Two-dimensional hydrodynamic flood inundation modeling method and system incorporating measured cross-sections
By integrating measurement cross-section data, the topography of dikes and river channels is accurately determined, solving the problems of topographic distortion and low accuracy in two-dimensional hydrodynamic models. This improves the accuracy and computational efficiency of river hydrodynamic simulation and supports the accuracy of flood risk assessment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NANJING HYDRAULIC RES INST
- Filing Date
- 2026-05-07
- Publication Date
- 2026-07-21
AI Technical Summary
Existing two-dimensional hydrodynamic models suffer from underwater topography distortion and limited accuracy in capturing micro-topography of dikes and shorelines in river areas, resulting in low accuracy and computational efficiency in flood simulation. Furthermore, coupled one-dimensional and two-dimensional models have problems such as spatial mismatch and non-conservation of water volume and momentum in the connection between cross sections and two-dimensional grids.
By integrating measurement cross-section data, extracting levee vector lines, constructing a two-dimensional grid and interpolating elevations, the levee elevation is accurately determined, enhancing the depiction of river topography. The measured elevation data is used to interpolate control point elevations, forming continuous control point elevation lines. Weir-type structures are then set up in the two-dimensional hydrodynamic model to simulate flood inundation.
It improves the accuracy and computational reliability of river hydrodynamic simulation, accurately depicts the topography of dikes and river channels, reduces errors in flow velocity and water level calculations, and realizes accurate simulation of the entire two-dimensional flood evolution process, providing more precise technical support for flood risk assessment.
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Figure CN122154563B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of hydrodynamic modeling and flood disaster simulation technology, and in particular to a two-dimensional hydrodynamic flood inundation modeling method and system that integrates measurement cross sections. Background Technology
[0002] Flood inundation simulation is a core technical support for flood control and disaster reduction decision-making. Current mainstream methods include one-dimensional hydrodynamic simulation, two-dimensional hydrodynamic simulation, and one-dimensional / two-dimensional coupled simulation. Among them, the two-dimensional hydrodynamic model directly calculates the two-dimensional flow field of the entire watershed based on DEM data. It can output the flood inundation range, flow velocity distribution, and other results required for flood inundation. Moreover, it is more likely to reflect the flood evolution characteristics such as floodplains and bypasses under complex terrain, and has become the mainstream tool for floodplain flood and urban flood control simulation.
[0003] However, the accuracy of two-dimensional hydrodynamic models is highly dependent on the quality of DEM data. Because conventional DEM data cannot penetrate the water body to obtain underwater riverbed morphology, the model suffers from "underwater topography distortion" in river areas. Furthermore, due to factors such as tree obstruction, DEMs have limited accuracy in capturing the micro-topography of dikes and shorelines. While one-dimensional hydrodynamic models can accurately simulate water levels along the river based on measured cross-sectional data, they cannot describe the two-dimensional flow regime. Coupled one-dimensional and two-dimensional models, although attempting to combine the advantages of both, generally suffer from spatial mismatches and non-conservation of water volume and momentum in the connection between cross-sections and two-dimensional meshes. Moreover, their complex modeling process, difficult debugging, and low computational efficiency hinder their widespread application in refined flood risk assessment. Summary of the Invention
[0004] Purpose of the invention: The purpose of this invention is to provide a two-dimensional hydrodynamic flood inundation modeling method and system that integrates measured cross sections. Without increasing the complexity of the coupled system, it effectively utilizes measured cross section data to improve the accuracy of the two-dimensional model in depicting river channel topography and enhance the computational efficiency and accuracy of flood simulation.
[0005] Technical solution: The present invention provides a two-dimensional hydrodynamic flood inundation modeling method based on fused measurement cross-sections, comprising the following steps:
[0006] Extract the levee vector lines based on remote sensing images of the watershed where the target reservoir is located and the measured cross-sections of the river channel;
[0007] A two-dimensional grid is constructed in the target reservoir and watershed area. The initial ground elevation of the grid cells is assigned by interpolation using measured elevation data to form a preliminary elevation field.
