The application of matter-element extension method based on gray clustering theory in the groundwater quality assessment of Jilin City

Taking Jilin City as the study area, on the basis of the gray clustering method to calculate weight, the matter-element extension method is used with the matter-elements of the groundwater quality level, assessment indexes and its characteristic value. Correlation functions are established according to the standard of groundwater quality. By calculating the correlation to judge the groundwater quality levels of the city, the ranks of groundwater of Jilin City are proved almost belong to V by this method. These outcomes are in accordance with the actual situation and the results of matter-element extension method, so this method is proved to be practical and efficient. At the same time, the model can contrast the samples with each other that are at the same level, so it can be used to evaluate the groundwater quality.