The Optimization Methods Of City Rainwater Pipe Network Based On GIS And SWMM

City storm pipe network GIS(Geographic Information System),with its superiority in visualization management,spatial analysis and other aspects,has become a support application in city storm pipe network information management.Nowadays,urban waterlogging occurs frequently under extreme rainstorm cases in many cities.Due to lack of professional models and the restriction of low level model integration methods,storm pipe network GIS is facing challenges in both methods and algorithms when applying to pipe network optimization in waterlogging prevention and other areas.Pipe network optimization method that is generally used in current urban planning industry is divided into automatic network optimization based on intelligent algorithm and subjective design of urban hydrological model with artificial experience.However,intelligent algorithm is difficult to fully consider the internal complex hydraulic characteristics of pipeline system and the artificial method always combined with low efficiency is difficult to list each potential optimization solution.According to the above,this paper proposes a method of rainwater pipe network optimization combining GIS data of rainwater pipe network,GIS analysis methods,Storm Water Management Model(SWMM)and differential evolution(DE).Based on the method,this paper carried out comprehensive research on rainwater pipe network optimization.The contents and results of the main research are as follows.Firstly,this paper,based on the summarization of SWMM model object's input requirements and the differences between rainwater pipe network GIS data and the SWMM model object's expression,rebuilds SWMM model object.In order to exchange data among rainwater pipe GIS,SWMM and rainwater pipe network optimization algorithm.Secondly,this paper designs the division method of urban sub catchment units.This method,through comprehensive considerations of urban artificial facilities'influence to rainfall runoff process and the characteristics of urban flow movement,implements SWMM sub catchment model object automatically and efficiently,based on rainwater pipe network GIS and SWMM model's objects.This method can build a reliable model base for the algorithm of rainwater pipe network optimization,which combines SWMM model.Finally,this paper proposes a rainwater pipe network optimization algorithm named "DE-SWMM" to achieve the optimization of the pipe diameter and depth.This algorithm,based on the theory of traditional DE algorithm and the characteristics of optimization of rainwater pipe network and pipeline data,combines the reasonable inspection algorithm for pipe network and the calculation of hydraulic performance constraint for pipe network.This paper use the data of Xianlin campus of Nanjing normal university as experimental data.The results show that this optimization method of rainwater pipe network,based on the dynamic process of the water flow in the pipe network,is able to design a rainwater pipe network reconstruction scheme that with better drainage capacity,higher efficiency and more reasonable.