identification of groundwater recharge and nitrate pollution in the Kanegawa alluvial fan of the Kofu Basin, Japan, using stable isotopes and ions

Abstract

Major ions and stable isotopic measurements were utilized in order to investigate the groundwater recharge and nitrate pollutant transformation of shallow alluvial groundwater aquifer. The spatial distribution and multivariate analysis of ions, combined with stable isotope analysis were performed. The result showed that precipitation contributed to the whole year groundwater recharge. Pollutants were transported from the land surface through an infiltration of precipitation. Sources of nitrate are from ammonium fertilizer, manure and septic waste. According to the ion and isotope characteristics, both denitrification and mixing process could take place. The statistical correlation and cluster analysis coupled by spatial analysis approach, based on isotope and ion data could be utilized for a quick assessment of groundwater recharge and nitrate pollution dynamics in an alluvial fan.