Watershed over-standard flood analog simulation method and watershed over-standard flood analog simulation system

Abstract

The invention relates to the technical field of model simulation, in particular to a watershed over-standard flood analog simulation method and system, and the method comprises the steps: obtaining the watershed flood impact based on the river diversity in a watershed and the impact condition of each river in the watershed converging into the watershed, and calculating the watershed over-standard flood impact according to the elevation variable coefficient of an upstream riverbed of the watershed; obtaining local flood energy aggregation of the drainage basin according to the difference between the river bed permeability of the upstream river bed of the drainage basin and the flood impact of the drainage basin; obtaining the flood resonance effect characteristics of the drainage basin according to the correlation between the upstream flow difference of the drainage basin before and after each rainfall and each rainfall and the difference between the flood volume peak value and the flood volume reference when each rainfall rises; according to the method, the related data of the river in the drainage basin can be comprehensively considered from multiple aspects, so that the assessment accuracy of the risk of generating the over-standard flood in the drainage basin is improved.

Description

Technical Field

[0001] This invention relates to the field of model simulation technology, specifically to a method and system for simulating and replicating super-standard floods in a watershed. Background Technology

[0002] Given the frequent occurrence of floods exceeding standard levels in river basins, it is crucial to establish effective flood simulation methods for flood early warning, emergency response, and disaster prevention and mitigation. Currently, river basin flood exceeding standard level simulation technologies mainly involve: acquiring relevant data about the risk of floods exceeding standard levels in the basin, and then conducting simulations based on the obtained risk model. These models primarily include hydrological models, hydrodynamic models, and water resource management models. However, existing methods estimate the risk of floods exceeding standard levels solely based on historical rainfall data, resulting in a limited range of parameters and impacting the accuracy of risk assessments. Summary of the Invention

[0003] To address the problem of low accuracy in assessing the risk of super-standard floods in existing watersheds, the present invention aims to provide a method and system for simulating super-standard floods in watersheds. The specific technical solution adopted is as follows:

[0004] In a first aspect of the present invention, a method for simulating super-standard floods in a watershed is provided, comprising:

[0005] Determine the river diversity within the watershed, which is derived from the hydrological and ecological conditions within the watershed;

[0006] Based on the river diversity and the impact of each river flowing into the basin, the basin flood impact is obtained, which is used to characterize the promoting effect on the accumulation of flood energy within the basin.

[0007] Based on the elevation variation coefficient of the upstream riverbed, the differences in riverbed permeability among the upstream riverbeds, and the flood impact of the basin, the local flood energy accumulation of the basin is obtained.

[0008] Based on the correlation between the difference in upstream flow before and after each rainfall and the amount of each rainfall, as well as the difference between the peak flood volume and the flood volume benchmark when the amount of each rainfall increases, the characteristics of the flood resonance effect in the basin are obtained.

[0009] The risk of a basin experiencing a flood exceeding the standard level is determined by fusing the characteristics of local flood energy concentration and flood resonance effect.

[0010] In an exemplary embodiment, the process of obtaining the watershed flood impact includes:

[0011] The correlation between slope and average flow velocity at multiple monitoring points for each river within the watershed is obtained, and combined with the average flow velocity of each river, the instantaneous impact sub-feature of each river on the confluence area is obtained; the instantaneous impact sub-feature is proportional to the correlation and the average flow velocity of the river.

[0012] The basin flood impact is obtained based on the overall characteristics of instantaneous impact and the river diversity. The basin flood impact is directly proportional to the overall characteristics of instantaneous impact and inversely proportional to the river diversity. The overall characteristics of instantaneous impact are obtained by fusing the instantaneous impact sub-characteristics of all rivers in the basin.

[0013] In one exemplary embodiment, the process of acquiring the local flood energy concentration includes:

[0014] The difference in riverbed permeability at any two different locations in the upstream riverbed of the basin is obtained to obtain the comprehensive riverbed permeability difference; the comprehensive riverbed permeability difference characterizes the overall situation of the difference in riverbed permeability in the upstream riverbed of the basin.

[0015] The local flood energy concentration is obtained based on the comprehensive riverbed permeability difference, elevation variation coefficient, and basin flood impact; the local flood energy concentration is directly proportional to the comprehensive riverbed permeability difference, elevation variation coefficient, and basin flood impact.

[0016] In one exemplary embodiment, the local flood energy concentration is obtained by multiplying the combined riverbed permeability difference, elevation variation coefficient, and basin flood impact.

[0017] In an exemplary embodiment, the process of obtaining the flood resonance effect characteristics includes:

[0018] Based on the difference in upstream flow before and after each rainfall event and the amount of rainfall each time, the similarity between the flow difference and the amount of rainfall is obtained;

[0019] The difference between the peak flood volume and the flood volume benchmark for each rainfall event is obtained, and the comprehensive flood volume difference is obtained; the comprehensive flood volume difference is used to characterize the difference between the peak flood volume and the flood volume benchmark for all rainfall events.

[0020] Based on the similarity and the difference in comprehensive flood volume, the flood resonance effect characteristics are obtained, and the flood resonance effect characteristics are proportional to the similarity and the difference in comprehensive flood volume.

