Method for sewer drainage capacity and land use planning based on hydrological-hydrodynamic model

Abstract

Based on hydrology-hydrodynamic model pipe network drainage capacity and land use planning method, including for the target area, build urban watershed, including collecting urban basic information, set urban rainfall scenario; Construct urban pipe network drainage capacity design and land use planning method based on hydrology-hydrodynamic integrated model, including hydrology physical model and 2D kinematic-wave hydrodynamic model; According to the historical observation data, the model parameters are calibrated and verified; Output urban pipe network drainage capacity design and land use planning.

Description

Technical Field

[0001] This invention discloses a method for designing urban pipe network drainage capacity based on a hydrological-hydrodynamic model and its land use planning method, belonging to the technical field of urban flooding disaster risk assessment. Background Technology

[0002] In recent years, with the development of urbanization in my country, urban hydrological problems have become prominent, among which urban flooding is a common issue. On the one hand, the "heat island effect" and "rain island effect" caused by urbanization increase the frequency and intensity of urban rainfall. Frequent urban rainfall leads to insufficient drainage capacity of stormwater pipe networks, resulting in frequent urban flooding. On the other hand, irrational urban land planning, coupled with urbanization increasing the area of ​​impervious surfaces, hinders rainwater infiltration, increases the surface runoff coefficient and runoff volume, and raises the risk of urban flooding. Inadequate stormwater pipe networks and irrational land use planning are important factors contributing to urban flooding.

[0003] Furthermore, in the existing technology for stormwater pipe network design, CN114117707A discloses a municipal stormwater pipe network planning and design system based on the spatial distribution characteristics of urban precipitation. This system includes a gridded urban precipitation simulation module, a gridded urban rainstorm intensity calculation module, a stormwater pipe network planning, design, and management module, and a stormwater pipe network planning and design scheme evaluation module. CN110717233A discloses a method and system for calculating stormwater pipe network flow based on GIS underlying surface analysis. This includes: creating a GIS generalized model of the stormwater pipe network system; dividing the catchment area to obtain sub-drainage zones; assigning different runoff coefficients to plots with different land uses and re-dividing the underlying surface of the drainage zone to obtain sub-underlying surfaces; and calculating the pipe catchment volume based on the polygonal geometric area of ​​the sub-underlying surface and the corresponding runoff coefficient. However, the above technologies still use a deductive formula method for stormwater flow calculation in urban runoff calculation. While simple and easy to implement, this method has a large deviation from reality, easily causing distortion in local areas and resulting in low calculation accuracy.

[0004] Currently, existing technology publication number CN111369059A discloses an urban flooding prediction method and system based on a rapid flooding simulation coupling model, including: collecting pipe network data and hydrological data of the study area; constructing a two-dimensional topographic model, and processing the elevation of the building area and road distribution area of ​​the two-dimensional topographic model respectively; building a two-dimensional hydrodynamic model based on the processed two-dimensional topographic model; constructing a hydrodynamic model and a hydrological model of the pipe network respectively, and coupling the above two models to obtain a drainage pipe network model; further coupling the two-dimensional hydrodynamic model and the drainage pipe network model to obtain an urban flooding simulation coupling model, which is used to predict the distribution of urban flooding points and the depth of water accumulation. Publication number CN109101706A discloses a coupling method between a lumped hydrological model and a two-dimensional hydrodynamic model. This includes: data processing; hydrological model construction and calculation; coupling using a downscaling method; and hydrodynamic model construction and calculation. However, the above technologies do not solve the problem of the complex calculation process and low computational efficiency of the hydrodynamic model during the coupling process.

[0005] The prior art disclosed by the applicant, CN114781718A, employs a hydrological-hydrodynamic model, integrating a hydrophysical model with a 2D kinematic-wave hydrodynamic model. This model can simulate and calculate water depth and flow velocity and is currently used in flood warning systems for natural watersheds. However, urban surfaces exhibit complex land use types, and water flow is easily influenced by topography. Urban runoff differs from that of natural watersheds, making this model unsuitable for direct connection to urban pipe networks and application in drainage capacity and land use planning. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide a method for urban pipe network drainage capacity design and land use planning based on a hydro-hydraulic integrated model. This method can directly calculate surface runoff through the hydro-hydraulic integrated model, take into account the impact of land use type on surface runoff, and connect with the urban pipe network to ultimately determine the distribution of urban stormwater pipe network drainage capacity. This overcomes the problems of complex calculation, low calculation efficiency, and low accuracy of stormwater pipe network design calculation results in existing hydro-hydraulic models.

