Research On Rainstorm Distribution Rule And Design Rainstorm In Tianjin Urban District

Speaking of the flood prevention in city of Tianjin, there are many weak links : Every time the urban district meeting rainstorm, some districts are submerged, and the phenomenon of the large rainstorm creating flooding disaster to the urban district still exist .As the river course of flood,the drainage function of Haihe river is not high. The goal of this topic research is grasping the change of Hydrometeorology essential factor such as precipitation which is caused by factors such as Tianjin urbanization development by analysis on the rainstorm distribution rule and the computation of designing rainstorm. I hope it can provide the scientific basis for the simulation on the concentration of flow , the draining water plan in Tianjin urban district,the flood prevention dispatch and management in main stream of Haihe River.Main content of this topic research:⑴Analysis on the temporal distribution characteristics of rainstorm in Tianjin urban district: mainly including the distribution characteristic of rainstorm in one year; the distribution characteristic of actual largest spot rainfall under different interval; analysis on the distribution characteristic of one rainstorm.⑵Analysis on the spatial distribution characteristics of rainstorm in Tianjin urban district: Mainly including the comparison of rainstorm between the urban and the suburb district; the comparison of actual largest rainfall under different interval between several hydrology station; the distribution characteristic of rainstorm in six areas; the comparison of rainstorm in the same time between Er-zha station and Shi-tai station; quantitative analysis on the nonuniformity of the spatial distribution of rainstorm; the influence created by urbanization to rainstorm.⑶The Computation of design rainstorm in Tianjin urban district: establishing and examining the formula of rainstorm; calculating Surface rainstorm;achieving time interval assignment of the design rainstorm.⑷The analysis on the dependency relation between rainstorm in Tianjin urban district and change of the level in main stream of Haihe River:using the designing rainstorm of 12h, whose frequency is 2%,5%,10%,20% and 50% by the model of PCSWMM to figures out the designing flood of five different frequency;achieving the analysis on the dependency relation between the change of the water level and channel storage capacity in main stream of Haihe River; establishing the relation between rainstorm and change of the level under the situation of design rainstorm, there are important instruction significance to flood prevention of Haihe River and the draining plan in Tianjin urban district .