APPLICATION OF MIKE 21/3 FM COUPLE TO SIMULATE THE HYDRAULIC OF DA NONG ESTUARY OF PHU YEN PROVINCE

Abstract

The paper presents the results of applying the model MIKE 21/3 FM Couple to simulate the hydrodynamic regime of Da Nong estuary. The data series of 2 surveys from 13 to 23 November 2015 and from May 18 to June 1, 2016 were used to calibrate and verify the model. After selecting the model parameters, hydrodynamic mode simulation with 3 different scenario groups to find the causes of sedimentation and erosion. The simulation results show that: During the northeast monsoon season, the hydrodynamic regime in the Da Nong estuary area is more changed than during the southwest monsoon. The flow velocity in the northeast monsoon season is greater than in the southwest monsoon. Velocity and hight of waves during the southwest monsoon in the estuary are very small; Due to the influence of wave directions, coastal currents and currents in the river, the topography of the estuary area is always changing. In the northern part of the river mouth and around the embankment, sediments occur within a distance of about 50m from the shoreline to the sea, erosion occurs within a distance of 50 to 200m from the shoreline. In the river mouth area is always formed a sand dune, this sand dunes have different sizes depending on the wave direction and coastal currents. In the area inside the estuary, there are erosion accretion points due to the interaction between the coastal currents, the waves from the sea and the flows from the rivers.