Research On Urban Flooding Model And Application Of Its Spatial Database

At present,the pace of urban construction is speeding up,and the problems brought about by urbanization are beginning to appear.Urban flooding caused by the reduction of pervious area and abnormal climate changes has become an urgent problem to be solved.The study of disasters in the local flooding area and the assessment of the current drainage network have become the key to a thorough analysis of the local flooding disasters.In addition,the city data,rainfall data and drainage system data and other data are numerous,the amount of data is large and cumbersome,data storage and management become a problem.Therefore,how to organize and store data information reasonably and systematically is also an important process in the establishment of the local flooding model.The research contents and related research results include the following aspects:(1)Using the rainfall intensity formula to design four different return periods of rainfall in 2,3,5 and 10 years,based on DHI MIKE to construct the urban flooding model of the selected research area of Y City;(2)Based on the pipe network result obtained from the MIKE Urban one-dimensional drainage pipe network model,the drainage capacity of the current drainage pipe network is evaluated from the aspects of surface production flow,pipe fullness and overflow nodes,and master the location of the main pipe section where the drainage of the pipe network is not smooth.The results show that the design standard of the drainage network in the study area is low.The length of maximum filling pipe in 2-year design rainfall return period has reached more than half of the entire drainage network,the poor drainage and the flooding nodes are mostly near the intersection;(3)Based on the MIKE Flood model,the water depth and water collection range of the water accumulation area are counted;The flood risk threshold method was used to divide the risk area of the local flooding area.The results show that the average maximum water depth of the four rainfall results exceeded the design standard of the watery area.The water accumulation range increased rapidly from 0.5h to 1h.After that,it gradually decreases,and the trend is slower.According to the calculated threshold,the local flooding risk area is divided into four grades,and the rate of medium risk area is largest.The disaster impact is mainly caused the flooding depth affecting traffic or slowing down water withdrawal.(4)Establishing the geodatabase spatial database,decompose and load the data required for the construction of the local flooding model into the urban flooding spatial database,applied to the construction of the local flooding model in the form of a database,and store the results of the pipe network and the results of the local flooding disasters into the urban flooding spatial database.In the data call analysis,the GIS platform can be used to directly retrieve the local flooding database in gdb format for data analysis,editing and display,realize systematic storage and management of data.