[0007] A method for planning drainage capacity and land use of pipe networks based on a hydrological-hydrodynamic model includes the following steps:

[0008] Step 1: For the target area, construct an urban watershed, including collecting basic urban information and setting urban rainfall scenarios;

[0009] Step 2: Construct a method for urban pipe network drainage capacity design and land use planning based on a hydrological-hydrodynamic integrated model, including a hydrophysical model and a 2D kinematic-wave hydrodynamic model;

[0010] Step 3: Calibrate and validate the model parameters based on historical observation data;

[0011] Step 4: Output the urban pipe network drainage capacity design and land use plan.

[0012] The present invention also discloses a non-volatile storage medium, characterized in that the non-volatile storage medium includes a stored program, wherein the program, when running, controls the device where the non-volatile storage medium is located to execute the method described thereon.

[0013] The present invention also discloses an electronic device, characterized in that it comprises a processor and a memory; the memory stores computer-readable instructions, and the processor is used to execute the computer-readable instructions, wherein the computer-readable instructions execute the method described thereon.

[0014] Beneficial effects

[0015] Surface runoff can be calculated directly using an integrated hydrological-hydrodynamic model, which reduces the calculation of coupled parts, especially the solution of partial differential equations in traditional hydrodynamic models, simplifies the data calculation process, and provides rapid solutions.

[0016] Different Manning coefficients are applied to different land use types to reflect the impact of different land use properties on surface runoff within the catchment area. A hydrological-hydrodynamic integrated model is used to calculate flow and water depth at any node in the city, better reflecting the spatial differences in the urban watershed and avoiding the limitations of traditional methods. Flow calculations for stormwater pipe networks under different land types are achieved, improving the accuracy of runoff calculations in the catchment area and enhancing the rationality and scientific validity of the results.

[0017] The calculation results can be quantified. By inputting different land use types, the distribution of node water depth and flow velocity under heavy rainfall and extreme rainstorm conditions can be predicted, thereby obtaining the distribution of urban pipe network drainage capacity and making the design scheme of rainwater pipe network more reasonable. Attached Figure Description

[0018] Figure 1 This is a flowchart of the present invention;

[0019] Figure 2 Figure 1 shows a specific embodiment of the present invention.

[0020] Figure 3 These are diagrams illustrating the rainstorm process under different scenarios according to the present invention.

[0021] Figure 4 This is a comparison chart of the simulated effect and the actual effect of the present invention;

[0022] Figure 5This is a schematic diagram of the current urban pipe network drainage capacity based on the existing land use.

[0023] Figure 6 This is a schematic diagram illustrating the urban pipe network drainage capacity for land use planning in this invention. Detailed Implementation

[0024] A method for urban pipe network drainage capacity design and land use planning based on a hydrological-hydraulic integrated model, such as Figure 1 As shown, it includes the following steps:

[0025] Step 1: For the target area, construct an urban watershed, including collecting basic urban information and setting urban rainfall scenarios;

[0026] Collect topographic data, pipeline infrastructure data, and land use data for the area.

[0027] Digital elevation information (DEM) is obtained from the topographic data of the area. A coordinate system and elevation system are set according to the coordinate system of the DEM location to form the urban watershed framework.

[0028] Node and pipeline information is obtained from the basic pipeline network data. The node information is loaded into the urban watershed framework to form discrete points representing the nodes, and the topographic gradient, cross-sectional width, and Manning coefficient of each node are obtained, resulting in a node point layer. The pipeline information is loaded into the urban watershed framework to form line segments representing the pipelines, resulting in a pipeline line layer. The node layer is divided in the urban watershed framework with digital elevation information to divide the nodes into catchment areas, resulting in sub-catchment areas. The area and average topographic gradient of each sub-catchment area are calculated, and a sub-catchment area surface layer is formed.

