Relationship between Spring Water Quality and Land Use Type in a Small Area

Abstract

The influence of different land use types on groundwater was evaluated on the basis of the relationship between the annual water quality fluctuation and the content of stable NO₃^- isotopes in winter in five spring water samples collected from a river terrace. The compositions of two spring water samples from the edge of the terrace with forested land use on the upstream side were very similar and were not affected by anthropogenic activity. Spring water collected from the terrace surface near a paddy field was influenced by ammonium sulfate, but contained low concentrations of NO₃-N. The quality of spring water from a terrace site surrounded by agricultural land (a vegetable field) suggested the influence of chemical fertilizers, such as magnesian lime and ammonium chloride. In spring water from a terrace site where a poultry farming facility and residential area were located, the concentration of N derived from organic matter and the K⁺, Na⁺, and Cl^- ion contents were high. This pollution from domestic drainage is a cause of concern.