A rapid simulation method of urban waterlogging coupling swmm and two-dimensional surface hydrodynamic model

Abstract

The application discloses a kind of coupling SWMM and urban waterlogging rapid simulation method of surface two-dimensional hydrodynamic model, it is related to urban rainfall waterlogging numerical simulation technical field.The method includes: obtaining basic data, constructs SWMM model;Utilize SWMM model to simulate target area rainfall runoff and pipe network hydrodynamic process, calculate each pipe network node overflow flow data;Surface two-dimensional hydrodynamic model is constructed;Pipe network node overflow data is corrected and input into surface two-dimensional hydrodynamic model, obtain simulation effect;Utilize historical inundation data to verify simulation effect;In the case where it is verified, based on SWMM model and surface two-dimensional hydrodynamic model simulation analysis different design rainfall condition urban rainfall waterlogging result.The application can give consideration to simulation accuracy and simulation efficiency, with the advantages of simple method, logic clear, strong operability, high simulation result precision.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of urban rainfall waterlogging numerical simulation, in particular to a method for rapidly simulating urban waterlogging by coupling SWMM and a two-dimensional surface hydrodynamic model. BACKGROUND

[0002] Urban waterlogging disaster simulation can not only identify potential risk areas of urban waterlogging, but also help to judge the effectiveness of different drainage measures under complex conditions. It is an important means to accurately estimate urban waterlogging risk and scientifically develop urban waterlogging disaster prevention and mitigation measures. SWMM is a commonly used one-dimensional urban waterlogging simulation model, which is free and open source and stable in operation. Its advantage is that it can better simulate the water dynamic process of the pipe network, but it cannot present the simulation results of surface flow, and it is difficult to give the results of urban waterlogging area, waterlogging depth and waterlogging duration, which is not conducive to correct assessment of urban waterlogging risk.

[0003] Currently, there are two types of technical means to try to solve the problem of surface overflow simulation of SWMM. The first is to combine SWMM with geographic information system (GIS) technology, which calculates the pipe network overflow flow by SWMM, and calculates the flooded area and flooded depth by GIS according to the overflow flow. The first method can achieve good results in areas with simple terrain, but when the terrain is complex, the lack of surface overflow process calculation can easily lead to deviations in the flooded area. The second method couples SWMM with two-dimensional models such as MIKE, LISFLOOD-FP and FVCOM, which are responsible for surface overflow process calculation, and has achieved certain results. However, the current coupling model uses tight coupling, which not only complicates the data interaction logic between models, but also further reduces the model calculation efficiency. Therefore, the present application proposes a method for rapidly simulating urban waterlogging by coupling SWMM and a two-dimensional surface hydrodynamic model, which can balance the simulation accuracy of urban waterlogging and the calculation efficiency of the model. SUMMARY

[0004] The present application proposes a method for rapidly simulating urban waterlogging by coupling SWMM and a two-dimensional surface hydrodynamic model, which decouples pipe network hydrodynamic calculation and surface hydrodynamic calculation, can accurately simulate pipe network hydrodynamic and surface hydrodynamic processes, and can simplify the data interaction logic of the coupling model and improve the calculation efficiency of the model.

[0005] To achieve the above purpose, the technical solution adopted by the present application is:

[0006] The present application provides a method for rapidly simulating urban waterlogging by coupling SWMM and a two-dimensional surface hydrodynamic model, comprising:

[0007] Obtaining basic data, resampling, interpolating and normalizing data with inconsistent time scale or space scale to obtain a data set; the data set includes measured rainfall data, terrain data, land use, soil type, surface building vector, pipe network data, pump station data and historical flooding data;

[0008] Based on the data set, a SWMM model is constructed;

[0009] Using the SWMM model to simulate rainfall runoff and pipe network hydrodynamic process in the target area, and calculating the overflow data of each pipe network node;

[0010] According to the terrain data, surface building vector, land use and soil type data, a two-dimensional surface hydrodynamic model is constructed;

[0011] The pipe network node overflow data is corrected and input into the two-dimensional surface hydrodynamic model to simulate the rainfall waterlogging process and obtain the simulation effect;

[0012] The historical flooding data is used to verify the simulation effect;

[0013] If the simulation effect is verified, the SWMM model and the two-dimensional surface hydrodynamic model are used to simulate and analyze the urban waterlogging results under different design rainfall conditions.

