Flood characteristic evaluation index system construction method

Abstract

The invention discloses a flood characteristic evaluation index system construction method, which systematically constructs a set of comprehensive evaluation index system from four core dimensions of magnitude, time, dynamics and morphology. In the magnitude dimension, indexes such as the total flood amount are selected to measure the flood scale and destructive power; in the time dimension, the time process is described by using indexes such as flood event duration; in the dynamic dimension, indexes such as average speed rise are adopted to reflect dynamic characteristics and energy; and in the morphological dimension, describing the geometric morphology of the flood hydrograph through indexes such as a hydrograph sharpness coefficient and the like. According to the index system constructed by the method, through organic combination of the four-dimensional indexes, the internal characteristics of the flood event can be extracted in an omnibearing and multi-angle manner, a systematic analysis tool and a quantitative basis are provided for mechanism research and risk management and control of basin flood, and the method is suitable for popularization and application. The method can be widely applied to the fields of hydrological analysis, flood control and disaster reduction, hydraulic engineering design, emergency management and the like.

Description

Technical Field

[0001] This invention relates to the fields of hydrology, water conservancy, and disaster prevention and mitigation, specifically to a method for constructing a flood characteristic evaluation index system. Background Technology

[0002] Floods are a common natural disaster with complex and ever-changing processes, posing a serious threat to human society and the ecological environment. Scientifically and accurately identifying and characterizing flood features is fundamental for flood classification, causal analysis, risk assessment, engineering design, and emergency management.

[0003] Currently, flood characteristic analysis often uses a single or a few indicators for description, such as peak flow and total flood volume. While this method is simple and intuitive, it has significant drawbacks. It focuses only on the "size" of the flood, ignoring the temporal distribution, dynamic strength, and morphological differences of the flood process. For example, a "slender" flood with an extremely high peak but short duration may have similar total volume to a "short and stout" flood with a moderate peak but long duration, but their formation mechanisms, destructive characteristics, and response strategies are completely different. Peak flow and total volume alone cannot distinguish between them.

[0004] Therefore, existing technologies suffer from problems such as a single dimension in describing flood characteristics and an incomplete indicator system, resulting in an insufficient and in-depth understanding of flood events, which restricts the level of flood scientific research and refined management. Summary of the Invention

[0005] The purpose of this invention is to provide a method for constructing a flood characteristic evaluation index system, which extracts the intrinsic characteristics of flood events from multiple core perspectives, and provides a complete set of quantitative analysis tools for flood characteristic analysis, mechanism research and comprehensive risk management.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A method for constructing a flood characteristic evaluation index system, the steps of which include: Acquire flood data within the study area; Determine the quantitative indicators of flood characteristics corresponding to four dimensions: magnitude, time, dynamics, and morphology. The quantitative indicators of flood characteristics corresponding to each dimension are systematically integrated to construct a flood characteristic evaluation index system. Based on the aforementioned flood characteristic evaluation index system, the target flood process data are analyzed and calculated, and the quantitative results of the indicators under each dimension are output, so as to achieve a comprehensive and systematic characterization of the flood event characteristics.

[0007] For each flood event window The corresponding index vector : , In the formula, This represents a quantitative index representing the flood characteristics corresponding to the magnitude dimension. This represents a quantitative index indicating the characteristics of floods over a time dimension. This represents a quantitative index representing the flood characteristics corresponding to the dynamic dimension. A quantitative index representing the flood characteristics corresponding to the morphological dimension.

[0008] According to the above technical solution, the quantitative indicators of flood characteristics in the magnitude dimension include at least: flood peak magnitude, total flood volume, flood volume exceeding the threshold, maximum flood volume in short duration, and flood peak per unit area; Among them, the flood peak level : In the formula, The flow process of this flood event The maximum value.

[0009] Total flood volume : In the formula, The starting point of the flood event. This marks the end of the flood event; To measure the baseflow at this hydrological station, the lower quantile or the smoothed lowest value segment can be used as the baseflow value within a long window.

[0010] Excess flood : In the formula, These are business thresholds, such as warning traffic / design traffic, which can be given in conjunction with forecasting and scheduling needs.

[0011] Maximum flood volume in short duration : ; ~ This corresponds to a window with a time step of j.

[0012] Peak flood per unit area : ; This refers to the area controlled by the hydrological station.

