A method and system for quantitatively identifying initial rainfall based on rainfall return period

Abstract

The present invention provides a method and system for quantitatively identifying initial rainwater based on rainfall recurrence period, and belongs to the technical field of urban initial rainwater pollution control. The identification method includes the following steps: S1, judging whether runoff is generated; S2, identifying the underlying surface characteristics of the catchment area; S3, simulating rainfall characteristics; S4, simulating the flushing characteristics of characteristic pollutants; S5, establishing a three-dimensional mathematical model; S6, determining the initial rainwater interception amount and interception time. The identification system includes: a rainfall process monitoring and recording module, a data extraction and input module, a model building module, a model operation module, and a result output module. The present invention solves the problem that the traditional engineering practice of identifying and quantifying initial rainwater ignores the temporal and spatial differences of rainfall characteristics and urban underlying surface characteristics, resulting in errors in the quantification process of initial rainwater, and has the advantages of reducing processing costs and optimizing processing effects.

Description

Technical Field

[0001] The invention relates to the technical field of urban initial rainwater pollution control, and in particular to a method and system for quantitatively identifying initial rainwater based on a rainfall recurrence period. Background Art

[0002] With the acceleration of urbanization, the proportion of impervious underlying surfaces has increased year by year, and the urban hydrological cycle has also changed significantly. Rainfall processes with a smaller return period can still produce an initial scouring process on the underlying surface. Initial rainwater has received widespread attention because it carries a large amount of pollutants that pollute the receiving water body. In engineering, initial rainwater is often intercepted for centralized treatment. However, there is still controversy over the quantification of initial rainwater. Currently, most projects use fixed single control indicators such as rainfall duration and rainfall depth to determine the initial rainwater interception amount, thereby determining the initial rainwater storage scale and treatment scale. This rough calculation results in excessive treatment costs or poor runoff pollution control effects. Therefore, there is an urgent need for a more accurate initial rainwater quantification method to guide engineering practice.

[0003] The scouring process of the urban underlying surface at the beginning of rainfall carries a large amount of pollutants into the receiving water body, becoming one of the main factors affecting the deterioration of water quality.

[0004] In traditional engineering practice, undifferentiated, single control indicators (rainfall duration, rainfall depth) are often used to identify and quantify initial rainwater, ignoring the temporal and spatial differences of climate change, rainfall characteristics, urban underlying surface characteristics, etc., resulting in errors in the quantification process of initial rainwater. A larger value increases the processing cost, while a smaller value results in poor pollutant interception. To address this problem, the present invention combines climate change, underlying surface scouring and other laws to establish a three-dimensional mathematical model based on rainfall recurrence period, pollutant load reduction rate and initial rainwater volume, as well as a model application system that can more accurately quantify initial rainwater. Summary of the invention

[0005] The purpose of the present invention is to provide a method and system for quantifying and identifying initial rainfall based on rainfall recurrence period to address the problem that inaccurate quantification of initial rainfall leads to excessive processing costs or poor runoff pollution control effects.

[0006] To solve the above problems, the technical solution of the present invention is as follows:

[0007] A method for quantitatively identifying initial rainfall based on rainfall return period comprises the following steps:

[0008] S1. Determine whether runoff is generated: After a rainfall event occurs, the rainfall process monitoring and recording module obtains rainfall process data through the rainfall forecast terminal of the Meteorological Bureau, and then quantitatively calculates the rainfall runoff under various underlying surface conditions through the runoff curve method (SCS) to determine whether the rainfall event generates runoff. When the rainfall event generates runoff, the runoff generation time T0 is obtained;

[0009] S2. Identify the underlying surface characteristics of the watershed area: The data extraction and input module extracts the underlying surface characteristic data based on the watershed area through the Geographic Information System (GIS) software;

[0010] S3, rainfall characteristics simulation: The rainfall process line construction submodule organizes the rainfall data of the catchment area and analyzes its rainfall pattern, and fits the rainfall process lines under various return periods by combining the rainfall intensity formula and the Chicago rain type simulation software;