[0014] Further, based on the data set, a SWMM model is constructed, including:

[0015] According to the terrain data, the target area is divided into different sub-catchment areas;

[0016] According to the pipe network data, the spatial layout of the pipe network is determined, including the starting point and ending point of the pipe, the length, diameter and slope;

[0017] The node position of the pipe network, the connection relationship between the sub-catchment area and the pipe network are determined;

[0018] The pipe length, diameter, slope and depth are digitized;

[0019] According to the pipe material and shape, the pipe roughness is set and it is determined whether the pipe is a pressure pipe.

[0020] Further, using the SWMM model to simulate rainfall runoff and pipe network hydrodynamic process in the target area, and calculating the overflow data of each pipe network node, including:

[0021] The measured rainfall data is input into the SWMM model to calculate the runoff, runoff time of the target area, and the pipe network flow, flow rate and pipe network node overflow data are calculated by using dynamic wave algorithm; the calculation formula of total overflow is as follows:

[0022]

[0023] In the formula: O t is the total overflow of the coupling model at time t; o it is the overflow of the i-th pipe network node at time t; n is the number of pipe network nodes overflowing at time t.

[0024] Further, according to the terrain data, the surface building vector, the land use and soil type data, a two-dimensional water dynamic model of the surface is constructed, including:

[0025] The surface of the target area is divided by using a triangular grid or a quadrilateral grid, and the surface building vector is considered during the division, so that the area where the surface building is located is set as an un-submergible area, and the influence of the surface building on the surface accumulated water is determined;

[0026] The terrain elevation data is interpolated into the divided surface grid to form a digital elevation terrain;

[0027] According to the land use and soil data, the initial roughness of the two-dimensional water dynamic model of the surface is set;

[0028] According to the coordinates of the pipe network nodes in the SWMM model, corresponding water source nodes are set and numbered in the two-dimensional water dynamic model of the surface, and the simulation data of the SWMM model and the two-dimensional water dynamic model of the surface are interacted, and the interaction data types include the pipe network node overflow and the surface accumulated water depth; wherein the pipe network nodes in the SWMM model are mapped to the two-dimensional water dynamic model of the surface by the following formula (2):

[0029]

[0030] In the formula: X, Y are the horizontal coordinate and vertical coordinate of the pipe network node in the two-dimensional water dynamic model of the surface, D X and D Y are the translation amounts of the pipe network node in the x and y directions during coordinate transformation; m is the scaling factor; θ is the rotation angle, x0, y0 are the horizontal coordinate and vertical coordinate of the pipe network node in the SWMM model.

[0031] Further, the pipe network node overflow data is corrected and input into the two-dimensional water dynamic model of the surface, the rainfall waterlogging process is simulated, and the simulation effect is obtained, including:

[0032] According to the pipe network node overflow state, the pipe network nodes are divided into three categories, as shown in formula (3) to formula (6):

[0033] n=A+B+C (3)

[0034] A={x A |o x≥ 0} (4)

[0035] B = {x B | o x < 0, Depth x ≥ TH} (5)

[0036] C = {x C | o x < 0, Depth x < TH} (6)

[0037] where: n is the total number of nodes in the coupled model pipe network; TH is the threshold of ponding depth; Set A represents the node overflow o x whose node number is greater than or equal to 0; Set B represents the node overflow o x whose node number is less than 0 and the ponding depth Depth x satisfies the threshold requirement of ponding depth; Set C represents the node overflow o x whose node number does not satisfy the threshold requirement of ponding depth.

