INFLUENCE OF UNDERGROUND STRUCTURE ON THE GROUND WATER AND SEDIMENT ENVIRONMENT IN AN ESTUARINE TIDAL FLAT

Abstract

The measurement of groundwater quality, sediment and biological survey have been performed in order to clarify the influence of sheet pile on groundwater, sediment and biological environment in an estuarine tidal flat. Observation results suggested that groundwater exchange (from surface to 4 m) was occurred by the difference between river water level and groundwater level of Ota river delta in the tidal flat where sheet pile was not inserted. On the contrary, the groundwater level decreased more than 1 m in the tidal flat where the sheet pile was inserted; this means that groundwater exchange between Ota river delta and river hardly occurs in the tidal flat. Moreover, the different of sediment and biological environment were appeared in relation to the difference of groundwater environment.