A flood inundation calculation method, device and medium applicable to humid mountainous areas

Abstract

The present invention discloses a flood inundation calculation method, device and medium applicable to humid mountainous areas, including: S1. Divide the target area into sub-watersheds and set the model calculation range; S2. Based on the framework of the three-source Xin'anjiang model, construct a lumped hydrological model for each sub-watershed. Through hydrological similarity analysis and the calculation of the unit hydrograph of each sub-watershed, calibrate the runoff generation and concentration parameters of the hydrological model, and transplant the calibrated model parameters to each sub-watershed; S3. Based on the alternating implicit ADI algorithm, construct a two-dimensional hydrodynamic model and optimize the roughness value of the model. The roughness value is used to calibrate the model parameters of the two-dimensional hydrodynamic model; S4. Couple the three-source Xin'anjiang model with the two-dimensional hydrodynamic model to perform inundation calculations for the entire process of runoff generation - concentration - evolution - overtopping. The present invention can accurately simulate the evolution and overtopping of floods under complex terrain, and accurately calculate the flood inundation range, depth and water flow states at different times.

Description

Technical Field

[0001] The present invention relates to the technical field of disaster simulation and prediction, and particularly to a flood inundation calculation method, device and storage medium applicable to humid mountainous areas. Background Technique

[0002] Mountain torrents are natural disasters triggered by high-intensity rainfall. Affected by the complex terrain and hydrometeorological disaster-forming environments in humid mountainous areas, mountain torrent events are widespread in terms of points and areas, with large spatio-temporal variations, high non-linearity, randomness and complexity, making it difficult to perform quantitative calculations. At the same time, traditional flood inundation calculation methods are mostly based on flat areas for modeling, and it is difficult to describe the water flow movement laws under the influence of multiple factors such as large terrain undulations, diverse soil types and high vegetation coverage in humid mountainous areas, resulting in large deviations in the calculation results of flood inundation ranges and depths.

[0003] In addition, for mountain flood inundation calculations, common methods all have certain pertinence and limitations:

[0004] (1) Determining the inundation situation based on historical flood data and measured data, and establishing empirical relationships between factors such as flood inundation range, depth and flood discharge, water level, etc., which can be used for mountain flood inundation calculations. However, it is obtained based on limited historical data of a specific basin, and its accuracy decreases when extended to other regions, with limited generality and accuracy;

[0005] (2) Conventional hydrological models process spatial information based on remote sensing tools such as Arcgis to obtain a large number of basic hydrological parameters, which can reflect the runoff generation and concentration processes under the conditions of uneven underlying surface conditions and rainfall spatial distribution. Conduct runoff generation and concentration calculations based on the rainfall-runoff process to achieve flood forecasting in mountainous basins. However, limited by the accuracy of basin geometric data, the parameters have strong uncertainties and it is difficult to reflect the water flow dynamic characteristics during flood evolution;

[0006] (3) Conventional hydrodynamic models describe the movement of flood waves in rivers, considering the influence of various complex factors such as terrain and landform, water flow resistance, and the interaction of river networks, etc., which can describe the movement and evolution laws of floods in rivers, and analyze the flood inundation range and dynamic inundation process, but do not consider the natural hydraulic connection between mountainous basins and rivers;

[0007] (4) Integrating the respective advantages of hydrological models and hydrodynamic models, coupling hydrological and hydrodynamic models to simulate mountainous rainstorm runoff and flood inundation conditions, which can meet the high-precision calculation of runoff simulation and the whole process of flood inundation in humid mountainous basins, and achieve 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 complex, and the computer performance requirements are relatively high to ensure both efficiency and accuracy. Moreover, the determination and verification of model parameters require certain professional knowledge and experience, and the workload is relatively large.

[0008] To this end, this application specifically proposes a flood inundation calculation method applicable to humid mountainous areas to solve the above technical problems. Summary of the Invention

[0009] The main purpose of the present invention is to provide a flood inundation calculation method applicable to humid mountainous areas to solve the technical problems proposed in the background art.

