根据1979,1996和2009年3个时期水深地形数据,利用GIS软件分析了岱山水道西部潮滩、水下岸坡和深槽区2个时段的冲淤变化.结果显示:1979-1996年的17a间,研究区大部分区域冲淤幅度一般在±1 m以内,只有深槽局部区域冲刷大于2m；1996-2009年的13a间,潮滩区冲淤变化与1979-1996年间类似,有±1 m冲淤变化,而水下岸坡和深槽区的冲刷幅度明显加大,水下岸坡平均冲刷幅度达2 m,深槽区平均冲刷幅度达3 m.据分析,1996年以后,水下岸坡和深槽区冲刷幅度明显加大的主要原因有两个:一是岱山水道水流流速较快,粘土质的底质容易遭受冲刷；另一个是在潮滩区至水下岸坡间建设了码头和栈桥,浅水区水流部分受阻,导致深水区域流速加大,从而加剧了水下岸坡和深槽区域的冲刷幅度.%Based on the underwater topography data of 1979,1996 and 2009, the scour and siltation of the tidal flat, subaqueous shore slope and deep trough to the west of Daishan channel were studied with GIS software for two different periods. The results show that the range of scour and siltation for the most part of the research area was ±1 m from 1979 to 1996, only part of the deep trough was more than 2 m; from 1996 to 2009, the scour and siltation of the tidal flat was similar to that from 1979 to 1996 with a range of - 1 ~1 m, but the scour and siltation of the subaqueous shore slope and deep trough was obviously enhanced with an average range of 2 m for the slope and 3 m for the trough. Analysis show that there are two main reasons for the enhancement of the scour of the subaqueous shore slope and deep trough after 1996: the first one is the high flow speed of the Daishan channel and the clay bottom material, and the second is the construction of wharf and jetty at the tidal flat and subaqueous shore slope, which blocked the flow in the shallow water and increased the flow speed in the deep water, which enhanced the scour and siltation of the subaqueous shore slope and deep trough.
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