Kazuya Watanabe, Hitoshi Tanaka


The Nagatsura-ura Lagoon in Miyagi Prefecture, Japan is a semi-enclosed water area that has been used for aquaculture of oyster for these forty years. Recently, however, death of oysters has frequently occurred due to anoxic water near the bottom, and is a big concern among stakeholders. The Nagatsura-ura Lagoon and Oppa Bay are connected by shallow tidal inlet, and its water depth greatly affects hydrodynamics and water environment in the lagoon. In this study, time variation of water level in the lagoon in response to tidal variation is investigated through spectral analysis to quantify the role of water depth in the hydrodynamic process. Furthermore, the relationship between the inlet water depth and the salinity concentration intruding into the lagoon is examined through 3-D numerical simulation.


water level variation; 3D numerical simulation;spectral analysis


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