Flood inundation method, device and electronic device for small rivers in mountainous areas

Abstract

This invention provides a method, apparatus, and electronic device for projecting flood inundation in small and medium-sized rivers in mountainous areas, relating to the fields of water conservancy engineering and flood control and disaster reduction. By fusing sparse measured cross-sections and satellite DEMs using a distance-varying weight function, the topography of mountain river channels is effectively reconstructed, eliminating excessive reliance on high-precision measured topography. By real-time identification of Froude numbers and adaptive switching between the energy equation and Manning formula, the problem of traditional models easily diverging under complex flow conditions is solved, ensuring stable water surface line calculations. Through spatial constraints, depth filtering, and connectivity checks, isolated spurious inundation patches are completely eliminated, resulting in a realistic and reliable flood inundation map that can be directly used for emergency decision-making.

Description

Technical Field

[0001] This invention relates to the field of water conservancy engineering and flood control and disaster reduction technology, and in particular to a method, device and electronic equipment for predicting flood inundation of small and medium-sized rivers in mountainous areas. Background Technology

[0002] Small and medium-sized rivers in mountainous areas are characterized by rapid confluence, steep channel gradients, and complex riverbed morphology, making them high-risk areas for flash floods. However, existing flood inundation projection methods face the following technical bottlenecks when applied to mountainous rivers: First, obtaining high-precision topographic data is difficult. Publicly available satellite digital elevation models (such as SRTM, ASTER, and ALOS) typically have a resolution of 12.5 to 30 meters, limited vertical accuracy, and are unable to accurately reflect the deep channel morphology of mountainous river channels that are only a few meters to a dozen meters wide. Directly using satellite digital elevation models for hydrodynamic simulations can lead to a "river without channel" phenomenon, with flood simulation results often showing widespread flooding on flat surfaces and severely distorted inundation areas.

[0003] Secondly, the flow patterns of mountain rivers are complex and variable. Due to the steep slopes and numerous drops in the riverbed, the water flow frequently switches between rapid flow (supercritical flow) and slow flow (subcritical flow). Traditional one-dimensional hydrodynamic models are mostly based on the assumption of slow flow (such as the standard step method). When encountering rapid flow sections, the governing equations are prone to multiple solutions or no solutions, leading to calculation divergence or program crashes, making it difficult to complete the stable estimation of the water surface line throughout the entire flow.

[0004] Finally, inundation area mapping suffers from artifact interference. Conventional "water level minus topography" inundation area extraction methods are prone to generating isolated pseudo-flood zones in low-lying areas far from the river channel (such as noise points in digital elevation models or real depressions). These pseudo-flood patches not only affect the accuracy of disaster situation assessment but may also mislead flood control decisions. Summary of the Invention

[0005] The purpose of this invention is to provide a method, apparatus, and electronic device for projecting flood inundation in small and medium-sized rivers in mountainous areas. By fusing sparse measured cross sections and satellite DEMs with a weight function that varies with distance, the topography of river channels in mountainous areas can be effectively reconstructed, eliminating the over-reliance on high-precision measured topography. By identifying Froude numbers in real time and adaptively switching between the energy equation or Manning formula, the problem of traditional models easily diverging under complex flow conditions is solved, ensuring stable water surface line projection. Through spatial constraints, depth filtering, and connectivity checks, isolated pseudo-inundation patches are completely eliminated, and the generated flood inundation map is realistic and reliable, which can be directly used for emergency decision-making.

[0006] In a first aspect, the present invention provides a method for extrapolating flood inundation in small and medium-sized rivers in mountainous areas, comprising: Acquire satellite digital elevation model data of the target area, centerline vector data of the river channel, and measured cross-sectional data of the river channel; Based on measured cross-sectional data, virtual groove correction is performed on satellite digital elevation model data by using a weight function that varies with the distance from grid points to the river centerline, thereby generating corrected hydrodynamic calculation terrain. Based on the corrected hydrodynamic topography, the water surface line is extrapolated along the river channel. During the extrapolation process, the cross-sectional Froude number is calculated in real time. Based on the rapid or slow flow state represented by the cross-sectional Froude number, the water level is extrapolated using the energy equation or Manning formula. When transcritical flow is detected, the momentum equation used to calculate the conjugate water depth is used to determine the hydraulic jump location. Based on the water surface line, an irregular triangular network is used to construct a water level surface within the river buffer zone. The water level surface is then superimposed with the corrected hydrodynamic topography to calculate the water depth. Unreasonable pseudo-inundation patches are removed through a multi-level filtering mechanism that includes spatial constraints, depth threshold filtering, and connectivity checks to obtain the final flood inundation map.

[0007] In some preferred embodiments of the present invention, virtual groove correction is performed using the following formula: ; in, This is the corrected grid elevation. The elevation of the original satellite digital elevation model. The corresponding riverbed elevation obtained by interpolation. The weighting function varies with the distance from the grid point to the river centerline. This represents the vertical distance from the grid point to the centerline of the river channel.

[0008] In some preferred embodiments of the present invention, the weighting function adopts a hybrid weighting strategy of "linear decay in the kernel and exponential decay in the periphery", including: dividing the river buffer zone into a kernel zone and a peripheral gradient zone according to the vertical distance from the grid point to the center line of the river channel, with the weight in the kernel zone decaying linearly and the weight in the peripheral gradient zone decaying exponentially.

[0009] In some preferred embodiments of the present invention, the weighting function is constrained by the following formula: ; in, The preset kernel area width, The preset width of the outer gradient area, This is the preset attenuation coefficient.

[0010] In some preferred embodiments of the present invention, the water level is calculated according to the rapid or slow flow state characterized by the Froude number of the cross-section, using the energy equation or Manning formula accordingly, including: If the current Froude number at the cross-section is less than 1, it is determined to be a slow flow, and the water level is calculated cross-section by cross-section from downstream to upstream using the Bernoulli energy equation. If the current cross-section's Froude number is greater than 1, it is determined to be a rapid current. Based on the preset local riverbed slope, the normal water depth is calculated using the following Manning formula as the control water depth for the current cross-section: ; in, For traffic, For roughness, For the water flow area, For local riverbed slope, This is the normal water depth.

