Flood inundation calculation method and device suitable for moist mountainous area and medium

Abstract

The invention discloses a flood inundation calculation method and device suitable for a humid mountainous area and a medium, and the method comprises the steps: S1, carrying out the sub-basin division of a target region, and setting a model calculation range; s2, on the basis of a three-water-source Xinanjiang model framework, a lumped hydrological model of each sub-basin is constructed, through hydrological similarity analysis and confluence unit line calculation of each sub-basin, hydrological model production and confluence parameters are calibrated, and the calibrated model parameters are transplanted to each sub-basin; s3, on the basis of an alternative implicit ADI algorithm, a two-dimensional hydrodynamic model is constructed, the roughness value of the model is optimized, and the roughness value is used for calibrating model parameters of the two-dimensional hydrodynamic model; and S4, coupling the three-water-source Xinanjiang model with the two-dimensional hydrodynamic model, and carrying out flooding calculation in the whole process of runoff production, confluence, evolution and overflow. According to the invention, evolution and overflow of flood in a complex terrain can be accurately simulated, and the flood inundation range, depth and water flow states at different moments can be accurately calculated.

Description

Technical Field

[0001] The present invention relates to the technical field of disaster simulation prediction, and in particular to a flood inundation calculation method, device and storage medium suitable for humid mountainous areas. Background Art

[0002] Flash torrents are a natural disaster caused by high-intensity rainfall. Humid mountainous areas are affected by complex topography, hydrological and meteorological disaster-prone environments. Flash torrent events are numerous and widespread, with large temporal and spatial variations. They are highly nonlinear, random and complex, and are difficult to calculate quantitatively. At the same time, traditional flood inundation calculation methods are mostly based on flat areas for modeling, which makes it difficult to describe the movement of water flow in humid mountainous areas under the influence of multiple factors such as large terrain fluctuations, diverse soil types, and high vegetation coverage. This leads to large deviations in the calculation results of flood inundation range and depth.

[0003] In addition, the commonly used methods for calculating flood inundation in mountainous areas have certain pertinence and limitations: (1) Based on historical flood data and measured data, the inundation situation is determined, and the empirical relationship between flood inundation range, depth, flood flow, water level and other factors is established. This can be used for flood inundation calculation in mountainous areas. However, it is based on limited historical data in a specific river basin, and its accuracy is reduced when extended to other areas, and its universality and precision are limited. (2) Conventional hydrological models process spatial information based on remote sensing tools such as ArcGIS to obtain a large number of basic hydrological parameters. They can reflect the runoff generation and runoff process under the conditions of underlying surface conditions and uneven spatial distribution of rainfall. They can calculate runoff generation and runoff based on the rainfall-runoff process and realize flood forecasting in mountainous basins. However, due to the limitations of basin geometry data accuracy, the parameters are highly uncertain and it is difficult to reflect the flow dynamic characteristics during the flood evolution process. (3) Conventional hydrodynamic models describe the movement of flood waves in river channels, taking into account the influence of multiple complex factors, such as topography, water flow resistance, and the interaction of river networks and water systems. They can describe the movement and evolution of floods in river channels and analyze the flood inundation range and dynamic inundation process, but they do not consider the natural hydraulic connection between mountain basins and river channels; (4) Integrating the advantages of the hydrological model and the hydrodynamic model, coupling the hydrological and hydrodynamic models to simulate rainstorm runoff and flood inundation in mountainous areas can meet the needs of high-precision calculation of the entire process of runoff simulation and flood inundation in humid mountainous areas, and realize high-precision flood forecasting under the influence of multiple factors. However, it requires certain basic data support, including high-precision terrain data, hydrological data, etc. The calculation process is complicated, and in order to ensure efficiency and accuracy, high computer performance is required. In addition, the determination and verification of model parameters require certain professional knowledge and experience, and the workload is large.

[0004] To this end, this application specifically proposes a flood inundation calculation method suitable for humid mountainous areas to solve the above technical problems. Summary of the invention

[0005] The main purpose of the present invention is to provide a flood inundation calculation method suitable for humid mountainous areas to solve the technical problems raised in the background technology.

