登州浅滩的形成、动态演化及其可恢复性研究

Discussion on the evolution cause and its recovery for the Dengzhou Shoal, China

登州浅滩是位于渤海海峡南部登州水道西侧海域的长条状水下沙洲,经海底地貌形态对比、沉积物取样及海区动力条件分析,初步推断为全新世以来形成的潮流沉积体的一部分,后经波浪和沿岸流等动力的长期改造逐渐稳定成为边缘坝地貌形态.20世纪80年代中期开始在登州浅滩进行的大规模人工挖沙严重破坏了沙体的动态平衡.利用水库模型估算,浅滩在短期内难以恢复到原来的规模.

The Dengzhou Shoal shaped in a stripped sub-water sandbar is located in south of the Miaodao Channel. Comparing the charts of 1974 with 1959, there is little change on the shoal with its topography and water depth. It shows that the shoal had been in a state of dynamical equilibrium. Detailecl analysis on the sub-water geomorphology, sediments composition and environmental conditions, it can be deduced that the Dengzhou Shoal is one part of the ebb-tidal sand ridges formed after the period of Holocene. It is like a submerged barrier preserved the Penglai northeastern coast from wave incursion. But since 1985, some companies have begun to dredge on the shoal and caused the huge sand lost. Till 1990, the resident area surrounded by the (-5 m)-isobath line was changed from the original (3.96 km^2) to (0.5 km^2). Estimated by the reservoir model, the shoal can be recovered but cannot returned to the original scale.