Flood influence simulation analysis method and device, computer equipment and storage medium

Abstract

The invention relates to a flood influence simulation analysis method and device, computer equipment and a storage medium. The method comprises the following steps: determining a target drainage basin, and determining sub-drainage basin units and sub-drainage basin nodes in regional data of the target drainage basin; constructing a plurality of hydrological models based on the relationship between the sub-basin units and the sub-basin nodes; determining a simulation analysis drainage basin in the target drainage basin, and determining at least one hydrological model in the simulation analysis drainage basin; calculating basin parameters in the simulation analysis basin based on the hydrological parameters in the simulation analysis basin and the at least one hydrological model; constructing a flood simulation model based on the topographic data of the simulation analysis drainage basin, performing flood simulation according to the flood simulation model and the drainage basin parameters, and performing analysis based on a flood simulation result to determine a flood influence; and the flood simulation model adopts a conservation form of a two-dimensional shallow water equation. The method can accurately reflect the spatio-temporal change of the confluence producing mechanism in the rainstorm flood process of the watershed.

Description

Technical Field

[0001] The present disclosure relates to the technical field of hydrological data processing, and particularly to a method, device, computer device, and storage medium for simulating and analyzing flood impacts. Background Art

[0002] To better cope with the challenges brought by extreme climate disasters, China has proposed to build an intelligent water conservancy flood prevention system, develop and build water conservancy professional models, and achieve dynamic representation of the spatio-temporal distribution characteristics of all water conservancy elements during the flood process, so as to enhance the understanding of the flood formation mechanism and disaster causes by managers, so as to formulate scientific and timely response measures.

[0003] Water conservancy professional models are an important foundation for supporting flood and drought disaster prevention work. However, in the process of simulating floods, traditional water conservancy patent models lack sufficient response to the regulating effect of reservoirs; there is no obvious improvement in the simulation of flood peaks and runoff depths for sudden floods; they perform poorly in flood forecasting in semi-humid, semi-arid, and arid regions, and thus cannot accurately reflect the spatio-temporal changes in the runoff generation and concentration mechanism during the basin rainstorm flood process. Summary of the Invention

[0004] Based on this, it is necessary to provide a method, device, computer device, and storage medium for simulating and analyzing flood impacts in view of the above technical problems.

[0005] In a first aspect, the present disclosure provides a method for simulating and analyzing flood impacts. The method includes:

[0006] Determine a target basin, and determine sub-basin units and sub-basin nodes in the regional data of the target basin;

[0007] Based on the relationship between the sub-basin units and sub-basin nodes, construct multiple hydrological models;

[0008] Determine a simulation analysis basin in the target basin, and determine at least one hydrological model in the simulation analysis basin;

[0009] Based on the hydrological parameters in the simulation analysis basin and the at least one hydrological model, calculate the basin parameters in the simulation analysis basin;

[0010] Construct a flood simulation model based on the topographic data of the simulation analysis basin, perform flood simulation according to the flood simulation model and the basin parameters, and analyze based on the results of the flood simulation to determine flood impacts; the flood simulation model adopts the conservation form of the two-dimensional shallow water equations.

[0011] In one embodiment, the basin parameters include: total water production flow; the flood simulation model includes: a one-dimensional hydrodynamic simulation model and a two-dimensional hydrodynamic simulation model; performing flood simulation according to the flood simulation model and the basin parameters includes:

[0012] Taking the total water production flow as input data and inputting it into the one-dimensional hydrodynamic simulation model, and using the one-dimensional hydrodynamic simulation model to perform a first flood simulation, where the first flood simulation includes: river flow simulation, water level prediction, and water flow velocity analysis;

[0013] Taking the total water production flow as input data and inputting it into the two-dimensional hydrodynamic simulation model, and using the two-dimensional hydrodynamic simulation model to perform a second flood simulation, where the second flood simulation includes: levee breach flood simulation.

[0014] In one embodiment, the hydrological parameters include: net rainfall on the ground, proportion of impervious area, infiltration capacity, water content in the preferential flow layer, maximum water content in the preferential flow layer of the surface soil, and drainage volume from the deep soil to the preferential flow layer after reaching the field capacity; the basin parameters further include: total runoff from the excess infiltration part and total runoff from the saturation part; calculating the basin parameters in the simulated analysis basin based on the hydrological parameters and the at least one hydrological model in the simulated analysis basin includes:

[0015] Calculating the excess infiltration runoff from the impervious layer and the excess infiltration runoff on the pervious layer according to the net rainfall on the ground in the simulated analysis basin, the proportion of impervious area in the simulated analysis basin, and the infiltration capacity of the simulated analysis basin within a preset time period;

[0016] Calculating the total runoff from the excess infiltration part according to the excess infiltration runoff from the impervious layer and the excess infiltration runoff on the pervious layer;

[0017] Calculating the saturated runoff from the preferential flow layer and the saturated runoff from the upward recharge after the lower soil is saturated according to the infiltration capacity, water content in the preferential flow layer, maximum water content in the preferential flow layer of the surface soil, and drainage volume from the deep soil to the preferential flow layer after reaching the field capacity in the simulated analysis basin;

[0018] Calculating the total runoff from the saturation part according to the saturated runoff from the preferential flow layer and the saturated runoff from the upward recharge after the lower soil is saturated.

[0019] In one embodiment, the hydrological parameters include: the linear coefficient and non-linear coefficient of the preferential flow layer outflow, the water content of the underlying soil in a preset period, the linear coefficient and non-linear coefficient of the underlying soil outflow, the water content of the groundwater reservoir, and the outflow coefficient of the groundwater reservoir; the basin parameters further include: the preferential flow discharge of the preferential flow layer of the surface soil, the subsurface flow discharge of the underlying soil, and the base flow; calculating the basin parameters in the simulated analysis basin based on the hydrological parameters in the simulated analysis basin and the at least one hydrological model includes:

[0020] Based on the water content of the preferential flow layer and the linear coefficient and non-linear coefficient of the preferential flow layer outflow, calculating the preferential flow discharge of the preferential flow layer of the surface soil;

[0021] Based on the water content of the underlying soil in the preset period, the linear coefficient and non-linear coefficient of the underlying soil outflow, calculating the subsurface flow discharge of the underlying soil;

[0022] Based on the water content of the groundwater reservoir and the outflow coefficient of the groundwater reservoir, calculating the base flow.

[0023] In one embodiment, the basin parameters include: the total water production flow rate, and calculating the basin parameters in the simulated analysis basin based on the hydrological parameters in the simulated analysis basin and the at least one hydrological model further includes:

[0024] Based on the sum of the total overland flow production flow rate, the total production flow rate of the saturation part, the preferential flow discharge of the preferential flow layer of the surface soil, the subsurface flow discharge of the underlying soil, and the base flow, obtaining the total water production flow rate.

[0025] In one embodiment, the method further includes:

[0026] Calculating the peak flood relative error and the coefficient of determination of each of the hydrological models;

[0027] Based on the peak flood relative error and the coefficient of determination, determining the evaluation index of each hydrological model;

[0028] In response to the evaluation index not meeting the preset index threshold, re-calibrating the hydrological model that does not meet the preset index threshold.

[0029] In a second aspect, the present disclosure also provides a flood impact simulation analysis device. The device includes:

[0030] A basin determination module, configured to determine a target basin, and determine sub-basin units and sub-basin nodes in the regional data of the target basin;

[0031] A model construction module, configured to construct a plurality of hydrological models based on the relationship between the sub-basin units and the sub-basins;

[0032] A basin analysis module for determining a simulated analysis basin in the target basin and determining at least one hydrological model in the simulated analysis basin;

[0033] A basin parameter determination module for calculating basin parameters in the simulated analysis basin based on hydrological parameters in the simulated analysis basin and the at least one hydrological model;

[0034] A flood simulation module for constructing a flood simulation model based on the topographic data of the simulated analysis basin, performing flood simulation according to the flood simulation model and the basin parameters, and analyzing based on the results of the flood simulation to determine flood impacts; the flood simulation model adopts the conservation form of the two-dimensional shallow water equations.

[0035] In a third aspect, the present disclosure also provides a computer device. The computer device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, the steps in any of the above method embodiments are implemented.

[0036] In a fourth aspect, the present disclosure also provides a computer-readable storage medium. On the computer-readable storage medium, a computer program is stored, and when the computer program is executed by a processor, the steps in any of the above method embodiments are implemented.

[0037] In a fifth aspect, the present disclosure also provides a computer program product. The computer program product includes a computer program, and when the computer program is executed by a processor, the steps in any of the above method embodiments are implemented.