[0006] The present invention adopts the following technical solutions to solve the above technical problems: A flood inundation calculation method suitable for humid mountainous areas, which comprehensively uses the hydrological and hydrodynamic model algorithm to simulate the entire evolution process of floods from formation, development to extinction, can accurately predict the possible scope and depth of floods, including the following specific operation steps: S1. Divide the target area into sub-basins and set the calculation range of the hydrological model and the hydrodynamic model; S2. Based on the framework of the Xin'anjiang model of the Three Water Sources, a lumped hydrological model of each sub-basin is constructed. Through hydrological similarity analysis and calculation of the runoff unit line of each sub-basin, the runoff parameters of the hydrological model are calibrated, and the calibrated model parameters are transplanted to each sub-basin; S3. Based on the alternating implicit ADI algorithm, a two-dimensional hydrodynamic model is constructed and the model roughness value is optimized. The roughness value is used to calibrate the model parameters of the two-dimensional hydrodynamic model; S4. Couple the Sanshuiyuan Xin'anjiang model with the two-dimensional hydrodynamic model to perform inundation calculations for the entire process of runoff generation-confluence-evolution-overflow.

[0007] Preferably, the specific operation process of step S1 includes: S11. Collection and collation of basic data of the study area, including high-precision DEM data, land use type data of the study area, the latest remote sensing data of the study area, observation data of monitoring stations (rainfall, water level and flow elements, etc.), flood trace data during historical floods, and topographic cross-section data of river systems; S12. Based on geographic information GIS software, multiple scattered original DEM data blocks are integrated into a complete DEM covering the research area required by the user through coordinate matching and data fusion algorithms; S13. Use hydrological analysis tools to process the DEM in order, including filling depressions, slope, and flow direction, divide the entire study area into different sub-basins, and analyze the confluence unit lines of each sub-basin; S14. Investigate the historical mountain torrent disasters and flood inundation in the study area, delineate the danger zone, and determine the calculation range of the hydrodynamic model.

[0008] Preferably, the specific operation process of step S2 includes: S21. Select the Sanshuiyuan Xin'anjiang model, which is well used in humid areas, as the basic model, and develop the Xin'anjiang model and comprehensive unit line calibration system. Select water volume error, peak error, logarithmic error, process matching degree and certainty coefficient as the objective function, and use a combination of manual optimization and computer automatic optimization to systematically identify the parameters of the model; S22. Using the principle of hydrological similarity, find the reference basin (basin with data) of the target basin (basin without data) through basin attributes, and use the model calibration parameters of the basin with existing data to deduce the model parameters of the sub-basin without data; S23. Using the slope flow velocity calculation formula, combined with the slope and flow direction data of each sub-basin, calculate the confluence time of each point in the basin to the basin outlet, and extract the confluence characteristic parameters of each sub-basin; S24. Use the runoff characteristic parameters to calibrate the hydrological model and transplant the calibrated model to each sub-basin. Preferably, the slope flow velocity calculation formula in step S23 is:

[0009] in, is the slope velocity, To reflect the empirical coefficient of slope roughness, It is the slope along the direction of water flow at a certain point in the basin.

[0010] Preferably, the specific operation process of constructing a two-dimensional hydrodynamic model and optimizing the model roughness value in step S3 includes: S31. Use GIS software to integrate the river section with high-precision DEM data, and consider the impact of levees, weirs, bridges, culverts, roads, and houses, further correct the elevation data, and finally generate a detailed, accurate digital terrain model DTM covering the flood calculation area; S32. Perform operations such as registration, clipping, and resampling on the land use type data to make the data coordinate system consistent with the pixel size and DTM, and then create a model partition roughness file according to the land use type; S33. Based on DTM and partition roughness file, the two-dimensional hydrodynamic model is developed by using alternating implicit ADI algorithm and OpenMP parallel computing technology; S34. Taking the flow process calculated by the hydrological model as the upper boundary and the measured water level process at the outlet station of the basin as the lower boundary, the inundation situation of typical flood years is reproduced, and the roughness value is optimized using historical flood marks and inundation range data.

[0011] Preferably, the specific operation process of developing the two-dimensional hydrodynamic model in step S33 includes: L1. The two-dimensional Saint-Venant equation is used as the basic equation for hydrodynamic calculation. In the Cartesian coordinate system, the vector form of the equation is expressed as:

[0012]

[0013]

[0014] in: is the spatial horizontal coordinate, is the spatial ordinate, For time, is the source term vector; is a variable vector, including the water level And single width flow , ; , is the flux vector, including the water depth , , Direction and Flow rate on is Xie Cai coefficient, is the Manning coefficient; L2. The mass and momentum equations are discretized by implicit and explicit alternating finite difference method, and the equation matrices generated in each direction are solved by pursuit method.

[0015] Preferably, in order to reduce computational time, OpenMP instructions are used to accelerate computationally intensive for loops in parallel.

[0016] Preferably, the specific data calculation method of the L2 step includes: L21. Divide a time step into two half steps. The first half step uses implicit and explicit formats in the x and y directions respectively, and the second half step uses explicit and implicit formats in the x and y directions respectively. The original more complex system of equations is transformed into two tridiagonal systems of equations, and the two-dimensional problem is decomposed into two one-dimensional implicit problems at each time step. L22. The central difference pursuit method is used to discretize and solve the continuity equation and momentum equation in the x and y directions respectively through one-dimensional advancement.

