洋浦湾南浅滩-深槽-拦门沙近40年冲淤变化分析

Accretion/erosion change of south shoal-groove-the outer at the Yangpu Bay in recent 40 years

本文根据1965、1984、1999和2005的海图对比分析,探讨了洋浦湾深槽、南浅滩以及口外拦门沙的冲淤变化,得出:1)1965—1984年之间,南浅滩呈淤涨之势,其西南部最大淤涨距离可达640m;1984—1999年南浅滩出现了侵蚀,这主要是由于洋浦湾波浪以及沿岸流的作用引起的;1999—2005年,靠近口门附近的南浅滩出现淤涨现象,主要是由于洋浦湾口门附近水动力的影响作用;但是目前整体基本上处于稳定的阶段。2)洋浦深槽段呈现出不同程度的西边坡淤涨,东边坡侵蚀后退,深泓断面缩窄、淤浅及东偏的趋势,特别是剖面5的变化比较复杂,值得关注。3)口外拦门沙近几十年来呈现出不同的时空冲淤变化,但是以淤积为主,1965—2005年拦门沙总的淤积厚度达到1m左右,但随着泥沙补给的减少,这种淤积趋势也随着减少。

By comparing and analyzing the maps of 1965, 1984, 1999, and 2005, the authors discuss accretion/erosion of the south shoal, groove and the outer at the Yangpu Bay. The results show that： 1） the south shoal was basically depositing during 1965-1984, with the largest distance of 640 m in the southwest part, and suffered erosion during 1984-1999, because of the wave and alongshore currents in the bay. The south shoal was deposited near the mouth of the bay, due to the hydrodynamic force at the mouth. The whole shoal was stable during the period. 2） The Yangpu groove showed unlikeness degree of change： accretion on the western border slope, erosion on the eastern border slope, narrowing and shoaling the groove line. Of par- ticular concern is the 5 profile. 3） The upper reach of the mouth bars showed different changes during recent years, but they are mainly accretion. The siltation depth of the outer-mouth bar was about 1 m during 1965-2005, but the magnitude of siltation will decrease in future due to sand reduction.