Surface water simulation method based on SWMM and vertical boundary coupling

Abstract

The present invention discloses a surface waterlogging simulation method based on SWMM and vertical boundary coupling. The method comprises the following steps: (1) making an inp input file of SWMM and simulating to obtain an out result file; (2) completing the topological association between the inspection well and the vertical boundary flow area grid; (3) extracting the SWMM simulation results and creating a vertical boundary flow area input file of the overflow / discharge time series process; (4) loading the vertical boundary flow area input file and other types of input files into a two-dimensional hydrodynamic model to simulate the distribution and depth of waterlogging in the relevant area under a specified rainfall scenario. The method of the present invention is helpful for effectively identifying the rising and retreating process, waterlogging area and waterlogging range of waterlogging in the SWMM and two-dimensional hydrodynamic coupling simulation, and is suitable for the evaluation of urban waterlogging prevention capacity and risk, urban drainage impact evaluation, rainstorm waterlogging risk forecast and early warning, and other related applications and research on urban waterlogging simulation.

Description

Technical Field

[0001] The present invention belongs to the technical field of municipal engineering, and relates to a surface waterlogging simulation method based on SWMM and vertical boundary coupling, which is suitable for simulation of urban waterlogging and risk identification. Background Art

[0002] At present, hydrodynamic models, as a mature digital simulation technology, have been widely used in urban stormwater simulation, such as the assessment of urban flood control capacity and risks, urban drainage impact assessment, and related research and application of rainstorm waterlogging risk forecasting and early warning.

[0003] The mainstream hydrodynamic model software include InfoWorks ICM software developed by the British company Valencia, MIKEUrban software developed by the Danish Hydraulic Institute, and SWMM software developed by the US Environmental Protection Agency. The former two can simulate the water flow process in pipes or rivers, as well as the surface water flow, but they are commercial software and relatively closed; the latter is open source software, open to the world, and is widely used and recognized by relevant industry workers and researchers in related fields, but SWMM can only simulate the water flow process in pipes or rivers, and cannot simulate the surface water flow process. Summary of the invention

[0004] In order to solve the problem that SWMM software cannot simulate the overflow process of surface water, the present invention proposes a surface water simulation method based on the coupling of SWMM and vertical boundaries, which can simulate the distribution of surface water and the depth of water.

[0005] Based on the surface waterlogging simulation method coupled with SWMM and vertical boundaries, the overflow / discharge time series process of the pipe network is extracted based on the SWMM simulation results, and set in the two-dimensional hydrodynamic model in the form of a vertical boundary flow area to simulate the process of water accumulation on the surface through the vertical boundary flow area and the discharge of the accumulated water through the vertical boundary flow area, so as to obtain the results of surface waterlogging distribution and water depth;

[0006] The steps include: (1) making the inp input file of SWMM and simulating to obtain the out result file; (2) completing the topological association between the inspection well and the vertical boundary flow area grid; (3) creating the vertical boundary flow area input file of the overflow / discharge time series process; (4) loading the vertical boundary flow area input file and other types of input files into the two-dimensional hydrodynamic model for calculation. The specific implementation method is as follows:

[0007] (1) Create the inp input file of SWMM and simulate to obtain the out result file. Create the inp input file of the SWMM one-dimensional pipe network hydrodynamic model based on the drainage pipe network vector data, land use data, and rainfall process data, and call the swmm dynamic link library to read the inp file to perform simulation and generate the out result file.

[0008] (2) Complete the topological association between the inspection well and the vertical boundary flow area grid. Use the vector file of the area to be simulated to create a two-dimensional surface grid, and match the two-dimensional surface grid with the inspection well in spatial position. The matched grid is the vertical boundary flow area grid (vector file), and the matching relationship between the vertical boundary flow area grid and the inspection well is obtained (including one-to-one and many-to-one matching relationships). Use the spatial connection tool of the geographic information system software to complete the association between the vertical boundary flow area grid and the inspection well.

[0009] (3) Create a vertical boundary flow area input file for the overflow / discharge time series process. According to the matching relationship between the vertical boundary flow area and the inspection well, and the topological connection relationship between the inspection well and the pipeline, read the relevant parameters (node ​​overflow, pipeline fullness, pipe diameter, slope) in the SWMM simulation results, write the overflow or calculate the remaining drainage capacity value according to the judgment rules, and obtain the vertical boundary flow area vector file with the overflow / discharge time series process, and convert it into the input file format required by the two-dimensional hydrodynamic model.