[0017] Preferably, the specific calculation process for discretizing and solving the continuity equation and momentum equation in step L22 includes: When solving the continuity equation and momentum equation in the x-direction, From n to n+1 / 2, From n to n+1, are the known values ​​from n+1 to n+1 / 2; when solving the continuity equation and momentum equation in the y direction, From n+1 / 2 to n+1, From n+1 / 2 to n+3 / 2, The values ​​from n to n+1 obtained by the previous calculation; Taking the x direction as an example, the continuity equation can be discretized as:

[0018] Discretize the momentum equation:

[0019] After sorting, the difference equation is in the form of:

[0020] The resulting tridiagonal matrix equation can be solved using the pursuit method; Similarly, the continuity equation and momentum equation in the y direction can be discretely solved according to the above method.

[0021] Preferably, the specific operation process of step S4 includes: S41. Plot the relationship between water level and flow at the outlet of the basin, fit the water level and flow relationship curve using the least squares method, and use it as the lower boundary of the model; S42. Calculate the hydrological model and hydrodynamic model in series in the form of point source and line source, calculate the confluence through the hydrological model, obtain the flow process of each sub-basin outlet under specified rainfall conditions, and then obtain the characteristic elements including the scope, water depth and duration of flooding through the hydrodynamic model.

[0022] On the other hand, the present invention further discloses a computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes the steps of the above method.

[0023] On the other hand, the present invention further discloses a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the above method.

[0024] It can be seen from the above technical solution that the present invention provides a flood inundation calculation method suitable for humid mountainous areas. Compared with the prior art, the present invention has the following advantages: 1. By coupling the Sanshuiyuan Xin'anjiang model with the two-dimensional hydrodynamic model, the present invention can accurately simulate the evolution and overflow of floods in complex terrain. Compared with a single model or simple empirical calculation method, it can more accurately calculate the flood inundation range, depth and water flow status at different times, providing reliable data for flood prevention and disaster reduction decisions.

[0025] 2. The present invention is designed for humid mountainous areas. After the sub-basin division, the calibrated lumped hydrological model parameters are transplanted using hydrological similarity analysis and geomorphic unit line method. This can fully consider the characteristics of humid mountainous areas such as abundant precipitation, complex terrain, and developed water systems, thereby improving modeling efficiency and accuracy. At the same time, it fully considers the effects of the complexity of the terrain in humid mountainous areas, avoiding the limitations of general methods when applied in special areas.

[0026] 3. The present invention adopts the alternating implicit ADI algorithm and OpenMP parallel computing technology in the two-dimensional hydrodynamic modeling process, which can optimize the model roughness value and improve the solution efficiency, while reducing the calculation time and ensuring the calculation accuracy.

[0027] 4. The present invention adopts the linear reservoir method to regulate soil flow and underground runoff in the confluence calculation, and uses the geomorphic unit line method to obtain the confluence characteristic parameters of each sub-basin, which can accurately reflect the generation mechanism of different water sources, thereby obtaining the runoff-confluence calculation results that are closer to the actual situation, which is convenient for fully displaying the dynamic process of flood from generation to flooding.

[0028] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become easy to understand through the following description. Of course, it is not necessary to achieve all of the advantages described above simultaneously for any product implementing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 A schematic diagram of the overall method operating system of the present invention; Figure 2 It is a schematic diagram of the watershed geographic information data GIS of the present invention; Figure 3 It is the flow process diagram of each tributary of the present invention; Figure 4 This is a schematic diagram of the final DTM data of the present invention; Figure 5 It is a schematic diagram showing the distributed roughness file of the present invention; Figure 6 It is a schematic diagram of comparative analysis between the flood mark point elevation calculated by the model of the present invention and the actual measurement; Figure 7 It is a schematic diagram of the water level and flooding range at 0 o'clock during the flood evolution process of the present invention; Figure 8A schematic diagram of the 24-hour water level and flooding range during the flood evolution process of the present invention; Fig. 9 It is a schematic diagram of the water level and flooding range at 36 o'clock during the flood evolution process of the present invention; Fig.10 It is a schematic diagram of the water level and flooding range at 42 o'clock during the flood evolution process of the present invention; Fig.11 It is a schematic diagram for comparing the maximum flooding range of the model of the present invention. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] In the embodiment, see Figures 1 to 11 .