[0013] The quantitative indicators of flood characteristics in the time dimension include at least: flood event duration, flood rise duration, flood receding duration, flood threshold duration, and peak relative location; Duration of the flood event : .

[0014] Duration of the flood : , for The corresponding moment.

[0015] Duration of floodwater receding : .

[0016] Overthreshold duration : In the formula, This indicates that the condition is met. The duration, here the condition is .

[0017] Peak relative position : .

[0018] The quantitative indicators of flood characteristics in the dynamic dimension include at least: average rise rate, maximum instantaneous rise rate, maximum acceleration during the rise phase, receding attenuation coefficient, and rise-fall asymmetry rate ratio; Among them, the average rate of rise in water level : .

[0019] Maximum instantaneous rate of increase : .

[0020] Maximum acceleration during the flood stage Defined as the second derivative of a flood time series, it can be approximated using differences: .

[0021] Drainage attenuation coefficient It was determined by linear regression estimation of the logarithm of the discharge section flow and the time series.

[0022] ; ; In the formula, In the receding section The coefficient of the fitted exponential decay can be obtained by adjusting the coefficient of the fitted exponential decay. and Linear regression estimation and run only in Fitting is performed when the value is above a certain lower limit to improve stability.

[0023] Fluctuation asymmetric rate ratio : .

[0024] The morphological dimension of flood characteristics quantification indicators includes at least: process line sharpness coefficient, process line asymmetry coefficient, and waveform complexity entropy.

[0025] Among them, the process line sharpness coefficient Defined as the ratio of peak flow to the mean flow of a flood event, it is used to characterize the steepness of a flood event. .

[0026] Process line asymmetry coefficient Defined as the ratio of the duration of rising water to the duration of receding water, it is used to characterize the skewness of the flood hydrograph on the time axis. .

[0027] Waveform complexity entropy is defined as the information entropy of flood wave energy. It quantitatively characterizes the uniformity and disorder of energy distribution over time during flood events: ; ; In the formula, To normalize the sequence into a probability distribution, , The information entropy value is calculated based on this, where N is the number of observation points during the flood event.

[0028] According to the above technical solution, the quantification results of the indicators under the four dimensions are used as the input feature vector of the downstream tasks, and numerical simulation, physical simulation, or data-physical coupled simulation techniques are used to conduct systematic analysis of the downstream tasks. The downstream tasks include automatic flood type classification, flood process similarity retrieval, basin flood disaster risk assessment, or generation of flood control scheduling schemes for water conservancy projects. Alternatively, the weighted quantification results of the indicators under the four dimensions can also be used as the input feature vector of the downstream tasks.

[0029] This indicator system is used to calculate and analyze measured or simulated flood hydrograph data, outputting a set of multi-dimensional quantitative characteristic values. These characteristic values ​​can serve as a "flood characteristic fingerprint" for subsequent in-depth analysis and applications.

[0030] This includes a technical solution, a system for constructing a flood characteristic evaluation index system, comprising: The data collection module is used to acquire flood data within the study area; The dimensional indicator confirmation module determines the quantitative indicators of flood characteristics corresponding to four dimensions: magnitude, time, dynamics, and morphology, based on flood data. The evaluation index system construction module integrates the quantitative indicators of flood characteristics corresponding to each dimension to construct a flood characteristic evaluation index system. The index quantification module, based on the flood characteristic evaluation index system, analyzes and calculates the target flood process line data, outputs the index quantification results under each dimension, and realizes a comprehensive and systematic characterization of flood event characteristics. The indicator application module uses the quantitative results of the indicators under the four dimensions as the input feature vector of the downstream task, and uses numerical simulation, physical simulation or data-physical coupling simulation technology to conduct systematic analysis on the downstream task.

[0031] The invention includes a technical solution, an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement a method for constructing a flood characteristic evaluation index system as described in the above technical solution.

[0032] The invention includes a technical solution, a computer-readable storage medium storing a computer program thereon, wherein when the program is executed by a processor, it implements a method for constructing a flood characteristic evaluation index system as described in the above technical solution.