[0029] The underlying surface data of the catchment area is obtained from the land use data, and different Manning coefficients are set for different land use types in the underlying surface of the catchment area to obtain an underlying surface layer; the underlying surface polygons of the underlying surface layer are divided with the sub-catchment areas in the sub-catchment area layer as the boundary to obtain sub-underlying surfaces, the average Manning coefficient of each sub-underlying surface is calculated, and a sub-underlying surface layer is formed.

[0030] Furthermore, an urban rainfall scenario is set up, and the design rainfall intensity and infiltration rate are determined based on the design rainfall data and measured infiltration data. The design rainfall data adopts the Chicago rainfall model, which is a typical rainfall process designed based on the storm intensity formula. By introducing a peak location coefficient r to describe the timing of the storm peak, the rainfall duration time series is divided into pre-peak and post-peak parts. The storm intensity formula under a certain return period is:

[0031]

[0032] Where: i is the rainfall intensity (mm / min); C is the rainfall force parameter, i.e., the design rainfall (mm) per minute under different return periods; t is the rainfall duration (min); m is the rainfall duration correction parameter; and n is the rainstorm attenuation index.

[0033] The rainfall intensity before and after the rain peak can be calculated using the following formula:

[0034]

[0035]

[0036] In the formula: i(t) b ) represents the instantaneous rainfall intensity before the peak (mm / min); t b For the corresponding duration before the peak, i(t) a ) represents the instantaneous rainfall intensity after the peak (mm / min); t a denoted as , where is the duration following the peak, and r is the peak location coefficient.

[0037] Using formulas (2) and (3), the hourly design rainfall intensity under a certain return period is calculated. This is then integrated with the urban watershed framework to construct an urban watershed.

[0038] Step 2: Construct a method for urban pipe network drainage capacity design and land use planning based on a hydrological-hydrodynamic integrated model, including a hydrophysical model and a 2D kinematic-wave hydrodynamic model;

[0039] A hydrophysical model is used, treating a catchment area as a water tank with openings on the sides and bottom to simulate infiltration and outflow. The initial water depth of the tank simulates the initial water depth of the watershed. Using the law of conservation of mass, a balance is established between the total input rate (rainfall intensity), the total water storage growth rate, and the total output rate (outflow rate, infiltration rate) within the catchment area. The equations of the constructed hydrological model are as follows:

[0040]

[0041] Q = q x ×A(x) (5)

[0042] In the formula, R is the rainfall intensity (mm / h); q x H represents the outflow velocity of the catchment area (m / s); x The average water depth (m) of the upstream catchment area is given by: I = I / (m / s); t = t / (s); Q = Q / (m³ / s). 3 / s); A(x) is the area of ​​the upstream catchment area at the calculated location (m²). 2 );

[0043] Simultaneously, according to the 2D kinematic-wave hydrodynamic model, in a certain catchment area, part of the rainfall infiltrates into the soil, and the remainder flows onto the surface as surface runoff. Surface runoff only considers planar flow in the x and y directions, neglecting the vertical flow in the z direction. Finally, the runoff in the watershed flows out through section x, establishing a hydraulic relationship between the outflow velocity and the average water depth at the section. The equations of the constructed hydrodynamic model are as follows:

[0044]

[0045]

[0046] In the formula, h is the water depth at the cross-section (m); n m Manning coefficient (s / m) 1 / 3 Q1 is the line output flow rate (m³ / s). 2 / s); S is the terrain gradient (1); l is the distance coordinate (m) on the slope.

[0047] Based on the above model, according to the hydrophysical model and the 2D kinematic-wave hydrodynamic model, the outflow velocity at the cross section and the total water storage in the catchment area should always be equal, and the total outflow (Q) is equal to the linear outflow (Q1) multiplied by the cross section width B(x). Therefore, a two-layered relationship between the two models is established:

[0048] Q = Q1B(x) (8)

[0049] By constructing an integrated hydrological-hydrodynamic model based on the above connections, substituting formula (5) into formula (8) yields:

[0050]

[0051] After transformation

[0052]

[0053] Right now,

[0054]

[0055] Multiplying formula (11) by the cross-sectional width B(x) and integrating along the catchment area, the total water storage capacity within the catchment area can be obtained:

[0056]

[0057] Based on the hydrophysical model, the average water depth in the upstream catchment area at the calculated location is H. x According to the law of conservation of mass:

[0058]

[0059] Substituting formula (12) into formula (13) yields:

[0060]

[0061] Let the complex term in formula (14) be:

[0062]

[0063] In the formula, b is the catchment area constant; c is the catchment area index.