[0010] The present invention adopts the following technical solutions to solve the above technical problems:

[0011] A flood inundation calculation method applicable to humid mountainous areas comprehensively uses the hydrological and hydrodynamic model algorithms, simulates the entire evolution process of flood from formation, development to extinction, and can accurately predict the possible inundation range and depth of the flood, including the following specific operation steps:

[0012] S1. Divide the target area into sub-basins and set the calculation ranges of the hydrological model and the hydrodynamic model;

[0013] S2. Based on the framework of the three-source Xin'anjiang model, construct a lumped hydrological model for each sub-basin. Through hydrological similarity analysis and the calculation of the unit hydrograph of each sub-basin, calibrate the runoff generation and concentration parameters of the hydrological model, and transplant the calibrated model parameters to each sub-basin;

[0014] S3. Based on the alternating implicit ADI algorithm, construct a two-dimensional hydrodynamic model and optimize the roughness value of the model. The roughness value is used to calibrate the model parameters of the two-dimensional hydrodynamic model;

[0015] S4. Couple the three-source Xin'anjiang model with the two-dimensional hydrodynamic model to perform the inundation calculation of the whole process of runoff generation - concentration - evolution - overtopping.

[0016] Preferably, the specific operation process of step S1 includes:

[0017] S11. Collect and organize the 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, flow elements, etc.), flood mark data during historical floods, and river system topographic section data;

[0018] S12. Based on the geographic information GIS software, integrate multiple scattered original DEM data blocks into a complete DEM covering the required study area of the user through coordinate matching and data fusion algorithms;

[0019] S13. Use hydrological analysis tools to perform operations such as filling depressions, slope, and flow direction on the DEM in sequence, divide the entire study area into different sub-basins, and analyze the unit hydrograph of each sub-basin;

[0020] S14. Investigate the historical mountain flood disasters and flood inundation conditions in the study area, delimit the danger zones, and determine the calculation scope of the hydrodynamic model.

[0021] Preferably, the specific operation process of the S2 step includes:

[0022] S21. Select the three-source Xin'anjiang model, which performs well in humid regions, as the basic model, and develop a calibration system for the Xin'anjiang model and the synthetic unit hydrograph. Select the water volume error, peak error, logarithmic error, process matching degree, and coefficient of determination as the objective functions, and adopt a method combining manual optimization and computer automatic optimization to systematically identify the parameters of the model;

[0023] S22. Utilize the hydrological similarity principle to find the reference basin (basin with data) of the target basin (basin without data) through basin attributes, and use the calibrated parameters of the model in the basin with existing data to deduce the model parameters of the sub-basins without data;

[0024] S23. Use the formula for calculating the overland flow velocity, combine the slope and flow direction data of each sub-basin, calculate the concentration time for each point in the basin to reach the basin outlet, and extract the concentration characteristic parameters of each sub-basin;

[0025] S24. Use the concentration characteristic parameters to calibrate the hydrological model, and transplant the calibrated model to each sub-basin.

[0026] Preferably, the formula for calculating the overland flow velocity in the S23 step is:

[0027]

[0028] Where is the overland flow velocity, is the empirical coefficient reflecting the overland roughness, is the slope of a certain place in the basin along the water flow direction.

[0029] Preferably, the specific operation process of constructing a two-dimensional hydrodynamic model and optimizing the roughness value of the model in the S3 step includes:

[0030] S31. Use GIS software to splice and integrate the river channel cross-section and high-precision DEM data, and consider the impacts of levees, weirs, bridges, culverts, roads, and houses to further correct the elevation data, and finally generate a detailed, accurate digital terrain model DTM covering the flood inundation calculation area;

[0031] 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 make a roughness file for model zoning according to the land use type;

[0032] S33. Based on the DTM and the sectional roughness coefficient file, develop a two-dimensional hydrodynamic model by using the alternating direction implicit (ADI) algorithm and the OpenMP parallel computing technology.

[0033] S34. Using the flow process calculated by the hydrological model as the upper boundary and the measured water level process at the basin outlet station as the lower boundary, reproduce the inundation situation of the flood in a typical year, and optimize the roughness coefficient value by using the historical flood marks and inundation area data.