[0033] Beneficial Effects: Compared with existing technologies, the beneficial effects of this invention are as follows: This invention systematically constructs a comprehensive evaluation index system from four core dimensions: magnitude, time, dynamics, and morphology. In the magnitude dimension, indicators such as total flood volume are selected to measure the scale and destructive power of floods; in the time dimension, indicators such as the duration of flood events are used to describe their temporal process; in the dynamics dimension, indicators such as the average rise rate are used to reflect dynamic characteristics and energy magnitude; and in the morphology dimension, indicators such as the sharpness coefficient of the flood process line are used to characterize the geometric shape of the flood process line. Through the organic combination of these four dimensions—magnitude, time, dynamics, and shape—the one-sidedness of traditional single-indicator systems is overcome, enabling a comprehensive and three-dimensional revelation of the intrinsic attributes of flood events, making the description of any flood more accurate and complete. The index system proposed in this invention has clear definitions and calculation methods, is easy to standardize and programmatically implement, and is convenient for promotion and comparative application in flood analyses of different river basins, countries, and regions. The indicator system constructed by this method, through the organic combination of the above four dimensions of indicators, can extract the intrinsic characteristics of flood events from all aspects and multiple perspectives, providing a systematic analytical tool and quantitative basis for the study of the mechanism of watershed floods and risk management. It can be widely applied in fields such as hydrological analysis, flood control and disaster reduction, water conservancy engineering design and emergency management. Attached Figure Description

[0034] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart illustrating the steps of constructing a flood characteristic evaluation index system according to the present invention. Figure 2 This is a flow process diagram of a flood event in an example; Figure 3 This is a diagram of the flood characteristic evaluation index system for an example. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Taking the flood event with flood number 20200731 at hydrological station A as an example, the flood event started at 22:00 on September 17, 2021, and ended at 15:00 on September 22, 2021. The steps for calculating the quantitative results of indicators under each dimension are as follows: Figure 1 )include: S1. Obtain flood data within the study area; flood event flow processes are shown in the appendix. Figure 2 The study identified four core dimensions for flood characteristic assessment: magnitude, time, dynamics, and morphology. The flood event window for flood number 20200731 was also discussed. Integrated indicator vector It could be: , In the formula, This represents a quantitative index representing the flood characteristics corresponding to the magnitude dimension. This represents a quantitative index indicating the characteristics of floods over a time dimension. This represents a quantitative index representing the flood characteristics corresponding to the dynamic dimension. A quantitative index representing the flood characteristics corresponding to the morphological dimension.

[0037] S2. For the four dimensions of magnitude, time, dynamics and morphology, a set of quantitative indicators that can characterize the flood characteristics of the corresponding dimension are selected and defined.

[0038] Among them, the magnitude-based indicators include at least: peak flood magnitude, total flood volume, flood volume exceeding the threshold, maximum flood volume in short duration, and peak flood volume per unit area. Specifically: flood peak level : , The flow process of this flood event The maximum value occurred at 7:00 on September 19, 2021.

[0039] Taking the base current as the 5th quantile, we get 187.8m 3 / s, calculate total flood volume : ; In the formula, The starting point of the flood event. This marks the end of the flood event; To measure the baseflow at this hydrological station, the lower quantile or the smoothed lowest value segment can be used as the baseflow value within a long window.

[0040] Calculate the flood volume exceeding the threshold, taking a warning flow rate of 500 m³ / s. : .

[0041] Take time step Calculate the maximum flood volume over a short duration of 3 hours. : .

[0042] Hydrological station A controls an area of ​​4623 km². 2 Calculate the peak flood level per unit area : .

[0043] Quantitative indicators of flood characteristics over time should include at least: flood event duration, flood rise duration, flood receding duration, flood threshold duration, and relative peak location. Specifically: Duration of the flood event : .

[0044] The corresponding time of the flood was 7:00 AM on September 19, 2021, and the duration of the flood was [not specified]. : .

[0045] Duration of floodwater receding : .

[0046] Overthreshold duration : ; In the formula, This indicates that the condition is met. The duration, here the condition is .

[0047] Peak relative position : .

[0048] Quantitative indicators of flood characteristics from a dynamic perspective include at least: average rise rate, maximum instantaneous rise rate, maximum acceleration during the rise phase, receding attenuation coefficient, and rise-fall asymmetry rate ratio; specifically: Average flood rate : .

[0049] Maximum instantaneous rate of increase : .

[0050] Maximum acceleration during the flood stage : The second derivative can be approximated by the difference.

[0051] Drainage attenuation coefficient , ; ; In the formula, In the receding section The coefficient of the fitted exponential decay can be obtained by adjusting the coefficient of the fitted exponential decay. and Linear regression estimation and run only in Fitting is performed when the value is above a certain lower limit to improve stability.

