Ecological cycle model construction method based on sponge city

Abstract

The invention discloses an ecological cycle model construction method based on a sponge city, and the method comprises the steps: carrying out the analysis of a city hydrological cycle, and obtaining a rainfall runoff process in a city which comprises different functional regions and municipal regions; establishing a water quantity balance table of the city, and solving rainfall, surface runoff, groundwater replenishment, lateral inflow and total runoff of different functional areas and municipal areas based on the water quantity balance table; in each functional area, an SWMM model is adopted, an urban rainfall-runoff-storage stagnation combined model is established, and water quality in each functional area is obtained through calculation; and by taking the water quality in different functional areas as a control target, solving the water quality of the municipal area according to the lateral inflow total amount of the municipal area, and constructing a sponge city ecological cycle model. According to the invention, water quality control and sponge city ecological cycle construction can be realized, and the efficiency of urban water resource management and the sustainability of the environment are improved.

Description

Technical Field

[0001] The present invention relates to the field of urban water resources management, and in particular to a method for constructing an ecological cycle model based on a sponge city. Background Art

[0002] Sponge city is a new concept of urban rainwater management, which aims to collect, purify, utilize and discharge urban rainwater by simulating the natural water cycle process, so as to reduce urban waterlogging, improve the urban ecological environment and increase the utilization rate of water resources. In the construction of sponge city, the construction of ecological cycle model is one of the key technologies, which involves the analysis of urban hydrological cycle, the calculation of water balance, and the simulation and control of water quality. Traditional urban drainage systems often adopt the fast drainage mode, that is, quickly draining rainwater into rivers or oceans through pipes and ditches. Although this mode can quickly drain the accumulated water, it ignores the utilization of rainwater resources and the protection of the ecological environment, which is easy to cause urban waterlogging, water pollution and ecological damage. With the acceleration of urbanization, the demand for urban water resources management and ecological environment protection is increasing, and the traditional drainage mode can no longer meet the requirements of sustainable development of modern cities.

[0003] In the process of implementing the embodiments of the present invention, the inventors found that there are at least the following problems or defects in the prior art: the existing urban hydrological cycle models and water balance calculation methods are often overly simplified and cannot accurately reflect the complex hydrological processes of different functional areas and municipal areas within the city; at the same time, there is a lack of effective water quality simulation and control methods, making it difficult to accurately predict and manage water quality changes during urban rainwater runoff. Summary of the invention

[0004] The embodiment of the present invention aims to provide a method for constructing an ecological cycle model based on a sponge city to solve the technical problems raised in the prior art.

[0005] The embodiment of the present invention solves the technical problem by adopting the following technical solution:

[0006] A method for constructing an ecological cycle model based on a sponge city is provided, including:

[0007] Analyze the urban hydrological cycle to obtain the rainfall runoff process within the city, wherein the city includes different functional areas and municipal areas;

[0008] Establish a water balance table for the city, and calculate the rainfall, surface flow, groundwater recharge, lateral inflow, and total runoff for different functional areas and municipal areas based on the water balance table;

[0009] In each functional area, the SWMM model is used to establish a joint model of urban rainfall-runoff-storage (i.e., runoff generation and confluence) to calculate the water quality in each functional area;

[0010] Taking the water quality in different functional areas as the control target, the water quality of the municipal area is solved according to the total lateral inflow into the municipal area, and the sponge city ecological cycle model is constructed.

[0011] Furthermore, in step 2, the rainfall, surface flow, groundwater recharge, lateral inflow, and total runoff of different functional areas and municipal areas are solved based on the water balance table. Specifically, the water volume is calculated using the water balance table assuming that the areas of each area are equal: different functional areas within the city, including rivers, green areas, construction areas, agricultural areas, commercial areas, and parks, with green areas and agricultural areas as the main areas;

[0012] In the green area, the impact of human activities on water balance is not considered, and water can be freely exchanged between the green area and the river. The water balance table is:

[0013] Green area: The inflow of the green area is equal to the water production of the green area itself and the lateral inflow of the river;

[0014] River channel: The outflow of a river channel is the flow produced by the river channel itself;

[0015] In the construction area, the impact of the construction area on the water balance is not considered, and water can be freely exchanged between the construction area and the municipal pipeline. The water balance table is:

[0016] Construction area: The inflow of the construction area is equal to the water production of the construction area itself and the lateral inflow of the municipal pipeline;

[0017] Municipal pipeline: The outflow of the municipal pipeline is equal to the water production of the municipal pipeline itself and the lateral inflow from the green area and the construction area;

[0018] The water balance relationship between green areas, rivers and construction areas is:

[0019] Green Area: I green =F 0 +M 0

[0020] River: O river =F 1

[0021] Construction Area: I build =F 2 +M 1

[0022] Municipal pipeline: O pipe =F pipe +M 2 +M 1

[0023] In the formula, F 0is the water production of the green area itself, in m 3 ;

[0024] F 1 is the flow of the river itself, in m 3 ; F 2 is the flow produced by the construction area itself, in m 3 ;M 0 is the lateral inflow from the green area to the river, in m 3 ;M 1 is the lateral inflow from the construction area to the municipal pipeline, in m 3 ;M 2 is the lateral inflow from the green area to the municipal pipeline, in m 3 ;

[0025] I green is the inflow to the green area, in m 3 ;

[0026] O river is the outflow of the river, in m 3 ;

[0027] I build is the inflow to the construction area, in m 3 ;

[0028] O pipe is the outflow of the municipal pipeline, in m 3 ;

[0029] F pipe is the water output of the municipal pipeline itself, in m 3 ;

[0030] Urban water surface, roads and shallow soil can be regarded as the same area, which is uniformly defined as the municipal area. Since the surface of the municipal area is exposed and has no ability to degrade pollutants, the pollution in the municipal area comes from:

[0031] The inflow of the municipal area is equal to its own rainfall, the inflow of each functional area and the lateral inflow; the outflow of the municipal area is equal to the total runoff of all areas (green areas, agricultural areas, commercial areas, parks, urban water surfaces, roads, shallow soil);

[0032] Municipal pipeline: The outflow of the municipal pipeline is equal to the water production of the municipal pipeline itself and the lateral inflow from the green area and the construction area. The inflow of the municipal pipeline is equal to the rainfall in the municipal area itself, the inflow of each functional area and the lateral inflow;