[0008] The embankment vector line is converted into an embankment closed loop, and the grid cell edges within the envelope of the embankment closed loop in the preliminary elevation field are extracted as embankment cell edges.
[0009] The edges of the dike units are connected into a continuous broken line according to the direction of water flow. The dike elevation is interpolated by spatial proximity analysis based on the measured cross-sectional data on the continuous broken line to obtain a continuous dike elevation.
[0010] Using the river area between adjacent measurement sections as a unit, the river is divided into equal sections at preset intervals according to the thalweg line within each unit to form a densified interpolation section.
[0011] The measurement section and the densification interpolation section are divided into left and right channels by the thalweg line, and control points are determined for each channel. The elevation of each control point is interpolated based on the measured elevation data to obtain a continuous control point elevation line.
[0012] The continuous control point elevation lines are interpolated into a two-dimensional grid. Based on the continuous levee elevations, levee weir structures are set up, and a two-dimensional hydrodynamic model is established to simulate flood inundation of the target reservoir.
[0013] Furthermore, a two-dimensional grid is constructed in the target reservoir and watershed area. Initial ground elevations are assigned to the grid cells using measured elevation data through interpolation, forming a preliminary elevation field including:
[0014] Increase the grid density in the main channel of the river and the area downstream of the dam, and set a gradual transition in side length at the junction of the river and the boundary.
[0015] Furthermore, after converting the levee vector line into a levee closed loop and extracting the grid cell edges within the envelope of the levee closed loop in the preliminary elevation field as levee cell edges, the process further includes: performing topological checks and geometric continuity processing on the levee cell edges to ensure that the levee cell edges are complete and continuous in the grid.
[0016] Furthermore, the edges of the dike units are connected into a continuous broken line according to the direction of water flow. Spatial proximity analysis is performed based on the measured cross-sections to interpolate the dike elevation, resulting in continuous dike elevations including:
[0017] For the edge of the dike unit with missing elevation data, calculate the cumulative starting point distance along the inflection point of the continuous polyline, and use the cumulative starting point distance as the independent variable to perform linear interpolation to complete the data using the measured elevation data before and after the edge of the dike unit.
[0018] For missing values at the beginning and end of a continuous broken line, the missing values are filled by extending outwards from the nearest measured elevation data.
[0019] Furthermore, taking the river area between adjacent river measurement sections as units, the river is divided equally within each unit according to the thalweg line at preset intervals to form a denser interpolation section, including:
[0020] Within each unit, several equidistant perpendicular lines are drawn along the thalweg line at preset intervals. Each perpendicular line intersects with the left and right embankment lines, dividing the river area within the unit into several densified interpolation sections.
[0021] Furthermore, the measurement section and the densified interpolation section are divided into left and right channels using the thalweg line as the boundary, and control points are determined for each channel. Based on the measured elevation data, the elevations of each control point are interpolated to obtain a continuous control point elevation line, including:
[0022] The number of control points is n, which is the maximum number of measured elevation points for the left and right channels in all cross sections. For cross sections with fewer than n measured elevation points, control points are added according to the principle of spatial equidism.
[0023] The elevation of each control point is obtained by linear interpolation based on the measured elevation data.
[0024] Connect the control points with the same serial number in each section in sequence to form n longitudinal broken lines. Smooth the longitudinal broken lines to obtain continuous control point elevation lines.
[0025] Furthermore, the vector lines of the dikes are extracted based on remote sensing images and measurement cross-sections of the watershed where the target reservoir is located, including:
[0026] The dike lines of the watershed are extracted from the remote sensing images, and the dike lines are checked using measurement cross-section data to obtain continuous dike vector lines.