[0021] In one exemplary embodiment, the flood volume benchmark is the upstream flood volume of the basin under no-rainfall conditions;

[0022] The process of obtaining the comprehensive flood volume difference includes: calculating the difference between the peak flood volume and the flood volume benchmark for each rainfall event, and calculating the average value of the obtained differences as the comprehensive flood volume difference.

[0023] In one exemplary embodiment, the process of acquiring river diversity includes:

[0024] Based on the length and flow velocity of each river within the basin, the diversity of hydrological characteristics of the basin is obtained;

[0025] The Simpson index is calculated from the relative abundance of each species in the watershed to obtain the watershed's ecodiversity;

[0026] The river diversity is obtained based on the aforementioned hydrological and ecological diversity.

[0027] In an exemplary embodiment, the process of obtaining the diversity of hydrological features includes:

[0028] Calculate the information entropy of the lengths of all rivers within the watershed;

[0029] Obtain the overall velocity difference of all rivers in the basin, where the overall velocity difference is the average of the average velocity differences between any two different rivers in the basin;

[0030] The hydrological feature diversity is obtained based on the information entropy and the overall flow velocity difference, and the hydrological feature diversity is directly proportional to both the information entropy and the overall flow velocity difference.

[0031] In an exemplary embodiment, the risk of the basin generating super-standard floods is obtained by averaging the characteristics of local flood energy concentration and flood resonance effect.

[0032] In a second aspect of the present invention, a watershed super-standard flood simulation system is provided, comprising: a memory and a processor; the memory is connected to the processor; the memory is used to store program instructions; the processor is used to implement the above-described watershed super-standard flood simulation method when the program instructions are executed.

[0033] This invention offers the following advantages: First, it determines the river diversity within the basin and, combined with the impact of each river flowing into the basin, obtains the basin's flood impact. Then, by considering the differences in the elevation variation coefficient and permeability of the upstream riverbed, it obtains the local flood energy accumulation characteristic of the basin. This local flood energy accumulation characterizes the potential degree of local energy accumulation in the basin's floodwaters. Higher local energy accumulation leads to a greater sustained increase in the magnitude of the flood's downstream propagation. Next, based on the correlation between the upstream flow difference before and after each rainfall event and the rainfall amount, as well as the difference between the peak flood volume and the baseline flood volume during each rainfall event, it obtains the flood resonance effect characteristics of the basin. Finally, by comprehensively analyzing the local flood energy accumulation and flood resonance effect characteristics, it obtains the risk of the basin experiencing floods exceeding standard levels. Compared to existing estimates that consider only a single parameter, this invention comprehensively considers relevant data from multiple aspects of the rivers within the basin, thereby improving the accuracy of the risk assessment for floods exceeding standard levels in the basin. Attached Figure Description

[0034] Figure 1 This is a flowchart of a method for simulating and mitigating super-standard floods in a watershed, provided by an embodiment of the present invention;

[0035] Figure 2 This is a flowchart of the process for obtaining river diversity according to one embodiment of the present invention;

[0036] Figure 3 This is a flowchart of the process for obtaining the impact of watershed floods according to an embodiment of the present invention;

[0037] Figure 4 This is a graph of the slope value fitting curve and the average flow velocity fitting curve provided in one embodiment of the present invention;

[0038] Figure 5 This is a flowchart illustrating the acquisition of local flood energy concentration according to an embodiment of the present invention;

[0039] Figure 6 This is a flowchart illustrating the acquisition of flood resonance effect characteristics according to an embodiment of the present invention. Detailed Implementation

[0040] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the specific implementation methods, structures, features, and effects of the present invention are described in detail below with reference to the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. All data and information collected in this application have been obtained with full consent, and the collection, use, and processing of such information must comply with the relevant laws, regulations, and standards of the relevant countries and regions.

[0042] This embodiment provides a method for simulating watershed floods exceeding standard levels. A watershed refers to a specific geographical area where all precipitation (such as rainwater or snowmelt) ultimately converges into a single body of water (such as a river, lake, or ocean). In other words, a watershed is the area where water flows converge, typically centered on a river and including the area traversed by that river and all its tributaries. Rainfall within the watershed ultimately flows into the main river. It includes the hydrological characteristics of the upper, middle, or lower reaches of the watershed and its surrounding areas, usually defined by ridges, mountain ranges, or other natural terrain features. Simulating watershed floods exceeding standard levels involves a comprehensive evaluation of multiple factors within the watershed, including precipitation, topography, soil, and hydrology. Through advanced model simulation technology, potential flood risks can be quantitatively assessed before a flood occurs, providing decision-makers with a scientific basis for taking effective prevention and control measures.

[0043] like Figure 1 As shown, a simulation method for simulating super-standard floods in a watershed includes:

[0044] Step S1: Determine the river diversity in the watershed, which is obtained from the hydrological and ecological conditions within the watershed;

[0045] Step S2: Based on river diversity and the impact of each river flowing into the basin, the basin flood impact is obtained. The basin flood impact is used to characterize the promoting effect on the accumulation of flood energy in the basin.