[0010] (4) Load the vertical boundary flow area input file and other types of basic input files into the two-dimensional hydrodynamic model for calculation. Load the vertical boundary grid input file obtained in the previous step and other types of input files required for two-dimensional hydrodynamic simulation into the software for calculation and simulation to obtain the evolution process, waterlogging area, and waterlogging range of the waterlogging.

[0011] Furthermore, in step (1), if there is measured data of the downhole liquid level process, after the inp input file of SWMM is prepared, the model can be calibrated to obtain the calibrated SWMM simulation results.

[0012] Furthermore, in step (2), since the vertical boundary flow area is a vector surface element, and the inspection well is a vector point element, the vector surface element has a certain spatial occupancy range, and there are multiple inspection wells in a vertical boundary flow area. The spatial connection tool of the geographic information system software generally has five main options: target element, connection element, input feature class, connection operation (one-to-one or one-to-many) and matching option. When the vertical boundary flow area is used as the target element to match the inspection well, the inspection well is the connection element. At this time, the connection operation needs to select a one-to-many operation, and the matching option selects intersection (the situation where the target element and the connection element intersect), and the output feature class is the vertical boundary flow area vector surface element with the inspection well matching information output after the spatial connection is completed.

[0013] Furthermore, step (3) mainly includes four steps: overflow / drainage state judgment, overflow volume writing, remaining drainage capacity calculation, and creation of overflow / drainage volume time series process for each vertical boundary flow zone. The results are read and judged by calling the SWMM dynamic link library, and then the remaining drainage capacity of the pipeline is calculated.

[0014] Furthermore, the overflow / drainage state judgment rule of step (3) is as follows: the overflow volume (node ​​flooding) of the node in the simulation result is read by the result step size. If it is not 0, it means that the node is in the overflow state at this time, and the overflow volume size at this moment is written; if it is 0, it means that the node is not overflowing at this time, then the fullness α of the downstream pipeline corresponding to the node is read, the state of the fullness is judged, and then the remaining drainage capacity of the pipeline is calculated.

[0015] Furthermore, the pipe fullness in step (3) is judged in five states: α = 0, 0 < α 0.5, α = 0.5, 0.5 < α < 1, and α = 1. When 0 < α < 0.5, the angle formed by half of the pipe wetted arc length and the pipe center is set to θ, and when 0.5 < α < 1, the angle formed by half of the pipe non-wetted arc length and the pipe center is set to θ, and the angle range of θ is 0 < θ < 180°.

[0016] Furthermore, the remaining drainage capacity of step (3) is calculated by formula 1:

[0017] q 剥 =q 设 -q 管 (1)

[0018] Where: q 剥 is the remaining drainage capacity of the pipeline, m 3 / s;q 设 is the designed drainage capacity of the pipeline, m 3 / s;q 管 is the flow rate of the pipeline section, m3 / s.q 设 With q 管 All are calculated by combining formulas 2, 3, and 4.

[0019] q=vA (2)

[0020] Where: q represents the flow rate of the pipeline section, m 3 / s; v is the flow velocity, m / s; A is the cross-sectional area of ​​the drainage pipe, m 2 .

[0021]

[0022] In the formula: v represents flow velocity, m / s; n represents the roughness coefficient of the drainage pipe (known), R represents the hydraulic radius, m; i represents the slope of the drainage pipe (known).

[0023]

[0024] Where: R represents the hydraulic radius, m; A represents the cross-sectional area of ​​the drainage pipe, m 2 ; x represents wetted perimeter, m.

[0025] Table 1 is the calculation of q 管 In the process, the simplified formulas for calculating the θ value, area and wetted perimeter corresponding to different filling conditions are obtained by geometric analysis of the cross section. Where A represents the cross-sectional area of ​​the drainage pipe, m 2 ; R represents the hydraulic radius, m; D represents the pipe diameter (known), m; α is the pipe fullness.