[0027] The present invention discloses a two-dimensional hydrodynamic flood inundation modeling system that integrates measurement cross sections, comprising:
[0028] The levee vector line extraction unit is used to extract levee vector lines based on remote sensing images of the watershed where the target reservoir is located and the measured cross-sections of the river channel.
[0029] The preliminary topographic field construction unit is used to construct a two-dimensional grid in the target reservoir and watershed area. The grid unit is assigned an initial ground elevation by interpolation using measured elevation data to form a preliminary elevation field.
[0030] The levee elevation extraction unit is used to convert the levee vector line into a levee closed loop and extract the grid cell edges within the envelope of the levee closed loop in the preliminary elevation field as levee cell edges.
[0031] The edges of the dike units are connected into a continuous broken line according to the direction of water flow. The dike elevation is interpolated by spatial proximity analysis based on the measured cross-sectional data on the continuous broken line to obtain a continuous dike elevation.
[0032] The encrypted interpolation section generation unit is used to divide the river channel into equally spaced sections according to the thalweg line within each unit, taking the river channel area between adjacent measurement sections as the unit, and forming an encrypted interpolation section.
[0033] The continuous control point elevation line establishment unit is used to divide the measurement section and the densification interpolation section into left and right channels with the thalweg as the boundary, and determine the control points respectively; the elevation of each control point is interpolated based on the measured elevation data to obtain the continuous control point elevation line;
[0034] The flood inundation simulation unit is used to interpolate the continuous control point elevation lines into a two-dimensional grid, set up dike and weir structures according to the continuous dike elevations, and establish a two-dimensional hydrodynamic model to simulate flood inundation of the target reservoir.
[0035] The computer program product of this invention includes a computer program that, when executed by a processor, implements the two-dimensional hydrodynamic flood inundation modeling method based on fused measurement sections. The electronic device of this invention includes a memory, a processor, and a computer program stored in the memory and executable on the processor; when loaded onto the processor, the computer program implements the two-dimensional hydrodynamic flood inundation modeling method based on fused measurement sections.
[0036] Beneficial Effects: Compared with existing technologies, this invention improves the two-dimensional hydrodynamic modeling method for rivers by integrating measurement cross-sections. This effectively solves the technical problems of distorted levee boundaries and coarse depiction of river topography within levees in traditional two-dimensional hydrodynamic modeling, significantly improving the accuracy, realism, and computational reliability of river hydrodynamic simulation. Specifically, ① this invention accurately determines the location and elevation parameters of levees on both banks of the river and simulates the levees as weir-type structures during the modeling process, achieving refined depiction of key flood control boundaries and restoring the control and obstruction effects of levees on river flow; ② it specifically corrects the river topography data of grid points on the inner side of the levees, effectively compensating for the lack of underwater topography in traditional sparse cross-section modeling and reducing calculation errors in flow velocity, water level, and flow field distribution caused by topographic distortion.
[0037] In summary, this invention accurately utilizes measured data such as river cross-sections, riverbanks, and thalways to improve the precision of terrain depiction and the accuracy of water-blocking structures, achieving a full two-dimensional simulation of flood evolution covering both the river channel and the floodplain, thus providing more precise and reliable technical support for the compilation of flood risk maps. Attached Figure Description
[0038] Figure 1 This is a flowchart of a two-dimensional hydrodynamic flood inundation modeling method according to an embodiment of the present invention.
[0039] Figure 2 This is a diagram showing the elevation changes along the left bank of the downstream river channel of Xiangshan Reservoir, according to an embodiment of the present invention.
[0040] Figure 3 This is a conceptual diagram of secondary topographic interpolation correction for river channels according to an embodiment of the present invention.
[0041] Figure 4 This is a comparison diagram of the results of local topographic adjustment of the river channel based on the measurement cross section in an embodiment of the present invention.
[0042] Figure 5 This is a flow process diagram of the main stream's frequent floods and the Xiangshan Reservoir dam break flood, which are embodiments of the present invention.