[0046] Step S3: Based on the elevation variation coefficient of the upstream riverbed, the differences in riverbed permeability among the upstream riverbeds, and the flood impact of the basin, the local flood energy accumulation of the basin is obtained.

[0047] Step S4: Based on the correlation between the upstream flow difference before and after each rainfall and the rainfall amount each time, as well as the difference between the peak flood volume and the flood volume benchmark when the rainfall amount increases each time, the flood resonance effect characteristics of the basin are obtained;

[0048] Step S5: Determine the risk of the basin generating floods exceeding the standard level. The risk is obtained by combining the characteristics of local flood energy accumulation and flood resonance effect.

[0049] The following detailed explanation of each step, in conjunction with the accompanying drawings, is provided.

[0050] Step S1: Determine the river diversity in the watershed, which is obtained from the hydrological and ecological conditions within the watershed.

[0051] The purpose of this step is to analyze the hydrological and ecological characteristics of multiple rivers within a watershed, and then combine these characteristics to determine river diversity. Rivers within a watershed typically consist of a main stream, tributaries, and multiple smaller rivers, each with varying drainage areas, discharges, and flow patterns. Analyzing this river diversity can improve the accuracy of flood simulation. Since river diversity within a watershed requires analysis of ecological and hydrological characteristics, a comprehensive assessment of river diversity can be achieved, thereby providing reliable data support for flood simulation.

[0052] In one exemplary embodiment, such as Figure 2 As shown, a specific process for obtaining river diversity is presented:

[0053] Step S1-1: Based on the length and flow velocity of each river in the basin, the diversity of hydrological characteristics of the basin is obtained.

[0054] The length of each river within the basin is obtained, which can be retrieved from the data server of the basin management department. Based on the length of each river within the basin, the information entropy of the lengths of all rivers in the basin is calculated. Information entropy represents the diversity of river types within the basin.

[0055] The average flow velocity of each river within the basin is obtained as follows: For any river, the river flow velocity detected at multiple time points within a historical period is obtained, and then the average value is calculated to obtain the average flow velocity of the river. This yields the average flow velocity of each river within the basin.

[0056] Then, the average velocity difference between any two different rivers within the basin is obtained. Specifically, the difference between the average velocity of any two different rivers within the basin is calculated, where the difference is the absolute value of the difference in average velocity. This yields the overall velocity difference of all rivers within the basin, which is the average of the average velocity differences between any two different rivers within the basin.

[0057] Finally, the diversity of hydrological features is obtained based on information entropy and overall flow velocity differences. A higher information entropy value indicates that the length of rivers within the basin contains more information; correspondingly, the river length situation is more complex, and the hydrological feature diversity of the basin is stronger. Overall flow velocity differences characterize the difference in average flow velocity between any two different rivers within the basin. A larger overall flow velocity difference indicates a greater difference in average flow velocity between rivers within the basin, a more complex river flow velocity situation, and stronger hydrological feature diversity. Therefore, hydrological feature diversity is directly proportional to both information entropy and overall flow velocity differences. In an exemplary embodiment, a specific quantification method for hydrological feature diversity is given below:

[0058]

[0059] Where f1 represents the diversity of hydrological characteristics in the basin, and H represents the information entropy of the lengths of all rivers within the basin; v o v represents the average flow velocity of the o-th river within the basin. e Let |v| represent the average flow velocity of the e-th river within the basin. o -v e | represents the difference in average flow velocity between the average flow velocity of river o and the average flow velocity of river e, which essentially refers to the difference in average flow velocity between any two different rivers within the basin. n represents the number of combinations that constitute any two different rivers within the basin, that is, the number of differences in average flow velocity between two different rivers within the basin; i represents one of the cases of differences in average flow velocity between any two different rivers within the basin.

[0060] The higher the value of the hydrological feature diversity of a watershed, the greater the differences between the rivers flowing into the watershed, that is, the higher the hydrological feature diversity.

[0061] Step S1-2: Calculate the Simpson index from the relative abundance of each species in the watershed to obtain the watershed's ecological diversity.

[0062] This embodiment retrieves the number of species existing in the watershed from the data server of the watershed management department, and then obtains the relative abundance of each species. Relative abundance is an important indicator in ecology describing the species composition within a community; it refers to the proportion of individuals of a particular species to the total number of individuals of all other species in the community, reflecting the species' numerical dominance or prevalence. Since the calculation method for relative abundance is existing technology, it will not be elaborated further.

[0063] Then, the Simpson index is calculated based on the relative abundance of each species, and finally, the ecological diversity of the watershed is obtained based on the Simpson index.

[0064] In one exemplary embodiment, a specific method for quantifying biodiversity is given below:

[0065]

[0066] Where f2 represents the biodiversity of the watershed, Let G represent the relative abundance of species of type j within the watershed, and let G represent the total number of species within the watershed.

[0067] The Simpson index represents the biodiversity in a watershed. Therefore, this embodiment uses the calculated Simpson index as the measure of biodiversity.

[0068] Steps S1-3: Based on the diversity of hydrological characteristics and ecological diversity, river diversity is obtained.

