WATER QUALITY VARIATION OF CONFINED GROUNDWATER AND BRANCH RIVER IN OTA RIVER

Abstract

 Variation of groundwater level and quality in the Ota River delta are affected by sea water and continental groundwater. To understand water circulation between river water and groundwater, variation factors of groundwater level and quality was discussed since 1970 to 2010. Moreover, variation of river water quality varied with groundwater level variation.

 Storage/discharge of unconfined groundwater is determined by water level difference between sea water and unconfined groundwater lelvel. River salinity and temperature in the long-term and seasonally corresponding to storage/discharge of unconfined groundwater. Moreover, the variation was also suggested to be associated with fish catches of Corbicula Japonica.