[0033] The water surface and shallow soil of green, agricultural, commercial and park areas can be regarded as the same area, which is uniformly defined as the municipal area and the municipal pipeline can exchange water, and the pollutants in the municipal area enter the municipal pipeline. The water balance table is as follows:

[0034] Municipal area: The outflow of a municipal area is the outflow produced by the municipal area itself;

[0035] Municipal pipeline: The outflow of the municipal pipeline is equal to the water production of the municipal pipeline itself and the lateral inflow of the municipal area;

[0036] The inflow of the municipal area is equal to its own rainfall, the inflow of each functional area, and the lateral inflow of the municipal pipeline, green area, and construction area; the lateral inflow of the municipal pipeline, green area, and construction area is 0;

[0037] Municipal pipelines, roads and shallow soil can be regarded as the same area, which is uniformly defined as the municipal area. Since the surface of the municipal area is exposed and does not have the ability to degrade pollutants, the pollution in the municipal area comes from: the outflow of the municipal area is the flow produced by the municipal area itself; the inflow of the municipal pipeline is equal to the rainfall in the municipal area itself, the inflow of each functional area, and the lateral inflow of the municipal pipeline, green area, and construction area; the lateral inflow of the municipal pipeline, green area, and construction area is 0;

[0038] Municipal pipelines, roads and shallow soil can be regarded as the same area, which are uniformly defined as the municipal area. The outflow of municipal pipelines is equal to the water production of the municipal pipelines themselves and the lateral inflow into the municipal area; the inflow of municipal pipelines is equal to the rainfall in the municipal area itself, the inflow of various functional areas, and the lateral inflow of municipal pipelines, green areas and construction areas.

[0039] Furthermore, in step 2, the total runoff after rainfall on the municipal surface is solved by the water balance table, and the calculation formula is:

[0040] W 2 =μ×W 0 -W 1

[0041] Where W 0 is the total rainfall in the municipal area, in m 3 ; W 1 is the total runoff in the municipal area, in m 3 ; W 2 is the total runoff of the municipal area, in m 3 ; μ is the municipal area runoff ratio.

[0042] Furthermore, for different functional areas of the city, agricultural pollution load is mainly ammonia nitrogen, and other functional areas are mainly phosphorus pollutants. The pollutant load of runoff in agricultural areas is:

[0043]

[0044] In the formula, A i % is the pollutant load of runoff from agricultural areas; A i,0 A is the pollutant content in the agricultural area at the initial time; i,t A is the pollutant content in the agricultural area at time t; i,settled is the soil pollutant content on the tth day after rainfall; K a % is the pollutant attenuation rate constant in agricultural areas; P is the duration of rainfall.

[0045] The pollutant loads of sewage treatment plants in green areas, commercial areas, parks, municipal areas and green areas are:

[0046]

[0047] In the formula, A m % is the pollutant load of sewage treatment plants in green areas, commercial areas, parks, municipal areas and green areas; A m,0 A is the pollutant content of green area, commercial area, park, municipal area and green area sewage treatment plant at the initial time; m,t is the pollutant content of green area, commercial area, park, municipal area and green area sewage treatment plant at time t;

[0048] A m,settled K is the pollutant content of green area, commercial area, park, municipal area and green area sewage treatment plant on the tth day after rainfall; m % is the pollutant attenuation rate constant of sewage treatment plants in green areas, commercial areas, parks, municipal areas and green areas; P is the duration of rainfall.

[0049] Furthermore, within the urban functional area, the SWMM model is used to construct an urban rainfall-runoff-storage joint model, specifically:

[0050] A. Construct urban subcatchment model, including land use, surface runoff, surface runoff, underground runoff, and underground runoff;

[0051] B. Construct the urban sub-pipeline network model, including pipe network hydraulic calculation, pipe network water environment calculation, pipeline and pump station equipment;

[0052] C. Construct a sub-river model for the city, including river hydraulic calculations, seawater inflow calculations, water environment calculations, and flood control facilities.

[0053] Furthermore, step 4 is specifically as follows:

[0054] According to the formula W 2 =μ×W 0 -W 1 Solve for the municipal area inflow; according to the formula Solve the ammonia nitrogen content of the municipal area water quality and the content of pollutants in each functional area obtained in step 3, compare the results with the preset pollutant emission standard data, and then solve the water quality of the municipal area.

[0055] Furthermore, the specific solution process of step 3 is:

[0056] Firstly, the urban sub-catchment model is calculated, and the urban land use parameters are set using the model to simulate surface runoff, surface runoff, underground runoff, and underground runoff after rainfall, and to simulate the water volume and water quality of the catchment area.

[0057] Then, the urban sub-pipeline network model is calculated. Combined with the inflow of water in the catchment area and underground confluence, the rainwater network hydraulic calculation, network water environment calculation, and network equipment calculation are performed to simulate the water volume and water quality of the network.

[0058] Then, the river model is calculated, and the water volume of the pipe network is used to calculate the river hydraulics, the river water environment, and the flood discharge facilities, and simulate the water volume and water quality of the river.

[0059] Finally, the information obtained from the catchment area, pipe network, and river simulation is summarized to conduct runoff generation and confluence of the entire basin and final river outflow. The water quality simulation data of each region are merged to solve the water quality of each region.

[0060] Furthermore, the specific process of step 1 is:

[0061] By collecting basic data from each functional area, building a two-dimensional surface model of different functional areas, and combining terrain data to establish a joint rainfall-runoff model for each functional area (including sub-catchment area model, sub-pipeline network model, and sub-river channel model), the runoff generation and confluence of each functional area after rainfall inflow is calculated. Finally, the urban hydrological cycle is analyzed with the Manning formula as a constraint to obtain the rainfall-runoff process inside the city. The Manning formula is:

[0062]

[0063] Where V is the flow velocity in m / s; R is the hydraulic radius in m; n is the Manning coefficient; and S is the gradient.

[0064] Furthermore, the combined simulation of rainfall and runoff in the city based on the two-dimensional surface model includes:

[0065] Urban land types can be divided into two categories, the first category is permeable surface, and the second category is impervious surface. The calculation formula is:

[0066] S=A imp % × D + A bg %×D

[0067] Where S is the surface hydrological factor; A imp % is the impervious surface area ratio; A bg % is the permeable surface area ratio; D is the waterway depth, in m.

[0068] Furthermore, different pipe network parameters, waterway depths, and gradients are set to calculate runoff generation and confluence, and the runoff process and runoff volume under different working conditions are obtained.