[0034] Preferably, the specific operation process of developing the two-dimensional hydrodynamic model in step S33 includes:

[0035] L1. Use the two-dimensional Saint-Venant equation as the basic equation for hydrodynamic calculation. In the Cartesian coordinate system, the vector form of the equation is expressed as:

[0036]

[0037]

[0038]

[0039] Where: is the spatial abscissa, is the spatial ordinate, is the time, is the source term vector;

[0040] is the variable vector, including the water level and the discharge per unit width 、 ;

[0041] 、 are the flux vectors, including the water depth , 、 are the flow velocities in the directions and respectively;

[0042] is the Chezy coefficient, is the Manning coefficient;

[0043] L2. Discretize the mass and momentum equations by using the implicit-explicit alternating finite difference method, and solve the equation matrices generated in each direction by using the chase method.

[0044] Preferably, to reduce the calculation time, use the OpenMP instruction to perform parallel acceleration on the computationally intensive for loop.

[0045] Preferably, the specific data calculation method in step L2 includes:

[0046] L21. Divide one time step into two half steps. In the first half step, use implicit and explicit formats in the x and y directions respectively, and in the second half step, use explicit and implicit formats in the x and y directions respectively. Transform the original relatively complex system of equations into two tridiagonal systems of equations, and decompose the two-dimensional problem into two one-dimensional implicit problems at each time step.

[0047] L22. Adopt the central difference chasing method, and discretize and solve the continuity equation and momentum equation in the x and y directions respectively by means of one-dimensional advancement.

[0048] Preferably, the specific calculation process for discretizing and solving the continuity equation and momentum equation in step L22 includes:

[0049] When solving the continuity equation and momentum equation in the x direction, From n to n + 1 / 2, From n to n + 1, The values from n + 1 to n + 1 / 2 are known; 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 from the previous calculation;

[0050] Taking the x direction as an example, its continuity equation can be discretized as:

[0051]

[0052] Discretize the momentum equation:

[0053]

[0054] After arrangement, the difference equation form is:

[0055]

[0056] The formed tridiagonal matrix equation can be solved by the chasing method;

[0057] Similarly, the continuity equation and momentum equation in the y direction can be discretized and solved with reference to the above method.

[0058] Preferably, the specific operation process of step S4 includes:

[0059] S41. Plot the water level - discharge relationship of the basin outlet station, fit the water level - discharge relationship curve using the least - squares method, and use it as the lower boundary of the model.

[0060] S42. Calculate the hydrological model and hydrodynamic model in series in the form of point sources and line sources. Calculate the confluence through the hydrological model to obtain the flow process at the outlets of each sub-basin under specified rainfall conditions, and then obtain characteristic elements such as the inundation range, water depth, and duration through the hydrodynamic model.

[0061] On the other hand, the present invention also discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to execute the steps of the above method.

[0062] On yet another aspect, the present invention also discloses a computer device including a memory and a processor, where the memory stores a computer program, which, when executed by the processor, causes the processor to execute the steps of the above method.

[0063] As can be seen from the above technical solutions, the present invention provides a method for calculating flood inundation applicable to humid mountainous areas. Compared with the prior art, the present invention has the following advantages:

[0064] 1. By coupling the three-source Xin'anjiang model with the two-dimensional hydrodynamic model, the present invention can accurately simulate the evolution and overtopping of floods under complex terrains. Compared with single models or simple empirical calculation methods, it can more accurately calculate the flood inundation range, depth, and water flow states at different times, providing reliable data for flood control and disaster reduction decisions.

[0065] 2. Designed for humid mountainous areas, after sub-basin division, the present invention uses hydrological similarity analysis and the geomorphic unit hydrograph method to transplant and calibrate the parameters of the lumped hydrological model, which can fully consider the characteristics of abundant precipitation, complex terrain, and developed water systems in humid mountainous areas, thereby improving the modeling efficiency and accuracy. At the same time, it fully considers the effect of the terrain complexity in humid mountainous areas, avoiding the limitations of general methods when applied in special regions.

[0066] 3. By adopting the alternating implicit ADI algorithm and OpenMP parallel computing technology in the two-dimensional hydrodynamic modeling process, the present invention can optimize the roughness coefficient value of the model and improve the solution efficiency, while reducing the calculation time-consuming and ensuring the calculation accuracy.

[0067] 4. By using the linear reservoir method to regulate the subsurface flow and groundwater runoff in the confluence calculation and using the geomorphic unit hydrograph method to obtain the confluence characteristic parameters of each sub-basin, the present invention can accurately reflect the generation mechanisms of different water sources, thereby obtaining runoff-confluence calculation results closer to the actual situation, facilitating the complete display of the dynamic process of floods from generation to inundation.

