Research On Waterlogging Simulation And Risk Assessment Base On Coupled Waterlogging Model In Jinan City

In recent years,global climate change and extreme weather events have occurred frequently.In addition,the urbanization process has accelerated,the scale of urban areas has continued to expand,and urban waterlogging disasters have become increasingly fierce.The important adverse factors of the life and property safety of the masses and the rapid development of the social economy,so the simulation prediction of urban waterlogging and risk prevention and control have become the focus of attention of scholars and management departments at home and abroad.In this thesis,the drainage area above the Huangtaiqiao Hydrological Station(cross section)in Jinan urban area is used as the research area,and the MIKE series software is used to construct a 1D and 2D surface flooding coupled waterlogging model in Jinan urban area.A 1D and 2D surface overflow coupling model was used to simulate the flooding situation of 070718 torrential rains in Jinan City under different scenarios.Based on the simulation results,the submerged water depth,area and duration,underlying surface conditions and social and economic conditions were established The waterlogging disaster risk assessment system of 9 indicators,etc.,with the help of Arcgis’ powerful spatial processing function,evaluated the waterlogging disaster risk of Jinan urban area under different scenarios.The main contents are as follows:(1)Analysis of the causes and characteristics of waterlogging in Jinan City.Based on the analysis of basic data such as physical geography,hydrometeorology,land use,etc.in Jinan,based on the historical waterlogging disasters and rainfall characteristics,the causes and characteristics of waterlogging in Jinan urban area were analyzed from the aspects of terrain,climate,hydrology,etc.Construction laid the foundation.The main factors for the formation of waterlogging in the urban area of Jinan are rainfall and terrain;the rainstorm flood formed by the rainfall in the flood season has the characteristics of extremely fast flow speed and short time and high harm to the lower terrain in the north;the flood channel in the urban area is only the Xiaoqing River,which is experiencing heavy rainfall The flood discharge in the northern part of Shicheng District was not smooth and formed waterlogging.(2)Research on a 1D and 2D surface flooding coupled waterlogging model in Jinan urban area.First,using the MIKE software,a one-dimensional river hydrodynamic model,a one-dimensional pipe network hydrodynamic model,a NAM rainfall runoff model and a two-dimensional surface flood model were constructed respectively.Second,using the MIKE Flood module,a one-dimensional two-dimensional surface in Jinan urban area was constructed The flood coupled waterlogging model;then,based on the NAM rainfall runoff model,the parameters of the NAM rainfall runoff model were calibrated;finally,the 070718 extraordinary heavy rain in Jinan was selected as the typical heavy rain event,using historical measured data and survey data To verify the established one-dimensional two-dimensional surface flooding coupled waterlogging model.The conclusion is as follows:1)When using one-dimensional pipe network model,one-dimensional river channel model and two-dimensional surface flooding alone,only the pipe network,river channel or terrain factors can be considered separately,and it is not possible to simulate the flow interaction between the pipe network,river channel and surface during the flooding process Process,simulation accuracy is limited.Using MIKE Flood to couple a two-dimensional model can make up for their respective disadvantages and improve simulation accuracy and reliability.2)In the NAM rainfall-runoff model,the most sensitive parameters of flood peak flow are TOF and CK12,the P statistics are-0.418 and-0.598,and the R statistics are 0.379 and 0.282,which are negatively correlated;the most sensitive parameter of the peak present time For CK12,P statistics and R statistics are 0.817 and 0.683,respectively,which are positively correlated;the most sensitive parameter of total runoff is TOF,and P statistics and R statistics are-0.594 and 0.434,respectively,which are negatively correlated.3)The simulation results of 070718 extraordinary heavy rain and waterlogging show that the roads running from north to south,such as Erhuan West Road and Erhuan East Road,have flooded by roads;Within the range of m,some of the water points exceed 2m,which is consistent with the characteristics of "Southern Flood and North Waterlogging" in Jinan City.The comparison and analysis of the simulated and measured data such as the inundation range,water depth and water point distribution show that The two-dimensional surface flooding coupled waterlogging model can simulate the flooding process in Jinan city.