Author(s): Masayoshi Kitagawa; Yasuo Nihei; Wataru Harada
Linked Author(s):
Keywords: Pollutant load; Groundwater; Nitrogen; Lake Inba-numa; Plowed field
Abstract: Nitrogen contamination in rural rivers may be caused by the pollutant load from plowed fields with excessive fertilization through groundwater. However, there have not been sufficient investigations on discharge and pollutant load of groundwater into rivers. We conducted field measurements to clarify the discharge and nitrogen flux of groundwater into the Takasakigawa River, which flows into Lake Inba-numa and contains nitrogen contamination. The results indicated that: 1) the nitrate concentration of groundwater was mostly higher than that of river water and 2) discharge and nitrate flux of groundwater into the river were 73～92% , and 81～95% , respectively, in the observed 1. 4-km stretch of river. 3) The source of the groundwater flowing into the Takasakigawa River is discussed using water quality data of groundwater in its catchment area.
Year: 2013