[0069] The above-mentioned embodiments of the present invention have at least the following beneficial effects: the method for constructing an ecological cycle model based on a sponge city provided by the present invention can conduct an in-depth analysis of the urban hydrological cycle, and accurately calculate key hydrological parameters such as rainfall, surface flow, and groundwater recharge in different functional areas and municipal areas by establishing a water balance table and using the SWMM model. This method can effectively simulate the urban rainfall runoff process, provide a scientific basis for urban water resources management and water quality control, and thus improve the efficiency of the urban drainage system and the sustainability of the urban environment.

[0070] In addition, the method of the present invention can also construct a highly adaptable sponge city ecological cycle model according to the water quality conditions of different functional areas. This method can optimize the utilization of urban rainwater resources, reduce urban waterlogging and water pollution, and protect and improve the urban ecological environment. Through the application of this method, it is possible to promote urban sustainable development, improve the quality of life of urban residents, and provide support for cities to cope with extreme weather events caused by climate change. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] One or more embodiments are exemplarily described by figures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0072] Figure 1 A flowchart of a method for constructing an ecological cycle model based on a sponge city provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0073] In order to facilitate the understanding of the present invention, the present invention is described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "connecting" another element, it can be directly on another element, or there can be one or more centered elements therebetween. The orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "upper end", "lower end", "top" and "bottom" used in this specification is based on the orientation or positional relationship shown in the accompanying drawings, only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0074] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0075] Combine the following Figure 1 , the ecological cycle model construction method 100 based on sponge city provided in the embodiment of the present application is described in detail through specific examples.

[0076] Figure 1 : is a flow chart of the method for constructing an ecological cycle model based on a sponge city provided by the present invention. The method for constructing an ecological cycle model based on a sponge city provided by one embodiment of the present invention includes:

[0077] Step 1, analyzing the urban hydrological cycle to obtain the rainfall runoff process within the city, wherein the city includes different functional areas and municipal areas;

[0078] Step 2: Establish a water balance table for the city, and solve the rainfall, surface flow, groundwater recharge, lateral inflow, and total runoff of different functional areas and municipal areas based on the water balance table;

[0079] Step 3: In each functional area, the SWMM model is used to establish a joint model of urban rainfall-runoff-storage (i.e., runoff generation and confluence) to calculate the water quality in each functional area;

[0080] Step 4: Taking the water quality in different functional areas as the control target, the water quality of the municipal area is solved according to the total lateral inflow of the municipal area, and the sponge city ecological cycle model is constructed.

[0081] It should be noted that this method first involves the analysis of the urban hydrological cycle to obtain the rainfall-runoff process within the city. The urban hydrological cycle here refers to the cycle of water within the city, including rainfall, surface runoff, groundwater recharge, etc. The rainfall-runoff process refers to the process in which water flows on the surface after rainfall and eventually flows into rivers or groundwater. Sponge city refers to an urban design concept that combines natural and artificial systems to collect, purify, utilize and discharge urban rainwater in order to reduce urban waterlogging, improve the urban ecological environment and increase the utilization rate of water resources.

[0082] Specifically, the method requires the establishment of a water balance sheet for the city, based on which rainfall, surface flow, groundwater recharge, lateral inflow, and total runoff for different functional areas and municipal areas are calculated. A water balance sheet is a tool used to calculate and record the input and output of water in an area to ensure water balance.

[0083] More specifically, in actual operation, this may involve collecting meteorological data, topographic data and land use information, as well as setting relevant parameters such as rainfall intensity, soil permeability, etc. to calculate the hydrological processes in different areas.

[0084] Preferably, the method further refines the application of the SWMM model to establish a combined urban rainfall-runoff-storage model to calculate the water quality in each functional area. The SWMM model, or Stormwater Runoff Management Model, is a computer model used to simulate surface runoff and water quality generated by rainfall in urban areas.

[0085] Furthermore, during implementation, different model parameters can be selected, such as the duration and intensity distribution of rainfall events, and the land use types in different areas of the city, to accurately simulate the rainfall-runoff process. In addition, alternatives can be selected according to actual conditions, such as using other rainfall-runoff models or adjusting model parameters to suit specific urban environments.

[0086] In some embodiments, in step 2, the rainfall, surface flow, groundwater recharge, lateral inflow, and total runoff of different functional areas and municipal areas are solved based on the water balance table, specifically: assuming that the areas of each area are equal, the water volume is calculated using the water balance table: different functional areas in the city, including rivers, green areas, construction areas, agricultural areas, commercial areas, and parks, with green areas and agricultural areas as the main areas;

[0087] In the green area, the impact of human activities on water balance is not considered, and water can be freely exchanged between the green area and the river. The water balance table is:

[0088] Green area: The inflow of the green area is equal to the water production of the green area itself and the lateral inflow of the river;

[0089] River channel: The outflow of a river channel is the flow produced by the river channel itself;

[0090] In the construction area, the impact of the construction area on the water balance is not considered, and water can be freely exchanged between the construction area and the municipal pipeline. The water balance table is:

[0091] Construction area: The inflow of the construction area is equal to the water production of the construction area itself and the lateral inflow of the municipal pipeline;

[0092] Municipal pipeline: The outflow of the municipal pipeline is equal to the water production of the municipal pipeline itself and the lateral inflow from the green area and the construction area;

[0093] The water balance relationship between green areas, rivers and construction areas is:

[0094] Green Area: I green =F 0 +M 0

[0095] River: O river =F 1

[0096] Construction Area: I build =F 2 +M 1

[0097] Municipal pipeline: O pipe =F pipe +M 2 +M 1

[0098] In the formula, F 0 is the water production of the green area itself, in m 3 ;

[0099] F 1 is the flow of the river itself, in m 3 ; F 2 is the flow produced by the construction area itself, in m 3 ;M 0 is the lateral inflow from the green area to the river, in m 3 ;M 1 is the lateral inflow from the construction area to the municipal pipeline, in m 3 ;M 2 is the lateral inflow from the green area to the municipal pipeline, in m 3 ;

[0100] I grren is the inflow to the green area, in m 3 ;

[0101] O riveris the outflow of the river, in m 3 ;

[0102] I build is the inflow to the construction area, in m 3 ;

[0103] O pipe is the outflow of the municipal pipeline, in m 3 ;

[0104] F pipe is the water output of the municipal pipeline itself, in m 3 ;

[0105] Urban water surface, roads and shallow soil can be regarded as the same area, which is uniformly defined as the municipal area. Since the surface of the municipal area is exposed and has no ability to degrade pollutants, the pollution in the municipal area comes from:

[0106] The inflow of the municipal area is equal to its own rainfall, the inflow of each functional area and the lateral inflow; the outflow of the municipal area is equal to the total runoff of all areas (green areas, agricultural areas, commercial areas, parks, urban water surfaces, roads, shallow soil);

[0107] Municipal pipeline: The outflow of the municipal pipeline is equal to the water production of the municipal pipeline itself and the lateral inflow from the green area and the construction area. The inflow of the municipal pipeline is equal to the rainfall in the municipal area itself, the inflow of each functional area and the lateral inflow;

[0108] The water surface and shallow soil of green, agricultural, commercial and park areas can be regarded as the same area, which is uniformly defined as the municipal area and the municipal pipeline can exchange water, and the pollutants in the municipal area enter the municipal pipeline. The water balance table is as follows:

[0109] Municipal area: The outflow of a municipal area is the outflow produced by the municipal area itself;

[0110] Municipal pipeline: The outflow of the municipal pipeline is equal to the water production of the municipal pipeline itself and the lateral inflow of the municipal area;

[0111] The inflow of the municipal area is equal to its own rainfall, the inflow of each functional area, and the lateral inflow of the municipal pipeline, green area, and construction area; the lateral inflow of the municipal pipeline, green area, and construction area is 0;

[0112] Municipal pipelines, roads and shallow soil can be regarded as the same area, which is uniformly defined as the municipal area. Since the surface of the municipal area is exposed and does not have the ability to degrade pollutants, the pollution in the municipal area comes from: the outflow of the municipal area is the flow produced by the municipal area itself; the inflow of the municipal pipeline is equal to the rainfall in the municipal area itself, the inflow of each functional area, and the lateral inflow of the municipal pipeline, green area, and construction area; the lateral inflow of the municipal pipeline, green area, and construction area is 0;

[0113] Municipal pipelines, roads and shallow soil can be regarded as the same area, which are uniformly defined as the municipal area. The outflow of municipal pipelines is equal to the water production of the municipal pipelines themselves and the lateral inflow into the municipal area; the inflow of municipal pipelines is equal to the rainfall in the municipal area itself, the inflow of various functional areas, and the lateral inflow of municipal pipelines, green areas and construction areas.

[0114] It should be noted that this implementation describes in detail the process of solving the hydrological parameters of different functional areas and municipal areas based on the water balance table. Here, the water balance table is a key tool for calculating and balancing the hydrological cycle of different areas in the city, including rainfall, surface flow, groundwater recharge, lateral inflow and total runoff. These parameters are crucial to understanding and simulating the urban hydrological cycle, and they help determine the hydrological response of the city under different rainfall conditions.

[0115] Specifically, the implementation involves assuming that the areas of various regions are equal and using a water balance table to calculate the water volume. For example, different functional areas within a city include rivers, green areas, construction areas, agricultural areas, commercial areas and parks, among which green areas and agricultural areas are the main considerations.

[0116] More specifically, in green areas, the impact of human activities on water balance is not considered, and water can be freely exchanged between green areas and rivers. This means that when calculating the water balance of green areas, it is necessary to consider the water production of the green areas themselves and the lateral inflow of the rivers. Specific parameter settings may include rainfall intensity, evaporation rate, soil permeability, etc. These parameters will be adjusted according to actual geographical and climatic conditions.

[0117] Preferably, the implementation further refines the water balance relationship between the green area, the river and the construction area. For example, the inflow of the green area is equal to the water production of the green area itself plus the lateral inflow of the river; the outflow of the river is the flow production of the river itself; the inflow of the construction area is equal to the water production of the construction area itself plus the lateral inflow of the municipal pipeline; the outflow of the municipal pipeline is equal to the water production of the municipal pipeline itself plus the lateral inflow of the green area and the construction area.

[0118] Furthermore, in actual operation, these relationships can be expressed by building mathematical models and calibrating model parameters by collecting field data. In addition, the parameters and structure of the model can also be adjusted according to the characteristics of the specific urban layout and functional areas to more accurately reflect the actual hydrological process.

[0119] In some embodiments, in step 2, the total runoff of the municipal area surface after rainfall is solved by the water balance table, and the calculation formula is:

[0120] W 2 =μ×W 0 -W 1

[0121] Where W 0 is the total rainfall in the municipal area, in m 3 ; W 1 is the total runoff in the municipal area, in m 3 ; W 2 is the total runoff of the municipal area, in m 3 ; μ is the municipal area runoff ratio.

[0122] It should be noted that this implementation method focuses on solving the calculation method of the total runoff after rainfall on the surface of the municipal area through the water balance table. Here, the total runoff refers to all the water flowing out of the surface of the municipal area after rainfall, including the flow generated by direct rainfall and surface flow. This calculation is crucial to understanding and managing the urban drainage system because it directly affects the city's flood control capacity and water resources management.

[0123] Specifically, the calculation formula mentioned in this implementation is: total runoff = runoff ratio × total rainfall - total flow production. In this formula, the runoff ratio is a key parameter, which reflects the proportion of rainfall converted into runoff. This ratio is affected by many factors, including the impervious area of ​​the surface, the permeability of the soil, vegetation cover, etc. The total rainfall refers to the total amount of rainfall that falls in the municipal area within a certain period of time, while the total flow production refers to the flow generated directly on the surface due to rainfall. The specific settings of these parameters need to be determined based on local climate data, topography and land use conditions.

[0124] Preferably, the embodiment can calibrate the value of the runoff ratio by collecting historical rainfall data and surface characteristic data. For example, the runoff ratio can be estimated by analyzing historical rainfall events and corresponding runoff volumes. In addition, geographic information systems (GIS) and remote sensing technology can be used to obtain more accurate surface characteristic data, such as the proportion of impervious areas and vegetation coverage.

[0125] Furthermore, in actual operation, different mathematical models or statistical methods can be considered to optimize the estimation of runoff ratio to improve the accuracy of total runoff calculation. These alternatives can include machine learning algorithms, hydrological simulation software or expert systems, which can help improve the predictive ability and adaptability of the model.

[0126] In some embodiments, for different functional areas of the city, the agricultural pollution load is mainly ammonia nitrogen, and other functional areas are mainly phosphorus pollutants. The pollutant load of runoff in the agricultural area is:

[0127]

[0128] In the formula, A i % is the pollutant load of runoff from agricultural areas; A i,0 A is the pollutant content in the agricultural area at the initial time; i,t is the pollutant content in the agricultural area at time t; A i,settled is the soil pollutant content on the tth day after rainfall; K a % is the pollutant attenuation rate constant in agricultural areas; P is the duration of rainfall.

