Research On Classical Methods And Innovatory Methods For Simulating And Predicting River Water Quality Illustrated With Huaihe River In Anhui Province

It is important and basic to simulate and predict the water quality for successfully accomplishing the tasks about water environment. The mechanism water quality models take into account the factors that have impact on change of water quality, so the simulating and predicting results are usually satisfactory. But they often require a great deal of background information, which makes them have some limits to application for many river systems. However, water quality models without considering mechanism often acquire satisfactory simulating and predicting results because they built models aiming at specific water quality system by using statistical method or other mathematical methods.The paper regards Huaihe River in Anhui Province as the subject by participating in the program of National Natural Science Fund River Water Quality's Virtual Regulation& Control Illustrated with Huaihe River in Anhui Province (50379003). By consulting the documents and summarizing mechanism water quality models, the paper discusses the application of classical methods and innovatory methods without considering mechanism for simulating and predicting water quality with the examples.As for classical methods without considering mechanism, the paper adopts Markov method of weighting, Markov method without weighting, and Auto Regressive time series method to simulate and predict water quality items, responsively. It also improves the traditional grey model by using combined model. The results of examples illustrate that these classical methods have some use value for simulating and predicting water quality.As for innovatory methods without considering mechanism, the paper adopts BP Artificial Neural Network. The simulating results of training data are satisfactory, and predicting results are acceptable. The paper tries to simulate and predict water quality by using chaos theory and fractal theory. The paper brings forward the idea of universe chaos prediction and its improvement by reducing dimension, method of sectioned variable dimension fractal, and fractal interpolation. Using examples, it discusses the feasibility of these methods to simulate and predict water quality. Therefore, the paper will provide new ideas and methods for the following tasks.