The Grey Differential Model of River Water Pollution and its Application

Based on the grey theory, grey characters of river environment system are analyzed, the velocity and dispersion coefficient and attenuation in river are considered as uncertainty parameters and expressed as gray parameters. A grey differential equation of contaminant diffusion in river is built. And the equation has special structure. The truncation error of finite differential method in solving the model is corrected. According to the model, distribution values of pollutant concentration under sudden pollutant discharged can be obtained directly, which can provide abundant and useful water quality information for the plan and control of water pollution. It is shown that the calculated results obtained from the gray model are reliable and reasonable.