[0026] Table 1. Simplified formulas for θ value calculation, area calculation and wetted perimeter calculation for different filling conditions

[0027]

[0028] Furthermore, in step (3), the overflow / discharge data read out need to be written into the file based on the matching relationship between the inspection well and the vertical boundary flow area grid, based on the vertical boundary flow area number. When the vertical boundary flow area grid matches multiple inspection wells, the overflow / discharge process values ​​at the same time of each inspection well need to be superimposed, and finally a one-to-one relationship between each vertical boundary flow area grid and the overflow / discharge process is obtained.

[0029] The method of the present invention reads the node overflow data and the water flow state data of the pipeline in the SWMM simulation results for calculation, and sets the overflow / discharge time series process in the form of a vertical boundary flow area in a two-dimensional surface simulation grid to perform surface water accumulation simulation, thereby obtaining the water accumulation distribution and water accumulation depth under the specified scenario.

[0030] The vertical boundary flow area refers to the designated boundary flow area within the simulation area. Surface water can leave the simulation area from these boundary flow areas (expressed as negative values); external water can also enter the simulation area from these boundary flow areas (expressed as positive values), thereby controlling the flow direction and size of water in the grid unit.

[0031] The premise of this method is that the 2D hydrodynamic model supports vertical boundary flow zone simulation or similar functions. When simulating surface waterlogging, the vertical boundary flow zone is set in the grid of the 2D hydrodynamic model, and the time series process of overflow / discharge extracted from the SWMM simulation results is set on the corresponding parameters.

[0032] The method of the present invention is based on the SWMM simulation results, reads the SWMM simulation results through a program and extracts the overflow / discharge time process, and innovatively uses the vertical boundary flow area instead of the inspection well to simulate the process of surface water overflowing or discharging through the inspection well in reality, thereby realizing the simulation of the surface water overflow process.

[0033] The method of the present invention can use SWMM to characterize node overflow and pipe drainage in the form of node positive / negative flow processes, and couple the flow process with the two-dimensional hydrodynamic model in the form of vertical boundaries to simulate the evolution of ground water accumulation, which is helpful for effectively identifying the rise and fall process, waterlogging area and waterlogging range of urban waterlogging in the coupled simulation of SWMM and two-dimensional hydrodynamics, and is suitable for related applications and research on urban waterlogging simulation, such as assessment of urban waterlogging prevention capacity and risks, urban drainage impact assessment, and rainstorm waterlogging risk forecasting and warning. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of five filling degree states of the pipeline of the present invention.

[0035] Figure 2 The program reading flow chart of the overflow / discharge time series process of the present invention.

[0036] Figure 3 This is the technical roadmap of the surface water simulation method based on SWMM and vertical boundary coupling in the present invention.

[0037] Figure 4 It is a schematic diagram of the vertical boundary flow area file production process of the present invention.

[0038] Figure 5 This is a comparison of the simulated waterlogging results of the SWMM coupling model of the present invention and the one- and two-dimensional coupled hydrodynamic model under the 0728 rainfall scenario.

[0039] Figure 6This is a comparison of the simulated waterlogging results of the SWMM coupling model of the present invention and the one- and two-dimensional coupled hydrodynamic model under the 0801 rainfall scenario. DETAILED DESCRIPTION

[0040] The specific technical solution of the present invention is explained in conjunction with embodiments.

[0041] like Figure 3 As shown in the figure, the steps include: (1) making the inp input file of SWMM and simulating to obtain the out result file; (2) completing the topological association between the inspection well and the vertical boundary flow area grid; (3) creating the vertical boundary flow area input file of the overflow / discharge time series process; the pipe fullness in step (3) is divided into five states for judgment, such as Figure 1 As shown; the program reading process of overflow / discharge time series process is as follows Figure 2 (4) Load the vertical boundary flow area input file and other types of input files into the two-dimensional hydrodynamic model for calculation, such as Figure 4 As shown, the vertical boundary flow area file production process.

[0042] Taking a certain area in Guangzhou as an example, the total area of ​​the area is about 13.1km 2 The generalized one-dimensional drainage network model contains 5272 network nodes, 226 outlets and 5443 pipes. The DEM is a 5m×5m resolution grid data. The model was constructed using the surface waterlogging simulation method coupled with SWMM and vertical boundaries (hereinafter referred to as the "SWMM coupled model") and the one- and two-dimensional coupled hydrodynamic model constructed using InfoWorks ICM software. Using the same runoff parameters and model, the distribution of waterlogging in the two measured rainfalls in the study area was simulated.