[0032] Humid mountainous areas usually refer to areas with humid climate, abundant precipitation and mountainous terrain. They have lush vegetation, rich species, forest coverage rate usually above 60%, diverse soil types, and important ecological protection value. However, flash floods occur frequently, are highly destructive, and are difficult to accurately predict, forecast and prevent. They can easily cause serious casualties and property losses, and have always been the focus and difficulty of flood and drought prevention. The flooding range is the basis of flash flood prevention and control planning. Simulating and analyzing the flooding situation when flash floods occur is an important means of evaluating the disaster situation of flash floods and an important data basis for emergency response and disaster relief. like Figure 1 The flood inundation calculation method applicable to humid mountainous areas proposed in the embodiment of the present invention comprises the following steps: Step S1: Collect spatial geographic information data, hydrological monitoring site data and water conservancy project data, combine the inundation situation of historical mountain torrent disasters, determine the calculation range of the hydrological model and the hydrodynamic model and the spatial location of the coupling connection between the two, divide the target area into sub-basins, and determine the calculation range of the hydrological model and the hydrodynamic model.

[0033] Specifically, the data collection process includes: S11. Collect and organize basic data of the study area, including downloading high-precision DEM data; downloading land use type data of the study area; collecting the latest remote sensing data of the study area; collecting observation data of monitoring stations, including rainfall, water level and flow elements, etc.; collecting flood trace data during historical floods; collecting topographic cross-section data of river systems; S12. Use GIS software to integrate multiple scattered original DEM data blocks into a complete DEM covering the study area required by the user through precise coordinate matching and data fusion algorithms; S13. Use hydrological analysis tools to process the DEM in order, such as filling depressions, slope, and flow direction, divide the entire study area into different sub-basins, and analyze the confluence unit lines of each sub-basin. The sub-basin confluence here uses the slope confluence formula; S14. Investigate the historical mountain torrent disasters and flood inundation in the study area, delineate the danger zone, and determine the calculation range of the hydrodynamic model.

[0034] Step S2: Based on the framework of the Sanshuiyuan Xin'anjiang model, a lumped hydrological model of each sub-basin is constructed. Through hydrological similarity analysis and calculation of the runoff unit lines of each sub-basin, the runoff parameters of the hydrological model are calibrated. After calibration, the model parameters are transplanted to each sub-basin.

[0035] The specific operation process of constructing the hydrological model of each sub-basin and identifying parameters includes: S21. Select the Sanshuiyuan Xin'anjiang model, which is well used in humid areas, as the basic model, and develop the Xin'anjiang model and comprehensive unit line calibration system. Select water volume error, peak error, logarithmic error, process matching degree and certainty coefficient as the objective function, and use a combination of manual optimization and computer automatic optimization to systematically identify the parameters of the model; It should be noted that the whole basin lumping here is mainly to obtain runoff parameters. In the confluence calculation of the whole basin lumped hydrological model, the subsoil flow and groundwater runoff are regulated by the linear reservoir method, and the surface runoff uses the Nash unit line (only for the whole basin lumped confluence). The formula is:

[0036] in, is the instantaneous unit line; is the number of linear reservoirs; is the regulation coefficient for each reservoir; is the instantaneous time; and The product of has a time dimension and is a measure of the time of confluence of the basin; In addition, it should be noted that the Sanshuiyuan Xin'anjiang model is based on the theory of full-storage runoff, which divides the runoff of the basin into three water sources: surface runoff, soil midstream and underground runoff. It comprehensively considers factors such as evapotranspiration and soil water storage capacity, and describes the runoff generation and convergence process of rainfall in the basin through a series of equations and parameters. The modeling ideas and model structure of the Xin'anjiang model reflect the law of runoff formation in humid areas, so it is used as a basic model to correctly simulate the hydrological process of the basin; S22. Using the principle of hydrological similarity, find the reference basin (basin with data) of the target basin (basin without data) through basin attributes, and use the model calibration parameters of the basin with existing data to deduce the model parameters of the sub-basin without data; use the overland flow velocity calculation formula, combined with the slope and flow direction data of each sub-basin, calculate the confluence time of each point in the basin to the basin outlet, and extract the confluence characteristic parameters such as the standard unit line of each sub-basin; According to the geomorphic unit line theory, the probability density distribution of the time for each point in the basin to reach the outlet of the basin is equivalent to the instantaneous unit line, and the distance from each point in the basin to the outlet of the basin is known, so in order to obtain the confluence time, the key issue is the calculation of flow velocity; This model uses the following formula to determine the slope flow velocity:

[0037] in, is the slope velocity, To reflect the empirical coefficient of slope roughness, It is the slope along the direction of water flow at a certain point in the basin.

[0038] In addition, it is necessary to explain that the construction of the hydrological model here first builds the aggregation of the entire basin and then builds the aggregation of the sub-basins.

