Analyze On The Urban Flood Channel Peak Discharge

Along with the development of urbanization, the function of city watercourses changes from irrigate function at first to integrated function, flood control and drainage function plays the leading role and ecological, landscape leisure, travel function as well. These changes lead to adaptability for design flow of watercourses, and discipline of storm runoff is interfered because of the changes on underlying surface factors and existing rainwater drainage system. Thus, studying the design flow of flood channel in urban area is feasible and practicable.In this paper, there are some problems in capture calculation of design flow for the flood channel of the city by analyzing the design of the existing calculations: the results is quiet different between the calculations from Municipal sector's storm water formula and Water Resources sector's design flood formula, and that two kinds of formula haven't considered enough surface conditions and storm water drainage system of urban, so the results aren't convinced.By analyzing the issues in calculating design flow of flood channel from process of urbanization and address them in this paper. First of all, analyzes the issues in selecting basic parameters in the formula of inquiring into the design flow by the rain, establishes the rainfall reappearing period relationship of two sampling methods. Secondly, studies the two commonly types used in calculating design flow of the channel flood, to indicate there's adaptability and give the reasons that can't used to calculate design flow of the flood channel, presents the iteration equation basing on the original formula. Thirdly, the paper concludes that design flow of the flood channel is made up of pipe-flow and surface-flow and gives the recommended formula by considering underlying surface factors and rainwater drainage system of the city and by analyzing the direction flow of rainfall and the component of stream flow. Finally, illustrates rationality of the recommended formula by calculating actual design flow of flood channel.