Water quality prediction and case study for urban river system of Beijing
北京城市水系水环境模拟及情景分析

Urban river system is the most vulnerable point of water environment management for river basin. In view of problems of bad hydrodynamic conditions, organic pollution and eutrophication, a QUAL2K model was applicated to predict the temporal and spatial variation of water quality in urban river system. And then, the proper and effective measures were explored for environmental management and pollution control of Beihuan water system. Modeling results showed that fitness of the model could reach 0.9135 after repeated adjustment, and the relative deviation between simulation and field value was less than 20% for water temperature, dissolved oxygen, COD, TN, TP and Chl-a. Therefore, the model was of high accuracy and could be used to simulate and predict the water environment changes in Beihuan water system. Under the water environment enhancement scenarios of doubling the quantity of source water and diminution of the point and non-point pollutions along the way, the water quality in different sections was improved in varying degrees. And efficiency for the three water environment improvement measures of point and non-point source co-elimination doubling the quantity of source water and point source elimination only is in a descending manner, which indicated that the non-point pollution is the major pollution and it is necessary to take water quantity-quality co-scheduling measures for the management of Beihuan water system.