[0011] In some preferred embodiments of the present invention, upon detection of transcritical flow, the hydraulic jump location is determined using a momentum equation for calculating the conjugate water depth, including: When it is detected that the upstream section is a rapid flow and the downstream section is a slow flow, the momentum equation is used to calculate the conjugate water depth, and the equivalent wide and shallow approximation is used, with the conjugate hydraulic depth replacing the water depth of the rectangular section. The upstream Froude number is constrained by the following formula: ; ; ; in, For the upstream Buddha Rude number, For traffic, The upstream water flow area, The width of the upstream water surface. The upstream hydraulic depth, It is the acceleration due to gravity; The conjugate hydraulic depth is constrained by the following formula: ; in, Furthermore, if the estimated hydraulic depth of the downstream control section is lower than... If a hydraulic jump occurs, the downstream water level is forcibly adjusted to meet the conservation of momentum.

[0012] In some preferred embodiments of the present invention, a multi-level filtering mechanism including spatial constraints, depth threshold filtering, and connectivity checks includes: Spatial constraints include: generating an irregular triangular network of water level surfaces only within a buffer zone with the river centerline as the axis and a width equal to the preset buffer zone length, and physically isolating low-lying areas far from the river channel; Depth threshold filtering includes: performing binarization masking on the calculated submerged water depth grid to remove minute noise points where the water depth is less than the preset minimum water depth threshold; Explicit connectivity checks include: performing connected component analysis on the depth-filtered flooded area, identifying all independent flooded patches using a connected component labeling algorithm; constructing a centerline seed region, retaining only connected components that are pixel-level connected to the centerline seed region, and removing all isolated patches; The effectiveness mask includes: using the removed effective water depth area as a mask to extract the water level grid in reverse, and filling the water level value of the area without water depth with a preset null value identifier.

[0013] In some preferred embodiments of the present invention, the method is encapsulated in a standardized Docker container image to achieve rapid cross-platform deployment and computation: The container base environment is a basic container environment built on a lightweight Linux distribution; Algorithm encapsulation includes: compiling the terrain reconstruction, hydrodynamic calculation, and inundation analysis modules into standalone executable programs or Python packages, and exposing standardized command-line interfaces through entry scripts; Data mounting includes: the container runtime accesses the host machine's input data directory and result output directory via volume mounting, thereby decoupling the computation process from the data.

[0014] Secondly, the present invention provides a device for predicting flood inundation in small and medium-sized rivers in mountainous areas, comprising: The data acquisition module is used to acquire satellite digital elevation model data of the target area, centerline vector data of the river channel, and measured cross-sectional data of the river channel; The terrain correction module is used to perform virtual groove correction on satellite digital elevation model data based on measured cross-sectional data, using a weight function that varies with the distance from the grid point to the river centerline, to generate the corrected hydrodynamic calculation terrain. The water surface line estimation module is used to estimate the water surface line along the river channel based on the corrected hydrodynamic topography. During the estimation process, the cross-sectional Froude number is calculated in real time. Based on the rapid or slow flow state represented by the cross-sectional Froude number, the water level is estimated using the energy equation or Manning formula. When transcritical flow is detected, the momentum equation used to calculate the conjugate water depth is used to determine the hydraulic jump location. The flood inundation map processing module is used to construct a water level surface within the river buffer zone based on the water surface line using an irregular triangular network; the water level surface is superimposed with the corrected hydrodynamic calculation topography to calculate the water depth; and unreasonable pseudo-inundation patches are removed through a multi-level filtering mechanism including spatial constraints, depth threshold filtering and connectivity checks to obtain the final flood inundation map.

[0015] Thirdly, the present invention provides an electronic device, including a processor and a memory, wherein the memory stores computer-executable instructions that can be executed by the processor, and the processor executes the computer-executable instructions to implement the flood inundation simulation method for small and medium-sized rivers in mountainous areas provided in the first aspect above.

[0016] This invention brings the following beneficial effects: This invention provides a method, apparatus, and electronic device for projecting flood inundation in small and medium-sized rivers in mountainous areas. The method includes: acquiring satellite digital elevation model data of the target area, centerline vector data of the river channel, and measured cross-sectional data of the river channel; based on the measured cross-sectional data, performing virtual grooving correction on the satellite digital elevation model data using a weighting function that varies with the distance from the grid point to the river channel centerline to generate a corrected hydrodynamic calculation terrain; based on the corrected hydrodynamic calculation terrain, projecting the water surface line along the river channel; wherein, during the projection process, the cross-sectional Froude number is calculated in real time, and the water level is calculated accordingly using the energy equation or Manning formula based on the rapid or slow flow state represented by the cross-sectional Froude number; when transcritical flow is detected, the momentum equation used to calculate the conjugate water depth is used to determine the hydraulic jump location; based on the water surface line, An irregular triangular network is used to construct a water level surface within the river buffer zone. The water level surface is then superimposed with the corrected hydrodynamic topography to calculate the water depth. An unreasonable spurious inundation patches are removed through a multi-level filtering mechanism that includes spatial constraints, depth threshold filtering, and connectivity checks, resulting in the final flood inundation map. By fusing sparse measured cross sections and satellite DEMs with a distance-varying weight function, the topography of mountain river channels is effectively reconstructed, reducing over-reliance on high-precision measured topography. By identifying Froude numbers in real time and adaptively switching between the energy equation or Manning formula, the problem of traditional models easily diverging under complex flow conditions is solved, ensuring stable water surface line calculations. Through spatial constraints, depth filtering, and connectivity checks, isolated spurious inundation patches are completely eliminated, resulting in a reliable and accurate flood inundation map that can be directly used for emergency decision-making. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 A flowchart illustrating a method for predicting flood inundation in small and medium-sized rivers in mountainous areas, provided by an embodiment of the present invention; Figure 2 A comparative schematic diagram of satellite DEM before and after correction is provided for an embodiment of the present invention; Figure 3A schematic diagram for calculating the water surface line is provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of a controlled TIN interpolation range provided in an embodiment of the present invention; Figure 5 This invention provides a schematic diagram of an interpolated water level obtained within a controlled TIN interpolation range based on one-dimensional model simulation results, as provided in an embodiment of the invention. Figure 6 An inundation depth map for eliminating unreasonable inundation areas provided in this embodiment of the invention; Figure 7 This is a schematic diagram of the structure of a flood inundation simulation device for small and medium-sized rivers in mountainous areas, provided in an embodiment of the present invention. Figure 8 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention.

