FLOW CHARACTERISTICS IN DOWNSTREAM AREA OF THE NAGARA RIVER ESTUARY BARRAGE

Abstract

In this study, the flow characteristics in downstream area of the Nagara river estuary barrage are estimated by means of observed data obtained from ADCP (Acoustic Doppler Current Profilers) and observation plane for water quality. The investigation results are summarized as follows. The flow in downstream area of the Nagara river estuary barrage in inflow of the tide is affected by the situation of density in mouth of river. In the case of existence of low density water in mouth of river, the flow becomes two layer flow because of existence of high density water in bottom. In the case of existence of high density water in mouth of river, the flow get into deep area of river. In the case of the ebb tide, down stream flow pass upon high density water. In the spring tide, inflow of the tide pass to the Ibi river because the water level in the area from the Nagara river barrage to joint point with the Ibi river more rapid increase than the Ibi river.