杭州湾南翼东部边滩时空演变特征及影响因素分析

Analysis on the Characteristics and Influencing Factors of the Spatial-temporal Evolution of the Eastern Flat in the South Flank of Hangzhou Bay

采用研究区不同历史时期的地形资料,结合水动力条件、泥沙来源与促淤围垦工程,探讨岸滩时空演变特征及其作用机制。结果表明:1959—2010年的51 a间,岸滩以0.08 m/a的速率持续淤积,但近年来淤积速率有所减缓;0,-2,-5 m等高线的淤进速度各不相同,其中0m线以61 m/a的速率向海淤进,速度最快,岸滩剖面呈逐渐变陡的态势。沿岸潮流的输沙作用以及围垦促淤工程是岸滩持续淤高的主要原因,但受涨潮流的抑制、风浪的冲蚀破坏以及杭州湾大规模的围垦和长江来沙量减少的宏观背景下,岸滩的淤涨速度将会日趋缓慢。

This article used the topographic data of the different historical periods of the study area to explore the characteristics of the coast and beach spatial - temporal evolution and action mechanism combining with the hydrodynamic conditions, sediment sources and siltation reclamation project. The results showed that during the 51 years from 1959 to 2010, the seashore continued silting up at a rate of 0.08 m/a, but the silting rate has slowed in recent years; areas at the contour lines of 0, - 2, - 5 m, etc. silted at different speeds. The area at the contour line of 0 m silts into the sea at the rate of 61 m/a, which is the fastest and the coastal profile showed a gradually steepening trend. The continuous siltation of the seashore is mainly the result of the sediment transportation of coastal tides and the reclamation project. But the silting rate will gradually slow down for themacro background- the flood current inhibition, the erosion of wind waves as well as the large scale reclamation projects at Hangzhou Bay and the decrease of sediment from Yangtze River.