[0038] At this time, the total overflow of the coupled model is shown in formula (7):

[0039] O n = O A + O B + O C (7)

[0040] where: O n is the total overflow of the pipe network node at time t, m 3 ; O A , O B and O C are the overflows of the pipe network nodes corresponding to sets A, B and C, respectively, m 3 .

[0041] For the pipe network node x A belonging to set A, its overflow is not corrected; for the pipe network node x B belonging to set B, its overflow O' x at the node x of the surface two-dimensional hydrodynamic model can be corrected by the overflow O x of the corresponding node of the SWMM model, as shown in formula (8) to formula (9); for the pipe network node x C belonging to set C, its overflow is set to 0 in the surface two-dimensional hydrodynamic model.

[0042]

[0043] where: k is the correction coefficient of the overflow.

[0044] The total surface water drainage volume of the coupled model is calculated using the following formula:

[0045]

[0046] In the formula: D t Let m be the total surface water drainage volume of the coupled model at time t. 3 α is the adjustment coefficient, calibrated using historical flooding data; m is the number of pumping stations; pump jt Let represent the pumping capacity of the j-th pumping station at time t. When pumping out accumulated water, the overflow rate is set to a negative number, indicating that the waterlogging has subsided.

[0047] The corrected overflow time series of the pipeline nodes is input into the surface hydrodynamic model to simulate the water accumulation and receding process of urban flooding. The simulation process is shown in equations (11) to (13):

[0048]

[0049] In the formula: x and y are Cartesian coordinates, m; t is time, s; h is water depth, m; u and v are the flow velocities in the x and y directions, respectively, m / s; z is water level, m; g is gravitational acceleration, m / s². 2 ;v t Here is the turbulent viscosity coefficient, in N·s / m. 2 n is the Manning roughness coefficient, m / s^(1 / 3).

[0050] Furthermore, the simulation effect is verified using the historical flooding data, including:

[0051] The maximum inundation range, maximum inundation depth, and water accumulation process data from the coupled simulation were compared with historical inundation data. The Nash efficiency coefficient, root mean square error, and coefficient of determination were used to evaluate the effectiveness of the coupled simulation and verify whether the model accuracy met the requirements. If the accuracy requirements were not met, an improved particle swarm optimization algorithm was used to iteratively adjust the coupled model parameters to reconstruct the SWMM model. The coupled model parameters include runoff coefficient, infiltration rate, surface roughness, pipe roughness, and pipe network outflow regulation coefficient. The iterative process of the improved particle swarm optimization algorithm is as follows:

[0052]

[0053] In the formula: Let represent the position of the i-th particle in the k-th iteration, and represent the value of the model parameter; Let P be the velocity of the i-th particle in the k-th iteration, representing the adjustment amount of the model parameters; best (i) represents the current optimal value of particle i; G bestis a global optimal value; c1 and c2 are learning factors with non-negative values; r1, r2 are uniform random numbers in the range of [0, 1], ω max and ω min are the maximum and minimum values of the inertia weight respectively; k is the current iteration number; T is the maximum iteration number; is the velocity of the i th particle in the k+1 th iteration, is the position of the i th particle in the k+1 th iteration;

[0054] The reconfigured SWMM model is used to simulate the rainfall runoff and water dynamic process of the target area, recalculate the overflow data of each pipe network node, correct the recalculated pipe network node overflow data and input the surface two-dimensional water dynamic model, simulate the rainfall waterlogging process, obtain new simulation results, and verify the new simulation results.

[0055] Further, based on the SWMM model and the surface two-dimensional water dynamic model, the urban waterlogging results under different design rainfall conditions are simulated and analyzed, including:

[0056] Different return period design rainfall processes are input into the SWMM model, and the output of the SWMM model is input into the two-dimensional water dynamic model to simulate and analyze the urban rainfall waterlogging process under different design rainfall scenarios, and finally output the pipe network overflow, maximum flooded area and flooded depth, different position flooded duration and flooded process data.