[0019] Icons: 310 - Data acquisition module; 320 - Terrain correction module; 330 - Water surface line calculation module; 340 - Flood inundation map processing module; 400 - Memory; 401 - Processor; 402 - Bus; 403 - Communication interface. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0023] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0024] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0025] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0027] Example 1 This invention provides a method for extrapolating flood inundation in small and medium-sized rivers in mountainous areas. (See also...) Figure 1 The flowchart shown in this embodiment of the invention provides a method for predicting flood inundation in small and medium-sized rivers in mountainous areas. The method includes: Step S102: Obtain satellite digital elevation model data of the target area, centerline vector data of the river channel, and measured cross-sectional data of the river channel.

[0028] Specifically, satellite digital elevation model (DEM) data can be sourced from publicly available products such as ALOS, SRTM, or ASTER, typically with a resolution of 12.5m or 30m, providing a broad background of surface elevation. River centerline vector data is used to determine the river's course and subsequent buffer zone. Measured cross-sectional data, usually sparsely distributed, contains riverbed elevation information at key locations, used to correct for riverbed topography that satellite DEMs cannot accurately reflect. By fusing multi-source data, the limitations of single-source data in representing mountainous river topography are overcome, laying a reliable data foundation for subsequent high-precision hydrodynamic simulations and effectively overcoming the simulation distortion problem of "river without channel" caused by a lack of topographic data.

[0029] Step S104: Based on the measured cross-sectional data, the satellite digital elevation model data is virtually grooved and corrected using a weighting function that varies with the distance from the grid point to the river centerline, thereby generating the corrected hydrodynamic calculation terrain.

[0030] Specifically, virtual groove correction modifies the satellite DEM by constructing a weighted field with the river channel centerline as the axis. For any grid point within the river channel buffer zone, its vertical distance to the centerline is calculated. And assign different weights based on distance. Corrected raster elevation From the original DEM elevation Interpolated riverbed elevation The weighted average is obtained. This correction method can effectively depict the true channel morphology on the DEM by relying solely on sparse measured cross sections, solving the defect of satellite DEMs having "rivers but no channels". This enables subsequent hydrodynamic calculations to accurately reflect the flow capacity of the river channel, thereby improving the accuracy of flood simulation.

[0031] Furthermore, in some preferred embodiments of the present invention, virtual groove correction is performed using the following formula: ;in, This is the corrected grid elevation. The elevation of the original satellite digital elevation model. The corresponding riverbed elevation obtained by interpolation. The weighting function varies with the distance from the grid point to the river centerline. This represents the vertical distance from the grid point to the centerline of the river channel.

[0032] Specifically, The weighting function is obtained by linear interpolation along the river channel using measured cross-sectional data and is used to characterize the bottom position of the actual riverbed. The measured riverbed elevation determines the degree to which it contributes to the final topography: the closer to the centerline, the greater the contribution. The larger the elevation, the closer the corrected elevation is to the riverbed; the farther the distance, the closer the corrected elevation is to the riverbed. The smaller the value, the more the terrain gradually transitions to the original DEM. This weighted fusion method ensures the continuity and natural transition of the corrected terrain, avoiding abrupt terrain changes caused by directly replacing elevations, thus providing a smooth and physically consistent computational grid for hydrodynamic calculations.

[0033] Furthermore, in some preferred embodiments of the present invention, the weighting function adopts a hybrid weighting strategy of "linear decay in the kernel and exponential decay in the periphery", including: dividing the river buffer zone into a kernel zone and a peripheral gradient zone according to the vertical distance from the grid point to the center line of the river channel, with the weight in the kernel zone decaying linearly and the weight in the peripheral gradient zone decaying exponentially.

[0034] Specifically, the core region is the area immediately adjacent to the centerline of the river channel (e.g., the distance is less than the preset core region width). This area is the core of the river channel and requires forced DEM downscaling to the riverbed position. Therefore, the weight is linearly reduced from 1.0 to 0.7 to ensure accurate river channel morphology; the outer gradient zone (distance between...) and The area between the artificial riverbed and the original topography (between the two sections) is used as a transition zone. An exponential decay method is employed to smoothly reduce the weights to 0, avoiding numerical oscillations in hydrodynamics caused by abrupt changes in topography. This hybrid weighting strategy ensures the accuracy of the riverbed while achieving a smooth transition between the artificial riverbed and the original topography, significantly improving the stability of subsequent hydrodynamic calculations.

[0035] Furthermore, in some preferred embodiments of the present invention, the weighting function is constrained by the following formula: ;in, The preset kernel area width, The preset width of the outer gradient area, This is the preset attenuation coefficient.

[0036] Specifically, kernel width The width can be set according to the actual width of the river channel, for example, taking 1 / 2 of the average river width; the width of the outer gradient zone The width of the river can be 2-3 times; the attenuation coefficient k controls the exponential attenuation rate, usually taken as 1.0-2.0. This formula realizes the mathematical expression of the weight decreasing linearly in the core region and decaying exponentially in the outer region. By adjusting... , and It can flexibly adapt to the riverbed morphology of different mountain rivers, giving the terrain correction algorithm good universality and adjustability, and can optimize the correction effect for specific watersheds.