[0129] The pollutant loads of sewage treatment plants in green areas, commercial areas, parks, municipal areas and green areas are:

[0130]

[0131] In the formula, A m % is the pollutant load of sewage treatment plants in green areas, commercial areas, parks, municipal areas and green areas; A m,0 A is the pollutant content of green area, commercial area, park, municipal area and green area sewage treatment plant at the initial time; m,t is the pollutant content of green area, commercial area, park, municipal area and green area sewage treatment plant at time t;

[0132] A m,settled K is the pollutant content of green area, commercial area, park, municipal area and green area sewage treatment plant on the tth day after rainfall; m % is the pollutant attenuation rate constant of sewage treatment plants in green areas, commercial areas, parks, municipal areas and green areas; P is the duration of rainfall.

[0133] It should be noted that this implementation method describes in detail how to calculate the runoff pollutant load of different functional areas in the city. Here, the runoff pollutant load refers to the total amount of pollutants lost with the runoff, which is an important indicator for measuring the degree of urban water pollution. Ammonia nitrogen is the main pollutant in agricultural areas, while phosphorus pollutants are the main pollutants in other functional areas. This distinction helps to carry out targeted pollution control and management.

[0134] Specifically, the implementation method mentions the calculation formula of the pollutant load of agricultural runoff: pollutant load =

[0135] Initial pollutant content - pollutant content at time t - soil pollutant content on the tth day after rainfall × (1-attenuation rate constant × rainfall duration)

[0136] More specifically, in this formula, the initial pollutant content refers to the total amount of pollutants in the soil before rainfall, the pollutant content at time t refers to the amount of pollutants in the soil at a certain time after rainfall, the soil pollutant content on the tth day after rainfall refers to the amount of pollutants in the soil a specific number of days after rainfall, the decay rate constant refers to the rate at which pollutants decay in the soil, and the duration of rainfall refers to the duration of rainfall. The setting of these parameters needs to be determined based on the specific soil characteristics, climate conditions, and pollutant characteristics.

[0137] Preferably, the embodiment can determine the initial content and decay rate constant of pollutants in soil by field sampling and laboratory analysis. For example, the initial pollutant content and decay rate constant can be estimated by regularly sampling soil in different functional areas and analyzing the pollutant content.

[0138] Furthermore, hydrological models and water quality models can be used to simulate the dynamic changes of pollutants during rainfall to more accurately predict the runoff pollutant load. In actual operation, it is also possible to consider using remote sensing technology and geographic information systems (GIS) to monitor and analyze the spatial distribution of pollutants, as well as adopting advanced pollution control technologies to reduce pollutant emissions. These alternatives can improve the accuracy of pollutant load calculations and provide more effective technical support for urban water environment management.

[0139] In some embodiments, within the urban functional area, the SWMM model is used to construct an urban rainfall-runoff-storage joint model, specifically:

[0140] A. Construct urban subcatchment models, including land use, surface runoff, surface runoff, underground runoff, and underground runoff;

[0141] B. Construct the urban sub-pipeline network model, including pipe network hydraulic calculation, pipe network water environment calculation, pipeline and pump station equipment;

[0142] C. Construct a sub-river model for the city, including river hydraulic calculations, seawater inflow calculations, water environment calculations, and flood control facilities.

[0143] It should be noted that this implementation describes the specific steps of using the SWMM model to construct an urban rainfall-runoff-storage joint model. The SWMM model, namely the Storm Flood Management Model, is a computer model used to simulate surface runoff and water quality generated by rainfall in urban areas. The model can comprehensively consider factors such as land use, surface runoff, surface runoff, underground runoff and underground runoff, and provide a scientific basis for urban hydrological cycle and water quality management.

[0144] Specifically, the implementation method includes three main parts: constructing an urban subcatchment model, an urban sub-pipeline model, and an urban sub-river model. The subcatchment model involves the setting of parameters such as land use, surface runoff, surface runoff, and underground runoff. For example, land use parameters can be set according to the actual use of different areas in the city, surface runoff parameters may include rainfall intensity, soil permeability, etc., and surface runoff parameters involve water flow velocity and direction.

[0145] More specifically, the sub-pipeline network model includes the hydraulic calculation of the pipeline network, the water environment calculation of the pipeline network, and the configuration of pipelines and pump station equipment. The sub-river model focuses on the hydraulic calculation of the river channel, the calculation of the amount of water entering the sea, the water environment calculation, and the design of flood control facilities. The parameter settings of these models need to be determined according to the actual urban geography, climate, and infrastructure conditions.

[0146] Preferably, the implementation can improve the accuracy and applicability of the simulation by refining model parameters and increasing model functions. For example, in the sub-catchment model, the specific characteristics of different land use types, such as vegetation coverage, soil type, etc., can be further considered. In the sub-pipeline network model, factors such as pipeline aging and blockage can be considered to more realistically simulate the hydraulic behavior of the pipeline network. In the sub-river model, dynamic factors such as river siltation and water quality changes can be introduced to more comprehensively evaluate the hydrological and water quality conditions of the river.

[0147] Furthermore, it is also possible to consider using real-time monitoring data to calibrate model parameters, or adopt a multi-model integration approach to improve the reliability of simulation results. These refinements and alternatives can help improve the prediction accuracy of the model and provide stronger support for urban hydrological management and water quality control.

[0148] In some embodiments, step 4 is specifically:

[0149] According to the formula W 2 =μ×W 0 -W 1 Solve for the municipal area inflow; according to the formula Solve the ammonia nitrogen content of the municipal area water quality and the content of pollutants in each functional area obtained in step 3, compare the results with the preset pollutant emission standard data, and then solve the water quality of the municipal area.

[0150] It should be noted that this implementation involves solving the municipal area inflow and the ammonia nitrogen content in the water quality according to a specific calculation formula, and comparing the results with the preset pollutant emission standards. The municipal area inflow here refers to the water flow entering the municipal pipe network, including rainwater and surface runoff, and the ammonia nitrogen content refers to the total amount of nitrogen in the form of ammonia and ammonium ions in the water, which is an important indicator for water quality assessment.

