甬江建闸的环境影响分析

甬江建闸能够阻咸蓄淡,带来一定的社会经济效益;但也会出现泥沙淤积、水体富营养化、水生生物减少等一系列问题,尤其是泥沙淤积,将对防洪排涝、出海航运和现有港口等产生严重的负面影响.就防洪排涝而言,如果建设甬江大闸,那么泥沙淤积后的镇海口将难以通过20年一遇和50年一遇的洪峰流量.综合考虑岸线前进、地面沉降和海面上升的结果,提出甬江大闸还是不建为宜.

On environmental effect of constructing tidal gate of the Yongjiang River

Constructing the tidal gate of the Yongjiang River can block sea water and store fresh water, which gives rise to certain socioeconomic benefit. But it may result in a series of problems such as the sediment silting, water eutrophication and aquatic organism reduction. Especially the sediment silting will have a serious negative effect on the flood protection and waterlogging drainage,ocean shipping and seaport. As far as the flood protection and waterlogging drainage is concerned, if the tidal gate of the Yongjiang River is constructed, it will be difficult to pass the peak drainage of 3823m~3/s (occurring once again per 20 years) and 4146m~3/s (occurring once again per 50 years) at Zhenhai estuary after sediment silting. Comprehensively considering the results of coast-line advancing and earth's surface sinking and sea's surface rising, the view point is put forward that constructing the tidal gate of the Yongjiang River is not suitable.