Surface water quality changes in Shanghai City in past 20 years
上海市地表水水质近20年的变化

Based on the monitoring datum of surface water quality and some relative statistics of nature, economy and society, the trend and law of water quality changes and their coupling relationship with development of society and economy were discussed. This paper indicates that: (1) Three phases: slow deterioration, accelerated deterioration and gradual amendment of water quality changes were divided and 1996 were believed to be the turning point. (2) There is only a little relationship existed between precipitation, flux from up stream of Huangpu River and water quality changes. (3) Trend of water quality changes was mainly related with the pollution produced by industry of breed livestock and people living; (4) The great increase of capacity of sewage treatment was the most important factor which contributed the turning point of 1996, while pollution produced by breed livestock and people living were hold back and industry pollution decreased continually. (5) The rapid course of highly urbanization in Shanghai have already changed to be positive factor and impetus which take a important role in water quality improvement after 1996.