[0039] Step S3: Based on the alternating implicit ADI algorithm, a two-dimensional hydrodynamic model is constructed and the model parameters are calibrated.

[0040] At this time, it is necessary to build a two-dimensional hydrodynamic calculation model and optimize its roughness value. The specific operation process includes: S31. Use GIS software to stitch and integrate river sections with high-precision DEM data, and consider the impact of levees, weirs, bridges, culverts, roads, and houses, further correct the elevation data, and finally generate a detailed and accurate digital terrain model DTM covering the flood calculation area.

[0041] S32. Perform operations such as registration, cropping, and resampling on the land use type data to make its coordinate system and pixel size consistent with the DTM, and preliminarily prepare the model partition roughness file according to the land use type.

[0042] S33. Based on DTM and partition roughness file, the two-dimensional hydrodynamic model is developed by using alternating implicit ADI algorithm and OpenMP parallel computing technology.

[0043] At this time, the implicit and explicit alternating finite difference method is used to discretize the mass and momentum equations, and the equation matrices generated in each direction are solved using the pursuit method. In order to reduce the calculation time, the OpenMP directive is used to parallelize the calculation-intensive for loop. The specific content is as follows: The ADI algorithm divides a time step into two half steps. The first half step uses implicit and explicit formats in the x and y directions respectively, and the second half step uses explicit and implicit formats in the x and y directions respectively. The original more complex set of equations is transformed into two tridiagonal sets of equations, and the two-dimensional problem is decomposed into two one-dimensional implicit problems in each time step, and solved by the pursuit method. This reduces the complexity of the calculation to a certain extent, reduces the amount of calculation, can quickly obtain numerical solutions, and has good numerical stability.

[0044] The central difference method is used to discretize and solve the equations in the x and y directions respectively through one-dimensional advancement.

[0045] It should also be noted that the two-dimensional hydrodynamic model is based on the Saint-Venant equation, which can describe the two-dimensional flow characteristics of floods on a plane, taking into account the horizontal flow velocity, water level changes, and interaction with terrain and buildings, and accurately simulating the evolution and spread of floods in complex terrain areas, including the flooding range, depth and flow velocity distribution.

[0046] S34. Taking the flow process calculated by the hydrological model in the above steps as the upper boundary and the measured water level process at the outlet station of the basin as the lower boundary, the inundation situation of typical flood years is reproduced, and the roughness value is further optimized using historical flood marks and inundation range data.

[0047] Step S4: Couple the Sanshuiyuan Xin'anjiang model with the two-dimensional hydrodynamic model to realize the inundation calculation of the whole process of runoff generation-confluence-evolution-overflow.

[0048] The specific calculation process includes: S41. Plot the relationship between water level and flow at the outlet of the basin, fit the water level and flow relationship curve using the least squares method, and use it as the lower boundary of the model; S42. Implement serial calculation of hydrological model and hydrodynamic model in the form of point source and line source. First, calculate runoff through hydrological model to obtain the flow process of each sub-basin outlet under specific rainfall conditions, and then obtain the flooding range, water depth, duration and other factors through hydrodynamic model.

[0049] The hydrological and hydrodynamic coupling model used in this application is a method that organically combines the basin hydrological model with the hydrodynamic model to accurately simulate and analyze the basin's hydrological processes and flood evolution.

[0050] At the same time, when the models are coupled, the basin outlet flow process calculated by the Sanshuiyuan Xin'anjiang model is generally used as the inflow boundary condition of the two-dimensional hydrodynamic model to provide it with the initial flood flow and process. At the same time, the two-dimensional hydrodynamic model will also feedback information such as the impact of floods on the basin underlying surface, which is used as input parameters for further calculations of the Sanshuiyuan Xin'anjiang model to achieve information interaction and collaborative calculation.

[0051] This coupled model combines the advantages of the three-source Xin'anjiang model in basin runoff calculation and the high-precision characteristics of the two-dimensional hydrodynamic model in flood evolution simulation. It can not only accurately simulate the runoff of different water sources in the basin, but also finely depict the dynamic evolution and inundation of floods in space. It can be widely used in flood forecasting, flood prevention and disaster reduction, water resources management and other fields, providing a more comprehensive and accurate scientific basis for relevant decision-making.

[0052] In a specific embodiment, taking region H as an example, region H is a humid mountainous area with complex terrain. One group of mountains rises high in the northwest, and another group of mountains blocks the southeast. The area of ​​mountains and hills is vast, and the overall terrain is dominated by mountainous areas.

