黄河三角洲孤东海域前缘岸坡演变分析

Analysis on Foreslope Evolution of Gudong Sea Area of the Yellow River Delta

对孤东海域1979～2002年前缘岸坡演变进行的分析表明：①浅水区呈蚀退状态,时段最大蚀退速率为314 m/a;②深水区为持续淤进,23 a累计淤进6 516～7 925 m;③侵蚀最大厚度在浅水区,时段最大侵蚀速率为0.272 m/a,23 a累计侵蚀3.625 m,深水区淤积厚度为3～5 m;④各等深线间的坡度均由陡变缓,用理论分析和图解法求得海堤坡脚处40 a后侵蚀极限深度在7.6 m左右.同时,指出波浪掀沙和潮流输送是海岸侵蚀的主要动力因素.

The analysis on foreslope evolution of Gudong sea area for the period of 1979~2002 shows that a) the maximum erosion recession rate of time interval is 314 m/a when shallow water region in erosion recession statement;b) the accumulated deposition of 23 a is 6 516 ~ 7 925 m when deep water area is continuously silting;c) the maximum erosion rate of time interval is 0.272 m/a,the accumulated deposition of 23 a 3.625 m and the thickness of deposition of deep water area 3~5 m when the maximum thickness of erosion is in the shallow water region and;d) each slope of bathymetric contour changes from steep to gentle and the erosion limiting depth is about 7.6 m after obtaining 40 a of foot of dyke slope by theoretical analysis and graphic method.It also points out that waving and tidal flowing are the main dynamic factors of coastal erosion.