The eight water systems in Zhejiang Province are the main water systems that support the economic development and ensure the drinking water sources.Currently the eight water systems are polluted to various extents.The main socioeconomic factors that affect the water systems pollution could be divided into five types by factor analysis

namel

regional economic development factor

agriculture development factor

agriculture and forestry services factor

fishery development factor

and population density factor.Yongjiang river ranked first based on the total socioeconomic scores among the eight water systems

followed by Tiaoxi river

Cao' a river

Aojiang river

Jiaojiang river

Qiantang river

Oujiang river

and Feiyunjiang river.Water was polluted at the least when the scores of all the five factors are between-1 and 0.On the other hand

the total score being above 3 or below-3 indicated that the water pollution degree was the lowest

with sort ofⅠ

Ⅱand Ⅲ water accounting for more than 90%.Water pollution is related to the level of economic development

but in a large degree

it is the result of the interaction between economic development and other factors

and is more closed to the balanced development of the five socioeconomic factors.The water pollution degree was positively related with the unit area of first output value in the region where agriculture and forestry are not prominent.