Author(s): Yangwen Jia; Hui Gao; Cunwen Niu
Keywords: River water quality; Dynamic modeling; Emergent management
Abstract: The Luanhe river water is the main source of domestic and industrial water supply to the downstream cities like Tianjin and Tangshan, thus it is important to be ready for the emergent management of the water supply when a water pollution accident occurs. In this study, we developed a 1-D dynamic river water quality model for the purpose based on the QUAL2E/2K model. The QUAL2E/2K model is a well-developed model but limited to steady river flow conditions, so we extended it to unsteady flow conditions based on the dynamic wave equations of river flow. We verified the improved model based on the model result of the Guojiatun to Panjiakou dam reach and the BOD observation from 29 July to2 August in 1991. Based on the water quality standard of water function zones, we discussed the required reduction of the point source of BOD in the ordinary case. Assuming a scenario case of emergent water pollution, we studied the pollution alleviation effect of urgent discharge of upstream dam water. The analysis result shows: 1) in the ordinary case, the point source of BOD is required to reduce to 60%of the present actual level to make the whole reach satisfy the Class-III water quality standard; 2) in the emergent water pollution scenario, the peak concentration will decrease and the appearing time will become earlier with the increase of upstream dam water discharge, thus the mitigation measure is effective. The study is believed to be of a referential value for the water environment management in the river basin.