[0057] The application has the advantages that:

[0058] The application integrates the advantages of the one-dimensional pipe network model and the two-dimensional ground water dynamic model, simplifies the complex data interaction logic in the coupling simulation of the one-dimensional and two-dimensional models, has high simulation accuracy and simulation efficiency, and has the advantages of simple method, clear logic, strong operability, and high simulation result accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0059] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0060] Figure 1 A flowchart of a coupling SWMM and surface two-dimensional water dynamic model urban waterlogging rapid simulation method provided by an embodiment of the application;

[0061] Figure 2 SWMM and surface two-dimensional water dynamic model coupling construction results provided by an embodiment of the application, wherein (a) is an SWMM model; (b) is a surface two-dimensional water dynamic model;

[0062] Figure 3A comparison diagram of historical and simulated flooding processes provided for embodiments of this application;

[0063] Figure 4 The image shows the simulation results of the water depth in the target area during rainfall-induced flooding, as provided in the embodiments of this application.

[0064] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0065] The following examples are merely illustrative of the invention, and the scope of the invention is not limited to the embodiments described. Therefore, any non-essential modifications and adjustments made by those skilled in the art based on the above description to other embodiments are still within the scope of protection of this invention.

[0066] The invention will now be further described with reference to the accompanying drawings.

[0067] This application provides a method for rapid simulation of urban flooding that couples SWMM and a two-dimensional surface hydrodynamic model. Figure 1 A flowchart illustrating a rapid urban flooding simulation method coupled with a two-dimensional surface hydrodynamic model, provided as an embodiment of this application. Figure 1 As shown, the method includes steps 1 to 7 as follows.

[0068] Step 1: Obtain basic data. Perform resampling, interpolation, and normalization on the basic data to obtain a dataset. The dataset includes measured rainfall data, topographic data, land use, soil type, surface building vectors, pipeline data, pumping station data, and historical inundation data.

[0069] In this embodiment, the data sources can be basic data collected from the National Meteorological Science Data Center, the Resource and Environmental Science and Data Center of the Chinese Academy of Sciences, the Municipal Water Resources Bureau, and the Housing and Urban-Rural Development Bureau. This includes hourly measured rainfall data, topographic, land use, and soil type data of the modeling area, surface building vector data, underground pipe network length, diameter, and flow direction data, pump station distribution and installed capacity, and historical inundation data. The basic data undergoes resampling and interpolation processing, and data with inconsistent time or spatial scales is normalized.

[0070] Step 2: Based on the dataset, construct the SWMM model.

[0071] In this embodiment, the target area is divided into different sub-catchment areas by using GIS to extract the elevation, slope, flow direction, etc. According to the municipal pipe network data, the spatial layout of the pipe network is determined, including the pipe starting point and ending point, length, diameter, slope, etc. The node position of the pipe network, the connection relationship between the sub-catchment area and the pipe network are determined. According to the land use, soil type, etc., the runoff coefficient, infiltration rate, etc. of the sub-catchment area are preliminarily set; the pipe length, diameter, slope, buried depth, etc. information is digitized and input into the model, and the pipe network roughness and whether it is a pressure pipe are set according to the pipe network material and shape. Based on the above, the construction of the SWMM model can be completed, and the SWMM model construction result of this embodiment is as shown in Figure 2 (a).

[0072] Step 3, using the SWMM model to simulate the rainfall runoff and pipe network hydrodynamic process of the target area, and calculating the overflow flow data of each pipe network node.

[0073] In this embodiment, the measured rainfall data is input into the constructed SWMM model, and the runoff of the target area, the concentration time, etc. are calculated, and the dynamic wave algorithm is used to calculate the pipe network flow, flow velocity and pipe network node overflow flow data, which are used for two-dimensional water dynamic process calculation of the ground surface. The overflow flow time series calculation method is as formula (1):

[0074]

[0075] In the formula: O t is the total overflow flow of the coupling model at time t, m 3 ; o it is the overflow flow of the i-th pipe network node at time t, m 3 ; n is the number of pipe network nodes overflowing at time t.

