ABSTRACT
ABSTRACT: Lvdao lagoon is located in top of Sanggou bay, China. The water depth of Lvdao lagoon will have to be changed as a result of building living area around the lagoon. However, it is well known that the man-made topography changes will have impacts on water exchanges. Therefore, the present work will focus on studying and demonstrating which scheme is the most reasonable by simulating the water exchanges under the two schemes provided by the designing company. The two schemes are specified by two water depths, which are 2 m and 3 m respectively. The simulating area is the whole Sanggou Bay, which includes the Lvdao lagoon. However, more attention will be paid to the Lvdao lagoon as the result of no changes occurring except for the lagoon. The moving boundary technology is applied since bathymetry of engineering area of Sanggou lagoon includes large area of tidal flat. Unstructured triangle grid system is adopted in modeling of current and water exchanges environment of Lvdao lagoon. Around location of and within the lagoon, high grid resolution is provided because the lagoon has significant length being 1500 m only. Open boundary conditions of tide level and tidal current are provided with outputting results of “father” simulation with lower grid resolution and larger modeling area. The present engineering simulating area has the highest resolution being 30 m around the lagoon. The present concrete jobs consist of: 1) studying the effects of the two schemes of layout of yacht on current; 2) calculating and predicting water exchanges induced by the changes of water depth for the two layouts. Generally, the most important purpose of this study is to find the more reasonable layout available, in other words, the one most attenuates the severe effects on environment. As the original case concerned, the values of time series of water level and current velocity provided by simulation for Lvdao Lagoon have a good agreement on observed data. Therefore, the model can be reliable to simulate the evolution of water exchanges induced by changes of water depth.