[0064] Formula (16) can be derived:

[0065]

[0066] By combining formulas (4), (9), and (16), a hydrological-hydrodynamic integrated model is constructed:

[0067]

[0068] In the formula, q x To calculate the outflow velocity (m / s) at section x; The average Manning coefficient of the catchment area (s / m) 1 / 3 S is the terrain gradient at the calculated location (1); H represents the average topographic gradient of the catchment area (1); x Let be the average water depth (m) of the upstream catchment area at the calculation location; h be the water depth (m) at the calculation location; B(x) be the cross-sectional width (m) at the calculation location; and A(x) be the upstream catchment area (m²) corresponding to B(x) at the calculation location. 2 b is the catchment area constant; c is the catchment area index.

[0069] Further construct a method for urban pipe network drainage capacity design and land use planning based on a hydrological-hydrodynamic integrated model: Connect each node in the urban watershed built in step (1) to the calculation location x of the hydrological-hydrodynamic integrated model. Under the conditions of the corresponding land use type and design rainfall intensity, the runoff of each sub-catchment node is calculated by the hydrological-hydrodynamic integrated model and flows into its corresponding pipe. Assuming that the pipe flow is uniform at this time, the topographic gradient and resistance slope at the calculation location are equal, where the resistance slope is calculated using the Manning formula:

[0070]

[0071] In the formula, S f The slope is the resistance gradient; n is the Manning coefficient (s / m) of the calculation location x-section. 1 / 3R is the hydraulic radius (m).

[0072] By combining the two equations, we can obtain:

[0073]

[0074] This allows us to obtain the water depth in the pipe at that node and compare it with the pipe diameter to determine the pipe's drainage capacity. Therefore, we can obtain the flow rate, dynamic changes in water depth, and drainage capacity of each node at different times under this land use type.

[0075] In this step, surface runoff is calculated directly using a hydro-hydrodynamic integrated model, reducing the computation of coupled components, especially reducing the solution of partial differential equations in traditional hydrodynamic models. By designing rainfall intensity, the water depth and flow distribution at nodes under different land use types are obtained, simplifying the data calculation process and providing rapid solutions.

[0076] Step 3: Based on historical observation data (rainfall, node water depth, and pipeline flow, etc.), calibrate and verify the calculation parameters b and c in the above-mentioned urban pipe network drainage capacity design and land use planning method based on the hydrological-hydrodynamic integrated model. Perform parameter calibration based on measured data, compare the deviation between simulation results and measured results, and adjust the model parameters to meet certain error requirements, thus completing the model parameter calibration. Further verification using measured data is then conducted to assess whether the fit between the simulation results and measured results meets the requirements. Specifically, in this embodiment, the Nash efficiency coefficient (NSE) is used for parameter verification. Generally, an NSE ≥ 0.5 indicates that the simulation results are basically consistent with the monitored values. The closer the NSE value is to 1, the higher the fit between the simulation results and the monitored values. If the fit is low, the parameters need to be readjusted, and calibration and verification repeated until the fit meets the requirements.

[0077] Step 4: Output urban pipe network drainage capacity design and land use planning. This involves the urban pipe network drainage capacity design and land use planning method based on the hydrological-hydrodynamic integrated model obtained above. By inputting the constructed urban watershed, the dynamic changes in flow rate and water depth at each node at different times, as well as the drainage capacity of the pipes, can be obtained, and an urban pipe network drainage capacity distribution map can be generated.

[0078] This step visualizes the design results of urban pipe network drainage capacity and land use planning, and quantifies the calculation results. By inputting different land use types, it predicts the distribution of node water depth and flow velocity under heavy rainfall and extreme rainstorm conditions, thereby obtaining the distribution of urban pipe network drainage capacity and making the design scheme of stormwater pipe network more reliable and reasonable.