[0037] Step S106: Based on the corrected hydrodynamic topography, the water surface line is extrapolated along the river channel; wherein, the cross-sectional Froude number is calculated in real time during the extrapolation process, and the water level is extrapolated according to the rapid or slow flow state represented by the cross-sectional Froude number, using the energy equation or Manning formula accordingly; when transcritical flow is detected, the momentum equation used to calculate the conjugate water depth is used to determine the hydraulic jump location.

[0038] Specifically, this embodiment employs a one-dimensional steady-flow hydrodynamic model to calculate the water surface line section by section along the river channel from downstream to upstream or from upstream to downstream. At each section, the Froude number is first calculated. Where V is the average flow velocity at the cross section, and D is the hydraulic depth (D=A / T, where A is the cross-sectional area and T is the width of the water surface). The flow regime is determined based on the Fr value: Fr<1 indicates slow flow, which is calculated using the energy equation; Fr>1 indicates rapid flow, which is calculated using the Manning formula to determine the normal water depth. When a rapid flow is detected upstream and a slow flow downstream, a transcritical flow (hydraulic jump) occurs. At this point, the momentum equation is used to calculate the conjugate water depth and correct the downstream water level. This adaptive mechanism can handle the complex situation of frequent flow regime changes in mountainous rivers, ensuring stable convergence of the water surface line calculation process and avoiding the problem of traditional single equations failing or diverging in rapid flow sections.

[0039] Furthermore, in some preferred embodiments of the present invention, the water level is calculated according to the rapid or slow flow state characterized by the Froude number of the cross-section, using the energy equation or Manning formula accordingly. This includes: if the current Froude number of the cross-section is less than 1, it is determined to be a slow flow, and the water level is calculated cross-section by cross-section from downstream to upstream using the Bernoulli energy equation; if the current Froude number of the cross-section is greater than 1, it is determined to be a rapid flow, and the normal water depth is calculated using the following Manning formula based on a preset local riverbed slope as the control water depth of the current cross-section: ;in, For traffic, For roughness, For the water flow area, For local riverbed slope, This is the normal water depth.

[0040] Specifically, for slow-flowing sections, Bernoulli's energy equation (i.e., the principle of energy conservation) is used to calculate the energy level segment by segment from the known downstream water level to the upstream section, taking into account local head loss. For fast-flowing sections, since the energy equation may have multiple solutions or no solution, the model automatically switches to Manning's formula. The local riverbed slope is calculated based on the difference in riverbed elevation between adjacent sections. The normal water depth Hn is directly calculated using the Manning formula and used as the control water depth for this cross section. This rapid flow treatment method avoids the numerical difficulties of iterative solutions, significantly improves the robustness and computational efficiency of the model in steep river sections, and ensures the continuous extrapolation of the water surface line.

[0041] Furthermore, in some preferred embodiments of the present invention, when transcritical flow is detected, the hydraulic jump location is determined using the momentum equation for calculating the conjugate water depth, including: when a rapid flow is detected upstream and a slow flow is detected downstream, the conjugate water depth is calculated using the momentum equation, employing an equivalent wide-shallow approximation, replacing the water depth of the rectangular cross-section with the conjugate hydraulic depth; the upstream Froude number is constrained by the following formula: ; ; ;in, For the upstream Buddha Rude number, For traffic, The upstream water flow area, The width of the upstream water surface. The upstream hydraulic depth, The acceleration due to gravity; the conjugate hydraulic depth is constrained by the following formula: ;in, Furthermore, if the estimated hydraulic depth of the downstream control section is lower than... If a hydraulic jump occurs, the downstream water level is forcibly adjusted to meet the conservation of momentum.

[0042] Specifically, when the model detects that the upstream section is a rapid flow ( The downstream section has a slow flow () When the water level reaches a certain value (e.g., y1), it indicates a possible hydraulic jump. To determine the post-juxtaposition water depth, a conjugate water depth formula based on the momentum equation is used. Considering the irregular cross-section of natural river channels, an equivalent wide-shallow approximation is made using the hydraulic depth y=A / T. The theoretical conjugate hydraulic depth y2 is calculated from the upstream hydraulic depth y1 and the Froude number Fr1. If the hydraulic depth calculated from the downstream cross-section using conventional methods is less than y2, it indicates that the energy equation cannot satisfy momentum conservation. The model then forces a correction to the downstream water level corresponding to y2, thereby accurately simulating the hydraulic jump location and energy loss. This method allows the model to physically consistently handle abrupt changes from rapid to slow flow, improving the accuracy and physical plausibility of the simulation.

[0043] Step S108: Based on the water surface line, construct the water level surface in the river buffer zone using an irregular triangular network; overlay the water level surface with the corrected hydrodynamic calculation topography to calculate the water depth, and remove unreasonable pseudo-inundation patches through a multi-level filtering mechanism including spatial constraints, depth threshold filtering and connectivity checks to obtain the final flood inundation map.

[0044] Specifically, this step first constructs a continuous water level surface using the triangular network (TIN) interpolation method within a pre-defined buffer zone on both sides of the river centerline, based on the water level calculation results at each cross-section along the river. Then, this water level surface is subtracted grid-by-grid from the generated corrected hydrodynamic topography to obtain the preliminary inundation depth. However, since DEM noise or local depressions may create isolated pseudo-inundation zones, a multi-stage filtering mechanism is introduced.