[0076] Step 4, according to the terrain data, ground building vector, land use and soil type data, a two-dimensional water dynamic model of the ground surface is constructed.

[0077] In this embodiment, triangular or quadrilateral grids are used to divide the surface of the target area. Surface building vectors are considered during the division, and the areas where surface buildings are located are set as non-inundation zones to clarify the impact of surface buildings on surface water accumulation. Topographic elevation data is interpolated into the divided surface grid to form digital elevation topography of the target area. The initial roughness of the two-dimensional hydrodynamic model is set according to land use and soil data. Since the regional runoff calculation has already been completed by the SWMM model, no recalculation is performed when constructing the two-dimensional hydrodynamic model. According to the (x0, y0) coordinates of the pipeline nodes in the SWMM model, corresponding water source nodes are set and numbered in the two-dimensional hydrodynamic model of the surface for interaction between the simulation data of the SWMM model and the two-dimensional hydrodynamic model of the surface. The data types for interaction include pipeline node overflow and surface water accumulation depth. The pipeline node mapping method is shown in equation (2):

[0078]

[0079] In the formula: X and Y are the coordinates of the pipeline nodes in the two-dimensional hydrodynamic model on the ground surface, and D... X and D Y It represents the translation of the pipeline node in the x and y directions during coordinate transformation, in meters; m is the scaling factor considering scaling; θ is the rotation angle.

[0080] like Figure 2 As shown in (b), this is a schematic diagram of a two-dimensional hydrodynamic model of the Earth's surface.

[0081] Step 5: Correct the overflow data of the pipeline nodes and input it into the two-dimensional hydrodynamic model of the surface to simulate the rain-induced waterlogging process and obtain the simulation results.

[0082] In this embodiment, the SWMM model assumes that the overflow from the pipe network always exists at the overflow node and does not flow with the terrain, which is inconsistent with reality. Therefore, the time series of overflow flow at the pipe network node needs to be corrected. If the overflow flow at the pipe network node is positive, it indicates that the flow is overflowing from the pipe network node. At this time, the overflow data will be transmitted to the corresponding node position in the two-dimensional hydrodynamic model of the surface, and the surface hydrodynamic process will be simulated as free fluid, thus reflecting the overflow's diffuse state on the surface and its accumulation in low-lying areas. When the rainfall decreases, the drainage capacity of the pipe network will be greater than the drainage volume. At this time, the surface water will re-enter the pipe network and be drained away, and the overflow flow at the pipe network node will be negative. Since the SWMM overflow generation and water discharge both occur at the same node position, and the water is free-flowing in the two-dimensional hydrodynamic model of the surface, if the SWMM overflow data is mapped in situ to the nodes of the surface hydrodynamic model, some pipe network nodes with higher elevations will not be able to correctly simulate the receding process of urban flooding, which needs to be corrected.

[0083] First, based on the overflow status of the pipeline nodes, the pipeline nodes are divided into three categories, as shown in equations (3) to (6):

[0084] n = A + B + C (3)

[0085] A={x A |o x ≥0} (4)

[0086] B = {x} B |o x <0, Depth x ≥TH} (5)

[0087] C={x C |o x <0, Depth x <TH} (6)

[0088] In the formula: n is the total number of nodes in the coupled model network; TH is the water depth threshold, in cm; set A represents the node number where the overflow rate is greater than or equal to the node number; set B represents the node number where the overflow rate is less than 0, but the water depth at node x is less than 0. x The node numbers that meet the water depth threshold requirements; set C contains nodes with overflow rates less than 0 and water depth at node x. x Node numbers that do not meet the water depth threshold requirements.