[0011] S4. Simulation of flushing characteristics of characteristic pollutants: The flushing process equation construction submodule uses the Storm Flood Management Model (SWMM) software to couple the underlying surface characteristics and the runoff pollutant flushing dynamics model to establish the flushing process equation of characteristic pollutants;

[0012] S5. Establishment of three-dimensional mathematical model: The three-dimensional mathematical model building submodule establishes a three-dimensional mathematical model based on rainfall return period, pollutant load reduction rate and initial rainfall volume;

[0013] S6. Determination of initial rainwater retention amount and retention time: The model operation module inputs the three-dimensional mathematical model into Matlab software for calculation, and outputs the initial rainwater retention amount and retention time through the result output module.

[0014] Furthermore, the initial rainfall quantitative identification method further includes the following steps:

[0015] S7, the rainfall process monitoring and recording module organizes the rainfall data set stored in a stage and inputs it into the model parameter optimization module. The parameter optimization module calibrates and optimizes the parameters of the three-dimensional mathematical model after comparing the output result of the result output module with the rainfall data set;

[0016] S8. The parameter optimization module combines the parameters calibrated and optimized by the parameter optimization module and the underlying surface characteristic data of the catchment area to self-learn and optimize the three-dimensional mathematical model, and inputs the optimized three-dimensional mathematical model into the model operation module for the quantitative prediction and calculation of the initial rainfall in the next rainfall event.

[0017] From the above steps, it can be seen that based on the three-dimensional mathematical model, data preservation, self-learning and optimization can be continuously realized in the application, and the actual rainfall conditions are constantly approached, making the method more credible.

[0018] Furthermore, the underlying surface characteristic data in step S2 includes: land use data, underlying surface elevation data, forming a data set of each watershed area.

[0019] Furthermore, the land use data include: commercial areas, residential areas, industrial areas, green areas, water bodies, roads and squares, which shows that the method has a wide coverage and is suitable for all application scenarios.

[0020] Furthermore, the rainfall data in step S3 include: the annual average rainfall and annual average rainfall intensity in the catchment area that can be queried and recorded, and the rainfall pattern includes: the annual change trend of rainfall and rainfall intensity in the catchment area in the historical stage. The accumulation of historical data is beneficial to the self-learning of the three-dimensional mathematical model and optimizes the learning effect.

[0021] Furthermore, the characteristic pollutants in step S4 are solid suspended pollutants (SS). As characteristic pollutants, solid suspended pollutants have the advantages of being easy to observe and obtain.

[0022] The present invention also provides a system for quantitatively identifying initial rainfall based on rainfall recurrence period, comprising:

[0023] The rainfall process monitoring and recording module is used to obtain rainfall process data through the rainfall forecast terminal of the Meteorological Bureau, determine whether runoff is generated and record it. The rainfall process monitoring and recording module uses the runoff curve number method (SCS) to determine whether the rainfall event generates runoff.

[0024] The data extraction and input module is used to extract the data obtained by the rainfall process monitoring and recording module after sorting. The data extraction and input module extracts the underlying surface feature data in the unit of the catchment area through the geographic information system software.

[0025] A model building module for coupling the data extracted by the data extraction and input module to the storm flood management model (SWMM) software to build a three-dimensional mathematical model. The model building module includes: a rainfall process line building submodule, a flushing process equation building submodule, and a three-dimensional mathematical model building submodule.

[0026] A model operation module for operating the three-dimensional mathematical model, the model operation module includes: a constructed three-dimensional mathematical model, a Matlab calculation submodule,

[0027] The result output module is used to output the running results of the model running module. The output results of the result output module are: initial rainwater interception amount and initial rainwater interception time.

[0028] Preferably, the initial rainfall quantitative identification system further includes:

[0029] The parameter optimization module is used to calibrate and optimize the parameters of the three-dimensional mathematical model after comparing the operation results of the model operation module with the rainfall data set stored in a stage input by the rainfall process monitoring and recording module.