[0069] Steps S1-1 and S1-2 analyze river diversity within the watershed from both hydrological and ecological perspectives. Therefore, river diversity is obtained based on the diversity of hydrological characteristics and ecological diversity. In an exemplary embodiment, the product of hydrological characteristic diversity and ecological diversity is calculated and normalized; the normalized value is the river diversity. The normalization method here can be the sigmoid function.

[0070] The higher the diversity of hydrological features and ecology within a watershed, the greater the diversity of rivers within that watershed. River diversity within a watershed provides fundamental data and ecological context for subsequent analysis of flood confluence dynamics.

[0071] Step S2: Based on river diversity and the impact of each river flowing into the basin, the basin flood impact is obtained. The basin flood impact is used to characterize the promoting effect on the accumulation of flood energy in the basin.

[0072] It should be understood that different rivers within a watershed may have different slopes, widths, depths, and flow patterns. These differences in physical characteristics affect the velocity, flow rate, and confluence time of the water. In diverse river ecosystems, the diversity of aquatic vegetation and biological populations can influence the resistance to water flow and the residence time of the water.

[0073] Therefore, based on river diversity and the impact of rivers flowing into the basin, the basin flood impact is obtained.

[0074] The topographic slope and riverbed material of different rivers affect water flow velocity, infiltration rate, and flood propagation path. For example, steep mountain rivers may lead to rapid confluence and increased peak flow, while gentle rivers may cause wider inundation due to expanded overflow range. This diversity can result in asynchronous superposition of flood peaks from multiple tributaries.

[0075] In one exemplary embodiment, such as Figure 3 As shown, the following is a specific process for obtaining the impact of a watershed flood:

[0076] Step S2-1: Obtain the correlation between slope and average flow velocity at multiple monitoring points of each river in the basin, and combine the average flow velocity of each river to obtain the instantaneous impact sub-features of each river on the confluence area.

[0077] For ease of explanation, any river within the basin is defined as the first river. The flow path of the first river, including its journey to its confluence with the river, is marked. Multiple monitoring points are set along this path, and the average flow velocity at each point is monitored periodically. The river flow velocity at multiple points within a historical time period can be obtained, and the average flow velocity at that monitoring point can be calculated. The number of monitoring points and their specific locations are determined by actual conditions and are not limited in this embodiment.

[0078] Then, the slope value of the first river at each monitoring point is obtained. The slope value can be obtained directly from the hydrological monitoring station, or it can be obtained in the following ways: obtain the DEM (Digital Elevation Model) data of the first river from satellite imagery or topographic maps, process the DEM data of the first river using GIS (Geographic Information System) software, and then calculate the slope value of the first river at each monitoring point.

[0079] For the slope values ​​of each monitoring point along the first river, the slope values ​​are sorted from smallest to largest, and curve fitting is performed to obtain the slope value fitting curve, denoted as U. Then, according to the slope value sorting, the average flow velocity of each monitoring point is sorted, and curve fitting is performed to obtain the average flow velocity fitting curve, denoted as V. Figure 4 As shown, the horizontal axis represents the location of each monitoring point, and the vertical axis represents the amplitude of the corresponding type. The slope values ​​and average flow velocities used for curve fitting are normalized slope values.

[0080] Based on the slope value fitting curve U and the average flow velocity fitting curve V, the correlation between the slope and average flow velocity of the first river is obtained. In an exemplary embodiment, the correlation here can be the Pearson correlation coefficient, cosine similarity, etc., between the slope value fitting curve U and the average flow velocity fitting curve V. This embodiment uses cosine similarity as an example. The higher the correlation between slope and average flow velocity, the more the trend of average flow velocity change is affected by the river slope. This indicates that the first river is more likely to generate a large instantaneous impact on the confluence area during its flow into the basin, i.e., the higher the risk of causing floods exceeding standard levels.

[0081] The higher the average flow velocity of the first river, the greater the potential for it to exert a significant instantaneous impact on the confluence area during its flow into the basin, thus increasing the risk of floods exceeding standard levels. Therefore, based on the correlation between the slope and average flow velocity of the first river, and considering its average flow velocity, we derive the instantaneous impact sub-characteristics of the first river on the confluence area. These instantaneous impact sub-characteristics are directly proportional to the river's average flow velocity.

[0082] In one exemplary embodiment, the formula for calculating the transient impactor characteristics is as follows:

[0083] d e =norm[M(U e V e )×v e ];

[0084] Where, d e U represents the instantaneous impact sub-characteristic of the e-th river within the basin. e V represents the fitted curve of the slope value of the e-th river. e Let M(U) represent the fitted curve of the average flow velocity of the e-th river. e V e ) represents the fitted curve U of the slope value of the e-th river. e Fitting curve V with the average flow velocity of the e-th river e The correlation.

[0085] "norm" represents normalization, and here normalization can be achieved by obtaining the M(U) values ​​for each river within the basin. e V e )×v e The maximum and minimum values ​​in the equation are then normalized using the maximum and minimum values ​​method to obtain the M(U) value for the e-th river. e V e )×v e Normalize.

[0086] Step S2-2: Based on the overall characteristics of instantaneous impact and river diversity, the flood impact characteristics of the basin are obtained.

