WASP Water Quality Model Application And DO Models Evaluation

The application of water quality model in environmental protection becomes more and more important with the development of environmental technology. Some models require large amounts of external data, which are not easily accessed. To reduce the data requirement, many methods have been proposed such as the neural network method. But many of such kinds of methods are not mature enough to replace the kinetic models applied widely. The main work of this dissertation is to simplify kinetic formulas to reach the requirement of data reduced.The development and application of the water quality models are summarized. The WASP model is chosen in this approach because the rivers studied here are plain rivers where the flow velocity is low. Although this model has a lot of successful applications, it is still lack at evaluating its model parameters and optimizing DO models. The four DO models are compared in this approach.The water quality of the Brandywine River in 1999 is simulated with the WASP model. The results show good agreements with the field observation data. The sensitivity analysis for the selected model parameters such as temperature, flux, CBOD decay rate at 20℃, etc. is studied. It is found that the water temperature is the most sensitive coefficient. Four water dissolved oxygen formula with different complexity are compared in detail. The result shows that modified Streeter-Phelps equations meet the need of WASP water quality simulation. The effects of the dam on DO are found small.The water quality of Tang River, which goes through the urban of Qinhuangdao city, is selected to be simulated. The change of water quality of Tang River from June to August in 2006 is forecast by applying WASP model with the modified Streeter-Phelps equations. The results show good performances of WASP model.