Simulation Study On Waterlogging In Urban Area Of Changchun City Based Onrainfall Intensity And Surface Water Seepage Characteristics

In order to simulate the influence range of the flood disaster in the main urban area of Changchun City,this study uses Li DAR point cloud data and remote sensing image data to obtain the DEM and land use distribution map of the study area,and then completes the calculation of urban surface water accumulation,the realization of urban waterlogging simulation system and the analysis on the results of main urban waterlogging simulation.The main results of this study are as follows:(1)Using Li DAR point cloud data,a high-precision DEM in the study area was constructed with an accuracy of 0.24 meters.(2)Based on the high-precision DEM and the collected rainwater grate data in Changchun City,the sub-catchment division of the study area was completed,with a total of 1826.(3)Using Sentinel-2A remote sensing satellite date,through supervised classification,a total of 5 classification results of land use in the study area were obtained,of which5808.08 hectares of roads,accounting for 11.16%;30433.11 hectares of impervious surface,accounting for 58.43%;14071.75 hectares of green land,accounting for27.02%;1500.14 hectares of water area,accounting for 2.88%;267.50 hectares of bare land,accounting for 0.51%.(4)Combining the runoff coefficients of different features and the area of the classification results,the comprehensive runoff coefficient of the study area is calculated to be 0.61 by using the comprehensive runoff coefficient method,and the calculation of surface runoff parameters in the study area is completed.(5)Based on the basic theory of hydrology,the waterlogging simulation system of Changchun City is constructed by using C# language.The inundation range and inundation area of Changchun main urban area under four rainstorm recurrence periods of 1 year,5 years,10 years and 20 years are simulated.The main conclusions of this study are:(1)The DEM of the study area is constructed,and its precision reaches the accuracy requirement of 1:10000 DEM,which can be used as the basic topographic data for the scenario simulation of the waterlogging simulation system in Changchun City.(2)Using Sentinel-2A remote sensing satellite data,a total of 5 classification results of land use in the study area were obtained through supervised classification.The accuracy is high and it can be used to calculate the comprehensive runoff coefficient of the study area.(3)The simulation results of the inundation range and the inundation area of the main urban area of Changchun City under different rainstorm recurrence periods using the waterlogging simulation system constructed in this study are basically consistent with the actual impression.