[0038] In the above embodiments, by determining the target basin and further subdividing it into sub-basin units and sub-basin nodes, the limitation of treating the basin as a whole is broken, and the differences in terrain, land use, soil, etc. in different regions within the basin can be fully considered, making the understanding and management of the basin more refined. Based on the relationship between sub-basin units and sub-basin nodes, multiple hydrological models are constructed, which can better simulate the complex hydrological processes within the basin. Each sub-basin unit has its relatively independent hydrological characteristics. The combination of multiple interrelated hydrological models can reflect the generation, convergence, evolution, etc. of water flow within the entire basin more realistically compared to a single, lumped hydrological model. At the same time, selecting appropriate hydrological models according to the characteristics of the simulated analysis basin further ensures the adaptability of the model to the specific research area, making the simulation results more reliable and providing more accurate data support for relevant decisions. Calculating basin parameters based on the hydrological parameters in the simulated analysis basin and the determined hydrological models takes into account various factors, making the calculated basin parameters (such as roughness coefficient, soil infiltration parameter, water conservancy project related parameters, etc.) more in line with the actual situation. These accurate basin parameters are the key to subsequent flood simulation, enabling the flood simulation to more realistically restore the development process of floods within the basin and avoiding large deviations in simulation results due to inaccurate parameters. Using a flood simulation model based on the conservation form of the two-dimensional shallow water equations, combined with accurate basin terrain data and the basin parameters calculated previously for flood simulation, can meticulously present the movement state of floods on a two-dimensional plane, including key information such as flood inundation range, water level changes, and velocity distribution. Based on the analysis of the simulation results, the impacts of floods on various aspects such as population, buildings, transportation, infrastructure, and ecological environment can be comprehensively and intuitively determined, providing detailed basis for flood control and disaster reduction decisions. Description of the Drawings

[0039] In order to more clearly illustrate the specific embodiments of the present disclosure or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present disclosure. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0040] Figure 1 It is a schematic diagram of the application environment of the flood impact simulation analysis method in an embodiment;

[0041] Figure 2 It is a schematic diagram of the flow of the flood impact simulation analysis method in an embodiment;

[0042] Figure 3 It is a schematic diagram of the flow of step S210 in an embodiment;

[0043] Figure 4 It is a schematic flowchart of step S208 in an embodiment;

[0044] Figure 5 It is a schematic flowchart of step S208 in an embodiment;

[0045] Figure 6 It is a schematic diagram of the vertical mixing structure of a hydrological model in an embodiment;

[0046] Figure 7 It is a schematic flowchart of step S210 in an embodiment;

[0047] Figure 8 It is a schematic block diagram of the structure of a flood impact simulation analysis device in an embodiment;

[0048] Figure 9 It is a schematic internal structure diagram of a computer device in an embodiment;

[0049] Figure 10 It is a schematic internal structure diagram of a computer device in an embodiment. Specific Embodiments

[0050] In order to make the objectives, technical solutions and advantages of the present disclosure clearer and more understandable, the present disclosure will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present disclosure and are not used to limit the present disclosure.

[0051] It should be noted that the terms "first", "second", etc. in the specification and claims of this article and the above-mentioned drawings are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, device, product or equipment that includes a series of steps or units does not necessarily need to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or equipment.

[0052] In this article, the term "and / or" is only a relationship describing associated objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0053] As described in the background art, after decades of development of water conservancy professional models, distributed hydrological models with a physical basis have shown obvious advantages in considering the spatio-temporal non-uniformity of rainfall processes and the spatial heterogeneity of the underlying surface of river basins. They can accurately describe the spatio-temporal changes of water conservancy elements in hydrological processes, and thus have been favored by many scholars and experts. However, during the flood simulation process, the TOPKAPI model was used to simulate historical mountain floods in the Zhenjiang River Basin of Guangdong Province during the simulation test. The results were relatively good. The passing rate of 18 floods during the calibration period reached 67%, and the passing rate of 8 floods during the verification period was 75%. However, during the simulation process, this model also exposed the disadvantage of insufficient response to the reservoir regulation effect, so it still needs to be further improved and perfected. The TOPMODEL model can also be improved, and the FTOP model based on the fractional instantaneous unit hydrograph is proposed. Through comparative research, the FTOP model has significantly better simulation effects than the TOPMODEL model in the simulation of daily-scale hydrological processes, but no obvious improvement effects are shown in the simulation of flood peaks and runoff depths of sudden floods. Nine river basins located in different hydrological regions of China can also be selected for multi-model comparative simulation research. The results show that lumped hydrological models based on the classical full-infiltration runoff generation theory perform poorly in flood forecasting in semi-humid semi-arid and arid regions.

[0054] The embodiment of the present disclosure provides a flood impact simulation analysis method, which can be applied to an application environment as Figure 1 shown. Among them, the terminal 102 communicates with the server 104 through the network. The data storage system can store the data that the server 104 needs to process. The data storage system can be integrated on the server 104, or placed in the cloud or other network servers. The terminal 102 can determine the target river basin based on the map in the server 104, and determine the sub-basin units and sub-basin nodes in the regional data of the target river basin. The terminal 102 can construct multiple hydrological models based on the relationship between the sub-basin units and sub-basins. The terminal 102 can also determine the simulation analysis river basin in the target river basin, and determine at least one hydrological model in the simulation analysis river basin; calculate the basin parameters in the simulation analysis river basin based on the hydrological parameters in the simulation analysis river basin and the at least one hydrological model; construct a flood simulation model based on the topographic data of the simulation analysis river basin, and perform flood simulation according to the flood simulation model and the basin parameters, and analyze based on the results of the flood simulation to determine the flood impact; the flood simulation model adopts the conservation form of the two-dimensional shallow water equations. Among them, the terminal 102 can be, but is not limited to, various personal computers, laptop computers, smart phones, tablet computers, etc. The server 104 can be implemented by an independent server or a server cluster composed of multiple servers. It should be noted that this solution can also be independently applied to the terminal or the server to implement.

[0055] In one embodiment, as Figure 2 shown, a flood impact simulation analysis method is provided. Taking the method applied to Figure 1 the terminal 102 in

[0056] S202, determine the target basin and determine the sub-basin units and sub-basin nodes in the regional data of the target basin.

[0057] Among them, the sub-basin unit is a smaller and relatively independent basin area divided from a large basin according to certain rules and characteristics. These rules and characteristics usually include natural geographical elements such as topography, land use type, soil type, and vegetation cover. In a hydrological model, the sub-basin unit is the basic calculation unit. Each sub-basin unit has its relatively independent hydrological cycle process, including precipitation, evaporation, runoff generation, and confluence. By simulating the hydrological processes of each sub-basin unit separately, the hydrological characteristics of the entire basin can be more accurately reflected. The sub-basin node is a point with specific functions or meanings on the water flow path in the basin. These points usually include the confluence points of rivers, the locations of reservoirs, the sites of important water conservancy facilities (such as sluice dams), and the outlets of the basin. The sub-basin nodes are used to describe the flow path and convergence of water flow in the basin. After the water flow is generated from each sub-basin unit, it will flow along a certain path to the basin nodes, and the water flows of multiple sub-basin units may converge at the basin nodes to form a larger water flow. When constructing a hydrological model, the basin nodes are important connection and control units in the model. By analyzing and processing the basin nodes, the evolution process of water flow in the basin can be better simulated. For example, in flood simulation, the water level and flow rate changes at the basin nodes are of great significance for judging the propagation direction and speed of floods.

[0058] Specifically, by analyzing topographic contour maps and digital elevation models (DEMs), the target watershed can be determined. The target watershed can also be determined according to a preset area. In some embodiments of the present disclosure, there is no limitation on how the target watershed is determined. When using DEM data for hydrological analysis, first, depression filling operations are performed to remove the depression areas in the data, and then the flow direction is determined. Usually, the D8 algorithm (flow direction of the steepest slope) is used to calculate the flow direction of each grid. The flow accumulation is calculated based on the flow direction, that is, the upstream catchment area of each grid is statistically calculated. When the flow accumulation reaches a certain threshold, the position of the river network can be determined. Sub-watershed division: Based on the river network, the watershed is divided into multiple sub-watershed units. Usually, the small watershed area is controlled at about 10 - 30 km², and specific division can be adjusted according to the actual situation and research purpose of the study area, which is not limited here. In addition, when dividing sub-watershed units, land use types and soil types are also considered. Different land use patterns (such as farmland, forest, urban land, etc.) and soil types (such as sandy soil, loam, clay, etc.) will affect the runoff generation and concentration processes. Dividing areas with similar land use and soil types into the same sub-watershed unit helps to improve the accuracy of the hydrological model. Sub-watershed nodes usually include the confluence points of rivers. By analyzing the river system map or using the network analysis function in GIS software, the positions of river confluence points can be easily determined. These confluence points are important positions for water flow convergence and divergence and are important components of sub-watershed nodes. The locations of water conservancy project facilities such as reservoirs, sluices, and pumping stations are also sub-watershed nodes. These facilities will have a control and regulation effect on water flow and need to be considered as important nodes in the hydrological model. Through on-site investigations and consulting water conservancy project materials, the positions of these nodes can be determined. Some special topographic points, such as waterfalls and canyons, can also be determined as sub-watershed nodes. These topographic points will have a significant impact on the energy and velocity of water flow. In the present disclosure, there is no absolute limitation on how to determine sub-watershed units and sub-watershed nodes.

