Accretion/erosion change of south shoal-groove-the outer at the Yangpu Bay in recent 40 years
洋浦湾南浅滩-深槽-拦门沙近40年冲淤变化分析

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 particular 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.