[0068] 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 used to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. Of course, any product implementing the present invention does not necessarily need to achieve all the advantages described above simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic 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:

[0070] Figure 1 is a schematic diagram of the overall method operation system of the present invention;

[0071] Figure 2 is a schematic diagram of the basin geographic information data GIS of the present invention;

[0072] Figure 3 is a flow process diagram of each tributary of the present invention;

[0073] Figure 4 is a schematic diagram of the final DTM data of the present invention;

[0074] Figure 5 is a schematic diagram of the distributed roughness file display of the present invention;

[0075] Figure 6 is a schematic diagram of the comparison and analysis of the elevation of the flood mark points calculated by the model and the actual measurement of the present invention;

[0076] Figure 7 is a schematic diagram of the water level and inundation range at 0 o'clock during the flood routing process of the present invention;

[0077] Figure 8 is a schematic diagram of the water level and inundation range at 24 o'clock during the flood routing process of the present invention;

[0078] Figure 9 is a schematic diagram of the water level and inundation range at 36 o'clock during the flood routing process of the present invention;

[0079] Figure 10 is a schematic diagram of the water level and inundation range at 42 o'clock during the flood routing process of the present invention;

[0080] Figure 11 is a schematic diagram of the comparison of the maximum inundation range of the model of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0081] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0082] In the embodiment, specifically refer to Figures 1 to 11 .

[0083] A humid mountainous area generally refers to an area with humid climate, abundant precipitation and mainly mountainous terrain. It has lush vegetation, rich species, a forest coverage rate usually above 60%, diverse soil types, and important ecological protection value. However, flash floods occur frequently with strong destructive power, and are difficult to accurately predict, forecast and prevent, which are extremely likely to cause serious casualties and property losses. It has always been the focus and difficulty of flood and drought disaster prevention. The inundation range of flash floods is the basis of flash flood prevention and control planning. Simulating and analyzing the inundation situation during flash floods is an important means for flash flood disaster assessment and an important data basis for emergency response and disaster relief.

[0084] As Figure 1 shown. The flood inundation calculation method applicable to humid mountainous areas proposed in the embodiments of the present invention includes the following steps:

[0085] Step S1: Collect spatial geographic information data, hydrological monitoring station data and water conservancy project data, combine with the inundation situation of historical flash floods, determine the calculation ranges of the hydrological model and the hydrodynamic model and the spatial positions of their coupling and connection, divide the target area into sub-basins, and determine the calculation ranges of the hydrological model and the hydrodynamic model.

[0086] Specifically, the data collection process includes:

[0087] S11. Collect and sort out the 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 the observation data of monitoring stations, including rainfall, water level and flow elements, etc.; collecting flood mark data during historical floods; collecting river system topographic cross-section data;

[0088] S12. Use GIS software to integrate multiple scattered original DEM data blocks into a complete DEM covering the required study area of the user through accurate coordinate matching and data fusion algorithms;

[0089] S13. Use hydrological analysis tools to successively conduct treatments such as depression filling, slope, and flow direction on the DEM, divide the entire study area into different sub-basins, and analyze the unit hydrograph of confluence for each sub-basin. Here, the overland flow formula is used for the confluence of sub-basins.

[0090] S14. Investigate the historical mountain flood disasters and flood inundation conditions in the study area, delimit the danger zones, and determine the calculation scope of the hydrodynamic model.

[0091] Step S2: Based on the framework of the three-source Xin'anjiang model, construct a lumped hydrological model for each sub-basin. Through hydrological similarity analysis and the calculation of the unit hydrograph of confluence for each sub-basin, calibrate the runoff generation and confluence parameters of the hydrological model, and transplant the calibrated model parameters to each sub-basin.

[0092] The specific operation process of constructing the hydrological model for each sub-basin and identifying parameters includes:

[0093] S21. Select the three-source Xin'anjiang model, which performs well in humid regions, as the basic model, and develop a calibration system for the Xin'anjiang model and the synthetic unit hydrograph. Select the water volume error, peak error, logarithmic error, process matching degree, and coefficient of determination as the objective functions, and use a combination of manual optimization and computer automatic optimization methods to systematically identify the parameters of the model.