[0059] S204, construct multiple hydrological models based on the relationship between the sub-watershed units and sub-watershed nodes.

[0060] Among them, a hydrological model is a tool for generalizing and simulating the hydrological cycle process and hydrological phenomena in nature. It describes the hydrological processes such as precipitation, evaporation, soil moisture movement, surface runoff, and subsurface runoff in the watershed and their mutual relationships through mathematical formulas and physical mechanisms.

[0061] Specifically, sub - watershed units and sub - watershed nodes can be grouped according to the topological relationship of important cross - sections of the river system, and then multiple hydrological models can be constructed for the grouped sub - watershed units and sub - watershed nodes. For sub - watershed nodes (such as river confluences, reservoirs, etc.), determine which sub - watershed units' water flows will converge at this node, and which sub - watershed units the water flowing out of the node will enter. Group those with the same water flow into one group. Based on the spatial distribution characteristics of sub - watershed units and nodes, a distributed hydrological model is selected. For example, a distributed hydrological model based on physical processes is adopted, such as the TOPMODEL (Topography - based hydrological model) or the MIKE SHE (System Hydrologic European) model, etc. According to the characteristics of sub - watershed units and nodes, determine the value range of model parameters. For example, for the soil infiltration parameter of sub - watershed units, determine its possible value range according to the soil type; for the parameters of water conservancy project nodes (such as the discharge coefficient of sluice dams), obtain the initial value through engineering design data. Using historical hydrological data (such as historical flood processes, long - term flow observation data, etc.), an optimization algorithm (such as genetic algorithm, simplex method, etc.) is used to calibrate the model parameters. Compare the model simulation results with the measured data, and minimize the error between the simulation results and the measured data by adjusting the parameters. For example, indicators such as root mean square error (RMSE) and Nash efficiency coefficient (NSE) are used to evaluate the simulation effect, and finally multiple hydrological models are obtained.

[0062] S206, determine the simulation analysis watershed in the target watershed, and determine at least one hydrological model in the simulation analysis watershed.

[0063] Among them, the simulation analysis watershed can be the area where flood simulation analysis is required. The simulation analysis watershed can be the entire target watershed or a certain part of the target watershed.

[0064] Specifically, since multiple hydrological models have been constructed according to sub - watershed units and sub - watershed nodes in the above process. Therefore, the sub - watershed units and sub - watershed nodes included in the simulation analysis watershed can be determined, and then at least one hydrological model in the simulation analysis watershed can be determined according to the sub - watershed units and sub - watershed nodes. The simulation analysis watershed can include the upstream catchment area of the river (the main runoff - generating area of floods), the river channel and the areas on both sides that may be affected by floods (such as low - lying areas, towns, farmlands, etc.), and the downstream floodplain and flood detention areas.

[0065] S208, calculate the watershed parameters in the simulation analysis watershed based on the hydrological parameters in the simulation analysis watershed and the at least one hydrological model.

[0066] Among them, the basin parameters may include: the total runoff of the infiltration - excess part, the total runoff of the saturation - excess part, the preferential flow discharge of the preferential flow layer in the surface soil, the subsurface flow discharge of the lower - layer soil, the base flow, and the total water production flow. The hydrological parameters may include: the net rainfall on the ground, the proportion of impervious area, the infiltration capacity, the water content of the preferential flow layer, the maximum water content of the preferential flow layer in the surface soil, the drainage volume from the deep soil to the preferential flow layer after reaching the field water - holding capacity, etc.

[0067] Specifically, the basin parameters in the simulated analysis basin can be calculated according to the hydrological parameters and at least one hydrological model in the simulated analysis basin.

[0068] S210, construct a flood simulation model based on the topographic data of the simulated analysis basin, conduct flood simulation according to the flood simulation model and the basin parameters, and analyze based on the results of the flood simulation to determine the flood impact; the flood simulation model adopts the conservation form of the two - dimensional shallow - water equations.

[0069] Specifically, a flood simulation model can be constructed according to the topographic data (such as topographic parameters like elevation, slope, and aspect) of the simulated analysis basin. Determine the corresponding roughness coefficient according to different underlying surface types (such as river channels, grasslands, urban areas, etc.) within the basin. The roughness coefficient can be obtained by referring to literature, field measurement, or empirical formulas. For example, for a smooth concrete river channel, the roughness coefficient is small; while for a slope covered with vegetation, the roughness coefficient is large. Input the determined basin parameters into the flood simulation model, set the simulation time step and the total simulation duration. Solve the changes of variables such as water depth and flow velocity of grid cells according to the two - dimensional shallow - water equations. Through iterative calculation, simulate the evolution process of flood in the basin, including the spread of flood, the rise of water level, and the change of flow velocity. Determine the flooded area according to the simulated water depth data. Determine the grid cells with a water depth greater than a certain threshold (such as 0.1 m) as the flooded area, and draw a flood inundation range map through Geographic Information System (GIS) technology to visually display the areas that may be affected by the flood. By comparing the inundation range maps at different times, the spread speed and direction of the flood can be analyzed, and the dynamic evolution process of the flood in the basin can be understood. For example, determine whether the flood first inundates the low - lying areas near the river channel or quickly spreads to the surrounding plain areas through overbank flow.

[0070] In the above flood impact simulation analysis method, by determining the target basin and further subdividing it into sub-basin units and sub-basin nodes, the limitation of treating the basin as a whole is broken, and the differences in terrain, land use, soil, etc. in different regions within the basin can be fully considered, making the understanding and management of the basin more refined. Based on the relationship between sub-basin units and sub-basin nodes, multiple hydrological models are constructed, which can better simulate the complex hydrological processes within the basin. Each sub-basin unit has its relatively independent hydrological characteristics. The combination of multiple interrelated hydrological models can, compared with a single, lumped hydrological model, more realistically reflect the generation, convergence, evolution, etc. of water flow throughout the basin. At the same time, selecting a suitable hydrological model according to the characteristics of the simulated analysis basin further ensures the adaptability of the model to the specific research area, making the simulation results more reliable and providing more accurate data support for relevant decisions. Calculating the basin parameters based on the hydrological parameters in the simulated analysis basin and the determined hydrological model takes into account various factors, making the calculated basin parameters (such as roughness coefficient, soil infiltration parameter, water conservancy project related parameters, etc.) more in line with the actual situation. These accurate basin parameters are the key to subsequent flood simulation, enabling the flood simulation to more realistically restore the development process of floods within the basin and avoiding large deviations in simulation results due to inaccurate parameters. Using a flood simulation model based on the conservative form of the two-dimensional shallow water equations, combined with accurate basin terrain data and the basin parameters calculated previously for flood simulation, can meticulously present the movement state of floods on a two-dimensional plane, including key information such as flood inundation range, water level changes, and flow velocity distribution. Based on the analysis of the simulation results, the impacts of floods on various aspects such as population, buildings, transportation, infrastructure, and ecological environment can be comprehensively and intuitively determined, providing detailed basis for flood control and disaster reduction decisions.

[0071] In one embodiment, the basin parameters include: total water yield flow. Total water yield usually refers to the total amount of water that can be finally generated and flow out of a specific basin range after various hydrological processes. In the hydrological cycle, precipitation is received within the basin, but not all precipitation will directly transform into water that can flow out of the basin. A part of the precipitation will return to the atmosphere through evaporation, and some will infiltrate into the soil and be intercepted by the soil, supplement soil moisture, or further recharge groundwater, etc. After deducting these losses (such as evaporation, interception, infiltration, etc.), the remaining water volume that is transformed and can converge and flow out of the basin in the forms of surface runoff, subsurface flow, groundwater runoff, etc. is the total water yield flow.