[0030] It is used to self-learn and optimize the three-dimensional mathematical model by combining the parameters calibrated and optimized by the parameter optimization module and the underlying surface characteristic data of the catchment area, and input the optimized three-dimensional mathematical model into the model operation module for the quantitative prediction and calculation of the initial rainfall in the next rainfall event.

[0031] The initial rainfall quantitative identification system built based on the three-dimensional mathematical model can continuously realize data preservation, self-learning and optimization in the application.

[0032] Further preferably, the data of the data extraction and input module include: land use data of catchment areas, commercial areas, residential areas, industrial areas, green spaces, water bodies, roads and squares, land elevation data and scour coefficients of various characteristic underlying surfaces. The system has a wide regional coverage and can be applied to all application scenarios.

[0033] Further preferably, the formula of the three-dimensional mathematical model is:

[0034]

[0035] Where: F is the pollutant load removal rate; r is the scour coefficient; T is the initial rainwater interception time, in min; T0 is the time when runoff is generated, in min; A is the catchment area, in m 2 ; c represents the coefficient of variation of rainfall intensity; t represents rainfall duration, in min; b represents the correlation coefficient of rainfall duration; n represents the rainfall attenuation coefficient; p represents the rainfall recurrence period.

[0036] The beneficial effects of the present invention are:

[0037] (1) The three-dimensional mathematical model method based on rainfall return period, pollutant load reduction rate and initial rainfall volume can accurately quantify the initial rainfall, thereby reducing treatment costs and optimizing treatment effects;

[0038] (2) The initial rainfall quantitative identification system built based on the three-dimensional mathematical model can continuously realize data preservation, self-learning and optimization in the application. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The framework of the method for quantitatively identifying initial rainfall based on rainfall recurrence period described in Embodiment 1, Embodiment 2, Embodiment 3 and Embodiment 4 of the present invention;

[0040] Figure 2The initial rainfall quantification system based on rainfall return period described in Embodiment 1 and Embodiment 2 of the present invention;

[0041] Figure 3 The initial rainfall quantification system based on rainfall recurrence period described in Embodiment 3 and Embodiment 4 of the present invention;

[0042] Figure 4 A schematic diagram of initial rainwater interception in a catchment area of ​​the initial rainwater quantitative identification method based on rainfall return period described in Embodiment 1, Embodiment 2, Embodiment 3, and Embodiment 4 of the present invention;

[0043] Figure 5 A schematic diagram of land use of the underlying surface of the catchment area of ​​the method for quantitatively identifying initial rainfall based on rainfall return period described in Embodiment 1, Embodiment 2, Embodiment 3, and Embodiment 4 of the present invention;

[0044] Figure 6 This is a schematic diagram of a three-dimensional model of the method for quantitatively identifying initial rainfall based on rainfall recurrence period described in Embodiment 1, Embodiment 2, Embodiment 3, and Embodiment 4 of the present invention. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0047] Example 1

[0048] A quantitative identification system for initial rainfall based on rainfall return period, such as Figure 2 As shown, including:

[0049] The rainfall process monitoring and recording module is used to obtain rainfall process data through the rainfall forecast terminal of the Meteorological Bureau, determine whether runoff is generated and record it. The rainfall process monitoring and recording module uses the runoff curve number method (SCS) to determine whether the rainfall event generates runoff.

[0050] The data extraction and input module is used to extract the data obtained by the rainfall process monitoring and recording module after sorting. The data of the data extraction and input module includes: land use data of watershed areas, commercial areas, residential areas, industrial areas, green areas, water bodies, roads and squares, land elevation data and scour coefficients of various characteristic underlying surfaces. The data extraction and input module extracts underlying surface characteristic data in units of watershed areas through geographic information system (GIS) software.

[0051] A model building module for coupling the data extracted by the data extraction and input module to the storm flood management model (SWMM) software to build a three-dimensional mathematical model. The model building module includes: a rainfall process line building submodule, a flushing process equation building submodule, and a three-dimensional mathematical model building submodule.

