A number of islands exist in Japan, it is each has a unique environment and culture. But research on the water environment because of the limited water resources in the island is important, hydrological research in the current island are being carried out in various places. For example, in the East China Sea island of Iriomote Island are under the influence of acid deposition from the continent, the river water acid be less has been reported. For the Pacific Ocean of the Izu-Ogasawara Islands, progression and outflow decrease of eutrophic groundwater of eutrophication of coastal waters has been observed.But the literature on water environment and water quality on the island of Genkai On the other hand is still small. In this study, it is intended to explore issues present therein in helping revealed Iki Island water environment located in the Genkai.