FIELD MEASUREMENT AND NUMERICAL SIMULATION OF ESTUARINE CIRCULATION IN A RIVER ESTUARY

Abstract

Estuarine circulation in a river estuary was examined quantitatively by field measurement and numerical simulation. Vertical profiles of flow velocity were measured for ten days in the Tone river estuary by acoustic doppler current profiler (ADCP) placed on the river bed, and then the residual flow velocity was analyzed. The results showed that the estuarine circulation steadily existed in the estuary, and that the residual flow velocity in the lower layer was about 5 cm/s. The value means that it would take about 4 days for seawater to travel from the river mouth to the tip of the salt wedge.

The flow field in the estuary was simulated by the 2-D flow model including the k-ε turbulent model. The model reproduced the temporal variation of flow velocity and the residual velocity profile fairly well. Therefore, the model was considered to be useful for the prediction and evaluation of the estuarine circulation in the estuary.