[0087] Step S2-1 obtains the instantaneous impact sub-features of each river within the basin, and then fuses the instantaneous impact sub-features of all rivers within the basin to obtain the overall instantaneous impact feature. In an exemplary embodiment, the average value of the instantaneous impact sub-features of all rivers within the basin is calculated, and the result is the overall instantaneous impact feature. The higher the overall instantaneous impact feature, the stronger the impact of the flood within the basin; therefore, the overall instantaneous impact feature is directly proportional to the impact of the flood in the basin.

[0088] Rivers with high ecological diversity often possess diverse plant and animal communities. These organisms can effectively regulate water flow through structures such as root systems, wetlands, and riparian vegetation, reducing soil erosion and sediment loss, thus providing a buffer against the impact of floods. If the river diversity in a watershed is low, it cannot provide sufficient buffer against the impact of floods. Therefore, the greater the river diversity, the stronger the buffering effect against the impact of floods in the watershed, and the weaker the impact of floods in the watershed; the impact of floods in the watershed is inversely proportional to river diversity.

[0089] The impact of a basin flood characterizes the asynchronous superposition of flood peaks from multiple tributaries within the basin. The higher the impact of a basin flood, the higher the asynchronous superposition of flood peaks from multiple tributaries, which has a greater promoting effect on the local accumulation of flood energy in the basin.

[0090] In one exemplary embodiment, a specific method for quantifying the impact of watershed floods is given below:

[0091]

[0092] Where D represents the watershed flood impact, and F represents river diversity. It represents the overall characteristics of an instantaneous impact.

[0093] Step S3: Based on the elevation variation coefficient of the upstream riverbed, the differences in riverbed permeability among the upstream riverbeds, and the flood impact of the basin, the local flood energy accumulation of the basin is obtained.

[0094] Changes in river slope directly affect the speed and volume of water flow. In areas with steeper slopes, the water flow is usually faster, causing the water to accumulate rapidly and form floods, while in areas with gentler slopes, the water flow may be slower, and the water volume may accumulate at a relatively lower rate.

[0095] This step primarily analyzes the riverbed characteristics in different regions of the basin. Different riverbed characteristics lead to varying tolerances for flood energy in different regions, which can cause rapid concentration of water energy in the river, triggering localized flood energy accumulation. The basin can be divided into various regions according to different needs and research objectives. One common method is "upstream, middle reaches, and downstream." Since the upstream region plays a dominant role in influencing localized flood energy accumulation within the basin, this embodiment focuses on analyzing and explaining the upstream region.

[0096] This embodiment mainly uses a digital elevation model (DEM) to obtain the elevation changes and topographic features of the riverbed in the upstream section of the basin, in order to identify the slope, unevenness, etc. of the riverbed.

[0097] The coefficient of variation (CV) of elevation of the upstream riverbed is obtained. The CV is an important method for quantifying the spatial heterogeneity of riverbed elevation data by analyzing its dispersion. The calculation process of the CV is existing technology and will not be elaborated further. A higher CV indicates a greater variation in the relative elevation of the upstream riverbed compared to the average elevation, suggesting a greater likelihood of retaining floodwater.

[0098] Based on the elevation variation coefficient of the upstream riverbed, the differences in riverbed permeability among the upstream riverbeds, and the flood impact of the basin, the local flood energy accumulation of the basin is obtained. In an exemplary embodiment, such as... Figure 5 As shown, a specific process for obtaining the energy concentration of local floods is presented:

[0099] Step S3-1: Obtain the difference in riverbed permeability at any two different locations in the upstream riverbed of the basin, thereby obtaining the comprehensive riverbed permeability difference; the comprehensive riverbed permeability difference characterizes the overall situation of the difference in riverbed permeability in the upstream riverbed of the basin.

[0100] Multiple monitoring locations are set up in the riverbed upstream of the basin. It should be understood that these monitoring locations are different from the monitoring points set up along the river's flow path mentioned above, and the two do not affect each other. The number of monitoring locations and their placement are determined based on the actual situation, and this embodiment does not impose any limitations.

[0101] Obtain the riverbed permeability at each monitoring location. Riverbed permeability can be obtained through laboratory testing or field testing. The methods for obtaining riverbed permeability are existing technologies and will not be elaborated further.

[0102] For any two different monitoring locations on the upstream riverbed of the basin, the difference in riverbed permeability between these two locations is obtained. Specifically, the difference is the absolute value of the difference in riverbed permeability. This allows us to obtain the difference in riverbed permeability between any two different monitoring locations on the upstream riverbed of the basin.

[0103] The comprehensive riverbed permeability difference is obtained by considering the difference in riverbed permeability at any two different monitoring locations in the upstream riverbed of the basin. This comprehensive riverbed permeability difference characterizes the overall situation of the difference in riverbed permeability in the upstream riverbed of the basin. In an exemplary embodiment, the average value of the differences in riverbed permeability at all two different monitoring locations in the upstream riverbed of the basin is calculated as the comprehensive riverbed permeability difference.

[0104] Step S3-2: Based on the differences in riverbed permeability, elevation variation coefficient, and basin flood impact, the local flood energy concentration is obtained.

