Analysis of rainfall peak and duration of rainstorm for drainage and waterlogging prevention in Wuhan

In this study, the minute-level rainfall data at Wuhan National Basic Meteorological Observing Stations from 1980 to 2018 are used to ascertain the design storm hyetograph of 1 440 min for the main urban area of Wuhan by the homogenous frequency analysis method and the Huff hyetograph analysis method, respectively. The results about rain peak, time distribution of rainfall and ponding water in the calculation and simulation of rainwater pipe network by hydraulic model software named InfoWorks ICM will be discussed. Results show that: (1) The design storm hyetographs of 1 440 min for the main urban area of Wuhan present single-peak pattern uniformly on the base of the homogenous frequency analysis method and the Huff hyetograph analysis method. Both rain peak positions are slightly ahead of the top 2/3 quintile of the entire rainfall event, while in the stage of 60% to 70%, the rainfall intensity of the former increases rapidly, which is greater than the latter. (2) Under the design storm hyetograph of 1 440 min for the main urban area of Wuhan by the homogenous frequency analysis method, the submerged area of the main urban area of Hankou is larger than that by the Huff hyetograph analysis method, so are the peak values of water depth, flow and velocity. (3) For the main urban area of Wuhan, the proportion of standard pipe network in the system is lower and the water accumulation is more serious when under the design storm hyetograph by the homogenous frequency analysis method.