太田川デルタにおける河川と沿岸帯水層での水循環

抄録

The characteristic of water cycle across a tidal river and a coastal aquifer and the storage potential of Ota river delta were investigated from long-term observations and geological data. Tidal variations of water table and salinity in a deep aquifer were more prominent than those in a shallow aquifer. Subsurface water environment changes sharply in a surface layer of riverbeds where saline water infiltrates as a density flow. Groundwater recharges smoothly across riverbanks during typhoon's flooding, and the water storage potential of Ota River Delta was estimated to be 0.3 billion cubic meters.