Study Of The Relationship Between Dragon Lake Water System And Urban Flood Control In Zhengzhou

As the urbanization develops, the burden of city flood control in Zhengzhou becomes more and more heavy. The Dragon Water System, located at the lower reaches of the river around the city, is a project that combines zoology, scenery, tourism and water resources utilization. This paper analyzes the condition of river channels that have close relationship with the Dragon Water System when flood happens after the completion of the project. The relationship between the Dragon Lake and the city flood control is clearly analyzed after hydrological and hydraulic calculation. And the necessary and possible roles that Dragon Lake plays in the city flood control are also demonstrated.First, the study area is divided into two parts: developed and developing regions according to different conditions of underlying surface. Then, the study area is further divided and generalized according to the characteristics of the pipeline system and water system and corresponding methods of runoff generation and concentration computation is applied in different sub-regions. Finally, two models have been set up: the model of surface runoff generation and concentration in the developed region and pipe runoff concentration and the model of surface runoff generation and concentration in developing region. In the computing of hydrological factors of flood in river network, the unsteady flow computation based on Saint Venant equations solved by Preissmann Four Point linear implicit scheme is applied.Hydrological method of runoff generation and concentration and hydrodynamic method of river network is combined together in the paper and used to set up mathematic models. And the model of runoff generation and concentration in the developed region, the model of surface runoff generation and concentration in developing region and the model of hydraulic computing have been set up. The above models are used to analyze the effects of Dragon Lake water system to flood control in the city of Zhengzhou. Furthermore, the water network designing level at different recurring periods and different gate openings is simulated in the models. The methods adopted in this paper can be used to solve problems in other cities similar to Zhengzhou.