Abstract:

To explore the method of calculating river’s diffusion coefficient in the presence of pollution, a normal fuzzy linear regression model was built, and through the membership function of fuzzy set, the ranges of water quality parameters (transversal diffusion coefficient and average flow velocity) in the presence of different confidence levels were calculated. The model was built based on linear graphic method, and the tracer test data of water mass was analysed based on fuzzy numbers. The water quality parameters calculated by this model were very close to the real values, which accounts for the feasibility and rationality of this model. It could also reflect the uncertainty of river system and the effects of other uncertainties in practice.

Key words: fuzzy linear regression, normal fuzzy number, membership function, transversal diffusion coefficient, average flow velocity