[0151] Specifically, the formula for calculating the inflow to the municipal area mentioned in this implementation is: Inflow = Runoff Ratio × Total Rainfall - Total Flow Production. In this formula, the runoff ratio refers to the ratio of rainfall converted into runoff, the total rainfall refers to the total rainfall that falls on the municipal area within a certain period of time, and the total flow production refers to the flow directly generated on the surface due to rainfall. The formula for solving the ammonia nitrogen content of the municipal area water quality is: Ammonia Nitrogen Content = Initial Ammonia Nitrogen Content - Ammonia Nitrogen Content at Time t - Soil Ammonia Nitrogen Content on the Tth Day after Rainfall × (1-Decayence Rate Constant ×

[0152] The specific settings of these parameters need to be determined based on local climate data, topography and land use.

[0153] Preferably, the embodiment can calibrate model parameters such as runoff ratio and decay rate constant by collecting and analyzing historical hydrological and water quality data. For example, these parameters can be estimated by statistical analysis of historical rainfall events and corresponding water quality monitoring data.

[0154] Furthermore, real-time monitoring data can be used to dynamically adjust model parameters to improve the prediction accuracy of the model. In actual operation, it is also possible to consider using advanced water quality monitoring technologies, such as online monitoring systems, to obtain water quality data in real time and use these data for model calibration and verification. These refinements and alternatives help improve the applicability and accuracy of the model and provide more effective technical support for urban water environment management.

[0155] In some embodiments, the specific solution process of step 3 is:

[0156] Firstly, the urban sub-catchment model is calculated, and the urban land use parameters are set using the model to simulate surface runoff, surface runoff, underground runoff, and underground runoff after rainfall, and to simulate the water volume and water quality of the catchment area.

[0157] Then, the urban sub-pipeline network model is calculated. Combined with the inflow of water in the catchment area and underground confluence, the rainwater pipe network hydraulic calculation, pipe network water environment calculation, pipe network equipment calculation, and water volume and water quality simulation of the pipe network are carried out.

[0158] Subsequently, river model calculations are carried out. Using the inflow water volume of the pipe network, river hydraulic calculations, river water environment calculations, and flood control facility calculations are performed to simulate the water volume and water quality of the river.

[0159] Finally, the information obtained from the catchment area, pipe network, and river simulations is summarized to perform runoff concentration and final river outflow in the entire basin. The water quality simulation data of each region are combined to solve the water quality of each region.

[0160] It should be noted that this implementation method details the specific calculation steps of the urban sub-catchment area model, sub-pipe network model, and sub-river model. These models together constitute the urban rainfall-runoff-storage joint model, which is used to simulate the rainfall runoff process after setting urban land use parameters, including surface runoff generation, surface runoff concentration, subsurface runoff generation, and subsurface runoff concentration. Surface runoff generation refers to the water flow formed on the surface after rainfall, surface runoff concentration refers to the process of surface water flow concentration, subsurface runoff generation refers to the water flow formed after rainfall infiltrates into the ground, and subsurface runoff concentration refers to the process of subsurface water flow concentration.

[0161] Specifically, the implementation method first performs urban sub-catchment area model calculations, which involve setting urban land use parameters, simulating surface runoff generation and surface runoff concentration, as well as subsurface runoff generation and subsurface runoff concentration after rainfall. Parameter settings include rainfall intensity, soil permeability, land cover type, etc. Then, urban sub-pipe network model calculations are carried out. Combining the inflow water volume of the catchment area and subsurface runoff concentration, rainwater pipe network hydraulic calculations, pipe network water environment calculations, and pipe network equipment calculations of the pipe network are performed. Finally, river model calculations are carried out. Using the inflow water volume of the pipe network, river hydraulic calculations, river water environment calculations, and flood control facility calculations are performed. These calculations need to set parameters according to the actual urban pipe network layout, river characteristics, and hydrological conditions.

[0162] Preferably, this implementation method can improve the accuracy and practicality of the model by introducing more details. For example, in the urban sub-catchment area model, land use parameters can be refined to distinguish different vegetation types and building densities. In the sub-pipe network model, the age, material, and maintenance status of the pipe network, as well as the operation efficiency of the pump stations, can be considered. In the sub-river model, the curvature of the river, the roughness of the riverbed, and the influence of aquatic plants can be included.

[0163] Furthermore, high-precision remote sensing data and Geographic Information System (GIS) can also be used to improve the spatial resolution of the model, or real-time hydrological monitoring data can be adopted to dynamically adjust the model parameters. These alternative solutions can make the model more adaptable to different urban environments and climate changes, improving the prediction ability of the model and the support for management decisions.

[0164] In some embodiments, the specific process of step 1 is as follows:

[0165] By collecting basic data from each functional area, building a two-dimensional surface model of different functional areas, and combining terrain data to establish a joint rainfall-runoff model for each functional area (including sub-catchment area model, sub-pipeline network model, and sub-river channel model), the runoff generation and confluence of each functional area after rainfall inflow is calculated. Finally, the urban hydrological cycle is analyzed with the Manning formula as a constraint to obtain the rainfall-runoff process inside the city. The Manning formula is:

[0166]

[0167] Where V is the flow velocity in m / s; R is the hydraulic radius in m; n is the Manning coefficient; and S is the gradient.

[0168] It should be noted that this implementation method involves using the collected basic data of each functional area, constructing a two-dimensional surface model of different functional areas, and establishing a joint rainfall-runoff model for each functional area in combination with terrain data. The two-dimensional surface model here refers to a mathematical model that simulates surface characteristics and hydrological processes, which can describe the surface water flow dynamics and water quality changes. The joint rainfall-runoff model refers to a model that comprehensively considers rainfall and surface runoff processes, and is used to simulate the runoff generation and confluence after rainfall inflow.

[0169] Specifically, the basic data collection mentioned in the implementation method includes, but is not limited to, information such as topography, soil type, vegetation cover, and land use type. These data can be obtained through field surveys, satellite remote sensing, geographic information systems (GIS), and other means. The construction of a two-dimensional surface model requires the integration of these basic data and the establishment of a model based on the terrain data, which may involve the creation of a digital elevation model (DEM) and hydrological analysis. The parameter settings in the model include the flow velocity (V), hydraulic radius (R), and Manning coefficient (n) in the Manning formula, and these parameters need to be determined based on field measurements or empirical formulas.