[0045] To address the pseudo-flooding problem in simplified flooding calculation techniques, this embodiment abandons full-map subtraction and instead employs controlled TIN interpolation: Controlled generation—constructing water level TIN surfaces only within the effective buffer zones on both sides of the river centerline, thus eliminating the possibility of water accumulation from distant DEM noise points at the source; Deep cleaning—introducing a preset minimum water depth threshold hmin to automatically filter out thin layers of water depth (e.g., <5cm) caused by interpolation errors; Connectivity checking—although the TIN method limits the calculation range through the buffer, low-lying areas within the DEM itself may still form isolated water accumulation patches within the buffer. This invention adds an explicit post-processing step: Let the water depth raster be H(x,y), construct a binary flooding mask M(x,y)=I[H(x,y)≥h... min The label field L(x, y) is obtained by labeling the connected components of M using the 8-neighborhood connectivity criterion; the centerline is rasterized to obtain the seed mask C(x, y), and then dilated to obtain the seed region S(x, y); the retention rule is K={k| (x, y), L(x, y)=k∧S(x, y)=1}, ,in, This method serves as a mask after removing isolated patches. The final output water level file is strictly limited to the effective water depth range, with invalid areas filled with preset null values ​​(e.g., -999) for easy overlay display in GIS software. This approach solves the common problem of spurious inundation interference in traditional subtractive mapping, enabling the results to be directly used for disaster assessment and emergency decision-making, thus improving the reliability and practicality of inundation mapping.

[0046] Furthermore, in some preferred embodiments of the present invention, a multi-level filtering mechanism including spatial constraints, depth threshold filtering, and connectivity checks includes: spatial constraints, including generating an irregular triangular mesh water level surface only within a buffer zone with the river centerline as the axis and a width equal to a preset buffer zone length, physically isolating low-lying areas far from the river channel; depth threshold filtering, including performing binarization masking on the calculated inundation depth grid to remove tiny noise points with water depths less than a preset minimum water depth threshold; explicit connectivity checks, including performing connected component analysis on the inundation area after depth filtering, identifying all independent inundation patches using a connected component labeling algorithm; constructing a centerline seed region, retaining only connected components that have pixel-level connections with the centerline seed region, and removing all isolated patches; and effectiveness masking, including using the removed effective water depth area as a mask to extract the water level grid in reverse, and filling the water level values ​​of areas without water depth with preset null values.

[0047] Specifically, spatial constraints are determined by the buffer width L. buffer(For example, a number of times the river width) limits the water level interpolation range, excluding isolated depressions far from the river channel from the source. Depth threshold filtering is set to h. min (e.g., 0.05m) Raster cells with a water depth less than this threshold are considered invalid noise points to avoid artifacts caused by thin water layers. Explicit connectivity checks employ an 8-neighborhood connected component labeling algorithm to identify all connected regions. Then, using the seed region obtained from raster expansion along the river centerline as a baseline, only patches connected to the seed region are retained, completely eliminating isolated waterlogged areas caused by DEM noise. Finally, the effective water depth region is used as a mask to retain the corresponding water level values, while the rest are filled with NoData (e.g., -999), generating a water level raster that can be directly overlaid and displayed in GIS. This series of filtering measures ensures the physical accuracy of the inundation area and the aesthetic appeal of the map, improving the usability of the results.

[0048] For example, this embodiment takes a mountainous watershed as an example to verify the practical application effect of this method.

[0049] Basic data: Satellite DEM: The ALOS 12.5m resolution DEM was used as the base terrain.

[0050] River channel data: The centerline of the river channel was extracted for a length of approximately 18.8 km, and 110 measured cross sections were collected along the line.

[0051] Boundary conditions: The upstream inlet flow rate is set to 40 m³ / s, and the downstream outlet flow rate accumulates to 135.8 m³ / s.

[0052] Terrain Reconstruction: Virtual groove correction was performed on the original satellite DEM using riverbed elevation data from 110 measured cross-sections. (See also...) Figure 2 The illustration shows a comparison diagram of satellite DEMs before and after correction provided by an embodiment of the present invention. The corrected terrain clearly retains the river channel features with a width of only 5-10m, solving the problem of "having a river but no channel" in the original DEM in flat river valleys.

[0053] Adaptive hydrodynamic calculation: The model calculates the water surface profile section by section along the river centerline: See Figure 3 The illustrated embodiment of the present invention provides a schematic diagram for water surface line calculation. Near a distance of 4000m, the local slope of the river reaches 0.0237 (steep slope), causing the conventional energy equation calculation to diverge. This method detects that Fr>1 at this cross-section and automatically switches to a rapid flow mode.

[0054] At mileage 11,500m, the model encountered an extremely steep slope (slope > 1.0), but it still ran stably, avoiding program crashes through adaptive switching.

[0055] The final output is water level data for 110 cross-sections along the route, and the entire calculation process takes less than 5 seconds.

[0056] Controlled flood generation: See Figure 4 The diagram shown illustrates a controlled TIN interpolation range according to an embodiment of the present invention. Figure 5 The embodiment of the present invention shown provides an interpolated water level surface diagram obtained within the controlled TIN interpolation range based on the simulation results of a one-dimensional model. Based on the calculated water level along the river, a TIN water level surface is constructed on both sides of the river channel, and a modified DEM is superimposed to generate a flood depth map.

[0057] Raster resolution: The final output submerged water depth raster resolution is 4.57m (aligned with DEM resampling).

[0058] Results of the cleaning process: Through connectivity checks, several false flooding patches located far from the river channel were successfully removed. The final flood inundation map can be found here. Figure 6 The embodiment of the present invention shown provides an inundation depth map that eliminates unreasonable inundation areas. The map has clear and continuous boundaries and is highly consistent with the historical flood marks actually investigated.