[0052] A model operation module for operating the three-dimensional mathematical model, the model operation module includes: a constructed three-dimensional mathematical model, a Matlab calculation submodule,

[0053] The result output module is used to output the running results of the model running module. The output results of the result output module are: initial rainwater interception amount and initial rainwater interception time.

[0054] Among them, the formula of the three-dimensional mathematical model is:

[0055]

[0056] Where: F is the pollutant load removal rate; r is the scour coefficient; T is the initial rainwater interception time, in min; T0 is the time when runoff is generated, in min; A is the catchment area, in m 2 ; c represents the coefficient of variation of rainfall intensity; t represents rainfall duration, in min; b represents the correlation coefficient of rainfall duration; n represents the rainfall attenuation coefficient; p represents the rainfall recurrence period.

[0057] Figure 4 This is a schematic diagram of initial rainwater interception in the catchment area. The D0-D1 water holding capacity in the figure represents the rainfall retained due to the roughness of the underlying surface in the initial stage of rainfall; the D2 initial rainwater volume represents the rainfall with a high pollutant concentration after the runoff is generated and is calculated by the quantitative identification method. The system automatically controls the interception; the D1-D2 drainage volume represents the remaining rainfall discharged into the municipal pipe network after the initial rainwater interception system stops working.

[0058] Figure 5The figure is a schematic diagram of land use of the underlying surface of the catchment area. In this embodiment, the terrain features of the catchment area are identified and information is extracted through GIS software. The underlying surface is divided into six types of use, including high-density residential areas, low-density residential areas, commercial areas, green spaces, water bodies, roads and squares. Different land use types correspond to different runoff coefficients, which are used to input into the data extraction and input module of the initial rainwater quantification system to calculate the water volume.

[0059] Figure 6 It is a schematic diagram of a three-dimensional model. It establishes a three-dimensional model of rainfall recurrence period, pollutant removal load rate and initial rainwater interception time, which is convenient for quickly identifying the initial rainwater interception time and interception volume.

[0060] Example 2

[0061] This embodiment is a method for quantitatively identifying initial rainfall based on rainfall return period based on embodiment 1. Figure 1 As shown, the following steps are included:

[0062] S1. Determine whether runoff is generated: After a rainfall event occurs, the rainfall process monitoring and recording module obtains rainfall process data through the rainfall forecast terminal of the Meteorological Bureau, and then quantitatively calculates the rainfall runoff under various underlying surface conditions through the runoff curve method (SCS) to determine whether the rainfall event generates runoff. When the rainfall event generates runoff, the runoff generation time T0 is obtained;

[0063] S2. Identify the underlying surface characteristics of the watershed area: The data extraction and input module extracts the underlying surface characteristic data based on the watershed area through the Geographic Information System (GIS) software;

[0064] S3, rainfall characteristics simulation: The rainfall process line construction submodule organizes the rainfall data of the catchment area and analyzes its rainfall pattern, and fits the rainfall process lines under various return periods by combining the rainfall intensity formula and the Chicago rain type simulation software;

[0065] S4. Simulation of flushing characteristics of characteristic pollutants: The flushing process equation construction submodule uses the Storm Flood Management Model (SWMM) software to couple the underlying surface characteristics and the runoff pollutant flushing dynamics model to establish the flushing process equation of characteristic pollutants;

[0066] S5. Establishment of three-dimensional mathematical model: The three-dimensional mathematical model building submodule establishes a three-dimensional mathematical model based on rainfall return period, pollutant load reduction rate and initial rainfall volume;

[0067] S6. Determination of initial rainwater retention amount and retention time: The model operation module inputs the three-dimensional mathematical model into Matlab software for calculation, and outputs the initial rainwater retention amount and retention time through the result output module.

[0068] Example 3

[0069] The difference between this embodiment and embodiment 1 is that:

[0070] like Figure 3 As shown, the initial rainfall quantitative identification system also includes:

[0071] The parameter optimization module is used to calibrate and optimize the parameters of the three-dimensional mathematical model after comparing the operation results of the model operation module with the rainfall data set stored in a stage input by the rainfall process monitoring and recording module.