[0105] High riverbed permeability can reduce peak flood flow; conversely, if the riverbed has almost no infiltration, leading to a significant increase in the runoff coefficient, and if both high- and low-permeability river sections exist within the basin, localized flood energy accumulation may occur. Correspondingly, since the overall difference in riverbed permeability characterizes the overall variation in permeability across the upstream riverbed, a greater difference in overall permeability, and a greater difference in permeability between different monitoring locations in the upstream riverbed, increases the likelihood of localized flood energy accumulation. The greater the basin flood impact, the more likely localized flood energy accumulation will occur. Therefore, the overall difference in riverbed permeability, the coefficient of variation in elevation, and the basin flood impact are correlated with localized flood energy accumulation, allowing the determination of localized flood energy accumulation based on these factors. Localized flood energy accumulation is directly proportional to the overall difference in riverbed permeability, the coefficient of variation in elevation, and the basin flood impact.

[0106] The greater the local flood energy concentration, the more likely a strong local flood energy accumulation will form in the upstream riverbed of the basin. In an exemplary embodiment, a specific method for quantifying local flood energy concentration is given below:

[0107]

[0108] Where E represents the local flood energy concentration, and CV represents the elevation variation coefficient. This indicates the difference in overall riverbed permeability.

[0109] Indicates to The normalization here can be the sigmoid function.

[0110] Step S4: Based on the correlation between the upstream flow difference before and after each rainfall and the rainfall amount, as well as the difference between the peak flood volume and the flood volume benchmark when the rainfall amount increases, the flood resonance effect characteristics of the basin are obtained.

[0111] The local energy concentration of floods in a watershed varies, especially during periods of rainfall. A sudden increase in rainfall can cause upstream flood energy concentration to far exceed normal levels, resulting in a sustained strengthening of the flood peak as it propagates downstream. Therefore, this step requires analyzing the characteristics of the flood resonance effect in the watershed. This step primarily examines the linkage between flood behavior and climate (specifically, rainfall) changes in the watershed. Floods exceeding standard levels are often accompanied by the dynamic migration of rainfall centers. If the rainfall path matches the watershed morphology (e.g., moving along the main river channel), "flood resonance" may occur, representing a type of climate-topography coupling effect.

[0112] In one exemplary embodiment, such as Figure 6 As shown, a specific process for obtaining the characteristics of the flood resonance effect is presented:

[0113] Step S4-1: Based on the difference in upstream flow before and after each rainfall and the amount of each rainfall, obtain the similarity between the flow difference and the amount of rainfall.

[0114] By storing historical rainfall events in the upstream area within a historical time period in the hydrological monitoring system, the upstream flow before and after each rainfall is obtained, and then the difference in upstream flow before and after each rainfall, i.e., the flow change, is obtained. In an exemplary embodiment, for any rainfall, the absolute value of the difference between the flow after the rainfall and the flow before the rainfall is calculated as the difference in upstream flow before and after that rainfall. Then, according to the chronological order of the rainfall, the differences in upstream flow before and after each rainfall are sorted chronologically, and curve fitting is performed to obtain the flow difference fitting curve within the historical time period.

[0115] Then, the rainfall amount of each rainfall event in the historical rainfall event within the historical time period is obtained. According to the time sequence of the rainfall, the rainfall amount of each rainfall event is sorted by time sequence, and curve fitting is performed to obtain the rainfall fitting curve within the historical time period.

[0116] The similarity between the fitted curves for flow difference and rainfall is used as the similarity between flow difference and rainfall. Specifically, this similarity is the cosine similarity. It should be understood that since the greater the rainfall, the greater the flow difference before and after rainfall. Therefore, the trends of the flow difference fitted curve and the rainfall fitted curve should normally have a certain degree of similarity. Generally, there is no situation where the greater the rainfall, the smaller the flow difference before and after rainfall. Therefore, the numerical range of the cosine similarity obtained here is usually 0-1. Furthermore, the higher the similarity between flow difference and rainfall, the more it indicates that the flow difference before and after rainfall in the watershed changes accordingly with changes in rainfall. This further indicates a higher responsiveness of the watershed to rainfall intensity, and a more similar trend between the flow difference and rainfall.

[0117] Step S4-2: Obtain the difference between the peak flood volume and the flood volume benchmark for each rainfall event, and obtain the comprehensive flood volume difference.

[0118] During each rainfall event, flooding occurs in the upper reaches of the basin due to the rainfall. The amount of floodwater in the upper reaches of the basin during each rainfall event is monitored (the amount of floodwater can be the water level in the upper reaches of the basin at the corresponding moment). In an exemplary embodiment, for any rainfall event, the amount of floodwater in the upper reaches of the basin during the period from the start to the end of the rainfall event is monitored (essentially the floodwater change curve during this period, i.e., the water level change curve in the upper reaches of the basin), and the maximum amount of floodwater (i.e., the maximum water level) is obtained as the peak value of the floodwater in that rainfall event.

[0119] A flood volume benchmark is obtained, which is used for comparison with the peak flood volume of each rainfall event. In an exemplary embodiment, the flood volume benchmark is the flood volume in the upper reaches of the basin under no-rainfall conditions. Here, the flood volumes in the upper reaches of the basin under no-rainfall conditions for multiple time periods within a historical period are obtained, and then the average value is calculated as the flood volume benchmark. Therefore, the peak flood volume of each rainfall event is greater than the flood volume benchmark.