[0059] This invention provides a method for extrapolating flood inundation in small and medium-sized rivers in mountainous areas, comprising: acquiring satellite digital elevation model data of the target area, centerline vector data of the river channel, and measured cross-sectional data of the river channel; based on the measured cross-sectional data, performing virtual grooving correction on the satellite digital elevation model data using a weighting function that varies with the distance from the grid point to the river channel centerline, generating a corrected hydrodynamic calculation terrain; extrapolating the water surface line along the river channel based on the corrected hydrodynamic calculation terrain; wherein, during the extrapolation process, the cross-sectional Froude number is calculated in real time, and the water level is extrapolated using the energy equation or Manning formula according to the rapid or slow flow state represented by the cross-sectional Froude number; when transcritical flow is detected, the momentum equation used to calculate the conjugate water depth is used to determine the hydraulic jump location; based on the water surface line, using irregular... The triangulation network constructs a water level surface within the river buffer zone. The water level surface is then overlaid with the corrected hydrodynamic topography to calculate the water depth. A multi-level filtering mechanism, including spatial constraints, depth threshold filtering, and connectivity checks, removes unreasonable spurious inundation patches, resulting in the final flood inundation map. By fusing sparse measured cross-sections and satellite DEMs using a distance-varying weight function, the topography of mountain river channels is effectively reconstructed, reducing over-reliance on high-precision measured topography. Real-time identification of Froude numbers and adaptive switching between the energy equation and Manning formula solves the problem of traditional models easily diverging under complex flow conditions, ensuring stable water surface line calculations. Through spatial constraints, depth filtering, and connectivity checks, isolated spurious inundation patches are thoroughly eliminated, resulting in a reliable and accurate flood inundation map that can be directly used for emergency decision-making.

[0060] Example 2 The method provided in the above embodiments is encapsulated in a standardized Docker container image to achieve rapid cross-platform deployment and computation: the container base environment is a basic container environment built on a lightweight Linux distribution; algorithm encapsulation includes: compiling the terrain reconstruction, hydrodynamic calculation and flooding analysis modules into independent executable programs or Python packages, and exposing standardized command-line interfaces through entry scripts; data mounting includes: the container runtime accesses the host machine's input data directory and result output directory through volume mounting, thereby decoupling the computation process from the data.

[0061] Specifically, to address the cross-platform deployment challenges caused by the complexity of hydraulic model dependencies (such as GDAL, Rasterio, etc.), this embodiment employs Docker container technology for standardized encapsulation: Environment isolation: Build a lightweight base image based on Linux (such as Debian Slim), pre-install all necessary geospatial processing libraries, and shield the differences between the host operating systems.

[0062] Plug and play: The model algorithm is encapsulated as a standalone command-line tool that can be directly invoked through a Docker entry point. Users do not need to configure a complex Python environment; they only need to install the Docker engine to run it.

[0063] Data decoupling: By using the mounted volume method, the host machine's data directory is mapped to the inside of the container, realizing an efficient processing mode of "computation inside the container, data outside the container".

[0064] For example, to quickly deploy the system on a new server, there is no need to manually install the Python and GDAL libraries: Image building: Build the image using a Dockerfile: `docker build -t flood-model:v1 .`

[0065] To run the container: Execute the command `docker run -v / data / input: / app / input -v / data / output: / app / results flood-model:v1 --name "RiverX" --rain 3.0 100`.

[0066] Results Acquisition: After the calculation is completed, the flooding map results can be obtained directly from the / data / output directory on the host machine, without the need for any environment configuration.

[0067] Through the above-mentioned technical means, the embodiments of the present invention significantly improve the accuracy and reliability of flood simulation in mountainous areas with little or no data while ensuring computational efficiency, and greatly reduce the deployment threshold.

[0068] Example 3 Based on the above embodiments, this invention provides a device for predicting flood inundation in small and medium-sized rivers in mountainous areas. (See attached image.) Figure 7 The diagram shown is a structural schematic of a flood inundation simulation device for small and medium-sized rivers in mountainous areas, provided by an embodiment of the present invention. The device includes: The data acquisition module 310 is used to acquire satellite digital elevation model data of the target area, centerline vector data of the river channel, and measured cross-sectional data of the river channel. The terrain correction module 320 is used to perform virtual groove correction on satellite digital elevation model data based on measured cross-sectional data, using a weight function that varies with the distance from the grid point to the river centerline, to generate the corrected hydrodynamic calculation terrain. The water surface line calculation module 330 is used to calculate the water surface line along the river channel based on the corrected hydrodynamic topography. During the calculation process, the cross-sectional Froude number is calculated in real time. Based on the rapid or slow flow state represented by the cross-sectional Froude number, the water level is calculated accordingly using the energy equation or Manning formula. When transcritical flow is detected, the momentum equation used to calculate the conjugate water depth is used to determine the hydraulic jump location. The flood inundation map processing module 340 is used to construct a water level surface within the river buffer zone based on the water surface line using an irregular triangular network; the water level surface is superimposed with the corrected hydrodynamic calculation topography to calculate the water depth; and unreasonable pseudo-inundation patches are removed through a multi-level filtering mechanism including spatial constraints, depth threshold filtering and connectivity checks to obtain the final flood inundation map.

[0069] Furthermore, in some preferred embodiments of the present invention, the terrain correction module 320 is used to perform virtual groove correction using the following formula: ;in, This is the corrected grid elevation. The elevation of the original satellite digital elevation model. The corresponding riverbed elevation obtained by interpolation. The weighting function varies with the distance from the grid point to the river centerline. This represents the vertical distance from the grid point to the centerline of the river channel.

[0070] Furthermore, in some preferred embodiments of the present invention, the weighting function adopts a hybrid weighting strategy of "linear decay in the kernel and exponential decay in the periphery". The terrain correction module 320 is used to divide the river buffer zone into a kernel zone and a peripheral gradient zone according to the vertical distance from the grid point to the center line of the river channel. The weight in the kernel zone decays linearly, and the weight in the peripheral gradient zone decays exponentially.

[0071] Furthermore, in some preferred embodiments of the present invention, the terrain correction module 320 is used to constrain the weighting function based on the following formula: ;in, The preset kernel area width, The preset width of the outer gradient area, This is the preset attenuation coefficient.

