STUDY ON CHARACTERISTICS OF WATER QUALITY IN DOWN AREA OF THE CHIKUGO RIVER

Abstract

The Chikugo River is the longest river in Kyushu Island and a precious water environmental area. It is pointed out that water quality in the backwater of the-Chikugo weir is influenced by algal growth. After analyzing-long-term change of salinity in the-estuary of the Chikugo River, the-brackish level is increased. In this paper, water quality problem analysis in the backwater of the Chikugo weir and the estuary are carried out. It is shown that increasing of retention time in the backwater is promoted by intaking the river water, and causes an eutrophication problem under high water temperature. The eutrophication problem in the estuary of the Chikugo River is revealed because of water level rising in the Make Sea and the change of the water intake systems. The eutrophication phenomenon is realized by water quality simulation.