龙穴南航道整治工程对潮流泥沙影响的模拟

建立了覆盖珠江河口河网区与口外海滨区的大范围整体平面二维水沙数学模型,模拟计算了珠江河口的水沙空间分布特征。利用近期伶仃洋水域实测水文资料进行了验证,验证结果表明模型能够较好地模拟珠江口的潮流泥沙运动。在此基础上,通过局部加密,模拟了龙穴南航道整治工程实施前后潮流泥沙运动过程变化,计算并分析了工程实施对周边水域水动力条件的影响和航道沿程的水流条件变化以及航槽泥沙回淤状况等。研究结果表明:龙穴南水道内,潮流为西北-东南方向往复流;整治工程后,上段流速略有增大,下段流速略有减小,但总体流速变化较小。泥沙回淤预测结果显示,出海口以上航道有冲有淤,以淤积为主,平均淤积强度为0.12 m/a;出海口航道整体处于淤积状态,平均淤积强度为0.64 m/a。

Simulate the Impact of Channel Regulation on Tidal Current and Sediment in the Longxuenan Channel

A two dimensional flow and sediment numerical model of the entire Pearl River Estuary is established. The model simulates the spatial distribution of flow and sediment during spring and neap tides in the study area. And the comparison of model results with the measured hydrological data (including water level, current speed, current direction, discharge and suspended sediment concentration) indicates that the model can well simulate the currents and the transport of sediment. Furthermore, changes of flow and sediment field are detected by the model before and after the regulation project of the Longxuenan Channel and the model calculates and analyzes the impact of the project on hydrodynamic condition, flow condition and deposition in the surrounding area. It is found that the current is in the northwest-southeast direction. After dredging of the Longxuenan waterway, the current speed has a subtle change and the velocity increases in the upstream and decreases in the downstream in the waterway. The result of sediment deposition prediction indicated that there is erosion and siltation in the upstream of the estuary and the silting occurred mostly, and the average deposition intensity is 0.12m /a. The channel outside the estuary is silting, and the average deposition intensity is 0.64m/a.