[0079] Example

[0080] This case study is located in a city area of ​​approximately 1.5 square kilometers, with a stormwater drainage network of about 4.8 kilometers. Using an integrated hydrological-hydraulic model for urban drainage capacity design and land use planning, the distribution of urban drainage capacity under different land uses in this study area was determined. The specific steps and results are described below:

[0081] 1) Collect DEM data, pipeline network baseline data, and land use data for the study area. (See figure)

[0082] 2. Based on the DEM and stormwater drainage network baseline data, calculate the topographic gradient, cross-sectional width, and Manning coefficient for each node, and use the D8 method to determine the catchment area for each node; further calculate the catchment area and average topographic gradient for each node. Then, based on the DEM and land use data, calculate the average Manning coefficient for each catchment area.

[0083] 2) Collect design rainfall data and measured infiltration data for the study area to determine the design rainfall intensity and infiltration rate. The design rainfall pattern for this study area uses the Chicago method. The design rainfall patterns with a duration of 180 minutes and return periods of 1, 2, 3, 5, 10, 20, 30, 50, and 100 years are calculated. The relationship between rainfall intensity and duration for different return periods is shown below. Figure 3 As shown, this is used to simulate rainfall intensity under conditions of heavy rainfall and extreme rainstorms.

[0084] 3) Construct an integrated hydrological-hydraulic model using DEM data, pipeline network foundation data, land use data, design rainfall data, and measured infiltration data of the study area, and integrate it with step (1).

[0085] (2) Connect the established urban watersheds and construct urban pipe network drainage capacity design and land use planning methods based on the hydrological-hydrodynamic integrated model.

[0086] 4) Based on historical observation data (rainfall, node water depth, and pipeline flow), the calculation parameters b and c in the urban pipe network drainage capacity design and land use planning method based on the hydrological-hydrodynamic integrated model are calibrated and verified.

[0087] Table 1 shows the fitting parameters for specific embodiments of the present invention:

[0088] Table 1 Parameter Fitting Values

[0089] parameter b c Fitted values 3 0.24

[0090] Next, parameter verification is performed using the Nash efficiency coefficient (NSE). In practical parameter calibration and model validation, it is generally considered that an NSE ≥ 0.5 indicates that the simulation results are basically in line with the monitored values. The closer the NSE value is to 1, the higher the degree of fit between the simulation results and the monitored values. The calculation formula is as follows:

[0091]

[0092] In the formula, NSE is the Nash efficiency coefficient; The simulation results at time i (m 3 / s); For monitoring data at time i (m 3 / s); Q av The average value of the monitoring data (m) 3 / s).

[0093] Simulation results of urban pipe network drainage capacity design and land use planning methods based on hydrological-hydrodynamic integrated models can be found in [the following text is missing]. Figure 4 The verification results of the parameters are shown in Table 2:

[0094] Table 2 Parameter Verification

[0095] Historical observation data 1 Historical observation data 2 <![CDATA[NSE 节点水深 ]]> 0.9512 0.9704 <![CDATA[NSE 管道流量 ]]> 0.9631 0.9428

[0096] Based on the above calculation results, the model parameters fit the historical observation data very well, and the model parameters are consistent with the actual situation of the study area.

[0097] 5) Output the results of urban pipe network drainage capacity design and land use planning. Simulation results are as follows: Figure 5 and Figure 6 As shown.

[0098] Simulation results show that there are four areas with poor drainage capacity in the current land use and two areas with poor drainage capacity in the planned land use, with the drainage network in the central part of the study area having the worst capacity. Even with a shorter return period, insufficient drainage capacity was observed, requiring adjustments to the pipelines or land use.

[0099] Figure 5 and Figure 6 Different line thicknesses can be designed to correspond to the drainage capacity of the pipelines. By inputting the corresponding land use type, the distribution of urban pipe network drainage capacity under that land use type can be obtained, and the water depth and flow data of specified nodes can be extracted to obtain the drainage capacity of the corresponding pipelines, thus enabling the judgment of the drainage capacity of the corresponding pipelines.