[0072] The flood simulation model includes: a one-dimensional hydrodynamic simulation model and a two-dimensional hydrodynamic simulation model. The one-dimensional hydrodynamic simulation model is a mathematical model used to describe the flow characteristics of water bodies in one-dimensional space (usually along the longitudinal direction of a river or channel). It is based on physical principles such as mass conservation and momentum conservation, and simulates the movement process of water flow in narrow water bodies such as river channels by establishing a series of equations. The two-dimensional hydrodynamic simulation model is a mathematical model used to describe the flow characteristics of water bodies in a two-dimensional plane (usually the horizontal x - y plane). It is based on the basic principles of fluid mechanics, such as mass conservation and momentum conservation, to simulate the movement of water flow in a planar area, which can be a river, lake, estuary, ocean, or flood inundation area, etc. The flood detention and retarding areas can be included in the simulated basin.

[0073] As Figure 3 shown, performing flood simulation according to the flood simulation model and the basin parameters includes:

[0074] S302, taking the total water production flow rate as input data and inputting it into the one-dimensional hydrodynamic simulation model, and using the one-dimensional hydrodynamic simulation model to perform the first flood simulation, where the first flood simulation includes: river flow simulation, water level prediction, and water flow velocity analysis.

[0075] Among them, the one-dimensional hydrodynamic simulation model is: , where x is the river length, t is the time, A is the cross-sectional area of flow, Q is the cross-sectional discharge, Z is the cross-sectional water level, is the momentum correction coefficient, K is the discharge modulus, is the lateral inflow, is the velocity component of the inflow along the water flow direction. The four-point implicit Preissmann scheme can be used for discrete solution.

[0076] Specifically, check whether the time step of the total runoff data is consistent with that of the one-dimensional hydrodynamic simulation model. If not, data interpolation or resampling is required to make the time step of the total runoff data the same as that of the model. For example, if the time step of the model is 10 minutes and the total runoff data is one data point per hour, the total runoff data needs to be interpolated to one data point per 10 minutes. Input the total runoff as the upstream boundary condition into the one-dimensional hydrodynamic simulation model. For a simple river channel model, assuming there is only one inflow section at the upstream of the river channel, then the total runoff is directly input into this section as the inflow discharge. If there are multiple inflow points at the upstream of the river channel (such as multiple tributaries converging), the total runoff needs to be reasonably distributed to each inflow point according to the corresponding runoff generation areas of each inflow point. In addition to the total runoff, other parameters of the model also need to be set. These include the geometric shape parameters of the river channel (such as the variation of river channel width, depth, and cross-sectional shape with mileage), roughness coefficient (reflecting the resistance of the riverbed and riverbank to the water flow), downstream boundary condition (such as free outfall, given water level, etc.). These parameters can be determined through on-site measurement, Geographic Information System (GIS) data, or previous research experience. During the model operation, calculations are performed according to the mass conservation equation (continuity equation). Among them, after the total runoff is input as the upstream inflow (i.e., the value at the inflow section), as time goes by and the water flow moves in the river channel, the model will calculate the flow rate at each section at different times according to factors such as the geometric shape and roughness of the river channel. For example, when the total runoff enters the river channel, as the water flow propagates downstream, due to the possible change in the cross-sectional area of the river channel (such as the river channel widening or narrowing), and the possible existence of lateral inflows (such as other small tributaries converging), the model will dynamically calculate the change in the flow rate at each section. The flow rate results output by the model are a sequence that varies with time and space (along the river channel mileage). The propagation process of flood flow in the river channel can be visually analyzed by plotting a three-dimensional graph of flow rate - time - mileage or a two-dimensional graph of flow rate - mileage (at different times). For example, observe the advancing speed of the peak flood flow rate in the river channel, and the attenuation or increase of the flow rate in different river reaches.

[0077] Use the momentum conservation equation (motion equation) in the model , combined with the known geometric shape of the river channel (the relationship between A and Z) and the roughness coefficient, to calculate the water level from the flow rate. In this equation, the change in the flow rate will cause a change in the water level, and at the same time, the changes in flow velocity ( and terms), the action of gravity ( term), and frictional loss ( term) are considered.

[0078] As the total runoff enters the river channel, the model dynamically calculates the water level changes at each cross-section based on the changes in flow rate and the hydraulic characteristics of the river channel. For example, when the peak flood flow passes through, due to the sudden increase in flow rate, the cross-sectional area of the river channel cannot be adjusted in time, and the water level will rise rapidly; while when the flow rate decreases, the water level will gradually drop.

[0079] S304, input the total water production flow rate as input data into the two-dimensional hydrodynamic simulation model, and use the two-dimensional hydrodynamic simulation model to perform a second flood simulation, where the second flood simulation includes: levee breach flood simulation.

[0080] Among them, the conservation form of the two-dimensional shallow water equations (two-dimensional hydrodynamic simulation model) is as follows:

[0081]

[0082] , , , , , , , In the formula: h is the water depth, u is the flow velocity in the x direction, v is the flow velocity in the y direction, g is the acceleration due to gravity, and t is the time variable.

[0083] Among them: , are the top of the bottom slope in the x and y directions respectively, where Zb is the bottom elevation. are the friction slope drops in the x and y directions respectively, where n is the roughness coefficient.

[0084] Specifically, since the two-dimensional hydrodynamic simulation model conducts simulations based on a planar region, it is necessary to reasonably distribute the total water production flow to relevant positions within the two-dimensional region covered by the model according to the river system structure of the basin and the location of the levee breach, etc. For example, if simulating the flood situation after a levee breach in a certain river section, the total water production flow needs to be distributed to the corresponding grid cells at and around the levee breach point according to the position of the river on the plane and the possible inflow direction at the levee breach (the model often divides the simulation area into grids for calculation). Determine the corresponding roughness coefficient according to different underlying surface types (such as river channels, grasslands, urban areas, etc.) within the simulation analysis area. The roughness coefficient affects the friction between the water flow and the riverbed and the ground, thereby affecting the water flow velocity and the flood evolution process. The roughness coefficient values of each area can be obtained through methods such as consulting literature and on-site measurement, and assigned to the corresponding grid cells in the model. In addition to the total water production flow as part of the boundary conditions (such as the inflow conditions at the levee breach), other boundary conditions of the simulation area also need to be determined. For example, for the lateral boundary of the area, if it is an impermeable boundary (such as a terrain like a mountain that cuts off the water flow), it can be set as no water flow through; for the downstream boundary, if it flows into a large water body (such as a lake, ocean), it can be set as free outfall or given water level conditions according to the actual situation. The two-dimensional simulation area can be meshed according to the size of the simulation analysis area, the complexity of the terrain, and the requirements for simulation accuracy. In areas of key concern (such as around cities, important infrastructure, or areas where the impact of the expected levee breach is relatively large), a smaller grid size can be adopted to improve the simulation accuracy; while in areas with relatively simple terrain and less impact from floods, the grid size can be appropriately increased to balance the computational efficiency and accuracy requirements. At the same time, allocate the various prepared data (such as terrain, roughness coefficient, etc.) to the corresponding grid cells. The two-dimensional hydrodynamic simulation model is based on the conservation form of the two-dimensional shallow water equations Conduct simulations. Configure the conserved variable vector U (including variables such as water depth h, velocity u in the x - direction, velocity v in the y - direction, etc.) in the model, and clarify the specific calculation methods and parameter values of the flux vector F (involving calculation terms related to flow velocity and water depth such as convection terms and pressure terms) and the source term vector S (including bottom slope terms, friction slope drop terms, etc., related to terrain and roughness coefficient), ensuring that the equation can accurately reflect the water flow movement in the simulation area. Input the total water production flow rate into the breach or related areas according to the set spatial distribution method as the initial inflow condition. Combine other boundary conditions and initial information such as terrain and water level, and start the two - dimensional hydrodynamic simulation model. At this time, the variables such as water depth and flow velocity of each grid cell in the model are set with corresponding initial values according to the initial conditions. As the simulation progresses, within each time step, the model solves for the changes in variables such as water depth and flow velocity of each grid cell according to the two - dimensional shallow water equations. For example, when the total water production flow rate surges into the simulation area from the breach, under the influence of gravity and factors such as terrain and roughness, the flood will start to spread on the two - dimensional plane. The model simulates the flow, diffusion process of the flood in the x and y directions, as well as the rise and fall of the water level by calculating various terms such as the flux vector and the source term vector. At the same time, considering the frictional effect of the water flow on the underlying surface with different roughnesses, the simulated flood evolution process is made more in line with the actual situation. For the simulation of breach floods, focus on the outflow situation of the flood at the breach and the overflow, diffusion path and speed of the flood in the surrounding areas. The model will simulate how the flood spreads from the breach in a fan - shaped manner or according to the terrain trend to the surrounding areas over time, submerging surrounding towns, farmlands and other areas, and can present the flood inundation range, water depth distribution and flow velocity distribution at different times. For example, it is simulated that the flood first submerges the low - lying areas closer to the breach, and then as the water volume accumulates and flows, it gradually spreads to farther and higher - elevation areas until it reaches a relatively stable state or is connected to other water systems. According to the water depth data of each grid cell at different times obtained from the simulation, the grid cells with a water depth greater than a set threshold (such as 0.1 m, which can be adjusted according to the actual situation) are determined as the inundated areas. These grid cells are integrated and visually displayed through Geographic Information System (GIS) technology to form a flood inundation range map, intuitively presenting the possible affected area range of the flood after the breach and its change over time, providing spatial information reference for flood control and disaster reduction decision - making. Analyze the flood depth distribution in the simulation results to understand information such as the maximum flood depth and average flood depth in different regions, which is crucial for evaluating the damage degree of the flood to buildings, infrastructure and crops. At the same time, analyze the flow velocity distribution of the flood in each region. High - velocity areas are often prone to scouring damage to riverbanks, bridge foundations, etc. By determining these areas, it can provide a basis for flood control project reinforcement, personnel evacuation and other work. For example, take protective measures in advance for areas with high flow velocity and close to important facilities, or avoid high - velocity and high - risk areas when planning personnel evacuation routes.

