四十年来磨刀门河口水动力对地形的响应

Hydrodynamic Change with the Topographic Evolvement in the “Modaomen” Estuary During the Last Forty Years

磨刀门是珠江的主要泄洪通道之一,径流分配居珠江三角洲八大口门之首。从20世纪60年代开始,磨刀门经过大规模的人工整治,河床形态变化很大。利用磨刀门1964年、1977年、2003年的地形,通过ECOMSED模型模拟了磨刀门海域洪季水动力场,对潮流、水面坡降、潮能通量等特性进行对比,发现整治后磨刀门水动力强度加大,而且流速滩槽分异明显;落潮期间上游水位均大于下游水位,水面坡降落潮比涨潮大一个数量级;水深与流速是决定潮能大小的主要因素,同一位置随着泥沙淤积河床变浅,潮能通量也减小。

＂Modaomen＂ is one of the main flood-relief channels of the Zhujiang River, and its＇ run off distribution ranked the first among the eight major mouths over the Zhujiang River. Since the 1960s, ＂Modaomen＂ has been greatly renovated artificially. Based on the chart of Modaomen underwater topography in 1964, 1977 and 2003, through the numerical simulation by using the of ECOMSED ocean numerical model, the hydrodynamic field of modaomen in the flood season is simulated, and its＇ tidal flow, water level descent and tidal energy flux have been analysed. The result shows that the hydrodynamic intensity in the eastern trough of Heng Zhou channel was amplified and the flow velocity in the western shoal was low. Water level upstream is higher than that downstream during the ebb tide, and water level descent of ebb tide is one order bigger than that of flood tide. The depth and velocity are the main factors which determine the intensity of tidal energy. In the same location, along with the sediment filling up the river bed, the tidal energy is decreasing.