辽东湾北部潮滩及浅海区泥沙运移趋势

SUSPENSION TRANSPORTATION TENDENCY IN TIDAL FLAT AND SHALLOW-MARINE REGION IN THE NORTHERN LIAODONG BAY

本文根据多断面昼夜水文、泥沙观测,潮滩重复水准测量并借助^(210)Pb测年,分析了辽东湾北部潮滩和浅海区潮流及泥沙的分布和变化。结果表明:本区泥沙以纵向搬运为特征。双台子河口及西部来水来沙是东部沙洲和浅滩发育的主导因素。汛季大潮期,泥沙落淤在河口及附近浅海且泥沙自西向东运移;小潮期,泥沙除纵向扩散外(向东),存在净向海搬运。调查期滩面淤积强度自西向东减弱。高、中浓度泥沙浑位置与盐度梯度区的上部界面相符,多出现在25—30km以内的岸段(水深10—13m),30km以外泥沙骤减,海水亦由黄棕色变为兰绿色。

A 25-hour survey of tidal hydrology and suspension discharge was carried out for multi-sections, and tidal mud flat was surveyed three times during 1988. Based on the investigations and 210-Pb dating method, the paper tries to make clear the characteristics of tidal current and the distribution and variation of suspended sediment in the tidal mud flat and shallow marine area of the northern Liaodong Bay. The results indicate that suspended matter moves in longitudidal direction. Water and silt from the Shuangtaizi River and from the area west of the river are the main factors for the shoal development in the eastern part of this area. During spring tide, suspended matter of rivers and marine source can remain in river mouths and around shallow waters. Main dispersion directions of sediment are southeastwards in the western and central areas and northeastwards in the eastern part during flood tide. During neap tide, however, sediment from rivers and resuspended sediment from the estuary migrate in the same directions, and flow more than 30km away from the coast. It has been found that the tidal mud flat sees an accumulation and the accumulation is larger in the west than in the east. The content of the suspended sediment is high within 25-30km from the coastline, which is coincident with salinity gradient limit. The concentration of suspended matter (30km away from coastline) decreases abruptly and the colour varies from yellow to darker.