Hydrological Effects on Relationships Between [delta]15N of River Nitrate and Land Use in a Rural River Basin, Western Japan

This study aimed to examine how the relationship between [delta]15N of nitrate ([delta]15NNO3) in rivers and land use within a river basin changes with varying hydrological conditions. This information would aid in identifying the dominant source contributing to increased nitrate concentrations in rural rivers. For this, [delta]15NNO3 in river water was investigated monthly in the five subbasins of the Hii River basin (area: 911km2), western Japan, for 1year and 3months. There were significant correlations (p