[0072] Furthermore, in some preferred embodiments of the present invention, the water level estimation module 330 is used to determine the current as a slow flow if the Froude number at the current cross-section is less than 1, and to estimate the water level cross-section by cross-section using the Bernoulli energy equation from downstream to upstream; if the Froude number at the current cross-section is greater than 1, it is determined as a rapid flow, and the normal water depth is calculated based on a preset local riverbed slope using the following Manning formula as the control water depth for the current cross-section: ;in, For traffic, For roughness, For the water flow area, For local riverbed slope, This is the normal water depth.

[0073] Furthermore, in some preferred embodiments of the present invention, the water surface line estimation module 330 is used to calculate the conjugate water depth using the momentum equation when it is detected that the upstream cross-section is a rapid flow and the downstream cross-section is a slow flow. An equivalent wide-shallow approximation is used, replacing the water depth of the rectangular cross-section with the conjugate hydraulic depth; the upstream Froude number is constrained by the following formula: ; ; ;in, For the upstream Buddha Rude number, For traffic, The upstream water flow area, The width of the upstream water surface. The upstream hydraulic depth, The acceleration due to gravity; the conjugate hydraulic depth is constrained by the following formula: ;in, Furthermore, if the estimated hydraulic depth of the downstream control section is lower than... If a hydraulic jump occurs, the downstream water level is forcibly adjusted to meet the conservation of momentum.

[0074] Furthermore, in some preferred embodiments of the present invention, the flood inundation map processing module 340 is used for spatial constraints, including: generating an irregular triangular mesh water level surface only within a buffer zone with the river centerline as the axis and a width equal to the preset buffer zone length, physically isolating low-lying areas far from the river channel; depth threshold filtering, including: performing binarization masking on the calculated inundation depth grid to remove tiny noise points with water depths less than a preset minimum water depth threshold; explicit connectivity checking, including: performing connected component analysis on the inundation area after depth filtering, and using a connected component labeling algorithm to identify all independent inundation patches; constructing a centerline seed region, retaining only connected components that have pixel-level connections with the centerline seed region, and removing all isolated patches; and effectiveness masking, including: using the removed effective water depth area as a mask to extract the water level grid in reverse, and filling the water level values ​​of areas without water depth with preset null values.

[0075] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the flood inundation simulation device for small and medium-sized rivers in mountainous areas described above can be referred to the corresponding process in the aforementioned embodiments of the flood inundation simulation method for small and medium-sized rivers in mountainous areas, and will not be repeated here.

[0076] Example 4 This invention also provides an electronic device for running a flood inundation simulation method for small and medium-sized rivers in mountainous areas; see [link to related documentation]. Figure 8 The schematic diagram of an electronic device provided by the embodiment of the present invention shown above includes a memory 400 and a processor 401. The memory 400 is used to store one or more computer instructions, which are executed by the processor 401 to realize the above-mentioned method for predicting flood inundation of small and medium-sized rivers in mountainous areas.

[0077] Furthermore, Figure 8 The electronic device shown also includes a bus 402 and a communication interface 403. The processor 401, the communication interface 403 and the memory 400 are connected via the bus 402.

[0078] The memory 400 may include high-speed random access memory (RAM) and may also include non-volatile memory, such as at least one disk storage device. Communication between this system network element and at least one other network element is achieved through at least one communication interface 403 (which can be wired or wireless), such as the Internet, wide area network, local area network, metropolitan area network, etc. The bus 402 can be an ISA bus, PCI bus, or EISA bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 8The symbol is represented by a single double-headed arrow, but this does not mean that there is only one bus or one type of bus.

[0079] Processor 401 may be an integrated circuit chip with signal processing capabilities. In implementation, each step of the above method can be completed by the integrated logic circuitry in the hardware of processor 401 or by instructions in software form. Processor 401 can be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this invention. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this invention can be directly manifested as execution by a hardware decoding processor, or execution by a combination of hardware and software modules in the decoding processor. The software module can reside in a readily available storage medium in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in memory 400, and processor 401 reads information from memory 400 and, in conjunction with its hardware, completes the steps of the method described in the foregoing embodiments.

[0080] This invention also provides a computer-readable storage medium storing computer-executable instructions. When these computer-executable instructions are called and executed by a processor, they cause the processor to implement the above-mentioned method for extrapolating flood inundation in small and medium-sized rivers in mountainous areas. For specific implementation details, please refer to the method embodiments, which will not be repeated here.

[0081] The computer program product of the method, apparatus and electronic device for flood inundation simulation of small and medium rivers in mountainous areas provided in the embodiments of the present invention includes a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the methods in the preceding method embodiments. For specific implementation, please refer to the method embodiments, which will not be repeated here.

[0082] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the system and / or device described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0083] Furthermore, in the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0084] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for projecting flood inundation in small and medium-sized rivers in mountainous areas, characterized in that, include: Acquire satellite digital elevation model data of the target area, centerline vector data of the river channel, and measured cross-sectional data of the river channel; Based on the measured cross-sectional data, the satellite digital elevation model data is virtually grooved and corrected using a weighting function that varies with the distance from the grid point to the river centerline, thereby generating the corrected hydrodynamic calculation terrain. Based on the corrected hydrodynamic topography, the water surface line is extrapolated along the river channel; wherein, the cross-sectional Froude number is calculated in real time during the extrapolation process, and the water level is extrapolated according to the rapid or slow flow state represented by the cross-sectional Froude number, using the energy equation or Manning formula accordingly; when transcritical flow is detected, the momentum equation used to calculate the conjugate water depth is used to determine the hydraulic jump location. Based on the water surface line, an irregular triangular network is used to construct a water level surface within the river buffer zone; the water level surface is superimposed with the corrected hydrodynamic calculation topography to calculate the water depth, and unreasonable pseudo-inundation patches are removed through a multi-level filtering mechanism including spatial constraints, depth threshold filtering and connectivity checks to obtain the final flood inundation map.

