总结了槽蓄量计算中的常用的断面法、水沙平衡法和地形图量算法的原理和不足,利用1973-2002年的水下地形图为基础资料创建DEM,进行了精度分析;计算河道槽蓄量的大小;对不同时期的数据进行叠合分析,得到河道槽蓄量大小的变化及水下地形变化的可视化。结果表明:1)利用海图资料建立的DEM精度较高,其中1982年的中误差仅为0.78m。2)在1973-2002年间北港河段槽蓄量整体增大,即呈现冲刷之势,泥沙冲刷量为1.6×10^8m^3。在整个研究时段内,1982-1987年间槽蓄量变小,河道发生淤积。3)北港河床航道稳定性较差,河床逐渐演变。水流作用切滩下泄使大量泥沙迁移堆积:洪水造床作用在河口河槽演变过程中起着重要的作用。
This paper analyzes the principles and shortages of the calculation methods for channel storage volume which are commonly used, i.e. slice method, sediment-transport method and topographic method. Using the underwater terrain maps from 1973 to 2002, the paper creates DEM, then analyzes the precision, calculates the channel storage volume, and intersects different data, finds the change of channel storage volume and visualizes the change of underwater terrain, and comes into the following conclusions: (1) Precision of the DEM built based on chart data is very well, and the mean square error in 1982 is only 0.78 m; (2) During 1973-2002, the channel storage volume of the North Channel is enlarged, and the scouring volume is 1.60×10^8 m^3; During 1982-1987, the channel storage volume is reduced, and siltation occur in the channel; (3) The riverbed of the North Channel is unstable and changing. The stream makes sand remove and subside, and floods play an important role in the North Channel evolution.