and buffer zone.