BOD-DO Simulation And Emulation On The River System Of Chengdu Urban Region

This research is part of the "Water Management and Water-related Decision-making Supporting and Simulating System in Chengdu Urban Region" project and the paper systematically presents an application of numerical models running upon the platform of MATLAB/Simulink, which visually simulates and emulates the biochemical oxygen demand (BOD) and the dissolved oxygen (DO) in the Fu River, the Nan River and the Sha River within Chengdu urban region.The paper consists two parts mainly. Based on desk research, the first part presents principles, development, taxon and general measures in the simulation and emulation of the river system. The second part, the barycenter of this paper, constructs systematically and provides a holistic view on the regional river system simulation. Firstly, on the basis of the topographical, hydro logical and hydraulic characteristics of "the Three rivers" and fundamental information on the distributing of tributaries and pollution sources, zero-dimensional and one-dimensional water quality models were developed to simulate the river system; Secondly, through field research and experience formula, model parameters, such as BOD decay coefficient (K1), oxygen redissolving coefficient (K2), photosynthesis coefficient (P) and algae respiration coefficient(R), were identified; then, visual model under MATLAB/Simulink was built to simulate and emulate BOD and DO in three different water seasons. Finally, mathematical analyses wereperformed on the errors of the results to identify the precision of the model.The results show that the model has high accuracy and suitability relatively. It could be applied to predict, evaluate, simulate and emulate the engineering effect on the rivers of urban region other than Chengdu also.