[0043] Figure 6 This is a comparison diagram of the flood inundation results of Xiangshan Reservoir before and after the flood inundation modeling and fusion measurement section in an embodiment of the present invention. Detailed Implementation
[0044] The technical solution of the present invention will be further described below with reference to the accompanying drawings.
[0045] like Figure 1 As shown, the two-dimensional hydrodynamic flood inundation modeling method based on fused measurement cross-sections includes the following steps:
[0046] S1. Extract the levee line based on high-resolution remote sensing imagery and river channel measurement section data to form a levee vector line layer;
[0047] S2. A two-dimensional computational grid is constructed using unstructured grid technology. Initial ground elevations are assigned to grid cells using spatial interpolation of DEM data to obtain a preliminary topographic field.
[0048] S3. Convert the embankment vector line into a region and extract the boundary, then locate the corresponding embankment unit edge in the two-dimensional mesh;
[0049] S4. Connect the edges of the dike unit into a continuous broken line according to the direction of water flow and calculate the cumulative starting point distance. Interpolate the dike elevation by measuring the spatial proximity of the cross-section points. For missing values, linearly interpolate and extrapolate with the starting point distance as the independent variable to obtain the dike elevation that changes continuously along the river channel.
[0050] S5. Using the river area between adjacent measurement sections as units, divide the middle river section equally along the thalweg line according to the target spacing, intersect with the left and right levee lines, and generate a series of densified interpolation sections.
[0051] S6. Using the thalweg line as the boundary, the measured cross section and the interpolated cross section generated in S5 are divided into left and right channels. The maximum number of measured points in the left and right channels of each cross section is counted, and control points are added at even intervals in space, so that all left and right channels of the cross section have uniformly numbered control points. After interpolating the elevation of each control point based on the measured point elevation, the upstream and downstream control points with the same number are connected to construct a longitudinal broken line, and values are assigned to form a continuous elevation line.
[0052] S7. Correct the grid terrain and set up dike structures. Set the boundary conditions of upstream inflow and downstream water level according to the simulation requirements. Run the two-dimensional hydrodynamic model to simulate flood inundation and draw a flood risk map.
[0053] This embodiment takes Xiangshan Reservoir, a tributary of the Lishui River Basin, as an example to illustrate the implementation process and effect of the two-dimensional hydrodynamic flood inundation modeling method based on the fusion measurement section.
[0054] In S1, high-resolution remote sensing images of the Xiangshan Reservoir basin, DEM elevation data, key river channel measurement section data, and relevant design reports and scheduling regulations were first acquired. Some engineering characteristics of the Xiangshan Reservoir are shown in Table 1.
[0055] Table 1. Reservoir A Project Characteristics Report
[0056]
[0057] In S1, based on the acquired digital line map and high-resolution remote sensing imagery, the outline of the dikes on both banks of the downstream river channel of the reservoir is extracted through manual interpretation. Using river channel measurement sections, the spatial location of the extracted dike outlines is checked, the dike orientation in areas obscured by remote sensing imagery is supplemented, and the outlines are uniformly converted to the 1985 National Elevation Datum, ultimately forming a continuous dike vector line along the river channel.
[0058] In S2, a two-dimensional triangular computational grid was constructed, covering the reservoir area and the downstream river channel. During grid construction, local densification was applied to the main channel and downstream area of the dam, ensuring a higher grid density in key regions than in boundary regions. A gradual transition in side length was implemented at the junction of the river channel and the boundary to ensure smooth changes in grid cell area and prevent excessive differences in adjacent grid cell areas from affecting the stability of numerical calculations. Subsequently, using high-resolution DEM data, inverse distance weighting (IDW) was used to assign initial ground elevations to each triangular grid cell, forming a preliminary digital topographic field for the study area.