(3)Waterlogging simulation and risk assessment in Jinan City under different scenarios.Based on the multi-dimensional coupling waterlogging model of Jinan urban area,the risk assessment model of waterlogging disaster is constructed.With the strong spatial processing ability of ArcGIS,combined with population economic data,the risk assessment of waterlogging disaster in different periods of Jinan urban area under the same rainstorm is carried out,and the change trend of waterlogging disaster risk in different periods is analyzed by drawing waterlogging disaster risk map.The conclusion is as follows:1)With land use types in 1992,2002 and 2013 as input data,the inundation of urban area of Jinan City in different periods under 070718 extra-heavy rainstorms,3-hour and 24-hour design rainfalls is simulated.The simulation results show that:①For 3-hour design rainstorm,when rainstorm occurs once in 10 years,the area with 0.15～0.35 m depth of urban water in Jinan City in 1992,2002 and 2013 mainly distributes in the north of the city;when rainstorm occurs once in 20 years,road flooding occurs on the roads with large height difference from north to south,such as the West Ring Road and the East Ring Road.After the rainstorm recurrence period reaches 50 years,the distribution of urban water in Jinan City changes slightly.②For 24-hour design rainfall,when the rainfall intensity is heavy,the inundated area with the depth of accumulated water greater than 0.15m in Jinan City is mainly distributed in the areas of Jing Er Road,Baotuquan South Road,Minghu East Road in the north and middle north of the city;when the rainfall intensity is heavy,the inundated area with the depth of accumulated water greater than 0.35m is the main area;when the rainfall intensity is heavy and heavy,the urban underlying surface conditions areChange has greater impact on inundation scope and water depth of urban area.③For 070718 extra-heavy rainstorms,the inundation range is roughly the same in different periods.The flooded area is concentrated in the middle and north of Jinan City.The inundation depth of typical points increases.Compared with 1992,the inundation depth of typical points increases by 14.58%-45.1%in 2002 and 8.57%～36.36%in 2013 compared with 2002.2)The results of risk assessment of urban waterlogging disasters in Jinan City in different periods show that:① For 3-hour design rainstorm with a return period of 10 years and 20 years,the middle-risk area is mainly located in the lower-lying north urban area and the southern area with a larger road gradient;after the return period reaches 50 years,the distribution of middle-high risk area changes slightly.② For 24-hour design rainfall,during heavy rain and rainstorm,the middle-high risk grade areas are mainly distributed in Beiyuan Street,Lishan North Road and other areas,but there is no high-risk area in the southern part of the city;during heavy rainstorm,the drainage in the northern part of the city is not smooth,the water accumulation is aggravated,and some of the North-South flood discharge roads are in medium-high risk area;during the intensity of heavy rainstorm,no new middle-high risk area appears.However,the area of medium and high risk areas is larger.③ For 0,70718 heavy rainstorms,in 1992,2002 and 2013,the areas above medium-high risk level in Jinan City accounted for 7.3%,9.46%and 11.27%,mainly distributed in the areas east of Wushanshan Road,north of Beiyuan Street and west of Shunhe Elevation;the intersection area of Lishan North Road and Xiaoqing Hebei Road;the east of Shunhe Elevation,south of Minghu Road,West of Lishan Road and Luyuan Street.In the North region,through the intersection of Wushanshan Road,Lishan Road to Garden Road and Jiefang Road,the area of high-risk area increased by 3.9 km2 in 2002 compared with 1992,3.34 km2 in 2013 compared with 2002,and the area of high-risk area of waterlogging disaster mainly developed in Northwest direction,consistent with the direction of urban development,high-risk area in the north,etc.With the increase of grade I area,the pressure of "South Flood and North Flood" in Jinan city is increased.