[0100] In summary, this invention first constructs an urban watershed by collecting data, then builds a method for urban pipe network drainage capacity design and land use planning based on a hydrological-hydrodynamic integrated model. Further, it calibrates and verifies the calculation parameters based on historical observation data. Finally, it inputs the constructed urban watershed and outputs the distribution of urban pipe network drainage capacity under that land use type, thus realizing the design of urban pipe network drainage capacity and land use planning. In traditional hydrological-hydrodynamic models, surface runoff is calculated through a hydrological model and then input into the hydrodynamic model, which is a key condition for the coupling of the two models. Furthermore, the hydrodynamic model calculation involves solving partial differential equations, which are difficult to solve. This invention uses a hydrological-hydrodynamic integrated model, reducing the coupling process, and this model solves ordinary differential equations, making the solution simpler. Traditional methods for calculating stormwater runoff use sub-catchment areas as the basic unit of runoff generation and employ the runoff coefficient method. This generalizes the catchment area, fails to reflect spatial differences within the city, ignores the diversity of the underlying surface, and does not consider the impact of land use on runoff. This invention uses different Manning coefficients for different land use types to reflect the impact of different land use properties within the sub-catchment area on surface runoff. Furthermore, it calculates the flow and water depth at any node in the city using a hydrological-hydrodynamic integrated model, which better reflects the spatial differences in the urban watershed, avoids the limitations of traditional methods, enables flow calculation for stormwater networks under different land types, and generates a distribution of urban network drainage capacity. This visualization of the results improves their rationality and scientific validity.

[0101] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A method for sewer drainage capacity and land use planning based on hydro-hydraulic model, characterized in that: Comprising the following steps: Step 1: For the target area, build a city watershed, including collecting city basic information, setting city rainfall scenarios; Collect topographic data, pipe network basic data and land use data of the area; obtain digital elevation information DEM from the topographic data of the area, set coordinate system and elevation system according to the coordinate system of DEM, and form city watershed framework; Obtain node information and pipe information from pipe network basic data, load node information into city watershed framework to form discrete points representing the nodes, obtain terrain gradient, cross section width and Manning coefficient of each node, and obtain node point layer; load pipe information into city watershed framework to form line segments representing the pipes, and obtain pipe line layer; divide node point layer in city watershed framework with digital elevation information, divide catchment area for the nodes, obtain sub-catchment area, calculate area and average terrain gradient of each sub-catchment area, and form sub-catchment area surface layer; obtain catchment area underlying surface data from land use data, and set different Manning coefficients for different land use types in the catchment area underlying surface, obtain underlying surface surface layer; divide the underlying surface polygons in the underlying surface surface layer with the sub-catchment areas in the sub-catchment area layer as boundaries to obtain sub-underlying surfaces, calculate the average Manning coefficient of each sub-underlying surface, and form sub-underlying surface surface layer; set city rainfall scenarios, determine design rainfall intensity and infiltration rate according to design rainfall data and measured infiltration data; wherein the design rainfall data adopts Chicago method rain type, which is a typical rainfall process designed based on storm intensity formula; The rainfall duration time sequence is divided into two parts before and after the peak by introducing a rain peak position coefficient r to describe the time when the storm peak occurs; Step 2: Build a city pipe network drainage capacity design and land use planning method based on hydrology-hydrodynamic integrated model, including hydrology-physical model and 2D kinematic-wave hydrodynamic model; Connect each node in the city watershed built in step (1) to the calculation position x of the hydrology-hydrodynamic integrated model, calculate the runoff of each sub-catchment node under the conditions of corresponding land use type and design rainfall intensity by the hydrology-hydrodynamic integrated model, and flow into the corresponding pipe; assume that the pipe flow is uniform flow at this time, then the terrain gradient at this time is equal to the resistance slope, wherein the resistance slope is calculated by Manning formula: where S f is the slope of resistance; n is the Manning coefficient (s / m 1 / 3 ) at the calculation location x- cross section; R 水力 is the hydraulic radius (m); q x is the outflow rate (m / s) from the catchment area; Q is the outflow velocity (m 3 / s) from the catchment area; A(x) is the upstream catchment area (m 2 ) at the calculation location. S is the terrain gradient (1); Further, the pipe water depth of the node can be obtained, and compared with the pipe diameter of the node to judge the drainage capacity of the pipe; the dynamic change process of flow and water depth of each node and the drainage capacity of the pipe under different time and land use type can be obtained; Step 3: According to historical observation data, calibrate and verify the model parameters; Step 4: Output city pipe network drainage capacity design and land use planning.