[0085] In this embodiment, by respectively adopting one-dimensional and two-dimensional hydrodynamic simulation models and using the total water production flow rate as input data, the flood process can be simulated and analyzed from different dimensions. The one-dimensional hydrodynamic simulation focuses on the longitudinal water flow in the river, realizes river flow simulation, water level prediction, and water flow velocity analysis, which helps to clearly grasp the changing trend of the flow rate, the rise and fall of the water level, and the dynamic situation of the flow velocity when the flood flows downstream in the river channel. The two-dimensional hydrodynamic simulation focuses on showing the evolution of the flood on the plane. Especially for the simulation of levee breach floods, it can vividly present the entire process of the flood overflowing and spreading from the levee breach to the surrounding areas, including the inundation range, the water depth and flow velocity distribution in different areas, etc. In this way, the complex characteristics of the flood can be comprehensively understood from both the longitudinal and planar perspectives, providing key information in multiple aspects for subsequent flood prevention and mitigation work. Different flood simulation contents cover a variety of common and key flood scenarios. River flow simulation is very important for mastering the flood discharge capacity of the river channel during floods and judging whether there will be river channel overflows, etc.; water level prediction can know in advance the areas and depths that may be inundated by the flood, helping relevant departments to timely organize the evacuation of personnel and materials and take flood control reinforcement measures; water flow velocity analysis is of great significance for understanding the scouring effect of the flood on the river channel and surrounding infrastructure (such as bridges, levees, etc.), facilitating targeted protection work. The simulation of levee breach floods is even more for relatively extreme and serious situations. By simulating the flood diffusion path and influence range after the levee breach, decision-making departments can formulate emergency plans in advance and effectively respond to such sudden and destructive flood disasters.

[0086] In one embodiment, the hydrological parameters include: net rainfall on the ground, proportion of impervious area, infiltration capacity, water content in the preferential flow layer, maximum water content in the preferential flow layer of the surface soil, and drainage volume from the deep soil to the preferential flow layer after the deep soil reaches the field capacity. Net rainfall on the ground refers to the rainfall that actually reaches the ground and can participate in the basin hydrological process (such as runoff generation, infiltration, etc.) after deducting losses such as vegetation interception and evaporation. For example, during a rainfall event, part of the rainwater will be intercepted by leaves, the tops of buildings, etc., and part of the rainwater will directly evaporate back into the atmosphere during the fall, and the remaining rainwater that reaches the ground is the net rainfall on the ground. It is an important basis for runoff generation in the basin, and its size directly affects subsequent surface runoff, subsurface flow and other water volumes. Calculation method: Usually, it can be estimated by subtracting the interception amount and evaporation amount from the measured rainfall. The calculation of the interception amount will vary due to factors such as vegetation type and coverage, and the evaporation amount can be calculated through meteorological data and evaporation models (such as the Penman formula). In some simple cases, if the effects of interception and evaporation are ignored, the measured rainfall can also be approximately regarded as the net rainfall on the ground. The proportion of impervious area represents the proportion of the impervious surface area (such as roofs, cement pavements, asphalt roads, etc.) in the basin to the total basin area. This parameter reflects the influence of the underlying surface characteristics of the basin on the precipitation runoff generation process. The higher the proportion of impervious area, the greater the proportion of rainfall forming surface runoff, because it is difficult for water to infiltrate on the impervious surface and will quickly gather to form runoff. Infiltration capacity represents the maximum rate at which the soil allows water to infiltrate, which is a hydraulic property of the soil. The infiltration capacity depends on factors such as the texture of the soil (such as sandy soil, loam, clay), structure (aggregate structure, pore distribution, etc.) and initial water content. When the rainfall intensity is less than the soil infiltration capacity, all the rainwater will infiltrate into the soil; when the rainfall intensity is greater than the infiltration capacity, the excess rainwater will form surface runoff. Preferential flow refers to the water flow that preferentially moves rapidly in the soil pores due to the existence of large pores, fissures and other channels. The water content in the preferential flow layer refers to the water content in the soil layer where the preferential flow occurs. It reflects the water storage and movement in the special water flow channels in the soil. The maximum water content in the preferential flow layer of the surface soil refers to the maximum amount of water that the preferential flow layer in the surface soil can hold. It is an index characterizing the water holding capacity of the soil, similar to the field capacity, but for the preferential flow layer in the soil. When the water content in the preferential flow layer reaches this maximum value, the additional water may be discharged through other means (such as lateral flow, infiltration into the deep soil, etc.). The drainage volume from the deep soil to the preferential flow layer after the deep soil reaches the field capacity refers to the amount of water discharged from the deep soil to the preferential flow layer after its water content reaches the field capacity (the soil water content when the capillary suspension water in the soil reaches the maximum). This reflects the hydraulic connection and water redistribution process between different soil layers.

[0087] The watershed parameters also include: total flow production of the super-infiltration part and total flow production of the full storage part. The total flow production of the super-infiltration part refers to the sum of all runoffs generated by the super-infiltration flow production mechanism within a watershed. It depends on the rainfall intensity, rainfall duration, soil infiltration capacity, and the distribution of different underlying surfaces in the watershed (such as different soil types, vegetation coverage, etc.). For example, for a watershed with multiple soil textures, during rainfall, the sandy soil area may have a relatively small super-infiltration flow production due to its strong infiltration capacity; while the clay area has a weak infiltration capacity and the super-infiltration flow production may be large. Summarizing the flows generated by the super-infiltration mechanism in these different areas is the total flow production of the super-infiltration part. Super-infiltration flow production refers to the excess rainwater that forms runoff on the surface when the rainfall intensity exceeds the infiltration capacity of the soil during rainfall. This part of the runoff is the super-infiltration flow production. For example, in some arid areas or areas with poor vegetation coverage, the soil infiltration capacity is limited. When encountering a strong rainfall, the rainwater will not have time to infiltrate and will quickly form a water flow on the ground.

[0088] The total runoff of the full storage part refers to the sum of all runoff generated by the full storage runoff mechanism in a watershed. Its size is related to factors such as the previous soil moisture content, the total rainfall, the water storage characteristics of the soil in the watershed, and the land use pattern. For example, in a forested watershed, the soil has a strong water storage capacity. When the soil moisture content is low in the early stage, more rainfall is required to make the soil full of water and produce runoff; when the soil moisture content is high in the early stage, less rainfall can trigger full storage runoff. Adding the runoff generated by this mechanism in the entire watershed gives the total runoff of the full storage part. Full storage runoff refers to the process during which, when the soil moisture content reaches the field water holding capacity (i.e., the soil moisture content when the capillary suspension water in the soil pores reaches the maximum), subsequent rainfall will produce runoff. In other words, the soil is like a container. After being "filled" with rainwater, the excess rainwater begins to form runoff. This runoff generation mode is common in humid areas or areas with good vegetation coverage, and the soil water storage capacity plays a key role in the runoff generation process.

[0089] like Figure 4 As shown, the calculation of the basin parameters in the simulated analysis basin based on the hydrological parameters in the simulated analysis basin and the at least one hydrological model includes:

[0090] S402, according to the net rainfall falling in the simulated analysis basin, the proportion of impervious area in the simulated analysis basin, and the infiltration capacity of the simulated analysis basin in a preset time period, the excess seepage flow rate of the impervious layer and the excess seepage flow rate on the permeable layer are calculated.

[0091] S404, calculating the total flow rate of the excess seepage part according to the excess seepage flow rate of the impermeable layer and the excess seepage flow rate on the permeable layer.

