Drainage Waterlogging Planning Of A Small City Based On Mike Urban

Under the background of global warming,the frequency of extreme weather events significantly increased in recent decades. In our country, urban waterlogging caused by extreme rainfall occurred frequently, it has serious influence on the people’s lives and property security. Urban rainwater network system is one of the important infrastructure because the network has the function of collecting rainwater and eliminating the rain. In the past, the urban rainwater network design return period is about 1~3 years, rainfall over the standard is likely to cause the waterlogging disasters of the city. However, some basic general urban’s design return period is between 0.5 ~ 1 year, with backward drainage construction and insufficient emergency management,which lead to the frequent waterlogging problems. How to effectively improve the city’s drainage system and prevent the happening of the waterlogging disaster has become an important livelihood issue concerned by the government and the general public.The traditional drainage network calculation often uses the empirical formula method. In the process of calculation,this method makes more generalization, and the process only considers the peak flow, without the consideration of the overall rainfall process. Compare with the traditional method, the result obtained bythe software simulation is more accurate and complete. The main research contents and results are as follows.1. Analyze the causes of urban waterlogging. The causes of waterlogging mainly include the natural factors and human factors.2. Reorganize the basic information of the rainwater network. Use geographic information system(GIS) software to deal with the pipeline census data. Then turn the census data into hongye CAD file. In the process of establishing the simulation model, the collection, sorting and data entry of rainwater network basic information are the most laborious work, and moreover, have great effects on model precision.3. Convert the rainwater network information. Apply AMIAS software to pretreat the rainwater network of the A city in zhejiang province and turn rainwaternetwork information into the format recongnized by the Mike Urban. The arrangement and transformation of rainwater network information is the foundation of the following modeling work.4. Establish the rainwater network waterlogging simulation model.Take the rainwater network system of E city in zhejiang province as an example, according to the present situation of the city’s rainwater system, build the E city rainwater network waterlogging simulation model by Mike Urban software.First, confirm the basic parameters of rainwater network model. Second, devise and connect the watershed division. Third, ascertain the rainfall boundary conditions. Finally, set up the runoff-yield model and pipe flow model.5. Check the present rainwater network capacity and simulate Waterlogging.Calculate the flow capacity of the inspection well in a free outflow mode and a submerged outflow mode under different return periods. According to the result of the E city waterlogging model, get the various performance of the urban drainage system.Then judge the waterlogging distribution and find out the waterlogged points.6. Formulate the drainage waterlogging planning. According to the results of the rainwater network waterlogging model, make a targeted rainwater network planning,and work out a short-term emergency and a long-term sustainable solution for urban waterlogging.7. Put forward the countermeasures and suggestions for dealing with the urban waterlogging.