[0053] In view of the flood characteristics in this area, a modeling approach combining hydrology and hydrodynamics is adopted to establish a hydrological and hydrodynamic coupling model that can adapt to complex water flow conditions and flood scheduling requirements such as the interlaced river network of main and tributary rivers, backwater support, storage and discharge.

[0054] Based on the research of mathematical models, scenario simulation and historical flood re-enactment are used to simulate the entire evolution process of floods from formation, development to extinction, so as to accurately predict the possible scope and depth of flooding, and provide scientific basis and technical support for optimizing the layout of management projects and flood prevention and disaster reduction.

[0055] refer to Figure 1 , the above-mentioned flood inundation calculation method applicable to humid mountainous areas is used to simulate the calculation operation of area A, and the specific operation steps are as follows: S1: Collect geographic information data of the Xin'an River Basin within the scope of H area, relevant data of hydrological stations and water conservancy engineering facilities in the basin, and divide the basin into sub-basins, and use this to select the calculation range of the hydrological model and hydrodynamic model. Combined with the inundation of historical mountain torrents, determine the calculation range of the hydrological model and hydrodynamic model and the spatial location of the coupling between the two. Divide the target area into sub-basins and determine the calculation range of the hydrological model and hydrodynamic model.

[0056] The geographic information data collected at this time is as follows Figure 2The sub-basin division results are shown in the following table:

[0057] S2: The Sanshuiyuan Xin'anjiang model is selected as the basic model in the study area, and the Xin'anjiang model and the comprehensive unit line rate determination system are developed. The water volume error, peak error, logarithmic error, process matching degree and certainty coefficient are selected as the objective function, and the parameters of the model are systematically identified and rate determined by combining manual optimization and computer automatic optimization. At this time, the parameters of the basin secondary flood model are as follows:

[0058] In addition, there is a statistical table of calculation errors in the simulation of the basin secondary flood model:

[0059] Combining the above data, we can further obtain Figure 3 Schematic diagram of the inflow flow process of each sub-basin, Figure 3 (a) shows the inflow process of sub-basin A in region H. Figure 3 (b) shows the inflow process of sub-basin B in region H. Figure 3 (c) is the inflow process of sub-basin C in region H. Figure 3 (d) shows the inflow process of sub-basin D in region H.

[0060] S3: Use ArcGIS software to stitch and integrate the river section with high-precision DEM data, and consider the impact of levees, weirs, bridges, culverts, roads, and houses to further correct the elevation data, and finally generate a detailed and accurate DTM covering the flood calculation area.

[0061] Download the study area data from the professional land use data website, and make the coordinate system and pixel size of the land use data consistent with the DTM through operations such as registration, cropping, and resampling. Figure 5 The model partition roughness file shown in the figure is used in the two-dimensional hydrodynamic model. The flow process calculated by the hydrological model is used as the upper boundary, and the measured water level process at the designated hydrological station at the outlet of the basin is used as the lower boundary. The flooding situation in the typical year of 2022 is reproduced, and the initial roughness is further optimized using historical flood marks and flooding range data to obtain the following: Figure 4 Final DTM data shown.

[0062] Taking sub-basin A as an example, the comparison analysis of the flood mark elevation calculated by the model and the actual measurement (partial) is shown in the following table and Figure 6 shown.

[0063]

[0064] S4: Plot the relationship between the water level and flow rate of the designated hydrological station, fit the water level and flow rate relationship curve using the least squares method, and use it as the lower boundary of the model; realize the serial calculation of the hydrological model and the hydrodynamic model in the form of point source and line source, first calculate the runoff through the hydrological model to obtain the flow process of the outlet of each sub-basin under specific rainfall conditions, and then obtain the flooding range, water depth, duration and other elements through the hydrodynamic model.

[0065] The 48-hour flood evolution process is shown in the figure below: Figures 7 to 10 As shown, in Figure 7 Middle: (a) is the water level and flooding range at time 0; (b) is the water level and flooding range at time 24; (c) is the water level and flooding range at time 36; (d) is the water level and flooding range at time 42.

[0066] At the same time, the maximum flooding range is Fig.11 shown.