[0059] In S3, the levee vector line generated in S1 is used to generate a thickened area using the buffer tool. Then, it is processed by the area-to-line and feature vertex-to-point tools to obtain a closed loop around the levee. Using this levee closed loop, the two-dimensional grid cell edges within its envelope are selected, and the corresponding numbers and the start and end coordinates of all selected cell edges (i.e., levee cell edges) are extracted.
[0060] Furthermore, in S3, topological checks and geometric continuity processing are performed on the discontinuities of the selected dike unit edges. This is done by identifying the starting edge (denoted as the dike starting edge) and recursively searching adjacent edges to correct inconsistencies in edge direction and discontinuous numbering caused by the 2D mesh generation. Specifically, for dike unit edges with incorrect orientations, their starting and ending coordinates are swapped; for dike unit edges with discontinuous starting and ending coordinates, the process returns to the 2D mesh and uses point selection to reselect mesh unit edges to fill in the missing edges. This step is repeated to ensure that the dike unit edge segments are complete and their coordinates are continuous. The specific method is as follows:
[0061] a) Record the edge numbers of the upstream and downstream units of the dike on one side of the river channel in advance;
[0062] b) Each dike unit has two endpoints with two-dimensional coordinates (x and y coordinates). Find the starting endpoint coordinates and ending endpoint coordinates of each dike unit.
[0063] c) Starting from the upstream edge of the dike unit (the starting edge of the dike), search the edge unit by edge. If the coordinates of any endpoint of a certain dike unit edge B are the same as the coordinates of the endpoint of the starting edge of the dike, then the dike unit edge B is the downstream edge of the starting edge of the dike.
[0064] d) Continue searching for the downstream edge of dike unit edge B until the downstreammost dike unit edge is found; if no downstream edge is found for a certain dike unit edge C, it is considered that dike unit edge C is broken, and it is necessary to return to the 2D mesh and reselect the missing unit edge by point selection. In continuous dike unit edges, if the starting endpoint of dike unit edge D is identified as connected to its downstream edge, or the ending endpoint of dike unit edge D is identified as connected to its upstream edge, it is considered that the direction of dike unit edge D is disordered, and the coordinates of its starting endpoint and ending endpoint need to be swapped.
[0065] In S4, the continuous levee unit edges extracted in S3 are connected from upstream to downstream into a continuous polyline according to the river flow direction to ensure that the direction of each line segment is consistent. Spatial proximity analysis is used to interpolate the levee elevation. The specific method is as follows: set a spatial search threshold, take each measurement point of the measurement section as the control source, and match the nearest elevation value for each inflection point (i.e., the endpoint of the levee unit edge). If the distance is within the threshold range, the elevation of the point is assigned; otherwise, it is marked as missing.
[0066] Furthermore, in S4, for inflection points with missing elevations, the cumulative starting point distance from the two endpoints of the continuous broken line to the starting point of the dike is calculated. Using this starting point distance as the independent variable, linear interpolation is performed to complete the inflection point using inflection points before and after it that have measured elevation values. If the elevation of the starting or ending point of the dike is missing, it is completed by extending outwards using the two nearest measured elevation values. The average elevation of the inflection points corresponding to the two endpoints of the dike unit edge is the elevation of the dike unit edge. Finally, the elevation curve of the dike unit edge, which continuously varies longitudinally along the river channel, is output. The elevation variation along the left bank dike of the downstream channel of Xiangshan Reservoir is shown below. Figure 2 As shown.
[0067] In S5, the river area between two adjacent measurement sections is taken as an independent unit. Within each unit, equidistant vertical lines are drawn along the thalweg line at preset intervals to divide the middle river section equally. Each vertical line intersects with the left and right bank lines, thereby generating a series of densified interpolation sections, realizing the first topographic correction of the downstream river channel.
[0068] Furthermore, in S5, for river sections with drastic topographic changes, the interpolation accuracy is assessed by combining the density of measurement cross-sections, and then a preset spacing value is determined. The original measurement cross-sections are appropriately densified at river bends and abrupt topographic changes to ensure that the interpolated cross-sections can accurately reflect the river morphology. These cross-sections, together with the original measurement cross-sections, constitute the basis for river topographic control.