[0089] At this point, the total overflow of the coupled model is as shown in equation (7):

[0090] O n =O A +O B +O C (7)

[0091] In the formula: O n Let m be the total overflow of the pipeline nodes at time t. 3 ;O A O B and O C The overflow rates of the corresponding pipeline nodes in sets A, B, and C are m. 3 .

[0092] For network nodes x belonging to set A A The overflow is not corrected; for network node x belonging to set B B Its overflow O' at node x in the two-dimensional hydrodynamic model of the Earth's surface x The overflow O of the corresponding node in the SWMM model can be used as a reference. x The corrected results are shown in equations (8) to (9); for the network node x belonging to set C C Its overflow is set to 0 in the two-dimensional hydrodynamic model of the surface.

[0093]

[0094]

[0095] wherein k is a correction coefficient of the overflow.

[0096] The total surface water pumping capacity of the coupling model is calculated by the following formula:

[0097]

[0098] wherein D t is the total surface water pumping capacity of the coupling model at time t, m 3 ; a is an adjustment coefficient, mainly related to factors such as the submerged water depth of the pipe network node, whether the rainwater grate is covered by garbage, etc., and needs to be calibrated using historical submerged data; m is the number of pumping stations, and in municipal management, pumping stations need to be called to speed up the drainage of accumulated water in areas with deep accumulated water, and the value is obtained from research data; pump jt is the pumping capacity of the jth pumping station at time t, m 3 . When the accumulated water is pumped, the overflow is set to a negative number, representing the recession of waterlogging accumulated water.

[0099] The corrected pipe network node overflow time series is input into the surface water dynamic model to simulate the accumulated water and recession process of urban waterlogging, and the calculation method is shown in formulas (11) to (13):

[0100]

[0101] wherein x and y are Cartesian coordinate system coordinates, m; t is time, s; h is water depth, m; u and v are flow rates in x and y directions, respectively, m / s; z is water level, m; g is gravitational acceleration, m / s 2 ; v t is the turbulent viscosity coefficient, N·s / m 2 ; n is the Manning roughness coefficient, m / s^(1 / 3).

[0102] Step 6, verify the simulation effect using historical submerged data.

[0103] In this embodiment, the maximum submerged range, the maximum submerged depth, the accumulated water process and other data of the coupling simulation are compared with the historical submerged data, and the Nash efficiency coefficient (NSE), the root mean squared error (RMSE), the coefficient of determination (R 2) the coupling simulation effect is evaluated to check whether the model accuracy meets the requirements. If the accuracy requirements are not met, return to step 2, and use the improved particle swarm optimization algorithm to iterate and adjust the coupling model parameters such as runoff coefficient, infiltration rate, surface roughness, pipe roughness, and pipe network outflow adjustment coefficient. The principle of the improved particle swarm optimization algorithm is as follows:

[0104]

[0105]

[0106] In the formula: is the position of the i-th particle in the k-th iteration, which can represent the value of the model parameter; is the velocity of the i-th particle in the k-th iteration, which can represent the adjustment amount of the model parameter; best (i) is the optimal value of particle i so far; G best is the global optimal value; c1 and c2 are learning factors with non-negative values; r1 and r2 are uniform random numbers generated in the range of [0, 1]. max and ω min are the maximum and minimum values of the inertia weight, respectively; k is the current iteration number; T is the maximum iteration number.

[0107] Repeat steps 3 to 5 until the simulation accuracy meets the requirements. The model calibration and verification results of this embodiment are shown in Figure 3 .

[0108] Step 7, in the case where the simulation effect is verified, the urban waterlogging results under different design rainfall conditions are simulated and analyzed based on the SWMM model and the two-dimensional water dynamic model.

[0109] In this embodiment, a 24-hour design rainfall process with a 50-year return period is calculated. The 50-year return period design rainfall process is input into the model to simulate and analyze the urban rainfall waterlogging process under this design rainfall scenario, and output the pipe network overflow flow, maximum inundation range and inundation depth, inundation duration and inundation process at different locations, etc., to provide method tools and data support for urban drainage pipe network resilience assessment, waterlogging risk assessment, emergency management decision-making, etc. The simulation results of the target area rainfall waterlogging water depth are shown in Figure 4 .