2. The method for extrapolating flood inundation in small and medium-sized rivers in mountainous areas according to claim 1, characterized in that, The virtual groove correction is performed using the following formula: ； in, This is the corrected grid elevation. The elevation of the original satellite digital elevation model. The corresponding riverbed elevation obtained by interpolation. The weighting function that varies with the distance from the grid point to the river centerline. This represents the vertical distance from the grid point to the centerline of the river channel.

3. The method for extrapolating flood inundation in small and medium-sized rivers in mountainous areas according to claim 2, characterized in that, The weighting function adopts a hybrid weighting strategy of "linear decay in the kernel and exponential decay in the periphery", which includes: dividing the river buffer zone into a kernel zone and a peripheral gradient zone according to the vertical distance from the grid point to the river centerline, with the weight in the kernel zone decreasing linearly and the weight in the peripheral gradient zone decreasing exponentially.

4. The method for extrapolating flood inundation in small and medium-sized rivers in mountainous areas according to claim 3, characterized in that, The weighting function is constrained by the following formula: ； in, The preset kernel area width, The preset width of the outer gradient area, This is the preset attenuation coefficient.

5. The method for extrapolating flood inundation in small and medium-sized rivers in mountainous areas according to claim 1, characterized in that, Based on the Froude number representing the rapid or slow flow state at the cross-section, the water level is calculated using the energy equation or Manning formula, including: If the current Froude number at the cross-section is less than 1, it is determined to be a slow flow, and the water level is calculated cross-section by cross-section from downstream to upstream using the Bernoulli energy equation. If the current cross-section has a Froude number greater than 1, it is determined to be a rapid current. Based on the preset local riverbed slope, the normal water depth is calculated using the following Manning formula as the control water depth for the current cross-section: ； in, For traffic, For roughness, For the water flow area, The local riverbed slope, This refers to the normal water depth.

6. The method for extrapolating flood inundation in small and medium-sized rivers in mountainous areas according to claim 1, characterized in that, When transcritical flow is detected, the hydraulic jump location is determined using the momentum equation used to calculate the conjugate water depth, including: When it is detected that the upstream section is a rapid flow and the downstream section is a slow flow, the momentum equation is used to calculate the conjugate water depth, and the equivalent wide and shallow approximation is used, with the conjugate hydraulic depth replacing the water depth of the rectangular section. The upstream Froude number is constrained by the following formula: ； ； ； in, For the upstream Fruder number, For traffic, The upstream water flow area, The width of the upstream water surface. The upstream hydraulic depth, It is the acceleration due to gravity; The conjugate hydraulic depth is constrained by the following formula: ； in, Furthermore, if the estimated hydraulic depth of the downstream control section is lower than... If a hydraulic jump occurs, the downstream water level is forcibly adjusted to meet the conservation of momentum.

7. The method for extrapolating flood inundation in small and medium-sized rivers in mountainous areas according to claim 1, characterized in that, A multi-level filtering mechanism that includes spatial constraints, depth threshold filtering, and connectivity checks includes: Spatial constraints include: generating an irregular triangular network of water level surfaces only within a buffer zone with the river centerline as the axis and a width equal to the preset buffer zone length, and physically isolating low-lying areas far from the river channel; Depth threshold filtering includes: performing binarization masking on the calculated submerged water depth grid to remove minute noise points where the water depth is less than the preset minimum water depth threshold; Explicit connectivity checks include: performing connected component analysis on the depth-filtered flooded area, identifying all independent flooded patches using a connected component labeling algorithm; constructing a centerline seed region, retaining only connected components that are pixel-level connected to the centerline seed region, and removing all isolated patches; The effectiveness mask includes: using the removed effective water depth area as a mask to extract the water level grid in reverse, and filling the water level value of the area without water depth with a preset null value identifier.

8. The method for extrapolating flood inundation in small and medium-sized rivers in mountainous areas according to any one of claims 1 to 7, characterized in that, The method is encapsulated in a standardized Docker container image to enable rapid cross-platform deployment and computation. The container base environment is a basic container environment built on a lightweight Linux distribution; Algorithm encapsulation includes: compiling the terrain reconstruction, hydrodynamic calculation, and inundation analysis modules into standalone executable programs or Python packages, and exposing standardized command-line interfaces through entry scripts; Data mounting includes: the container runtime accesses the host machine's input data directory and result output directory via volume mounting, thereby decoupling the computation process from the data.

9. A device for predicting flood inundation in small and medium-sized rivers in mountainous areas, characterized in that, include: The data acquisition module is used to acquire satellite digital elevation model data of the target area, centerline vector data of the river channel, and measured cross-sectional data of the river channel; The terrain correction module is used to perform virtual groove correction on the satellite digital elevation model data based on the measured cross-section data, using a weight function that varies with the distance from the grid point to the river centerline, to generate the corrected hydrodynamic calculation terrain. The water surface line estimation module is used to estimate the water surface line along the river channel based on the corrected hydrodynamic calculation topography. During the estimation process, the cross-sectional Froude number is calculated in real time, and the water level is estimated accordingly using the energy equation or Manning formula based on the rapid or slow flow state represented by the cross-sectional Froude number. When transcritical flow is detected, the momentum equation used to calculate the conjugate water depth is used to determine the hydraulic jump location. The flood inundation map processing module is used to construct a water level surface within the river buffer zone based on the water surface line using an irregular triangular network; to calculate the water depth by superimposing the water level surface with the corrected hydrodynamic calculation topography; and to remove unreasonable pseudo-inundation patches through a multi-level filtering mechanism including spatial constraints, depth threshold filtering, and connectivity checks to obtain the final flood inundation map.

10. An electronic device, characterized in that, The method includes a processor and a memory, wherein the memory stores computer-executable instructions that can be executed by the processor, and the processor executes the computer-executable instructions to implement the flood inundation simulation method for small and medium-sized rivers in mountainous areas as described in any one of claims 1 to 7.

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