[0067] According to the scope and depth of flooding, different areas can be divided into risk zones. Areas that are extremely susceptible to flooding and have a large flooding depth are high-risk areas, usually low-lying areas along the river, areas close to the downstream of the reservoir and with obvious flood discharge effects. Once these areas encounter floods, they may be covered by a large amount of water in a short period of time, posing a serious threat to the safety of life and property of residents, and houses and infrastructure are extremely vulnerable to devastating damage. The possibility of flooding in medium-risk areas is relatively low, and the flooding depth is relatively shallow. Generally, it will only be affected when the flood flow is large, such as some areas that are a certain distance away from the river but have relatively flat terrain. However, when the flood lasts for a long time, deeper water may also appear, affecting the normal life of residents and the operation of some facilities. Low-risk areas are areas that are basically not flooded under normal flood conditions, and may only be slightly affected in extreme flood events, such as mountainous highlands with high terrain and far away from the water system. After clearly dividing different risk areas, targeted flood prevention and disaster reduction strategies can be formulated. For high-risk areas, it is necessary to strengthen the construction of flood control projects, such as building solid dams and improving drainage capacity. At the same time, residents' evacuation routes and resettlement sites should be planned in advance, and flood control drills should be carried out regularly to improve residents' emergency risk avoidance capabilities. Medium-risk areas should focus on the maintenance and upgrading of flood control facilities, strengthen flood monitoring and early warning, and guide residents to make certain flood prevention preparations. Although low-risk areas are less threatened by floods, they should not be taken lightly. Residents should be educated on flood prevention knowledge, and the public's awareness of flood prevention should be raised to ensure timely response in extreme cases.

[0068] In the above embodiment, the flow path and inundation range of floods in complex terrain can be accurately simulated, providing strong support for the division of risk areas; it has strong adaptability to the special hydrological conditions in humid mountainous areas, and can combine the temporal and spatial distribution of precipitation and the interaction of water bodies to realize the calculation of the whole process from rainfall to inundation range, accurately simulate the evolution of floods, and reliably predict inundation conditions. In terms of data acquisition, it does not rely on complex parameters, and accurate calculations can be achieved by integrating easily accessible data, which is conducive to carrying out simulation work in mountainous areas with limited monitoring sites. In addition, this method has high timeliness, effectively improves the calculation efficiency while ensuring the accuracy of calculation simulation, and efficiently quantifies the maximum inundation range of mountain basins.

[0069] On the other hand, the present invention further discloses a computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes the steps of the above method.

[0070] On the other hand, the present invention further discloses a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the above method.

[0071] In another embodiment provided in the present application, a computer program product including instructions is also provided, which, when executed on a computer, enables the computer to execute any of the flood inundation calculation methods in the above embodiments applicable to humid mountainous areas.

[0072] It is understandable that the system provided by the embodiment of the present invention corresponds to the method provided by the embodiment of the present invention, and the explanation, examples and beneficial effects of the relevant contents can refer to the corresponding parts in the above method.

[0073] The embodiment of the present application also provides an electronic device, including a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other through the communication bus. Memory, used to store computer programs; The processor is used to implement the above-mentioned flood inundation calculation method applicable to humid mountainous areas when executing the program stored in the memory.

[0074] The communication bus mentioned in the above electronic device may be a Peripheral Component Interconnect (PCI) bus or an Extended Industrial Standard Architecture (EISA) bus, etc. The communication bus may be divided into an address bus, a data bus, a control bus, etc.

[0075] The communication interface is used for communication between the above electronic device and other devices.

[0076] The memory may include a random access memory (RAM) or a non-volatile memory (NVM), such as at least one disk memory. Optionally, the memory may also be at least one storage device located away from the aforementioned processor.

[0077] The above-mentioned processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0078] It should also be noted that electronic devices also include terminal devices, which can also be called terminals, user equipment, mobile stations, mobile terminals, etc. Terminal devices can be mobile phones, smart TVs, wearable devices, tablet computers, computers with wireless transceiver functions, virtual reality terminal devices, augmented reality terminal devices, wireless terminals in industrial control, wireless terminals in unmanned driving, wireless terminals in remote surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, etc. The embodiments of this application do not limit the specific technology and specific device form used by the terminal devices.

[0079] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line DSL) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive Solid State Disk), etc.

[0080] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

[0081] In addition, it should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0082] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or schemes that A and B meet at the same time. In addition, in the embodiments of the present invention, "multiple" refers to more than two. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

Claims

1. A flood inundation calculation method suitable for humid mountainous areas, characterized in that: include: S1. Divide the target area into sub-basins and set the model calculation range; S2. Based on the framework of the Xin'anjiang model of the Three Water Sources, a lumped hydrological model of each sub-basin is constructed. Through hydrological similarity analysis and calculation of the runoff unit line of each sub-basin, the runoff parameters of the hydrological model are calibrated, and the calibrated model parameters are transplanted to each sub-basin; S3. constructing a two-dimensional hydrodynamic model and optimizing the model roughness value, the roughness value is used to calibrate the model parameters of the two-dimensional hydrodynamic model; S4. Couple the Sanshuiyuan Xin'anjiang model with the two-dimensional hydrodynamic model to perform inundation calculations for the entire process of runoff generation-confluence-evolution-overflow.

