Optimum plan of urban drainage system

Based on the characteristics of cities and urban drainage theories,the modern urban drainage system composed of storage,detention and drainage is put forward. DP(dynamic programming) was used to construct the urban drainage system model while DDDP(discrete differential DP) was used to calculate the model.In order to calculate the model quickly and easily,calculation program was compiled in Matlab.In order to explain the model,Shenyang city was taken as an example to plan the drainage system.The plan result shows that the urban drainage system model can not only provide guidance for cities′ development and drainage plan,but give decision support for the utilization of rainwater resources.