Water Quality Zoning of Rivers by the Technique of Fuzzy Clustering Analysis

Zoning the pollution of a river may be the first or even the most important step in water quality management. In order to resolve its pollution, fuzzy clustering analysis may be used whenever a composite classification of water quality incorporates mutiple parameters In such cases, the technique may be used as a complement or an alternative to comprehensive assessment. In fuzzy clustering analysis, the classification is achieved through a fuzzy relation. After a fuzzy similiarity matrix has been established and the fuzzy relation stabilized, a dynamic clustering chart can be developed. Given a suitable threshold, the appropriate classification is worked out. A general methodology for fuzzy clustering analysis is developed and illustrated with a case study of water quality evaluation for the Zayandeh-Rood river, the results of which have been represented in a pollution zoning manner.