Assessment Of The Causes Of Waterlogging In Wuhan Yuxian Town And The Effectiveness Of Waterlogging Management

In recent years,frequent urban waterlogging has brought great impact on daily life and life and property safety of urban residents,and has brought immeasurable losses to our economic and social development.In early July 2016,Wuhan was attacked by a series of heavy rainstorms.The maximum precipitation occurred in Yuxian Town in Caidian District,with a daily maximum precipitation of 346.5mm.Yuxian Town was forced to transfer nearly 20,000 villagers from 12 villages in an emergency manner for a week.In this study,the core area of Yuxian Town is taken as the research object,the causes of waterlogging in Yuxian Town are analyzed through on-site investigation and data collection,and comprehensive waterlogging control measures are put forward accordingly.A two-dimensional InfoWorksICM model is built,the time and depth of waterlogging are selected as evaluation indexes,the waterlogging evaluation method based on risk index is established,and the area map of waterlogging risk is drawn.The numerical simulation analysis of the waterlogging situation before and after waterlogging treatment is carried out to evaluate the effect of waterlogging treatment.The main work and research results of this paper are as follows:(1)Through on-site investigation,data collection and Infoworks ICM two-dimensional model software,the current drainage model of Yuxian Town is built,and the model is verified by a measured rainfall,which ensures the accuracy of model parameters.Based on GIS technology and current drainage model,the main causes of waterlogging in Yuxian Town are analyzed as follows: low coverage and standard of current pipeline network,low local topography,high water level close to lake,resulting in river overflow and pipe network top support,poor drainage channel and increase of impermeable surface area.(2)According to the causes of waterlogging and relevant planning,the waterlogging treatment scheme of Yuxian Town is put forward,which is a comprehensive treatment measure combining source control,drainage pipe network system reform and river channel reform measures.(3)Infoworks ICM two-dimensional model software is used to build the model of waterlogging control measures,and the effect of waterlogging control is analyzed and evaluated.The evaluation is carried out in two levels: 1.The capability of the new pipeline network system is evaluated separately,and the optimization scheme of the pipeline network transformation is put forward.With the increase of P in the rainstorm return period,the number of overflow nodes,the number of overload pipelines with insufficient capacity and the area of waterlogging are increasing constantly;the number of rainwater pipelines meeting the standard P=3 in the rainstorm return period in Yuxian Town is increasing.The quantity is 40 pieces,and the optimization scheme for 16 pipe networks which do not meet the requirements is proposed.(2)Evaluate the effects of three comprehensive measures implemented at the same time.After multi-measures combined with waterlogging treatment,the area of waterlogging risk in Yuxian Town is significantly reduced,and the reduction effect of waterlogging risk is reduced with the increase of design rainfall return period.The research results in this paper can provide technical support and guidance for network system transformation,flood control planning and waterlogging risk earlywarning in Yuxian Town,and also provide reference for waterlogging prevention and control work in the same region.