[0072] It is used to self-learn and optimize the three-dimensional mathematical model by combining the parameters calibrated and optimized by the parameter optimization module and the characteristic data of the underlying surface of the catchment area, and input the optimized three-dimensional mathematical model into the model operation module for the quantitative prediction and calculation of the initial rainfall in the next rainfall event.

[0073] Example 4

[0074] This embodiment is a method for quantitatively identifying initial rainfall based on rainfall return period based on Embodiment 3, and includes the following steps:

[0075] S1. Determine whether runoff is generated: After a rainfall event occurs, the rainfall process monitoring and recording module obtains rainfall process data through the rainfall forecast terminal of the Meteorological Bureau, and then quantitatively calculates the rainfall runoff under various underlying surface conditions through the runoff curve method (SCS) to determine whether the rainfall event generates runoff. When the rainfall event generates runoff, the runoff generation time T0 is obtained;

[0076] S2. Identify the underlying surface characteristics of the watershed area: The data extraction and input module extracts the underlying surface characteristic data based on the watershed area through the Geographic Information System (GIS) software;

[0077] S3, rainfall characteristics simulation: The rainfall process line construction submodule organizes the rainfall data of the catchment area and analyzes its rainfall pattern, and fits the rainfall process lines under various return periods by combining the rainfall intensity formula and the Chicago rain type simulation software;

[0078] S4. Simulation of flushing characteristics of characteristic pollutants: The flushing process equation construction submodule uses the Storm Flood Management Model (SWMM) software to couple the underlying surface characteristics and the runoff pollutant flushing dynamics model to establish the flushing process equation of characteristic pollutants;

[0079] S5. Establishment of three-dimensional mathematical model: The three-dimensional mathematical model building submodule establishes a three-dimensional mathematical model based on rainfall return period, pollutant load reduction rate and initial rainfall volume;

[0080] S6. Determination of initial rainwater interception amount and interception time: The model operation module inputs the three-dimensional mathematical model into Matlab software for calculation, and outputs the initial rainwater interception amount and interception time through the result output module;

[0081] S7, the rainfall process monitoring and recording module organizes the rainfall data set stored in a stage and inputs it into the model parameter optimization module. The parameter optimization module calibrates and optimizes the parameters of the three-dimensional mathematical model after comparing the output result of the result output module with the rainfall data set;

[0082] S8. The parameter optimization module combines the parameters calibrated and optimized by the parameter optimization module and the underlying surface characteristic data of the catchment area to self-learn and optimize the three-dimensional mathematical model, and inputs the optimized three-dimensional mathematical model into the model operation module for the quantitative prediction and calculation of the initial rainfall in the next rainfall event.

Claims

1. A quantitative identification method for initial rainfall based on rainfall return period, characterized in that: The following steps are involved: S1. Determine whether runoff is generated: After a rainfall event occurs, the rainfall process monitoring and recording module obtains rainfall process data through the rainfall forecast terminal of the Meteorological Bureau, and then quantitatively calculates the rainfall runoff under various underlying surface conditions through the runoff curve method to determine whether the rainfall event generates runoff. When the rainfall event generates runoff, the runoff generation time T0 is obtained; S2. Identify the underlying surface characteristics of the watershed area: The data extraction and input module extracts the underlying surface characteristic data based on the watershed area through the geographic information system software; S3, rainfall characteristics simulation: The rainfall process line construction submodule organizes the rainfall data of the catchment area and analyzes its rainfall pattern, and fits the rainfall process lines under various return periods by combining the rainfall intensity formula and the Chicago rain type simulation software; S4. Simulation of flushing characteristics of characteristic pollutants: The flushing process equation construction submodule uses the stormwater flood management model software to couple the underlying surface characteristics and the runoff pollutant flushing dynamics model to establish the flushing process equation of characteristic pollutants; S5. Establishment of three-dimensional mathematical model: The three-dimensional mathematical model building submodule establishes a three-dimensional mathematical model based on rainfall return period, pollutant load reduction rate and initial rainfall volume; S6. Determination of initial rainwater interception amount and interception time: The model operation module inputs the three-dimensional mathematical model into Matlab software for calculation, and outputs the initial rainwater interception amount and interception time through the result output module.