[0092] Specifically, the excess infiltration runoff on the permeable layer can be calculated based on the net rainfall on the ground in the simulated analysis basin and the proportion of the impervious area in the simulated analysis basin. The excess infiltration runoff of the impervious layer can be calculated based on the net rainfall on the ground in the simulated analysis basin, the proportion of the impervious area in the simulated analysis basin, and the infiltration capacity of the simulated analysis basin within a preset time period.

[0093] In some exemplary embodiments, the following formula can be used to calculate the excess infiltration runoff of the impervious layer and the excess infiltration runoff of the permeable layer:

[0094]

[0095] where R h is the total excess infiltration runoff of the main calculation unit determined to be mixed runoff, and the excess infiltration runoff is composed of the excess infiltration runoff R h1 of the impervious layer and the excess infiltration runoff R h2 on the permeable layer. PE is the net rainfall on the ground, and per ip is the proportion of the impervious area in the geomorphic hydrological response unit is the infiltration capacity.

[0096] S406. Calculate the full - storage runoff of the preferential flow layer and the full - storage runoff of the lower - layer soil that replenishes upward after being full - stored according to the infiltration capacity, the water content of the preferential flow layer, the maximum water content of the preferential flow layer in the surface soil, and the drainage volume from the deep soil to the preferential flow layer after reaching the field water - holding capacity in the simulated analysis basin.

[0097] S408. Calculate the total full - storage runoff according to the full - storage runoff of the preferential flow layer and the full - storage runoff of the lower - layer soil that replenishes upward after being full - stored.

[0098] Specifically, the full - storage runoff of the preferential flow layer can be calculated according to the infiltration capacity, the water content of the preferential flow layer, and the maximum water content of the preferential flow layer in the surface soil in the simulated analysis basin. The full - storage runoff of the lower - layer soil that replenishes upward after being full - stored can be calculated according to the water content of the preferential flow layer, the maximum water content of the preferential flow layer in the surface soil, and the drainage volume from the deep soil to the preferential flow layer after reaching the field water - holding capacity.

[0099] In some exemplary embodiments, the following formula can be used to calculate the full - storage runoff of the lower - layer soil that replenishes upward after being full - stored and the full - storage runoff of the preferential flow layer:

[0100]

[0101] where the total full - storage runoff R d is composed of the full - storage runoff R d1 of the preferential flow layer and the full - storage runoff R of the lower - layer soil that replenishes upward after being full - storedd2 Composed of. is the water content of the preferential flow layer in the soil; is the maximum water content of the preferential flow layer in the surface soil; is the drainage volume from the deep soil to the preferential flow layer after reaching the field capacity.

[0102] In one embodiment, the hydrological parameters include: the linear coefficient and non-linear coefficient of preferential flow layer outflow, the water content of the underlying soil in a preset period, the linear coefficient and non-linear coefficient of underlying soil outflow, the water content of the underground reservoir, and the outflow coefficient of the underground reservoir. The linear coefficient of preferential flow layer outflow refers to: when describing the water flow outflow characteristics of the preferential flow layer (the layer in the soil where water moves preferentially and rapidly due to large pores, fractures, etc.), the linear coefficient is a proportionality coefficient used to represent the simple linear relationship between the preferential flow layer outflow and a certain driving factor (such as water level difference, pressure difference, etc.). For example, when it is assumed that the outflow velocity of the preferential flow layer is linearly related to the water level difference between the preferential flow layer and the underlying soil layer, this linear coefficient determines the outflow flow rate corresponding to a unit water level difference. The non-linear coefficient of preferential flow layer outflow is used to describe the part that does not conform to the simple linear relationship during the preferential flow layer outflow process. Due to the complexity of soil structure and the diversity of water flow movement (such as non-linear flow of water in complex pore structures), the outflow of the preferential flow layer is often not completely described by a simple linear relationship. This non-linear coefficient takes into account the non-linear outflow characteristics caused by these complex factors. The water content of the underlying soil in a preset period refers to the amount of water contained in the underlying soil (relative to the surface soil, usually referring to the soil layer below a certain depth) within a specific, pre-set period of time. This water content can be expressed by volumetric water content (i.e., the volume ratio of water in the unit volume of soil) or gravimetric water content (the weight ratio of water in the unit weight of soil). The linear coefficient of underlying soil outflow is similar to the linear coefficient of preferential flow layer outflow. It is a proportionality coefficient used to describe the linear relationship between the underlying soil outflow (such as the flow of subsurface flow from the underlying soil to deeper soil or groundwater body) and a certain driving factor (such as hydraulic gradient). For example, in the case where the simple Darcy's law applies, the outflow velocity of the underlying soil is linearly related to the hydraulic gradient, and this linear coefficient reflects the proportionality of this linear relationship. The non-linear coefficient of underlying soil outflow is a coefficient that takes into account the non-linear characteristics caused by factors such as uneven soil structure and complex water flow paths during the underlying soil outflow process. In the actual soil environment, the outflow of the underlying soil may be affected by various factors such as soil particle aggregation, uneven fracture distribution, and the interaction between water flow and soil particles, resulting in a non-linear relationship between the outflow and the driving factor. This coefficient is used to describe this non-linear part. The water content of the underground reservoir regards the underground aquifer as an "underground reservoir", and its water content refers to the total amount of water stored in the underground aquifer. The magnitude of this water volume is related to factors such as the porosity of the aquifer, the area and thickness of the aquifer, and the groundwater level. The outflow coefficient of the underground reservoir is a coefficient used to represent the ability of the underground reservoir (aquifer) to outflow water. It is usually related to factors such as the hydraulic conductivity of the aquifer, the water level difference, and the characteristics of the outflow path.The outflow coefficient determines the amount of water flowing out of the underground reservoir into the surrounding environment (such as rivers, lakes, or other aquifers) under certain hydraulic conditions.

[0103] The basin parameters also include: the preferential flow rate in the preferential flow layer of the surface soil, the subsurface flow rate in the lower soil, and the base flow rate; the preferential flow rate in the preferential flow layer of the surface soil refers to the water flow rate generated in the preferential flow layer of the surface soil due to the preferential flow mechanism (through fast channels such as macropores and fractures). It is a special form of water flow in the surface soil, different from ordinary infiltration and subsurface flow. Its flow rate is affected by various factors such as the pore characteristics, water content, hydraulic gradient of the preferential flow layer, and the hydraulic connection with the surrounding soil layers. The subsurface flow rate in the lower soil refers to the water flow rate formed by the lateral or vertical flow of water in the pores of the lower soil (usually the soil layer at a certain depth below the surface soil) under the action of gravity and hydraulic gradient. Subsurface flow is an important part of soil water movement. It is between surface runoff and groundwater, and its flow rate is closely related to factors such as soil texture, structure, water content, and hydraulic gradient. The base flow rate refers to the relatively stable part of the flow formed by groundwater recharge during the flow process of a river. The base flow rate does not include surface runoff (such as flood flow formed by rainfall). It mainly reflects the interaction between groundwater and surface water. The magnitude of the base flow rate depends on factors such as the characteristics of the underground aquifer (such as the thickness, porosity, and hydraulic conductivity of the aquifer), the height of the groundwater level, and the hydraulic connection between the river and the aquifer.

[0104] Such as Figure 5 As shown, calculating the basin parameters in the simulation analysis basin based on the hydrological parameters and the at least one hydrological model in the simulation analysis basin includes:

[0105] S502, calculating the preferential flow rate in the preferential flow layer of the surface soil based on the water content of the preferential flow layer and the linear and non-linear coefficients of the preferential flow layer outflow.

[0106] S504, calculating the subsurface flow rate in the lower soil based on the water content of the lower soil in a preset time period, the linear and non-linear coefficients of the lower soil outflow.

[0107] S506, calculating the base flow rate based on the water content of the underground reservoir and the outflow coefficient of the underground reservoir.

[0108] Specifically, the preferential flow rate in the preferential flow layer of the surface soil can be calculated using the following formula. The preferential flow rate R in the preferential flow layer of the surface soil pr is:

[0109]

[0110] where kpr1 and k pr2 are the linear and non - linear coefficients of the outflow from the preferential flow layer.

[0111] The subsurface flow rate of the lower - layer soil can be obtained by using the following formula. The subsurface flow rate R of the lower - layer soil i is:

[0112]

[0113] where S i is the water content of the lower - layer soil in the preset time period; k i1 and k i2 are the linear and non - linear coefficients of the outflow from the lower - layer soil.

[0114] The base flow can be obtained by using the following formula. The base flow R g is:

[0115]

[0116] where S g is the water content of the underground reservoir; k g is the outflow coefficient of the underground reservoir.

