乐清湾的动力沉积过程

THE DYNAMICAL PROCESS OF SEDIMENTATION IN LEQING BAY

主要采用二维潮波、泥沙输运途径的数值模拟,定量地展示了泥沙在乐清湾内的输运途径和沉降过程。模拟结果表明,乐清湾大致以10m等深线为界,其东部的涨潮流主要来自玉环岛与横趾山之间的深槽;水流在一周日内的轨迹为一宽约1km的狭带;此流态有利于泥沙向南的净输运,从而有利于此海域深水航道的维持。10m等深线以西水流轨迹为一较宽的带状结构,有利于泥沙向西、西北的净输运。华歧潮滩附近水流运动轨迹利于泥沙向北、向西的净输运,从而有利于华歧潮滩的发育。此外,本文还定性讨论了楚门潮滩特征的成因,主要是漩门口堵截前丰富的湾外泥沙以及驻波型潮波与漏斗状地形。

A two-dimensional numerical simulation is made for the tide and the path of sedimental transportation in Leqing Bay. It presents the processes of the transportation, siltafion of the sediment quantitatively.The results show that the 10 m isobath is the demarcation line. In the eastern area off this line, the flood current comes mainly from the waterway between the Yuhuan Island and the Henzhi Island. The trajectory of the flow in one spring tidal day is a narrow belt. For the net transportation of sediment from north to south it is the dynamical condition of maintaining the deep waterway off the Damaiyu Port. In the western area off 10 m isobath the trajectory of flow is for the transportation of sediment to west and north-west, the trajectory of flow near the Huaqi Flat is for the transportation of sediment to north and west, both contributing to the development of the Huaqi Flat.Before building the Xuanmen Dam, the standing wave of tide and funnel-type topography are the main condition for the formation of the characteristic Chumen Flat.