Research On The Rainstorm Intensity Formula Derivation Of Huangshan City

With the global climate change, rapid urbanization and social development, people tend to have stricter demand on city drainage and flood control. So the present rainstorm intensity formula of Huangshan City has been unable to meet the need of city development. According to the reality, we investigate the local rainstorm characteristics and propose a more precise formula, which is based on a long series of storm data. This new formula will provide basis for designing the city drainage and flood control projects.In this paper, Tunxi station, which has a long series of rainfall data (from 1965 to 2013), is selected as the representative station of Huangshan City. Based on the comparative analysis of several sampling methods, we choose the annual maximum method to sample the raw rainfall data in different periods. And curve fitting method is applied to solve out the T～i～t parameters and simulate the frequency curves, including the Pearson-Ⅲ distribution, exponential distribution and Gumbel distribution curve. Then we calculate the error between frequency curve and measured values, the Gumbel distribution curve shows the best fitting effect. Among Gauss Newton, Levenberg-Marqardt-Hartley, Genetic Algorithm and Quasi-Newton method, Levenberg-Marqardt-Hartley and Quasi-Newton method tend to be more accurate and efficient than others by the calculation of MATLAB. Therefore, we choose Gumbel distribution curve and analyse the frequency of annual maximum values by curve fitting method. Based on SPSS and MATLAB, we select accurate parameters of rainstorm intensity formula and finally derive the new rainstorm intensity formula of Huangshan City. At the end of this paper, two practical cases are provided, which verifies the formula application to the design of storm and drainage system in Huangshan. Meanwhile the given cases can also present the criteria connection between municipal and water conservancy engineering. This new formula developed in our study will eventually offer some guidance to the city construction and social development of Huangshan.