[0117] The basin parameters include: the total water production flow rate. Based on the hydrological parameters in the simulated analysis basin and the at least one hydrological model, calculating the basin parameters in the simulated analysis basin further includes:

[0118] S508, obtaining the total water production flow rate based on the sum of the total over - infiltration production flow rate, the total production flow rate of the full - storage part, the preferential flow rate of the preferential flow layer of the surface soil, the subsurface flow rate of the lower - layer soil, and the base flow.

[0119] Total production flow rate is:

[0120]

[0121] In some exemplary embodiments, as Figure 6 shown, it is a schematic diagram of the vertical mixing structure of the hydrological model. The meanings of the parameters in the figure are shown in Table 1, the main parameters of the hydrological model.

[0122] Table 1, the main parameters of the hydrological model

[0123]

[0124] In one embodiment, as Figure 7 shown, the method further includes:

[0125] S602, calculating the peak - flow relative error and the coefficient of determination of each of the hydrological models.

[0126] S604. Determine the evaluation index of each hydrological model based on the peak flood relative error and the coefficient of determination.

[0127] S606. In response to the evaluation index not meeting the preset index threshold, recalibrate the hydrological model that does not meet the preset index threshold.

[0128] Among them, the peak flood relative error is an important index used to measure the deviation degree between the simulation result and the actual observation value in the fields of flood simulation, hydrological analysis, etc. The coefficient of determination is an index widely used in statistics and data analysis to evaluate the goodness of fit of the model, that is, the ability of the model to explain the observed data. Calibration refers to the process of adjusting the parameters in the hydrological model to make the simulation result of the model as close as possible to the actual observed data. Simply put, it is to find a set of optimal model parameters to make the model better reflect the hydrological process in the study area.

[0129] Specifically, the actual flood measurement data of a certain area (for example, the simulation analysis basin) can be obtained, and then the flood simulation data can be determined by using the simulation value of the simulation analysis basin calculated by the hydrological model. The peak flood relative error can be calculated according to the actual flood measurement data and the flood simulation data. The coefficient of determination can also be calculated by using the measured value and the simulated value of the total flow of the simulation analysis basin. Then, the evaluation index of each hydrological model is determined by using the peak flood relative error and the coefficient of determination. When the evaluation index does not meet the preset index threshold, the hydrological model that does not meet the preset index threshold is recalibrated.

[0130] In some exemplary embodiments, the following formulas can be used to calculate the peak flood relative error and the coefficient of determination:

[0131] Peak flood relative error (REP):

[0132]

[0133] In the formula, x sim represents the flood simulation data, and x obs represents the actual flood measurement data.

[0134] Coefficient of determination (NSE):

[0135]

[0136] In the formula, in the formula refers to the observed value, refers to the simulated value, represents the th value at the It represents the overall average of the observed values. In addition, it should be noted that the evaluation index of each hydrological model can be determined based on the total value of the relative peak flood error and the coefficient of determination, or can be determined after weighting the relative peak flood error and the coefficient of determination. In some embodiments of the present disclosure, how to calculate the evaluation index is not limited.

[0137] In this embodiment, calculating the relative peak flood error and the coefficient of determination can accurately quantify the simulation effect of the hydrological model from different perspectives. The relative peak flood error focuses on the key index of peak flood discharge, clearly showing the deviation degree between the model prediction value and the actual observed value, and directly reflecting the accuracy of the model in simulating the flood peak. The coefficient of determination, on the other hand, measures the overall explanatory ability of the model for the observed data and comprehensively evaluates the goodness of fit of the model to the entire hydrological process. For example, in a flood simulation scenario, through these two indicators, it can be clearly known how the model performs in capturing the flood peak characteristics and simulating the overall flood process. Determining the evaluation index based on the relative peak flood error and the coefficient of determination is not a judgment based on a single index, but a comprehensive consideration of the model's performance in different aspects. This avoids the one-sidedness brought by relying solely on a single index and makes the evaluation of the model more scientific and reasonable. For example, if only the relative peak flood error is used as the evaluation basis, the fitting ability of the model to the overall flood process may be ignored; conversely, if only looking at the coefficient of determination, the key factor of flood peak simulation accuracy may not be highlighted.

[0138] It should be understood that although the steps in the flowcharts involved in the above-described embodiments are displayed in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless there is a clear indication in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-described embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be executed alternately or in turn with at least a part of other steps or steps or stages in other steps.

[0139] Based on the same inventive concept, the embodiments of the present disclosure also provide a flood impact simulation analysis device for implementing the flood impact simulation analysis method described above. The solution provided by this device to solve the problem is similar to the solution described in the above method. Therefore, the specific limitations in one or more embodiments of the flood impact simulation analysis device provided below can refer to the limitations on the flood impact simulation analysis method in the above text, and will not be repeated here.

[0140] In one embodiment, as Figure 8As shown in the figure, a flood impact simulation and analysis device 700 is provided, including: a watershed determination module 702, a model construction module 704, a watershed analysis module 706, a watershed parameter determination module 708, and a flood simulation module 710, where:

[0141] The watershed determination module 702 is used to determine the target watershed and determine the sub-watershed units and sub-watershed nodes in the regional data of the target watershed;

[0142] The model construction module 704 is used to construct multiple hydrological models based on the relationship between the sub-watershed units and sub-watersheds;

[0143] The watershed analysis module 706 is used to determine the simulation analysis watershed in the target watershed and determine at least one hydrological model in the simulation analysis watershed;

[0144] The watershed parameter determination module 708 is used to calculate the watershed parameters in the simulation analysis watershed based on the hydrological parameters in the simulation analysis watershed and the at least one hydrological model;

[0145] The flood simulation module 710 is used to construct a flood simulation model based on the topographic data of the simulation analysis watershed, perform flood simulation according to the flood simulation model and the watershed parameters, analyze based on the results of the flood simulation, and determine the flood impact; the flood simulation model adopts the conservation form of the two-dimensional shallow water equations.

[0146] In an embodiment of the device, the watershed parameters include: total water production flow; the flood simulation model includes: a one-dimensional hydrodynamic simulation model and a two-dimensional hydrodynamic simulation model; the flood simulation module 710 includes:

[0147] The first simulation module is used to input the total water production flow as input data into the one-dimensional hydrodynamic simulation model, and use the one-dimensional hydrodynamic simulation model to perform the first flood simulation, and the first flood simulation includes: river flow simulation, water level prediction, and water flow velocity analysis.

[0148] The second simulation module is used to input the total water production flow as input data into the two-dimensional hydrodynamic simulation model, and use the two-dimensional hydrodynamic simulation model to perform the second flood simulation, and the second flood simulation includes: levee breach flood simulation.

[0149] In one embodiment of the device, the hydrological parameters include: net rainfall on the ground, proportion of impervious area, infiltration capacity, water content in the preferential flow layer, maximum water content in the preferential flow layer in the surface soil, drainage volume from the deep soil to the preferential flow layer after the deep soil reaches the field capacity; the basin parameters further include: total runoff from the excess infiltration part and total runoff from the full storage part; the basin parameter determination module 708 is further configured to calculate the overland flow from the impervious layer and the overland flow on the pervious layer according to the net rainfall on the ground in the simulated analysis basin, the proportion of impervious area in the simulated analysis basin, and the infiltration capacity of the simulated analysis basin within a preset time period; calculate the total runoff from the excess infiltration part according to the overland flow from the impervious layer and the overland flow on the pervious layer; calculate the full storage runoff of the preferential flow layer and the full storage runoff replenished upward after the lower layer soil is full according to the infiltration capacity, water content in the preferential flow layer, maximum water content in the preferential flow layer in the surface soil, and drainage volume from the deep soil to the preferential flow layer after the deep soil reaches the field capacity in the simulated analysis basin; calculate the total runoff from the full storage part according to the full storage runoff of the preferential flow layer and the full storage runoff replenished upward after the lower layer soil is full.

[0150] In one embodiment of the device, the hydrological parameters include: linear coefficient and non-linear coefficient of the preferential flow layer outflow, water content of the lower layer soil within a preset time period, linear coefficient and non-linear coefficient of the lower layer soil outflow, water content of the underground reservoir, and outflow coefficient of the underground reservoir; the basin parameters further include: preferential flow of the preferential flow layer in the surface soil, interflow of the lower layer soil, and base flow; the basin parameter determination module 708 is further configured to calculate the preferential flow of the preferential flow layer in the surface soil based on the water content of the preferential flow layer and the linear coefficient and non-linear coefficient of the preferential flow layer outflow; calculate the interflow of the lower layer soil based on the water content of the lower layer soil within a preset time period, the linear coefficient and non-linear coefficient of the lower layer soil outflow; calculate the base flow based on the water content of the underground reservoir and the outflow coefficient of the underground reservoir.