[0170] Preferably, the embodiment can improve the accuracy and applicability of the model by further refining the model construction steps and parameter settings. For example, when constructing a two-dimensional surface model, the unevenness of the surface can be considered, such as the impact of road surfaces of different materials and areas covered by different vegetation on water flow. When applying the Manning formula, different Manning coefficients can be set according to different terrains and land use types.

[0171] Furthermore, real-time rainfall and flow monitoring data can be introduced to dynamically adjust model parameters and improve the model's responsiveness to actual hydrological processes. These alternatives can make the model more accurately reflect complex surface hydrological processes and provide stronger support for urban hydrological cycles and water quality management.

[0172] In some embodiments, when performing a combined simulation of rainfall and runoff within a city based on a two-dimensional surface model, the method includes:

[0173] Urban land types can be divided into two categories, the first category is permeable surface, and the second category is impervious surface. The calculation formula is:

[0174] S=A imp % × D + A bg %×D

[0175] Where S is the surface hydrological factor; A imp % is the impervious surface area ratio; A bg % is the permeable surface area ratio; D is the waterway depth, in m.

[0176] It should be noted that this implementation describes the process of combined simulation of rainfall and runoff in the city based on a two-dimensional surface model, which includes the classification of urban land types and the calculation of corresponding hydrological factors. Here, permeable surface refers to the surface that allows water to penetrate, such as green space and farmland, while impermeable surface refers to the surface that prevents water from penetrating, such as concrete and asphalt pavement. Surface hydrological factors refer to parameters that affect surface hydrological processes, such as the ratio of impervious area and the ratio of permeable area.

[0177] Specifically, the implementation method mentions that urban land types are divided into permeable surfaces and impermeable surfaces, and provides a calculation formula: S = (impermeable surface area ratio × D) + (permeable surface area ratio × D). In this formula, S is the surface hydrological factor, D is the waterway depth, and the impermeable surface area ratio and the permeable surface area ratio represent the area ratios of impermeable and permeable surfaces in the city, respectively. The setting of these parameters needs to be determined based on the actual land use and topography of the city, which can be obtained through GIS data and field surveys.

[0178] Preferably, the embodiment can improve the accuracy of the model by further refining the classification and parameter setting of land types. For example, a more detailed ratio of impervious and permeable surface areas can be set according to the specific characteristics of different land use types, such as soil type, vegetation type, building density, etc.

[0179] Furthermore, the waterway depth D can be determined based on the design standards of the urban drainage system and historical hydrological data. In actual operation, it is also possible to consider using high-resolution remote sensing images and ground measurement data to improve the calculation accuracy of the ratio of impervious and permeable surfaces. These alternatives can make the model more accurately reflect the hydrological characteristics of the urban surface and provide more accurate data support for urban hydrological simulation and management.

[0180] In some embodiments, different pipe network parameters, waterway depths, and gradients are set to calculate runoff generation and confluence, and the runoff process and runoff volume under different working conditions are obtained.

[0181] It should be noted that this implementation method involves setting different pipe network parameters, waterway depths and gradients to calculate runoff generation and confluence, and obtain the process and amount of runoff under different working conditions. Here, runoff generation and confluence refers to the process of confluence of surface runoff and groundwater runoff generated by rainfall, and working conditions refer to specific environmental conditions or scenarios, such as different rainfall intensities or land use conditions.

[0182] Specifically, the implementation method requires setting the pipe network parameters, including pipe diameter, length, slope, etc., according to the actual layout and design parameters of the urban drainage system. The waterway depth refers to the depth of the water flow in the pipe or river, and the gradient refers to the slope of the water flow along the way, that is, the vertical drop within a unit horizontal distance. The setting of these parameters needs to be based on urban drainage design specifications, historical hydrological data, and topographic features. For example, the pipe diameter and length can be determined based on the pipe network layout diagram, and the slope can be calculated based on the terrain elevation data.

[0183] Preferably, the embodiment can improve the adaptability and accuracy of the model by introducing more details and dynamic factors. For example, the pipe network parameters and waterway depth can be adjusted according to the characteristics of different rainfall events to simulate the flow generation and convergence under different rainfall conditions. In addition, the slope can be dynamically adjusted using real-time rainfall and flow monitoring data to more accurately simulate the actual hydrological process.

[0184] Furthermore, in actual operation, it is also possible to consider using numerical simulation software to simulate the runoff process under different working conditions, or using machine learning algorithms to optimize parameter settings and improve the model's predictive ability. These alternatives can make the model more flexible to adapt to different environmental conditions and provide more effective support for urban drainage management and flood warning.

[0185] The above-mentioned embodiments of the present invention have the following beneficial effects: the method for constructing an ecological cycle model based on a sponge city described in the present invention can comprehensively analyze the urban hydrological cycle, and accurately calculate and simulate the hydrological processes of different functional areas and municipal areas by establishing a water balance table and a SWMM model. This method can optimize urban water resource management, improve the utilization efficiency of rainwater resources, reduce urban waterlogging and water pollution, and at the same time protect and improve the urban ecological environment and enhance the ecological resilience of the city.

[0186] In addition, the technical solutions described in detail in these claims can provide a scientific means for cities to control water quality and assess pollutant loads. By simulating and calculating pollutant loads in different functional areas, urban water quality can be managed and controlled more effectively, reducing the impact of pollutants on the environment. The application of this method can promote sustainable urban development, improve the quality of life of urban residents, and provide support for cities to cope with extreme weather events caused by climate change.

[0187] Furthermore, the storage medium of the embodiment of the present application stores program instructions that can implement all the above methods, wherein the program instructions can be stored in the above storage medium in the form of a software product, including several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) or a processor to execute all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, or terminal devices such as a computer, a server, a mobile phone, and a tablet.

[0188] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes in different aspects of the present invention as above, which are not provided in detail for the sake of simplicity. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, 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 invention.

Claims

1. A method for constructing an ecological cycle model based on a sponge city, characterized in that: Here are the steps: Step 1, analyzing the urban hydrological cycle to obtain the rainfall runoff process within the city, wherein the city includes different functional areas and municipal areas; Step 2: Establish a water balance table for the city, and solve the rainfall, surface flow, groundwater recharge, lateral inflow, and total runoff of different functional areas and municipal areas based on the water balance table; Step 3: In each functional area, the SWMM model is used to establish an urban rainfall-runoff-storage joint model to calculate the water quality in each functional area; Step 4: Taking the water quality in different functional areas as the control target, the water quality of the municipal area is solved according to the total lateral inflow of the municipal area, and the sponge city ecological cycle model is constructed.