2. The flood inundation calculation method applicable to humid mountainous areas as claimed in claim 1, characterized in that: The specific operation process of the S2 step includes: S21. Select the designated Sanshuiyuan Xin'anjiang model as the basic model, select the water volume error, peak error, logarithmic error, process fit degree and certainty coefficient as the objective function, and perform systematic identification on the model parameters; S22. Using the hydrological similarity principle, find the reference basin of the model target basin through basin attributes, and use the model calibration parameters of the reference basin to deduce the model parameters of the target basin; S23. Using the slope flow velocity calculation formula, combined with the slope and flow direction data of each sub-basin, calculate the confluence time of each point in the basin to the basin outlet, and extract the confluence characteristic parameters of each sub-basin; S24. Use the runoff characteristic parameters to calibrate the hydrological model and transplant the calibrated model to each sub-basin.

3. The flood inundation calculation method applicable to humid mountainous areas as claimed in claim 2, characterized in that: The slope flow velocity calculation formula in step S23 is: in, is the slope velocity, To reflect the empirical coefficient of slope roughness, It is the slope along the direction of water flow at a certain point in the basin.

4. The flood inundation calculation method applicable to humid mountainous areas as claimed in claim 1, characterized in that: The specific operation process of constructing a two-dimensional hydrodynamic model and optimizing the model roughness value in step S3 includes: S31. Combine the river section with the high-precision DEM data and correct the elevation data to generate a digital terrain model DTM covering the flood calculation area; S32. Perform registration, clipping, and resampling operations on the land use type data to make the data coordinate system consistent with the pixel size and DTM, and then create a model partition roughness file according to the land use type; S33. Based on DTM and partition roughness file, the two-dimensional hydrodynamic model is developed by using alternating implicit ADI algorithm and OpenMP parallel computing technology; S34. The flow process calculated by the hydrological model is taken as the upper boundary, and the measured water level process at the outlet station of the basin is taken as the lower boundary. The inundation situation of typical flood years is reproduced, and the roughness value is optimized using historical flood marks and inundation range data.

5. The flood inundation calculation method applicable to humid mountainous areas as claimed in claim 4, characterized in that: The specific operation process of developing the two-dimensional hydrodynamic model in step S33 includes: L1. The two-dimensional Saint-Venant equation is used as the basic equation for hydrodynamic calculation. In the Cartesian coordinate system, the vector form of the equation is expressed as: in: is the spatial horizontal coordinate, is the spatial ordinate, For time, is the source term vector; is a variable vector, including the water level And single width flow , ; , is the flux vector, including the water depth , , Direction and Flow rate on is Xie Cai coefficient, is the Manning coefficient; L2. The mass and momentum equations are discretized by implicit and explicit alternating finite difference method, and the equation matrices generated in each direction are solved by pursuit method.

6. The flood inundation calculation method applicable to humid mountainous areas as claimed in claim 5, characterized in that: The specific data calculation method of the L2 step includes: L21. Divide a time step into two half steps. The first half step uses implicit and explicit formats in the x and y directions respectively, and the second half step uses explicit and implicit formats in the x and y directions respectively. The original more complex system of equations is transformed into two tridiagonal systems of equations, and the two-dimensional problem is decomposed into two one-dimensional implicit problems at each time step. L22. The central difference pursuit method is used to discretize and solve the continuity equation and momentum equation in the x and y directions respectively through one-dimensional advancement.

7. The flood inundation calculation method applicable to humid mountainous areas as claimed in claim 1, characterized in that: The specific operation process of the S4 step includes: S41. Plot the relationship between water level and flow at the outlet of the basin, fit the water level and flow relationship curve using the least squares method, and use it as the lower boundary of the model; S42. Calculate the hydrological model and hydrodynamic model in series in the form of point source and line source, calculate the confluence through the hydrological model, obtain the flow process of each sub-basin outlet under specified rainfall conditions, and then obtain the characteristic elements including the scope, water depth and duration of flooding through the hydrodynamic model.

8. The flood inundation calculation method applicable to humid mountainous areas as claimed in claim 1, characterized in that: In the runoff calculation of the whole basin lumped hydrological model, the subsurface flow and underground runoff are regulated by the linear reservoir method, and the surface runoff is regulated by the Nash unit line, and the formula is: in, is the instantaneous unit line; is the number of linear reservoirs; is the regulation coefficient for each reservoir; For instantaneous time.

9. A computer-readable storage medium, characterized in that: A computer program is stored, and when the computer program is executed by a processor, the processor is caused to perform the steps of the method according to any one of claims 1 to 8.

10. A computer device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method according to any one of claims 1 to 8.

Images