2. The method for quantitatively identifying initial rainfall based on rainfall return period according to claim 1, characterized in that: The initial rainfall quantitative identification method further comprises the following steps: S7, the rainfall process monitoring and recording module organizes the rainfall data set stored in a stage and inputs it into the model parameter optimization module, and the parameter optimization module calibrates and optimizes the parameters of the three-dimensional mathematical model after comparing the output result of the result output module with the rainfall data set; S8. The parameter optimization module performs self-learning and optimization on the three-dimensional mathematical model in combination with the parameters calibrated and optimized by the parameter optimization module and the underlying surface characteristic data of the catchment area, and inputs the optimized three-dimensional mathematical model into the model operation module for quantitative prediction and calculation of initial rainfall in the next rainfall event.

3. The method for quantitatively identifying initial rainfall based on rainfall return period according to claim 1, characterized in that: The underlying surface characteristic data in step S2 includes: land use data and underlying surface elevation data.

4. The method for quantitatively identifying initial rainfall based on rainfall return period as claimed in claim 3, characterized in that: The land use data includes: commercial areas, residential areas, industrial areas, green areas, water bodies, roads and squares.

5. The method for quantitatively identifying initial rainfall based on rainfall return period according to claim 1, characterized in that: The rainfall data in step S3 include: the annual average rainfall and annual average rainfall intensity of the catchment area that can be queried and recorded, and the rainfall pattern includes: the annual variation trend of rainfall and rainfall intensity in the catchment area in the historical stage.

6. The method for quantitatively identifying initial rainfall based on rainfall return period according to claim 1, characterized in that: The characteristic pollutants in step S4 are solid suspended pollutants.

7. A system for quantitatively identifying initial rainfall based on rainfall return period, based on a method for quantitatively identifying initial rainfall based on rainfall return period as claimed in any one of claims 1 to 6, characterized in that: include: A rainfall process monitoring and recording module is used to obtain rainfall process data through the rainfall forecast terminal of the meteorological bureau, determine whether runoff is generated and record it, and the rainfall process monitoring and recording module determines whether the rainfall event generates runoff through the runoff curve number method. A data extraction and input module for arranging and extracting data acquired by the rainfall process monitoring and recording module, wherein the data extraction and input module extracts underlying surface characteristic data in units of catchment areas through geographic information system software, A model building module for coupling the data extracted by the data extraction and input module with the storm flood management model software to build a three-dimensional mathematical model, wherein the model building module includes: a rainfall process line building submodule, a flushing process equation building submodule, and a three-dimensional mathematical model building submodule. A model operation module for operating the three-dimensional mathematical model, wherein the model operation module comprises: a constructed three-dimensional mathematical model, a Matlab calculation submodule, A result output module is used to output the operation result of the model operation module, and the output results of the result output module are: initial rainwater interception amount and initial rainwater interception time.

8. The system according to claim 7, characterized in that The initial rainfall quantitative identification system also includes: a parameter optimization module for calibrating and optimizing the parameters of the three-dimensional mathematical model after comparing the operation result of the model operation module with a rainfall data set stored in a stage input by the rainfall process monitoring and recording module, It is used to self-learn and optimize the three-dimensional mathematical model by combining the parameters calibrated and optimized by the parameter optimization module and the underlying surface characteristic data of the catchment area, and input the optimized three-dimensional mathematical model into the model operation module for quantitative prediction and calculation of initial rainfall in the next rainfall event.

9. The system according to claim 8, characterized in that The data of the data extraction and input module include: land use data of catchment areas, commercial areas, residential areas, industrial areas, green areas, water bodies, roads and squares, land elevation data and scour coefficients of various characteristic underlying surfaces.

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