[0094] It should be noted that the lumping of the entire basin mainly aims to obtain runoff generation parameters. In the confluence calculation of the lumped hydrological model for the entire basin, the interflow and baseflow are regulated by the linear reservoir method to obtain the outflow process, and the surface runoff uses the Nash unit hydrograph (only for the confluence of the entire basin). Its formula is:

[0095]

[0096] Among them, is the instantaneous unit hydrograph; is the number of linear reservoirs; is the regulation coefficient of each reservoir; is the instantaneous time; The product of and

[0097] has the dimension of time and is a measure of the basin confluence time.

[0098] S22. Using the principle of hydrological similarity, the reference basin (basin with data) for the target basin (basin without data) is found through basin attributes, and the model parameters of the sub-basins without data are derived by calibrating the parameters of the model using the data of the existing data basin; using the calculation formula for overland flow velocity, combined with the slope and flow direction data of each sub-basin, the concentration time for each point in the basin to reach the basin outlet is calculated, and the concentration characteristics parameters such as the standard unit hydrograph of each sub-basin are extracted;

[0099] According to the theory of geomorphic unit hydrograph, the probability density distribution of the concentration time for each point in the basin to reach the basin outlet is equivalent to the instantaneous unit hydrograph, and the distance from each point in the basin to the basin outlet is known. Therefore, the key issue for obtaining the concentration time is the calculation of velocity;

[0100] The following formula is used in this model to determine the overland flow velocity:

[0101]

[0102] where, is the overland flow velocity, is the empirical coefficient reflecting the overland roughness, is the slope of a certain place on the basin along the water flow direction.

[0103] In addition, it should be explained that for the construction of the hydrological model here, the lumping of the entire basin is first carried out, and then the lumping of the sub-basins is carried out.

[0104] Step S3: Based on the alternating direction implicit (ADI) algorithm, a two-dimensional hydrodynamic model is constructed and the model parameters are calibrated.

[0105] At this time, a two-dimensional hydrodynamic calculation model needs to be constructed and its roughness value optimized. The specific operation process includes:

[0106] S31. Using GIS software, splice and integrate the river cross-section and high-precision DEM data, and considering the impacts 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 inundation calculation area.

[0107] S32. Perform operations such as registration, clipping, and resampling on the land use type data to make its coordinate system and pixel size consistent with the DTM, and initially create a model zoning roughness file according to the land use type.

[0108] S33. Based on the DTM and the zoning roughness file, use the alternating direction implicit (ADI) algorithm and OpenMP parallel computing technology to develop a two-dimensional hydrodynamic model.

[0109] At this time, the implicit-explicit alternating finite difference method is used to discretize the mass and momentum equations, and the equation matrices generated in each direction are solved by the tridiagonal matrix algorithm. To reduce the calculation time, OpenMP instructions are used to parallelize and accelerate the computationally intensive for loops. The specific content is as follows:

[0110] The ADI algorithm divides a time step into two half steps. In the first half step, implicit and explicit formats are used in the x and y directions respectively, and in the second half step, explicit and implicit formats are used in the x and y directions respectively. This simplifies the original complex system of equations into two tridiagonal systems of equations, decomposes the two-dimensional problem into two one-dimensional implicit problems at each time step, and solves them using the tridiagonal matrix algorithm. This reduces the computational complexity to a certain extent, decreases the amount of calculation, can quickly obtain the numerical solution, and has good numerical stability at the same time.

[0111] The central difference method is adopted, and the equations are discretized and solved in the x and y directions by one-dimensional advancement.

[0112] In addition, it should be noted that the two-dimensional hydrodynamic model is based on the Saint-Venant equations, can describe the two-dimensional flow characteristics of floods on the plane, takes into account the flow velocity, water level changes in the horizontal direction and the interaction with the terrain and buildings, and accurately simulates the evolution and diffusion of floods in complex terrain areas, including the inundation range, depth and velocity distribution, etc.

[0113] S34. Using the flow process calculated by the hydrological model in the above steps as the upper boundary and the measured water level process at the basin outlet station as the lower boundary, the inundation situation of the flood in a typical year is reproduced, and the roughness coefficient value is further optimized using historical flood marks and inundation range data.

