GIS支持下长江口深水航道治理一、二期工程对北槽拦门沙的影响分析

A GIS-Supported Study of the Influence on the North Passage Bar after Executing Yangtze Estuary Deepwater Channel Regulation Phase I & II Project

将1995～2003年间10幅不同时期的长江口海图资料数字化，利用地理信息系统（ArcInfo8．3）相应的模块进行处理，建立起不同时期的长江口水下数字高程模型。以此作为基础资料，从横断面、深泓线纵剖面以及平面变化等不同角度，对长江口北槽航道水下地形变化进行定量分析。结果表明：整治一期工程完成后，增加了主槽流速，减少了航道回淤，北槽形成了一条深8～10m的微弯深槽，水深基本稳定。二期工程基本保持了一期工程的河势，河床断面未发生重大调整。

A number of charts of the Yangtze Estuary in the period of 1995-2003 are digitized. Supported by GIS tools （ArcInfo8.3） ,digital elevation models （DEM） of the Yangtze Estuary are then established with the Kriging girding method. Based on the DEM, underwater terrain variations of North Passage of the Yangtze Estuary are modeled quantitatively through various representations, including cross-sections, thalweg sections, and overall terrain variations. It is in an attempt to quantify the scouring and silting sediment distribution and its variations in the mouth bar area of North Passage prior and after the First Phase of Yangtze Estuary Deepwater Channel Regulation Project. The results show that the 1st phase regulation project has increased the velocity of flow and reduced the sedimentation of the channel, and it has also resulted in an 8-10 m microbending trough. The 2nd-phase regulation project has retained the form of lst-phase one with less modification in the profile of the channel.