[0110] The above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the description of the present application.

Claims

1. A method for rapid simulation of urban waterlogging coupling SWMM and a two-dimensional surface hydrodynamic model, characterized in that, The method comprises the following steps: acquiring basic data, resampling, interpolating and normalizing data with inconsistent time scale or space scale to obtain a data set; the data set comprises measured rainfall data, terrain data, land use, soil type, surface building vector, pipe network data, pump station data and historical flooding data; constructing a SWMM model based on the data set; simulating rainfall runoff and pipe network hydrodynamic process in the target area by using the SWMM model, and calculating overflow data of each pipe network node; constructing a surface two-dimensional hydrodynamic model according to terrain data, surface building vector, land use and soil type data; correcting the pipe network node overflow data and inputting the surface two-dimensional hydrodynamic model to simulate the rainfall waterlogging process and obtain the simulation effect; verifying the simulation effect by using the historical flooding data; if the simulation effect is verified, simulating and analyzing urban rainfall waterlogging results under different design rainfall conditions based on the SWMM model and the surface two-dimensional hydrodynamic model; correcting the pipe network node overflow data and inputting the surface two-dimensional hydrodynamic model to simulate the rainfall waterlogging process and obtain the simulation effect, comprising: dividing the pipe network nodes into three categories according to the pipe network node overflow state, as shown in formulas (3) to (6): （3） （4） （5） （6） where n is the total number of nodes in the coupled model pipe network; is the water depth threshold; Set A represents the node overflow flow o x is the node number greater than or equal to 0; Set B represents the node overflow flow o x is less than 0 and the water depth at x node is the node number satisfying the water depth threshold requirement; Set C represents the node overflow flow o is the node number not satisfying the water depth threshold requirement; the total overflow of the coupling model is shown in formula (7): （7） In the formula: is the total overflow flow of the pipe network nodes at time t; , and are the overflow flows of the pipe network nodes corresponding to sets A, B, and C, respectively. For pipe network node x belonging to set A A whose overflow flow is not corrected; for pipe network node x belonging to set B B whose overflow flow at surface two-dimensional hydrodynamic model node x is corrected by the overflow flow of the corresponding node of the SWMM model , as shown in equations (8) to (9); for pipe network node x belonging to set C C whose overflow flow is set to 0 in the surface two-dimensional hydrodynamic model; （8） （9） wherein k is the overflow correction coefficient; the total surface water pumping capacity of the coupling model is calculated by the following formula: （10） wherein: is the total surface water pumping capacity of the coupling model at time t, is a calibration factor calibrated using historical inundation data; is the number of pumping stations; is the pumping capacity of the jth pumping station at time t, and the overflow is set to negative during water pumping, representing the subsidence of waterlogging. inputting the corrected pipe network node overflow time sequence into the surface hydrodynamic model to simulate the accumulation and recession process of urban waterlogging, and the simulation process is shown in formulas (11) to (13): （11） （12） （13） In the formula: x, y are the coordinates of the Cartesian coordinate system; t is time; h is water depth, u, v are the flow velocities in x, y directions respectively; z is water level; g is gravity acceleration; is the turbulent viscosity coefficient; n is the Manning roughness coefficient.

2. The method of claim 1, wherein, constructing a SWMM model based on the data set, comprising: dividing the target area into different sub-catchment areas according to terrain data; determining the spatial layout of the pipe network, including the starting point and ending point of the pipe, the length, diameter and slope of the pipe; determining the node position of the pipe network, the connection relationship between the sub-catchment area and the pipe network; digitizing the length, diameter, slope and burial depth of the pipe; setting the pipe roughness according to the pipe material and shape, and determining whether the pipe is a pressure pipe.

