ESTIMATION OF GROUNDWATER FLOW SYSTEM IN THE KUROBE RIVER BASIN BASED ON GROUNDWATER LEVEL AND WATER QUALITY OBSERVATIONS

Abstract

 The purpose of this study is to clarify current situation and the long-term change of the groundwater environment in the Kurobe River alluvial fan (KRAF). The groundwater level and water quality observations in the KRAF were carried out in 2012 and 2013. This study compared the results between the field observation in 2012, 2013 and in 1990 and 2002. As a result of the field observation in 2013, groundwater level in February (winter) was approximately 2-5 m lower than that in August (summer) in whole alluvial fan because there were no irrigation water in the paddy and the discharge of the Kurobe River was too small. It is clarified that the KRAF has three different groundwater flow systems. As groundwater level, EC, water temperature, pH and ion components in 2012 and 2013 were compared between the observation in 1990 and in 2002, there were not large difference. Thus, the groundwater environment has been changed in the past 23 years in the KRAF.