[0052] Fluctuation asymmetric rate ratio : .

[0053] Quantitative indicators of flood characteristics from a morphological perspective include at least: process line sharpness coefficient, process line asymmetry coefficient, and waveform complexity entropy. Specifically: Process line sharpness factor : ; Process line asymmetry coefficient : ; Waveform complexity entropy : ; ; In the formula, To normalize the sequence into a probability distribution, , The information entropy value is calculated based on this, where N is the number of observation points during the flood event.

[0054] S3. Integrate the four dimensions of indicators defined in S2 to construct a multi-dimensional, multi-indicator flood characteristic evaluation index system. The constructed flood characteristic evaluation index system is attached. Figure 3 .

[0055] S4. Based on the aforementioned indicator system, analyze and calculate the target flood process data, outputting the quantitative results of the indicators under each dimension to achieve a comprehensive and systematic characterization of the flood event. Use the quantitative results of the indicators under the four dimensions as input feature vectors for downstream tasks, and conduct systematic analysis of the downstream tasks using numerical simulation, physical simulation, or coupled data-physical simulation techniques. Downstream tasks include automatic flood type classification, flood process similarity retrieval, basin flood disaster risk assessment, or generation of flood control scheduling schemes for water conservancy projects.

[0056] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0057] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for constructing a flood characteristic evaluation index system, characterized in that, The steps include: Acquire flood data within the study area; Determine the quantitative indicators of flood characteristics corresponding to four dimensions: magnitude, time, dynamics, and morphology. The quantitative indicators of flood characteristics corresponding to each dimension are systematically integrated to construct a flood characteristic evaluation index system. Based on the aforementioned flood characteristic evaluation index system, the target flood process data are analyzed and calculated, and the quantitative results of the indicators under each dimension are output, so as to achieve a comprehensive and systematic characterization of the flood event characteristics.

2. The method for constructing a flood characteristic evaluation index system according to claim 1, characterized in that, The quantitative indicators of flood characteristics in the magnitude dimension include at least: flood peak magnitude, total flood volume, flood volume exceeding the threshold, maximum flood volume in short duration, and flood peak per unit area; The quantitative indicators of flood characteristics in the time dimension include at least: flood event duration, flood rise duration, flood receding duration, flood threshold duration, and peak relative location; The quantitative indicators of flood characteristics in the dynamic dimension include at least: average rise rate, maximum instantaneous rise rate, maximum acceleration during the rise phase, receding attenuation coefficient, and rise-fall asymmetry rate ratio; The morphological dimension of flood characteristics quantification indicators includes at least: process line sharpness coefficient, process line asymmetry coefficient, and waveform complexity entropy.

3. The method for constructing a flood characteristic evaluation index system according to claim 2, characterized in that, The maximum acceleration during the rising water stage is the second derivative of the flood time series; the receding water attenuation coefficient is determined by linear regression estimation of the logarithm of the receding water section flow and the time series.

4. The method for constructing a flood characteristic evaluation index system according to claim 3, characterized in that, The process line sharpness coefficient is the ratio of peak flow to the mean flow of the flood event; The process line asymmetry coefficient is the ratio of the duration of rising water to the duration of receding water. The waveform complexity entropy is the information entropy of flood wave energy.

5. The method for constructing a flood characteristic evaluation index system according to claim 4, characterized in that, The quantitative results of the indicators under the four dimensions are used as the input feature vectors of the downstream tasks, and the downstream tasks are systematically analyzed by numerical simulation, physical simulation or data-physical coupling simulation techniques.

6. A system for constructing a flood characteristic evaluation index system, characterized in that, include: The data collection module is used to acquire flood data within the study area; The dimensional indicator confirmation module determines the quantitative indicators of flood characteristics corresponding to four dimensions: magnitude, time, dynamics, and morphology, based on flood data. The evaluation index system construction module integrates the quantitative indicators of flood characteristics corresponding to each dimension to construct a flood characteristic evaluation index system. The index quantification module, based on the flood characteristic evaluation index system, analyzes and calculates the target flood process line data, outputs the index quantification results under each dimension, and realizes a comprehensive and systematic characterization of flood event characteristics. The indicator application module uses the quantitative results of the indicators under the four dimensions as the input feature vector of the downstream task, and uses numerical simulation, physical simulation or data-physical coupling simulation technology to conduct systematic analysis on the downstream task.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the method as described in any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the method as described in any one of claims 1 to 5.

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