3. The method of claim 1, wherein, simulating rainfall runoff and pipe network hydrodynamic process in the target area by using the SWMM model, and calculating overflow data of each pipe network node, comprising: inputting the measured rainfall data into the SWMM model to calculate the runoff, runoff time of the target area, and calculating the pipe network flow, flow rate and pipe network node overflow data by using the dynamic wave algorithm; the calculation formula of the total overflow is as follows: （1） In the formula: is the total overflow flow of the coupling model at time t; is the overflow flow of the i-th pipe network node at time t; n is the number of pipe network nodes overflowing at time t.

4. The method of claim 3, wherein, constructing a surface two-dimensional hydrodynamic model according to terrain data, surface building vector, land use and soil type data, comprising: dividing the surface of the target area by using triangular grid or quadrilateral grid, considering the surface building vector when dividing, setting the area where the surface building is located as an un-floodable area, and clearly defining the influence of the surface building on the surface water accumulation; interpolating the terrain elevation data into the divided surface grid to form a digital elevation terrain; setting the initial roughness of the surface two-dimensional hydrodynamic model according to the land use and soil data; According to the coordinates of the pipe network nodes in the SWMM model, corresponding water source nodes are set and numbered in the two-dimensional surface hydrodynamic model, for interaction of simulation data of the SWMM model and the two-dimensional surface hydrodynamic model, the interaction data types include pipe network node overflow and surface water depth; wherein the pipe network nodes of the SWMM model are mapped to the two-dimensional surface hydrodynamic model by the following formula (2): （2） wherein: X, Y are the horizontal and vertical coordinates of the pipe network node in the two-dimensional surface water dynamic model, and are the translation of the pipe network node in the x and y directions during the coordinate transformation; m is the scaling factor; is the rotation angle, x0, y0 are the horizontal and vertical coordinates of the pipe network node in the SWMM model.

5. The method of claim 1, wherein, The simulation effect is verified by using the historical inundation data, including; The maximum inundation range, the highest inundation depth and the water accumulation process data of the coupled simulation are compared with the historical inundation data, Nash efficiency coefficient, root mean square error and determination coefficient are used to evaluate the coupled simulation effect, and whether the model precision meets the requirements is tested; in the case of not meeting the precision requirements, the improved particle swarm optimization algorithm is used to iterate and adjust the coupled model parameters to reconstruct the SWMM model; wherein the coupled model parameters include runoff coefficient, infiltration rate, surface roughness, pipe roughness and pipe network outflow adjustment coefficient, and the improved particle swarm optimization algorithm iteration process is as follows: （14） （15） （16） wherein: is the position of the i-th particle in the k-th iteration, and represents the value of the model parameters; is the velocity of the i-th particle in the k-th iteration, and represents the adjustment of the model parameters; is the current optimal value of the particle i; is the global optimal value; c1 and c2 are learning factors with non-negative values; r1, r2 are uniform random numbers generated in the range of [0, 1], and are the maximum and minimum values of the inertia weight, respectively; k is the current iteration number; T is the maximum iteration number; is the velocity of the i-th particle in the k+1-th iteration, is the position of the i-th particle in the k+1-th iteration; The SWMM model is simulated to simulate the rainfall runoff and pipe network hydrodynamic process of the target area, the pipe network node overflow data is recalculated, the recalculated pipe network node overflow data is corrected and input into the two-dimensional surface hydrodynamic model, the rainfall waterlogging process is simulated, a new simulation effect is obtained, and the new simulation effect is verified.

6. The method of claim 1, wherein, Based on the SWMM model and the two-dimensional surface hydrodynamic model, the urban waterlogging results under different design rainfall conditions are simulated and analyzed, including: The different return period design rainfall processes are input into the SWMM model, the output of the SWMM model is input into the two-dimensional surface hydrodynamic model, the urban rainfall waterlogging process under different design rainfall scenarios is simulated and analyzed, and finally the pipe network overflow, the maximum inundation range and the inundation depth, the inundation time and the inundation process data at different positions are output.

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