连云港西大堤工程建设影响作用评价

西大堤的建成使连云港由原来的海峡通道型港口变为半封闭的人工海湾型港口,风浪条件改善,可利用的港口岸线大大加长,为连云港亿吨大港的建设提供了契机,也改善了连云港与东西连岛的交通条件,促进了旅游业的发展.另一方面,也改变了海湾内水动力与沉积环境.大堤建成后,湾内潮波由前进波转变为驻波,水体交换能力减弱,湾内水质污染加重,尤其是湾顶水域污染最重;同时加剧了湾内泥沙的淤积,在西大堤内侧形成新的潮滩,位于湾顶的老海滨浴场被淤废.由于西大堤封堵了连云海峡西口门,使得近岸泥沙的运移路径改变,北部的泥沙流自海州湾东去沿大堤折向东西连岛方向,在大堤的外侧和东西连岛外缘形成新的落淤场所,大沙湾和苏马湾海滨浴场受到影响.沉积作用的加剧已影响到港口及周边海岸与水利设施的正常运作,因而应加强对港区及周边海洋环境的监测与研究,缓建西大堤内侧北港区码头,并对西大堤西端进行透空式改造,以从根本上解决港区泥沙淤积问题.

The Impact Assessment of the West Breakwater Project in Lian-Yun- Gang, Jiangsu Province, China

The Lianyungang harbor has changed from a strait channel to a semi-closed artificial embayment after the construction of West Breakwater in 1996. Wind wave became weak, and the length of coastline increased greatly, which has improved the condition for the further development of Lianynngang harbor. Furthermore, it advances the transportation between the Lianyungang city and the offshore island named Dongxiliandao, which provides good opportunities for the local tourism to develop the island tour. On the other hand, the dynamic and depositional environment has also been changed after the project. The progressive tidal wave changed into the standing wave in the artificial embayment, which weakened the water exchange. As a result, the water quality inside of the embayment decreased, and the water in the head area was polluted. Meanwhile, the siltation inside of the embayment became aggravated, a new tidal flat has been formed along the inner part of West Breakwater, and the old tourist beach at the head of the embayment can not be used now. Since West Breakwater blocked the west mouth of Lianyun Strait, the moving route of the nearshore sediment has been changed. The sediment coming from northern part flows eastwards along West Breakwater, then turns southeastwards along Dongxiliandao, and finally deposits in the new places, which goes a threat to the tourist beaches along the northern coast of the island. The strengthened siltation processes have also impacted the use of harbor, concerned coastline and hydraulic facilities. Thus, it is important to monitor and study the marine environment in the harbor area and nearby. Further construction along the inner side of West Breakwater should be stopped. Also, in order to solve the siltation problem in the harbor once and for all, west part of the West Breakwater needs to be rebuilt to keep the water exchange.