[0043] The one- and two-dimensional coupled hydrodynamic model used for comparison of experimental results was simulated based on InfoWorks ICM software. InfoWorks ICM can fully simulate the urban rainwater circulation system, realize the integration of the urban drainage network system model and the river model, and more realistically simulate the interaction between the underground drainage network system and the surface water body. It organically integrates the one-dimensional hydraulic model of the urban drainage network and the river, the two-dimensional flood inundation model of the city / watershed, the simulation of the low-impact development system of the sponge city (including the utilization of rainwater resources), and the flood risk assessment in an independent simulation engine. It is the first software to combine these model engines and functions in a single simulation engine. The software has been widely recognized and used by professionals in the industry.

[0044] This example simulates the distribution of waterlogging in the two models of "SWMM coupling model" and "one-two-dimensional coupling hydrodynamic model" under the two measured rainfall scenarios of 0728 and 0801. The intuitive comparison of the simulation effects of the two models can be seen in Figure 5 and Figure 6 The similar areas simulated by the two models are marked with black ellipses and numbered in the figure, and the simulation results and relative errors of the two models are statistically analyzed (see Table 2 and Table 3).

[0045] Taking the simulation results of the “one- and two-dimensional coupled hydrodynamic model” as the benchmark, the simulation results and relative errors of the “SWMM coupling model” were evaluated based on the maximum waterlogging depth and waterlogging area. The statistical results of the 0728 rainfall event are shown in Table 2, and the statistical results of the 0801 rainfall event are shown in Table 3.

[0046] Table 2. Comparison of simulation results between “SWMM coupled model” and “one-two-dimensional coupled hydrodynamic model” (0728 rainfall events)

[0047]

[0048]

[0049] Table 3. Comparison of simulation results between “SWMM coupled model” and “one-two-dimensional coupled hydrodynamic model” (0801 rainfall)

[0050]

[0051] The maximum waterlogging depth and waterlogging area were statistically analyzed with relative errors for areas with similar waterlogging ranges obtained from the two rainfall simulations. As shown in Table 2, under the 0728 rainfall, there were 6 points with relative errors of waterlogging depth within ±30%, and the relative errors of waterlogging area were all within ±50%. As shown in Table 3, under the 0801 rainfall, there were 5 points with relative errors of waterlogging depth within ±30%, and there were 7 areas with relative errors of waterlogging area within ±50%. In summary, the "SWMM coupling model" can more accurately identify the distribution and risk level of waterlogging risks in the region, and its simulated maximum waterlogging depth and waterlogging area have certain reference value.

Claims

1. The surface water simulation method based on SWMM coupled with vertical boundaries is characterized by: Based on the SWMM simulation results, the overflow / discharge time series process of the pipe network is extracted and set in the two-dimensional hydrodynamic model in the form of a vertical boundary flow area. The process of water accumulation on the surface through the vertical boundary flow area and the discharge of the accumulated water through the vertical boundary flow area is simulated, so that the results of surface water accumulation distribution and water depth can be obtained, including the following steps: (1) Create the SWMM inp input file and simulate to get the out result file; (2) Complete the topological association between the inspection well and the vertical boundary flow area grid; (3) Extract SWMM simulation results and create vertical boundary flow zone input files for overflow / discharge time series processes; (4) Load the vertical boundary flow area input file and other types of input files into the two-dimensional hydrodynamic model to simulate the distribution and depth of waterlogging in the relevant area under the specified rainfall scenario; The specific steps include the following: (1) Create the SWMM one-dimensional pipe network hydrodynamic model inp input file based on the drainage pipe network vector data, land use data, and rainfall process data, and call the SWMM dynamic link library to read the inp file to perform simulation and generate the out result file; (2) Using the vector file of the study area to create a two-dimensional surface grid, the spatial connection tool of the geographic information system software is used to match the two-dimensional surface grid with the inspection wells in terms of spatial position, including one-to-one and many-to-one matching relationships, to obtain the vertical boundary flow area vector surface and the matching relationship between the vertical boundary flow area number and the inspection well number; (3) Read the SWMM simulation results based on the matching relationship between the vertical boundary flow zone number and the inspection well number, obtain the overflow / discharge time series process of each vertical boundary flow zone, and convert it into the input file format required by the two-dimensional hydrodynamic model; (4) The vertical boundary flow area input file and other types of basic input files are loaded into the two-dimensional hydrodynamic model for simulation calculation to obtain the evolution process, waterlogging area, and waterlogging range of the urban waterlogging.