[0120] The difference between the peak flood volume and the baseline flood volume for each rainfall event is obtained, specifically the absolute value of the difference between the peak flood volume and the baseline flood volume for each rainfall event. Then, the average value of the difference between the peak flood volume and the baseline flood volume for each rainfall event is calculated, and the result is the comprehensive flood volume difference.

[0121] Step S4-3: Based on the similarity and the difference in comprehensive flood volume, obtain the characteristics of flood resonance effect.

[0122] The similarity between flow differences and rainfall amounts characterizes the relationship between precipitation intensity and the response between watersheds. Greater similarity indicates a more pronounced flood resonance effect. A greater difference in total flood volume indicates that the peak flood volume of each rainfall event is larger than the baseline flood volume, further highlighting the flood resonance effect. Therefore, similarity and differences in total flood volume influence the flood resonance effect characteristics, which can be derived from these factors. The flood resonance effect characteristics are directly proportional to the similarity between flow differences and rainfall amounts, and also to the differences in total flood volume. The flood resonance effect characteristics characterize the flood resonance effect within a watershed. Higher values ​​indicate stronger interactions between rainfall, watershed characteristics, and water flow, leading to a significant increase in flow within the watershed, thus indicating a higher flood resonance effect. A significant increase in flood flow caused by specific meteorological conditions (such as heavy rainfall or watershed morphology) reflects the watershed's sensitivity to floods and its potential risks.

[0123] In one exemplary embodiment, the product of the similarity between the flow difference and the rainfall and the difference in the total flood volume is calculated and the product is normalized to obtain the flood resonance effect characteristics.

[0124] Step S5: Determine the risk of the basin generating floods exceeding the standard level. The risk is obtained by combining the characteristics of local flood energy accumulation and flood resonance effect.

[0125] This embodiment comprehensively analyzes the risk of a watershed experiencing floods exceeding standard levels from two aspects: the watershed's energy accumulation capacity and its flood response capacity, thereby obtaining the risk of such floods. Therefore, the risk of a watershed experiencing floods exceeding standard levels is comprehensively affected by the characteristics of local flood energy accumulation and flood resonance effects. In an exemplary embodiment, the average value of the local flood energy accumulation and flood resonance effect characteristics is calculated, and the result is the risk of the watershed experiencing floods exceeding standard levels. The higher the value, the higher the risk of the watershed experiencing floods exceeding standard levels, indicating a higher risk of the watershed experiencing floods exceeding standard levels under extreme weather conditions, which may exceed the watershed's tolerance for floods, meaning the watershed has a low tolerance rate for floods exceeding standard levels.

[0126] In subsequent steps, the obtained risk of the basin experiencing a flood exceeding the standard can be used to simulate a flood exceeding the standard model for the basin. In an exemplary embodiment, the tolerance rate of the basin under a flood exceeding the standard is first obtained based on the risk of the basin experiencing a flood exceeding the standard. The tolerance rate of the basin for a flood exceeding the standard refers to the basin's ability to withstand and adapt to flood conditions; a higher tolerance rate indicates a relatively lower risk of flooding. Therefore, the tolerance rate is inversely proportional to the risk of the basin experiencing a flood exceeding the standard. Accordingly, the difference between the value 1 and the risk of the basin experiencing a flood exceeding the standard is calculated to obtain the tolerance rate of the basin for a flood exceeding the standard.

[0127] Obtaining the tolerance rate helps identify high-risk areas and potential flood impacts, and the simulation model can more flexibly adapt to different watershed characteristics and meteorological conditions, making it more valuable for practical applications. Furthermore, emergency response strategies can be quickly adjusted based on the tolerance rate output by the model. After obtaining the watershed's tolerance rate for floods exceeding standard levels, a suitable hydrological model can be selected, such as the SWAT (Soil and Water Assessment Tool) model. This model can effectively simulate processes such as rainfall inflow, surface runoff, and river flow. Then, based on the watershed characteristics, the main parameters of the model are set, including parameters such as riverbed permeability, river velocity, watershed channel diversity, and slope. The calculated tolerance rate is then used as the model's input parameter, influencing the model's response to flood events. Based on the expected flood scenarios exceeding standard levels, different parameters such as rainfall intensity and duration are set to conduct multi-scenario simulations. Therefore, the input parameters (risk of the basin experiencing floods exceeding standard levels, or tolerance rate) are updated in real time according to the actual situation to ensure the accuracy of the simulation model during long-term use; the model output results are used to support the decision-making process of basin management and to propose suggestions for flood control facility construction, flood early warning mechanisms, and emergency response plans.

[0128] This embodiment also provides a watershed super-standard flood simulation system, including: a memory and a processor; the memory is connected to the processor, and the memory is used to store program instructions; the processor is used to implement the steps in the above-described watershed super-standard flood simulation method embodiment when the program instructions are executed.

[0129] In one exemplary embodiment, the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps in the above-described embodiments of the method for simulating and mitigating super-standard floods in watersheds.

