Total Investigation of Physical and Biological Environments in Isahaya Bay under the 6.27 judgement by Saga District Court

本项目的目的是详细调查伊沙哈雅围垦堤南北闸开通前，伊沙哈雅湾的水流、水质和海底水质的环境特性，并积累有意义和有用的数据，以揭示伊沙哈雅围垦堤南北闸开通后的环境变化，作为基准数据。得到的主要结果如下：(1)依沙垭湾的海底质量环境性质从海湾口向湾内方向恶化，向湾内方向恶化的速率也增大。(2)雨季在伊沙哈雅湾整个地区形成盐度分层，主要是由于Chikugo河的排放造成的。(3)低氧水团倾向于在Konagai附近产生，并在伊沙哈雅湾整个地区变大。

The objectives of this project are to investigate in details the environmental properties of flow, water quality and seabed quality in Isahaya Bay before opening the north and south gates of Isahaya reclamation dike and to accumulate significant and useful data to reveal the change in environments after opening the gates as benchmark data.The obtained main results are as follows.1)The environmental properties of seabed quality in Isahaya Bay become worse toward the inner area of bay from the bay mouth and the deterioration rate also increases toward the inner area of bay.2)The salinity stratification is formed over the whole region of Isahaya Bay in the rainy season and it is mainly due to the discharge from Chikugo River.3)The hypoxic water mass tends to be generated off Konagai and become large over the whole region of Isahaya Bay.