2. The surface water simulation method based on SWMM and vertical boundary coupling according to claim 1 is characterized in that: In step (1), if there is measured data of the downhole liquid level process, after completing the preparation of the SWMM inp input file, the model is calibrated to obtain the calibrated SWMM simulation results.

3. The surface water simulation method based on SWMM and vertical boundary coupling according to claim 1 is characterized in that: In step (2), when the vertical boundary flow area is used as the target element to match the inspection well, the inspection well is the connection element; at this time, the connection operation selects a one-to-many operation, and the matching option selects intersection, that is, the target element and the connection element intersect, and the output feature class is the vertical boundary flow area vector surface element with the inspection well matching information output after the spatial connection is completed.

4. The surface water simulation method based on SWMM and vertical boundary coupling according to claim 1 is characterized in that: Step (3) includes four steps: overflow / drainage status judgment, overflow volume writing, remaining drainage capacity calculation, and creation of overflow / drainage volume time series process for each vertical boundary flow zone; the results are read and judged by calling the SWMM dynamic link library, and then the remaining drainage capacity of the pipeline is calculated.

5. The surface water simulation method based on SWMM and vertical boundary coupling according to claim 4 is characterized in that: The overflow / drainage state judgment rule of step (3) is as follows: read the overflow volume of the node in the simulation result step by step. If it is not 0, it means that the node is in the overflow state at this time, and then write the overflow volume size at this moment; if it is 0, it means that the node is not overflowing at this time, then read the fullness α of the downstream pipeline corresponding to the node, judge the state of the fullness, and then calculate the remaining drainage capacity of the pipeline.

6. The surface water simulation method based on SWMM and vertical boundary coupling according to claim 5 is characterized in that: The pipe fullness in step (3) is judged in five states: α=0, α<0.5, α=0.5, 0.5<α<1, and α=1; wherein, when 0<α<0.5, the angle formed by half of the pipe wetted arc length and the pipe center is set to θ, and when 0.5<α<1, the angle formed by half of the pipe non-wetted arc length and the pipe center is set to θ, and the angle range of θ is 0<θ<180°.

7. The surface water simulation method based on SWMM and vertical boundary coupling according to claim 4 is characterized in that: The remaining drainage capacity in step (3) is calculated using formula 1: q 剩 =q 设 -q 管 (1) Where: q 剩 is the remaining drainage capacity of the pipeline, in m 3 / s;q 设 is the designed drainage capacity of the pipeline, in m 3 / s;q 管 is the flow rate of the pipeline section, in m 3 / s;q 设 With q 管 All are calculated by combining formulas 2, 3, and 4: q=vA (2) Where: q represents the flow rate of the pipeline section, the unit is m 3 / s; v represents the flow velocity in m / s; A represents the cross-sectional area of ​​the drainage pipe in m 2 ; Where: v represents the flow velocity, in m / s; n represents the roughness coefficient of the drainage pipe; R represents the hydraulic radius, in m; i represents the slope of the drainage pipe; Where: R represents the hydraulic radius, in m; A represents the cross-sectional area of ​​the drainage pipe, in m 2 ; χ represents the wetted perimeter, in m.

8. The surface water simulation method based on SWMM and vertical boundary coupling according to claim 1 is characterized in that: In step (3), the overflow / discharge data read shall be written into the file based on the vertical boundary flow area number according to the matching relationship between the inspection well and the vertical boundary flow area grid; when the vertical boundary flow area grid matches multiple inspection wells, the overflow / discharge process of each inspection well shall be superimposed at the same time, and finally a one-to-one relationship between each vertical boundary flow area grid and the overflow / discharge process shall be obtained.

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