The application of fuzzy comprehensive evaluation on the water quality of Changjiang River

This article, using the fundamental theory of fuzzy mathematics and basic methods, applies the concepts of subordinate function and subordinate degree of fuzzy mathematics into the water quality evaluation of Changjiang River. By means of establishing several fuzzy collections such as volumes of factors, volumes of evaluation, subordinate function and weight which consist of several polluted evaluated factors, and decide the weight according to the influential differences between every polluted factor and the water quality. By combining the principle of maximum subordinate degree and weighting average principle, we apply the fuzzy comprehensive evaluation to the water quality of Changjiang River. We decided the rank of the water quality, and reach several water pollution features and regularities.