[0114] Step S4: Couple the three-source Xin'anjiang model with the two-dimensional hydrodynamic model to realize the inundation calculation of the whole process of runoff generation - confluence - evolution - overtopping.

[0115] The specific calculation process includes:

[0116] S41. Plot the water level-discharge relationship at the basin outlet station, fit the water level-discharge relationship curve using the least squares method, and use it as the lower boundary of the model;

[0117] S42. Realize the series calculation of the hydrological model and the hydrodynamic model in the form of point sources and line sources. First, calculate the runoff generation and confluence through the hydrological model to obtain the flow process at the outlet of each sub-basin under specific rainfall conditions, and then obtain elements such as the inundation range, water depth, and duration through the hydrodynamic model.

[0118] The hydrological-hydrodynamic coupling model adopted in this application is a method that organically combines the basin hydrological model and the hydrodynamic model to accurately simulate and analyze the basin hydrological process and flood evolution, etc.

[0119] Meanwhile, when coupling the models, generally the flow process at the basin outlet calculated by the three-source Xin'anjiang model is used as the inflow boundary condition for the two-dimensional hydrodynamic model, providing the initial flood flow rate and process for it. 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 the input parameters for further calculations of the three-source Xin'anjiang model, realizing information interaction and collaborative calculations.

[0120] This coupled model combines the advantages of the three-source Xin'anjiang model in calculating runoff yield and concentration in the basin and the high-precision characteristics of the two-dimensional hydrodynamic model in simulating flood routing. It can not only accurately simulate the runoff yield and concentration of different water sources in the basin but also finely depict the dynamic routing and inundation of floods in space. It can be widely applied in fields such as flood forecasting, flood control and disaster reduction, and water resources management, providing a more comprehensive and accurate scientific basis for relevant decisions.

[0121] In a specific embodiment, taking region H as an example, region H is a humid mountainous area with complex terrain. A group of mountains tower in the northwest, and another group of mountains block in the southeast. The area of mountains and hills is vast, and the overall terrain is mainly mountainous.

[0122] In view of the flood characteristics of this region, a combined hydrological and hydrodynamic modeling approach is adopted to establish a hydrological-hydrodynamic coupled model that can adapt to complex flow conditions such as the interlacing of main and tributary river networks, backwater backwater, flood diversion and detention, and flood control requirements.

[0123] Based on the research of mathematical models, through scenario simulation and historical flood recurrence, the entire evolution process of floods from formation, development to disappearance is simulated to accurately predict the possible inundation range and depth of floods, providing a scientific basis and technical support for optimizing the layout of treatment projects and flood control and disaster reduction.

[0124] Reference Figure 1 , the above flood inundation calculation method applicable to humid mountainous areas is used to perform simulation calculation operations on region A, and the following specific operation steps are as follows:

[0125] S1: Collect the geographical information data of the Xin'anjiang River Basin within the scope of region H, the relevant data of hydrological stations and water conservancy project facilities in the basin, and divide the basin into sub-basins. Then, based on this, determine the calculation ranges of the hydrological model and the hydrodynamic model, and combine the inundation situation of historical mountain floods to determine the calculation ranges of the hydrological model and the hydrodynamic model and the spatial positions of their coupling and connection. Divide the target area into sub-basins to determine the calculation ranges of the hydrological model and the hydrodynamic model.

[0126] The geographical information data collected at this time is as Figure 2 shown, and the sub-basin division results are as shown in the following table:

[0127]

[0128] S2: The three-source Xin'anjiang model is selected as the basic model for the research area, and a calibration system for the Xin'anjiang model and the synthetic unit hydrograph is developed. The water volume error, peak error, logarithmic error, process matching degree, and coefficient of determination are selected as the objective functions. A method combining manual optimization and computer automatic optimization is used to systematically identify and calibrate the parameters of the model. At this time, the parameter table of the sub-basin single-flood model is as follows:

[0129]

[0130] In addition, the statistical table of the simulation calculation error of the sub-basin single-flood model is as follows:

[0131]

[0132] Based on the above data, the inflow hydrograph process diagrams of each sub-basin as shown in Figure 3 can be further obtained. Figure 3 In (a), it is the inflow hydrograph process of sub-basin A in region H. Figure 3 In (b), it is the inflow hydrograph process of sub-basin B in region H. Figure 3 In (c), it is the inflow hydrograph process of sub-basin C in region H. Figure 3 In (d), it is the inflow hydrograph process of sub-basin D in region H.