[0130] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0131] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A simulation method for simulating super-standard floods in a watershed, characterized in that, include: Determine the river diversity within the watershed, which is derived from the hydrological and ecological conditions within the watershed; Based on the river diversity and the impact of each river flowing into the basin, the basin flood impact is obtained, which is used to characterize the promoting effect on the accumulation of flood energy within the basin. Based on the elevation variation coefficient of the upstream riverbed, the differences in riverbed permeability among the upstream riverbeds, and the flood impact of the basin, the local flood energy accumulation of the basin is obtained. Based on the correlation between the difference in upstream flow before and after each rainfall and the amount of each rainfall, as well as the difference between the peak flood volume and the flood volume benchmark when the amount of each rainfall increases, the characteristics of the flood resonance effect in the basin are obtained. The risk of a basin experiencing a flood exceeding the standard level is determined by fusing the characteristics of local flood energy concentration and flood resonance effect.

2. The method for simulating and modeling watershed floods exceeding standard levels as described in claim 1, characterized in that, The process of obtaining the impact of the basin flood includes: The correlation between slope and average flow velocity at multiple monitoring points for each river within the watershed is obtained, and combined with the average flow velocity of each river, the instantaneous impact sub-feature of each river on the confluence area is obtained; the instantaneous impact sub-feature is proportional to the correlation and the average flow velocity of the river. The basin flood impact is obtained based on the overall characteristics of instantaneous impact and the river diversity. The basin flood impact is directly proportional to the overall characteristics of instantaneous impact and inversely proportional to the river diversity. The overall characteristics of instantaneous impact are obtained by fusing the instantaneous impact sub-characteristics of all rivers in the basin.

3. The method for simulating and modeling watershed floods exceeding standard levels as described in claim 1, characterized in that, The process of acquiring the energy concentration of local floods includes: The difference in riverbed permeability at any two different locations in the upstream riverbed of the basin is obtained to obtain the comprehensive riverbed permeability difference; the comprehensive riverbed permeability difference characterizes the overall situation of the difference in riverbed permeability in the upstream riverbed of the basin. The local flood energy concentration is obtained based on the comprehensive riverbed permeability difference, elevation variation coefficient, and basin flood impact; the local flood energy concentration is directly proportional to the comprehensive riverbed permeability difference, elevation variation coefficient, and basin flood impact.

4. The method for simulating and modeling super-standard floods in a watershed as described in claim 3, characterized in that, The local flood energy concentration is obtained by multiplying the combined riverbed permeability difference, elevation variation coefficient, and basin flood impact.

5. The method for simulating and modeling watershed floods exceeding standard levels as described in claim 1, characterized in that, The process of obtaining the characteristics of the flood resonance effect includes: Based on the difference in upstream flow before and after each rainfall event and the amount of rainfall each time, the similarity between the flow difference and the amount of rainfall is obtained; The difference between the peak flood volume and the flood volume benchmark for each rainfall event is obtained, and the comprehensive flood volume difference is obtained; the comprehensive flood volume difference is used to characterize the difference between the peak flood volume and the flood volume benchmark for all rainfall events. Based on the similarity and the difference in comprehensive flood volume, the flood resonance effect characteristics are obtained, and the flood resonance effect characteristics are proportional to the similarity and the difference in comprehensive flood volume.

6. The method for simulating and modeling watershed floods exceeding standard levels as described in claim 5, characterized in that, The flood volume benchmark is the upstream flood volume of the basin under conditions of no precipitation; The process of obtaining the comprehensive flood volume difference includes: calculating the difference between the peak flood volume and the flood volume benchmark for each rainfall event, and calculating the average value of the obtained differences as the comprehensive flood volume difference.

7. The method for simulating and modeling super-standard floods in a watershed as described in claim 1, characterized in that, The process of obtaining the river diversity includes: Based on the length and flow velocity of each river within the basin, the diversity of hydrological characteristics of the basin is obtained; The Simpson index is calculated from the relative abundance of each species in the watershed to obtain the watershed's ecodiversity; The river diversity is obtained based on the aforementioned hydrological and ecological diversity.

8. The method for simulating and modeling super-standard floods in a watershed as described in claim 7, characterized in that, The process of obtaining the diversity of hydrological features includes: Calculate the information entropy of the lengths of all rivers within the watershed; Obtain the overall velocity difference of all rivers in the basin, where the overall velocity difference is the average of the average velocity differences between any two different rivers in the basin; The hydrological feature diversity is obtained based on the information entropy and the overall flow velocity difference, and the hydrological feature diversity is directly proportional to both the information entropy and the overall flow velocity difference.

9. The method for simulating and modeling watershed floods exceeding standard levels as described in claim 1, characterized in that, The risk of the basin experiencing floods exceeding standard levels is obtained by averaging the characteristics of local flood energy concentration and flood resonance effect.

10. A system for simulating super-standard floods in a watershed, characterized in that it includes: Memory and processor; The memory is connected to the processor; The memory is used to store program instructions; The processor is configured to implement the method for simulating super-standard floods in a watershed as described in any one of claims 1-9 when program instructions are executed.

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