2. The method for constructing an ecological cycle model based on a sponge city according to claim 1, characterized in that: Based on the water balance table, the rainfall, surface flow, groundwater recharge, lateral inflow, and total runoff of different functional areas and municipal areas are solved, specifically: The water volume is calculated using a water balance sheet, which is: The inflow to the green area is equal to the water production of the green area itself and the lateral inflow from the river; The outflow of a river is the flow produced by the river itself; The inflow to the construction area is equal to the water production of the construction area itself and the lateral inflow from the municipal pipeline; The outflow from the municipal pipeline is equal to the water production of the municipal pipeline itself and the lateral inflow from the green area and the construction area; The water balance relationship between green areas, rivers and construction areas is: Green Area: I green =F0+M0 River: O river =F1 Construction Area: I build =F2+M1 Municipal pipeline: O pipe =F pipe +M2+M1 Where F0 is the water production of the green area itself, in m 3 ; F1 is the flow rate of the river itself, in m 3 ; F2 is the flow produced by the construction area itself, in m 3 ; M0 is the lateral inflow from the green area to the river, in m 3 ; M1 is the lateral inflow from the construction area to the municipal pipeline, in m 3 ; M2 is the lateral inflow from the green area to the municipal pipeline, in m 3 ; I green is the inflow to the green area, in m 3 ; O river is the outflow of the river, in m 3 ; I build is the inflow to the construction area, in m 3 ; O pipe is the outflow of the municipal pipeline, in m 3 ; F pipe is the water output of the municipal pipeline itself, in m 3 .

3. The method for constructing an ecological cycle model based on a sponge city according to claim 2 is characterized in that: In step 2, the total runoff after rainfall on the municipal surface is solved through the water balance table, and the calculation formula is: W2=μ×W0-W1 Where W0 is the total rainfall in the municipal area, in m 3 ; W1 is the total runoff in the municipal area, in m 3 ; W2 is the total runoff in the municipal area, in m 3 ; μ is the municipal area runoff ratio.

4. The method for constructing an ecological cycle model based on a sponge city according to claim 3 is characterized in that: For different functional areas of the city, the pollutant load of runoff from agricultural areas is: In the formula, A i % is the pollutant load of runoff from agricultural areas; A i，0 A is the pollutant content in the agricultural area at the initial time; i，t is the pollutant content in the agricultural area at time t; A i，settled is the soil pollutant content on the tth day after rainfall; K a % is the pollutant attenuation rate constant in agricultural areas; P is the duration of rainfall. The pollutant loads of sewage treatment plants in green areas, commercial areas, parks, municipal areas and green areas are: In the formula, A m % is the pollutant load of sewage treatment plants in green areas, commercial areas, parks, municipal areas and green areas; A m，0 A is the pollutant content of green area, commercial area, park, municipal area and green area sewage treatment plant at the initial time; m，t is the pollutant content of green area, commercial area, park, municipal area and green area sewage treatment plant at time t; A m，settled K is the pollutant content of green area, commercial area, park, municipal area and green area sewage treatment plant on the tth day after rainfall; m % is the pollutant attenuation rate constant of sewage treatment plants in green areas, commercial areas, parks, municipal areas and green areas; P is the duration of rainfall.

5. The method for constructing an ecological cycle model based on a sponge city according to claim 4 is characterized in that: Within the urban functional area, the SWMM model is used to construct the urban rainfall-runoff-storage joint model, specifically: A. Construct urban subcatchment models, including land use, surface runoff, surface runoff, underground runoff, and underground runoff; B. Construct the urban sub-pipeline network model, including pipe network hydraulic calculation, pipe network water environment calculation, pipeline and pump station equipment; C. Construct a sub-river model for the city, including river hydraulic calculations, seawater inflow calculations, water environment calculations, and flood control facilities.

6. The method for constructing an ecological cycle model based on a sponge city according to claim 5 is characterized in that: Step 4 is as follows: The municipal area inflow is solved according to the formula W2 = μ × W0-W1; Solve the ammonia nitrogen content of the municipal area water quality and the content of pollutants in each functional area obtained in step 3, compare the results with the preset pollutant emission standard data, and then solve the water quality of the municipal area.

7. The method for constructing an ecological cycle model based on a sponge city according to claim 6, characterized in that: In step 3, the water quality in each functional area is calculated to include: Carry out urban sub-catchment model calculation, use the model to set urban land use parameters, simulate surface runoff after rainfall, surface runoff simulation, underground runoff, underground runoff, and simulate water volume and water quality in the catchment area; Carry out urban sub-pipeline network model calculation, combine the inflow of water in the catchment area and underground confluence, carry out rainwater pipe network hydraulic calculation, pipe network water environment calculation, pipe network equipment calculation, and simulate the water volume and water quality of the pipe network; Carry out river model calculations, use the inflow of water from the pipe network to perform river hydraulic calculations, river water environment calculations, flood discharge facility calculations, and simulate the water volume and water quality of the river; Summarize the information obtained from the catchment area, pipe network, and river simulation to conduct runoff generation and confluence of the entire basin and final river outflow, merge the water quality simulation data of each region, and solve the water quality of each region.

8. The method for constructing an ecological cycle model based on a sponge city according to claim 7, characterized in that: The specific process of step 1 is: By collecting basic data of each functional area, building a two-dimensional surface model of different functional areas, and combining terrain data to establish a joint model of rainfall-runoff in each functional area, the runoff generation and confluence of each functional area after rainfall inflow is calculated. Finally, the urban hydrological cycle is analyzed with the Manning formula as a constraint to obtain the rainfall-runoff process inside the city. The Manning formula is: Where V is the flow velocity in m / s; R is the hydraulic radius in m; n is the Manning coefficient; and S is the gradient.

9. The method for constructing an ecological cycle model based on a sponge city according to claim 8, characterized in that: When conducting a joint simulation of rainfall and runoff in an urban area based on a two-dimensional surface model, it includes: Urban land types can be divided into two categories, the first category is permeable surface, and the second category is impervious surface. The calculation formula is: S=A imp %×D+A bg %×D Where S is the surface hydrological factor; A imp % is the impervious surface area ratio; A bg % is the permeable surface area ratio; D is the waterway depth, in m.

10. The method for constructing an ecological cycle model based on a sponge city according to claim 9, characterized in that: Different pipe network parameters, waterway depths and gradients are set to calculate the runoff generation and confluence, and the runoff process and runoff volume under different working conditions are obtained.

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