2. The method for pipe network drainage capacity and land use planning based on hydrology-hydrodynamic model according to claim 1, characterized in that step 1 further comprises the following contents: The storm intensity formula under a certain return period is: ​ In the formula, i is rainfall intensity (mm / min); C is rain force parameter, that is, 1 min design rainfall (mm) under different return periods; t is rainfall duration (min); m is rainfall duration correction parameter; and n is rainstorm attenuation index. wherein, Rainfall intensity before and after the rain peak can be calculated by the following formula: where i(t b ) is the pre-peak instantaneous rainfall intensity (mm / min); t b is the corresponding duration, i(t a ) is the post-peak instantaneous rainfall intensity (mm / min); t a is the corresponding duration, and r is the rain peak position coefficient. The hourly design rainfall intensity under a certain return period is calculated using formulas (2) and (3), and a city watershed is built with the city watershed framework.

3. The method for drainage capacity of sewer network and land use planning based on hydrodynamic model according to claim 1, characterized in that: A hydrological physical model, that is, regarding a catchment area as a water tank with holes in the side and bottom for simulating infiltration and outflow, and the original water storage depth of the water tank simulating the initial water depth of the basin, is used to build an equation of the hydrological model by using the mass conservation law to establish a balance relationship among total input rate, total water storage growth rate and total output rate in the catchment area. Q＝ q x × A(x) (5) where R is the rainfall intensity (mm / h); q x is the outflow rate of the catchment (m / s); H x is the average water depth upstream of the calculation location (m); I is the infiltration rate of the catchment (m / s); t is time (s); Q is the outflow velocity of the catchment (m 3 / s); and A(x) is the area of the catchment upstream of the calculation location (m 2 ).

4. The method for drainage capacity of sewerage network and land use planning based on hydrological and hydrodynamic model according to claim 3, characterized in that: The 2D kinematic-wave hydrodynamic model establishes a hydraulic connection between cross-section outflow velocity and cross-section average water depth. where h is the water depth at the cross section (m); n m is the Manning coefficient (s / m 1 / 3 ); Q1 is the linear outflow (m 2 / s); S is the terrain gradient (1); and l is the distance coordinate on the slope (m). According to the cross-section outflow velocity and total water storage in the catchment area obtained by the hydrological physical model and the 2D kinematic-wave hydrodynamic model, the total outflow Q is equal to the linear outflow Q1 multiplied by the cross-section width B(x), and a two-layer simultaneous relationship of the two models is built: Q = Q1B(x) (8) Through the above connection, an integrated hydrological-hydrodynamic model is built, formula (5) is substituted into formula (8) That is, After transformation, That is, Formula (11) is multiplied by the cross-section width B(x) and integrated along the catchment area to obtain the total water storage in the catchment area: From the hydro-physical model, the average water depth H of the upstream catchment area at the location is calculated x From the law of conservation of mass, we have: Formula (12) is substituted into formula (13) to obtain: Let the complex term in formula (14) be In the formula, b is a catchment area constant; Formula (16) can be derived: The integrated hydrological-hydrodynamic model is built by simultaneously solving formula (4), formula (9) and formula (16). where q x is the outflow rate at the cross-section at location x (m / s); is the average Manning coefficient of the catchment (s / m 1 / 3 ); S is the topographic gradient at the location (1); is the average topographic gradient of the catchment (1); H x is the average water depth upstream of the location of computation (m); h is the water depth at the location of computation (m); B(x) is the cross-section width at the location of computation (m); A(x) is the upstream catchment area corresponding to B(x) at the location of computation (m 2 ); b is the catchment area constant; and c is the catchment area exponent.

5. A non-volatile storage medium, characterized by: The non-volatile storage medium comprises a stored program, wherein the program controls the device in which the non-volatile storage medium is located to execute the method of any one of claims 1 to 4 when running. 6.An electronic device, characterized by comprising: The non-volatile storage medium comprises a stored program, wherein the program controls the device in which the non-volatile storage medium is located to execute the method of any one of claims 1 to 4 when running.

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