Study Of Water Exchange And Eco-embankment Design Of Tianjin Harbor

There are more and more land reclamation projects along with the development of coastal cities. These projects have changed the original landscape of the coastline, reduced the area of the sea and the water exchange capacity. The artificial embankment has damaged the ecological equilibrium and easy to be eroded. This paper, as a part of Tianjin Lingang Economic Area artificial embankment ecology repair and reconstruction project, has built hydrodynamic model, tracer diffusion model and Lagrange particle tracking model for Tianjin harbor area and North pond, and also analyzed the water exchange capacity of the Tianjin Lingang Economic Area and the result of the ecological reconstruction of the North Harbor area. The main work and conclusion are as follows:EFDC hydrodynamic model was established with the consideration of the affection of the wind and the tidal wave on the North Harbor water exchange capacity. And then divided the harbor basin into 10 subareas according to the terrain and functional area, also compared the difference in the water exchange capacity among different subareas. The computation result indicated that the northwest wind has strengthened the water exchange capacity and the southeast wind has weakened this ability. The difference of the water exchange capacity between different subareas is very obvious. The harbor end has the best water exchange capacity and the top is the minimum. Using different time scales as the evaluation index of the water exchange capacity, the contrast relationships of different areas will change. So for different regional characteristics, we should choose a suitable time scale.Embankments of 3 different gradients were designed and the water circulation conditions of the embankment adjacent waters were also calculated. The 30°slope was decided to be the final solution after consideration. The effect of aquatic plants on the drag force of the water body and the tidal force and wave force were also took into consideration. After comparing of the extreme tidal force, the wave force and the maximum tensile force, the Cyperusirial of 200 plants per m2, 1.5cm diameter and 1.2m height need to add vegetation measures like 3D mesh pad and the concrete frame in order to survive.