长江流域社会经济发展对长江口水域功能开发的影响

EFFECT ON THE EXPLOITATION OF THE WATER FUNCTION OF THE MOUTH OF THE YANGTZE RIVER WITH THE SOCIAL AND ECONOMIC DEVELOPMENT OF THE YANGTZE BASIN

长江口水域是上海市重要水源地,同时兼具工农业取水、通航、纳污、围垦、生态等多种功能,长江口已成为上海市建设世界级城市的重要支撑之一,其水资源的开发、利用和保护已成为人们关注的焦点。本文重点分析了随着长江流域社会经济的发展,流域水旱灾害、水土流失、污染物排放、大型水利工程建设等因素对长江口水域功能的影响,特别是近年来在上述因素影响下长江口水、沙、盐的动态变化,提出长江口现状过境水资源量为9335×10~8m^3/a,上海市最大可开发利用的资源量约在3680×10~8m^3/a;长江口水域水质基本符合Ⅱ类标准,但近岸水域的污染不容忽视;长江口咸潮入侵成为长江口水资源利用的最大障碍,每年长江口的氯化物超标天数在45d;长江流域的来沙量有减少的趋势,多年平均输沙量为4.35×10~8t。最后,就河口水域功能开发提出了相关的对策建议。

The mouth of Yangtze River is one of the main wa- ter source of Shanghai City as well as the functions of water in- takes of industry and agriculture,navigation,admitting pollutant, inning and environment,etc.It has become one of the im- portant sustentation factors of Shanghai City as the modem and international metropolis.It was focused much on its de- velopment,utilization and conservation of water resources. With the social and economic development of the Yangtze Basin,the flood and drought disasters,the soil and water erosion,the pollutant discharge and the construction of the large hydraulic engineering have affected the water functions of the mouth of the Yangtze River,especially the dynamic drift of water,sediment and salt.It is brought forward that the actual quantity of the transit water resources is about 9335×10~8m^3/a and the most exploitable quantity of Shanghai City is about 3680×10~8m^3/a.The water quality of the mouth of the Yangtze fiver meet the environmental quality standard for surface water of Ⅱ,but the coastal pollution can not be overlooked.The salinity intrusion in the mouth of the Yangtze River has become the obstacle to the exploitation of water resources.The average number of day exceeding the standard of chloride is 45 days every year.The incoming sediment has gradually decreased and the mean annual sed- iment discharge is 4.35×10~8t/a.The proposal is put forward on the development of the water functions of the mouth of the Yangtze River in the end of the paper.