[0133] S3: Using Arcgis software, splice and integrate the river cross-section and high-precision DEM data, and consider the impacts 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 inundation calculation area.

[0134] Download the data of the research area from the professional website of land use data. Through operations such as registration, clipping, and resampling, make the coordinate system and pixel size of the land use data consistent with those of the DTM. Initially produce a roughness file for model zoning as shown in Figure 5 . The two-dimensional hydrodynamic model takes the flow process calculated by the hydrological model as the upper boundary and the measured water level process of the designated hydrological station at the basin outlet as the lower boundary to reproduce the inundation situation of the flood in 2022, a typical year. Use the historical flood marks and inundation range data to further optimize the initial roughness to obtain the final DTM data as shown in Figure 4 .

[0135] At this time, taking sub-basin A as an example, the comparative analysis (partial) of the elevation of the flood mark points calculated by the model and the measured values is as follows in the table and Figure 6 as shown.

[0136]

[0137] S4: Plot the water level-discharge relationship of the specified hydrological station, fit the water level-discharge relationship curve using the least squares method, and use it as the lower boundary of the model; realize the series calculation of the hydrological model and the hydrodynamic model in the form of point sources and line sources. First, calculate the runoff yield and concentration through the hydrological model to obtain the flow process at the outlets of each sub-basin under specific rainfall conditions, and then obtain elements such as the inundation range, water depth, and duration through the hydrodynamic model.

[0138] The 48-hour flood routing process diagram at this time is as Figures 7 to 10 shown, in Figure 7 : (a) shows the water level and inundation range at 0 hour; (b) shows the water level and inundation range at 24 hours; (c) shows the water level and inundation range at 36 hours; (d) shows the water level and inundation range at 42 hours.

[0139] At the same time, the maximum inundation range is as Figure 11 shown.

[0140] According to the inundation range and depth, different regions can be divided into risk zones. Areas that are extremely vulnerable to flood inundation and have a relatively large inundation depth are high-risk zones, usually low-lying areas along rivers, areas near the downstream of reservoirs with obvious flood discharge impacts, etc. Once these areas are hit by floods, they may be covered by a large amount of accumulated water in a short time, posing a serious threat to the safety of residents' lives and property, and houses, infrastructure, etc. are extremely vulnerable to destructive damage. The inundation possibility of medium-risk zones is relatively low, and the inundation depth is also relatively shallow. Generally, they are only affected when the flood flow is large, such as some areas that are at a certain distance from the river channel but have a relatively flat terrain. However, when the flood lasts for a long time, relatively deep water accumulation may also occur, affecting the normal life of residents and the operation of some facilities. Low-risk zones are areas that are basically not inundated under normal flood conditions and are only slightly affected in the event of extreme flood events, such as mountain highlands with high terrain and far from water systems. After clearly dividing different risk zones, targeted flood control and disaster reduction strategies can be formulated. For high-risk zones, it is necessary to strengthen the construction of flood control projects, such as building strong dikes and improving drainage capabilities. At the same time, plan the evacuation routes and resettlement sites for residents in advance, and regularly carry out flood control drills to improve the emergency avoidance ability of residents. Medium-risk zones should pay attention to the maintenance and upgrading of flood control facilities, strengthen flood monitoring and early warning, and guide residents to make certain flood control preparations. Although low-risk zones are less threatened by floods, they cannot be taken lightly. It is necessary to strengthen the publicity and education of flood control knowledge for residents to improve the flood control awareness of the whole people and ensure that they can respond in a timely manner in extreme situations.

[0141] In the above embodiments, it can accurately simulate the flow path and inundation range of floods in complex terrains, providing strong support for risk zone division; it has strong adaptability to the special hydrological conditions in humid mountainous areas, can combine the spatio-temporal distribution of precipitation and the interaction of water bodies, and realizes the whole-process calculation from rainfall to inundation range, accurately simulating flood evolution and reliably predicting inundation situations. In terms of data acquisition, it does not rely on complex parameters and can achieve accurate calculation by integrating easily obtainable data, which is beneficial for carrying out simulation work in mountainous areas with limited monitoring stations. In addition, this method has high timeliness, effectively improves the calculation efficiency on the basis of ensuring the accuracy of calculation simulation, and efficiently quantifies the maximum inundation range of mountainous basins.