[0151] In one embodiment of the device, the basin parameters include: total water production flow, and the basin parameter determination module 708 is further configured to obtain the total water production flow based on the sum of the total runoff from the excess infiltration part, the total runoff from the full storage part, the preferential flow of the preferential flow layer in the surface soil, the interflow of the lower layer soil, and the base flow.

[0152] In one embodiment of the device, the device further includes: a calibration module, configured to calculate the peak flow relative error and the coefficient of determination of each hydrological model; determine the evaluation index of each hydrological model based on the peak flow relative error and the coefficient of determination; and re-calibrate the hydrological model that does not meet the preset index threshold in response to the evaluation index not satisfying the preset index threshold.

[0153] Each module in the above flood impact simulation analysis device can be implemented in whole or in part by software, hardware, or a combination thereof. Each of the above modules can be embedded in the processor of the computer device in hardware form or independent of it, or stored in the memory of the computer device in software form, so that the processor can call and execute the operations corresponding to each of the above modules.

[0154] In one embodiment, a computer device is provided. The computer device can be a server, and its internal structure diagram can be as Figure 9 shown. The computer device includes a processor, a memory, and a network interface connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store target basin data. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, it implements a flood impact simulation analysis method.

[0155] In one embodiment, a computer device is provided. The computer device can be a terminal, and its internal structure diagram can be as Figure 10 shown. The computer device includes a processor, a memory, a communication interface, a display screen, and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner. The wireless manner can be achieved through WIFI, a mobile cellular network, NFC (Near Field Communication), or other technologies. When the computer program is executed by the processor, it implements a flood impact simulation analysis method. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen. The input device of the computer device can be a touch layer covering the display screen, or a button, a trackball, or a touchpad provided on the housing of the computer device, or an external keyboard, touchpad, or mouse, etc.

[0156] Those skilled in the art can understand that Figure 9 the structures shown in FIGS. 3 or 10 are merely block diagrams of some structures related to the present disclosure solution, and do not constitute a limitation on the computer device to which the present disclosure solution is applied. The specific computer device may include more or fewer components than those shown in the figures, or combine some components, or have a different component layout.

[0157] In one embodiment, a computer device is provided, including a memory and a processor. A computer program is stored in the memory, and when the processor executes the computer program, the steps in the above method embodiments are implemented.

[0158] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0159] In one embodiment, a computer program product is provided, including a computer program. When the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0160] It should be noted that the topographic parameters, hydrological data, etc. of the simulated analysis watershed involved in this disclosure are all information and data authorized by the user or fully authorized by all parties.

[0161] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided by the present disclosure can include at least one of non-volatile and volatile memories. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The databases involved in the embodiments provided by the present disclosure can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided by the present disclosure can be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, data processing logics based on quantum computing, etc., without limitation.

[0162] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0163] The above-described embodiments merely represent several implementation manners of the present disclosure. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present disclosure. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present disclosure, several modifications and improvements can still be made, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the appended claims.

Claims

1. A flood impact simulation analysis method, characterized in that: The method comprises: Determine a target watershed, and determine sub-watershed units and sub-watershed nodes in regional data of the target watershed; constructing a plurality of hydrological models based on the relationship between the sub-basin units and the sub-basin nodes; Determine a simulation analysis watershed in the target watershed, and determine at least one hydrological model in the simulation analysis watershed; Calculating basin parameters in the simulated analysis basin based on the hydrological parameters in the simulated analysis basin and the at least one hydrological model; A flood simulation model is constructed based on the terrain data of the simulation analysis basin, a flood simulation is performed according to the flood simulation model and the basin parameters, and an analysis is performed based on the results of the flood simulation to determine the flood impact; the flood simulation model adopts the conservation form of the two-dimensional shallow water equation.

2. The method according to claim 1, characterized in that The basin parameters include: total water flow; the flood simulation model includes: a one-dimensional hydrodynamic simulation model and a two-dimensional hydrodynamic simulation model; the flood simulation is performed according to the flood simulation model and the basin parameters, including: The total water production flow is used as input data and input into the one-dimensional hydrodynamic simulation model, and the one-dimensional hydrodynamic simulation model is used to perform a first flood simulation, wherein the first flood simulation includes: river flow simulation, water level prediction and water flow velocity analysis; The total water production flow is used as input data and input into the two-dimensional hydrodynamic simulation model. The two-dimensional hydrodynamic simulation model is used to perform a second flood simulation, wherein the second flood simulation includes: a dam breach flood simulation.

3. The method according to claim 2, characterized in that The hydrological parameters include: net rainfall on the ground, proportion of impervious area, infiltration capacity, water content of the preferential flow layer, maximum water content of the preferential flow layer in the surface soil, and drainage of the preferential flow layer after the deep soil reaches the field water holding capacity; the watershed parameters also include: total flow production of the super-infiltration part and total flow production of the full storage part; the calculation of the watershed parameters in the simulated analysis watershed based on the hydrological parameters in the simulated analysis watershed and the at least one hydrological model includes: According to the net rainfall in the simulated analysis basin, the proportion of impervious area in the simulated analysis basin, and the infiltration capacity of the simulated analysis basin in a preset period of time, the excess infiltration flow rate of the impervious layer and the excess infiltration flow rate on the permeable layer are calculated; The total flow rate of the super-seepage part is calculated according to the super-seepage flow rate of the impermeable layer and the super-seepage flow rate on the permeable layer; According to the simulation analysis of the infiltration capacity in the watershed, the water content of the preferential flow layer, the maximum water content of the preferential flow layer in the surface soil, and the drainage of the preferential flow layer after the deep soil reaches the field water holding capacity, the full flow rate of the preferential flow layer and the full flow rate of the upper recharge after the lower soil is full are calculated; The total flow rate of the full storage part is calculated based on the full storage flow rate of the preferential flow layer and the full storage flow rate of the lower soil layer replenished upward after being full.

4. The method according to claim 3, characterized in that The hydrological parameters include: the linear coefficient and nonlinear coefficient of the outflow of the preferential flow layer, the water content of the lower soil in a preset period, the linear coefficient and nonlinear coefficient of the outflow of the lower soil, the water content of the groundwater reservoir and the outflow coefficient of the groundwater reservoir; the watershed parameters also include: the preferential flow rate of the preferential flow layer of the surface soil, the intersoil flow rate and base flow of the lower soil; the calculation of the watershed parameters in the simulated analysis watershed based on the hydrological parameters in the simulated analysis watershed and the at least one hydrological model includes: Based on the water content of the preferential flow layer and the outflow linear coefficient and nonlinear coefficient of the preferential flow layer, the preferential flow flow rate of the surface soil preferential flow layer is calculated; The flow rate of the lower soil layer is calculated based on the water content of the lower soil layer in a preset period of time, the linear coefficient and the nonlinear coefficient of the lower soil outflow; The base flow is calculated based on the water content of the groundwater reservoir and the groundwater reservoir outflow coefficient.

5. The method according to claim 4, characterized in that The basin parameters include: total water production flow, the calculation of the basin parameters in the simulated analysis basin based on the hydrological parameters in the simulated analysis basin and the at least one hydrological model also includes: The total water production flow is obtained based on the sum of the total flow of the super-infiltration part, the total flow of the full storage part, the preferential flow flow of the surface soil preferential flow layer, the intersoil flow of the lower soil layer and the base flow.

6. The method according to claim 1, characterized in that The method further comprises: Calculating the relative error and coefficient of certainty of the flood peak of each of the hydrological models; Determining the evaluation index of each hydrological model based on the flood peak relative error and the certainty coefficient; In response to the evaluation index not satisfying a preset index threshold, the hydrological model that does not satisfy the preset index threshold is recalibrated.

7. A flood impact simulation and analysis device, characterized in that: The device comprises: A watershed determination module, used to determine a target watershed, and determine sub-watershed units and sub-watershed nodes in regional data of the target watershed; A model building module, used for building a plurality of hydrological models based on the relationship between the sub-basin units and the sub-basins; A watershed analysis module, used to determine a simulated analysis watershed in the target watershed, and to determine at least one hydrological model in the simulated analysis watershed; A watershed parameter determination module, used for calculating the watershed parameters in the simulated analysis watershed based on the hydrological parameters in the simulated analysis watershed and the at least one hydrological model; The flood simulation module is used to construct a flood simulation model based on the terrain data of the simulation analysis basin, perform flood simulation according to the flood simulation model and the basin parameters, and analyze based on the results of the flood simulation to determine the flood impact; the flood simulation model adopts the conservation form of the two-dimensional shallow water equation.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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