控制长江口北支咸潮倒灌支持南水北调

对上海市原水供应的形势和长江口咸潮入侵的态势进行分析.结果表明,在枯水季节,长江口水源地易受咸潮入侵影响,入侵路径为南支咸潮直接入侵和北支咸潮倒灌间接入侵(水文测验数据表明,后者影响较大);南水北调工程尤其是东线工程建成后,在枯水季节运行将减小长江口径流量,降低长江口水位,从而加剧咸潮入侵长江口水源地.为了既保护长江口南支河段淡水资源,又支持南水北调工程上马,上海市水务局已立项对控制北支咸潮倒灌的工程措施以及合理调度和配置长江水资源的非工程措施进行专题研究.

Prevention of salt-tide down-draught from north branch of Yangtze River Estuary to support South-to-North Water Transfer

There are two drinking water sources in Shanghai, i.e. the Songpu Bridge water source on the upper Huangpu River, and the Chenhang Reservoir water source at the Yangtze River Estuary. The former supplies 80% of the total volume of raw water, being the grade IV surface water, and the latter supplies 20%, being the grade II surface water. To increase the total volume of water supply and improve the quality of raw water, it is necessary to strengthen the development and utilization of fresh water resources at the Yangtze River Estuary. However, in the dry season, the water quality at the Yangtze River Estuary is prone to be polluted by direct salt tide encroachment from the south branch and indirect salt tide down draught from the north branch, and hydrological tests show that the impacts of the latter is more serious. Furthermore, after the completion of the South to North Water Transfer Project, especially the west route project, the operation of the project will decrease the runoff through the Yangtze River Estuary, and lower the water level at the estuary, further aggravating the salt water encroachment to the Yangtze River Estuary. For protection of the fresh water resources of the south branch of the Yangtze River Estuary and promotion of the South to North Water Transfer Project, Shanghai Water Authority has granted a special project to search for engineering measures to prevent the salt tide down draught from the north branch and non engineering measures for reasonable dispatch and allocation of water resources of the Yangtze River.