[0142] On the other hand, the present invention also discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to execute the steps of the above method.

[0143] On yet another hand, the present invention also discloses a computer device including a memory and a processor, where the memory stores a computer program, which, when executed by the processor, causes the processor to execute the steps of the above method.

[0144] In yet another embodiment provided by the present application, there is also provided a computer program product containing instructions, which, when running on a computer, causes the computer to execute any one of the flood inundation calculation methods applicable to humid mountainous areas in the above embodiments.

[0145] It can be understood that the system provided by the embodiments of the present invention corresponds to the method provided by the embodiments of the present invention, and the explanations, examples, and beneficial effects of the relevant content can refer to the corresponding parts in the above method.

[0146] The embodiments of the present application also provide an electronic device including a processor, a communication interface, a memory, and a communication bus. Among them, the processor, the communication interface, and the memory complete communication with each other through the communication bus.

[0147] The memory is used to store a computer program.

[0148] The processor is used to implement the above flood inundation calculation method applicable to humid mountainous areas when executing the program stored in the memory.

[0149] The communication bus mentioned in the above electronic device may be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. This communication bus can be divided into an address bus, a data bus, a control bus, etc.

[0150] The communication interface is used for communication between the above electronic device and other devices.

[0151] The memory may include a random access memory (RAM), or may also include 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.

[0152] The aforementioned processor may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may 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.

[0153] It should also be noted that the electronic device further includes a terminal device, which may also be referred to as a terminal, a user equipment, a mobile station, a mobile terminal, etc. The terminal device may be a mobile phone, a smart TV, a wearable device, a tablet computer, a computer with wireless transceiver function, a virtual reality terminal device, an augmented reality terminal device, a wireless terminal in industrial control, a wireless terminal in unmanned driving, a wireless terminal in remote surgery, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, etc. The embodiments of the present application do not limit the specific technologies and specific device forms adopted by the terminal device.

[0154] 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 processes or functions described in the embodiments of the present application are generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. 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 one website, computer, server, or data center to another website, computer, server, or data center in a wired manner (such as coaxial cable, optical fiber, digital subscriber line DSL) or a wireless manner (such as infrared, wireless, microwave, etc.). The computer-readable storage medium may be any available medium that can be accessed by a computer, or a data storage device such as a server or a data center that includes one or more integrated available media. The available medium may be a magnetic medium (such as a floppy disk, a hard disk, a magnetic tape), an optical medium (such as a DVD), or a semiconductor medium (such as a solid state disk).

[0155] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

[0156] In addition, it should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present invention, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0157] 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 for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and / or" appearing throughout the text includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or a solution where A and B are satisfied simultaneously. In addition, in the embodiments of the present invention, "a plurality of" means two or more. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope 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 flooding calculations for the entire process of runoff generation, confluence, evolution, and overflow; 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.

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: V=aS 1 / 2 Among them, V is the slope flow velocity, a is the empirical coefficient reflecting the slope roughness, and S is the slope along the water flow direction 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 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: Where: x is the spatial horizontal coordinate, y is the spatial vertical coordinate, t is the time, and S is the source term vector; U is a variable vector, including water level ζ and single-width flow q x ,q y ; F and G are flux vectors, including water depth h, and u and v are flow velocities in directions x and y, respectively; C f =gn 2 / h 1 / 3 is Xie Cai coefficient, n is 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.

5. The flood inundation calculation method applicable to humid mountainous areas as claimed in claim 4, 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.

6. 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.

7. The flood inundation calculation method applicable to humid mountainous areas as claimed in claim 1, characterized in that: In the runoff calculation of the lumped hydrological model, the subsurface flow and groundwater runoff are regulated by the linear reservoir method, and the surface runoff is regulated by the Nash unit line, and the formula is: Among them, u(t) is the instantaneous unit line; n is the number of linear reservoirs; k is the regulation coefficient of each reservoir; and t is the instantaneous time.

8. 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 7.

9. 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 7.

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