舟山凉潭岛填海工程对水动力及海床演变影响的模拟预测分析

Prediction of the effect of reclamation near Liangtan Island in Zhoushan water area

用一个三维(ECOMSED)模式对舟山凉潭岛填海工程前后的潮流场变化进行模拟,做出预测。潮流场模拟结果与实测基本吻合。经分析可知,工程对潮流的影响主要在围堤的东南角小范围内:工程后流速明显减小,造成淤积现象,但淤积程度不大,1年后的淤积为13cm左右,5年后的淤积为0.8—1.2m左右。工程对较深水层的潮流运动影响很小。通过对施工期间产生的悬浮物在涨落潮时的分布模拟可知,涨潮时,悬浮物从工程区域的一个悬浮物源不断排出,主要对工程附近及其上游地区造成一定的影响;落潮时,悬浮物主要影响工程外围及其下游地区,整个落潮期间悬浮物能影响的范围比涨潮期间要大。总体上工程对该附近海域的潮流场及冲淤影响很小。

A three-dimensional ocean model （ECOMSED） is used to simulate and predict the effect of reclamation activity on the local tidal current near Liangtan Island in Zhoushan. The computed results of tidal current basically agree with the observations. It is shown that the local tidal current is affected by the reclamation mainly in a small area located at the southeast corner of the reclaimed area where a pronounced reduction appears in tidal current velocity and causes a slight sedimentation. The extent of the sedimentation is 13 cm and 0.8-1.2 m one year and five years after the reclamation, respectively. The reclamation has a slight influence on the deeper current. The distribution of the suspended substance caused by the reclamation shows that the suspended substance coming from an unceasing discharging source has a main effect on the adjacent and up- stream areas during the flood tide period, and on the periphery and downstream areas during the ebb tide period. Furthermore, the affected area is larger during the ebb tide period than during the flood tide period. As a whole, the reclamation project has a slight effect on the local tidal current as well as erosion and siltation.