Application Research Of Grey System In Surface Water Assessment And Predication

In recent years, the seriously pollution of the surface water affects human health and the development of social economic. Therefore, we need to take some measures to control the pollution. At percent we can establish water quality model to evaluate and forecast the surface water system. The grey system is one kind of mathematical method that is used to establish the model recently. In this paper, we discuss the application of this method on the surface water quality evaluation and prediction and make some improvement on it.In the article, we analyze the basic methods of the grey system which are system analyzing method and the method to build a grey model.First of all, on the basis of the grey theory, we establish the grey fuzzy clustering model which matches the grey relation analysis with the fuzzy theory and use the model to evaluate the surface water. According to the inspection data about the Yellow River in Lanzhou, we use the procedure of grey correlation analysis to analyze the monitoring data and the surface water quality standards, and then determine their quality. It shows that the quality of the water belongs toâ… andâ…¡. It's difficult for us to compare the similar water quality. So in the paper we use the fuzzy clustering analysis to make further division. According to the result we can know that the evaluation model is applicable to surface water quality evaluation.In addition, we study the mechanism of the grey GM(1,1) forecasting model and make improvement by changing the calculation type or steps. The results of the test model which bases on the data of Shenzhen River from October to November compared to the traditional model shows that the accuracy has been greatly improved and forecast can describe the water quality trends accurately. We forecast the data in the year of 2007 by the data in the year of 2006, which can be used by the management department as basis of making schema when the water quality changed.