Comprehensive Water Quality Identification Index for EnvironmentalQuality Assessment of Surface Water

Based on the single factor water quality identification index,the comprehensive water quality identification index,which is a new tool for general water quality assessment of surface water,is presented.The comprehensive water quality identification index can fully depict the general water quality of surface water,and its characteristics are listed as follows.Firstly,it can evaluate general water quality both qualitatively and quantitatively; secondly,it assesses general water quality by a group of typical assessing items instead of deciding by the worst assessing item,so the assessment of general water quality is reasonable; thirdly,it can be used to compare general water quality of different stations of the same river and different rivers,and it can also be used to compare general water quality with the same classification of classes Ⅰ～Ⅴand the class worse than classⅤ.Nowadays the comprehensive water quality identification index has been applied in evaluating the general water quality of Shanghai's rivers,and very convincing conclusions have been drawn.In addition,the criterion for river's blackness and stink is ascertained.