[0069] In S6, the measured cross-section and the densified interpolation cross-section generated in S5 are re-divided into left and right channels using the thalweg line as the boundary. The maximum number of measured cross-section points, n, in all cross-sections is counted for the left and right channels. For cross-sections with fewer than n measured cross-section points, control points are added according to the principle of spatial equidism, so that all cross-sections have standardized control points with unified serial numbers for both left and right channels. Based on this, the elevation of each serial number control point is calculated using a linear interpolation method based on the measured elevation values of the measured cross-section.
[0070] By sequentially connecting control points k with the same serial number in each cross-section of the upstream and downstream sections, a series of longitudinal polylines (n lines) are constructed. Each longitudinal polyline is then smoothed using linear interpolation, forming a series of continuous elevation lines from the dam site to the downstream river channel. This achieves a second topographic correction of the downstream river channel. The conceptual diagram of this secondary topographic interpolation correction for the downstream river channel of Xiangshan Reservoir is shown below. Figure 3 As shown.
[0071] In S7, using the dike lines on both banks generated in S1 as boundaries, the elevation of the control points obtained in S6 is mapped to the grid nodes using inverse distance weighted interpolation. Grid nodes closer to the control points are more significantly affected, thus forming a smoothly transitioning elevation field and achieving the third topographic correction of the downstream river channel. A comparison of the local topographic adjustment results of the downstream river channel of Xiangshan Reservoir based on the measurement cross-section is shown in the figure below. Figure 4 As shown.
[0072] In step S7, the continuous levee elevations determined in step S4 are incorporated into the two-dimensional hydrodynamic model as weir-type structures, and elevation values are assigned. Specifically, in the model control file, the edges of the levee units (i.e., the edge numbers of the grid unit edges) are set as weir-type structures, and the weir crest elevation is set as the corresponding levee unit edge elevation. Flood simulation calculations are then performed based on this.
[0073] This example calculates the flood inundation scenario of a dam-break flood at Xiangshan Reservoir. In setting the model boundary conditions, based on simulation requirements, the upper boundary is defined by the frequently occurring flood process in the upstream main stream and the dam-break flow process at the dam site. The flow processes of the frequently occurring flood in the main stream and the dam-break flood at Xiangshan Reservoir are as follows: Figure 5 As shown. The lower boundary is calculated using an empirical formula to reduce the maximum dam break flood peak flow along the course. When it reduces to the safe discharge capacity of the downstream river channel, this point is taken as the lower boundary of the calculation range, resulting in the corresponding 10-year return period control water level of 55.28m for the main stream section. This water level is used as the fixed water level boundary for the model calculation; its solid wall boundary must be larger than the inundation range of the overall model in the interval.
[0074] A two-dimensional hydrodynamic model was constructed for flood inundation calculations. After the simulation was completed, the inundation situation before and after the fusion of measurement sections was compared. The results are as follows: Figure 6 As shown in Table 2, the comparison reveals that the refined generalization of topography and dikes significantly alters the evolution and inundation characteristics of dam-break floods. Before fusion, due to insufficient coupling of dike and river cross-section measurement information, the model lacked sufficient representation of the water-blocking structures along the river course. Floods lacked effective constraints on their overflow paths, exhibiting a large-scale free diffusion pattern, with an inundated area of 31.52 km². However, limited by the dispersion of flood discharge energy, the average maximum water depth in the inundated area was only 2.59 m. After fusion, the spatial distribution of dikes and the actual river topography were accurately embedded into the model, significantly enhancing the dike's interception and channeling functions during flood evolution. The overflow path was strictly constrained, and the inundated area was reduced to 14.71 km². Simultaneously, due to the concentrated flow capacity of the river channel, the water energy per unit area increased, raising the average maximum water depth in the inundated area to 4.83 m.
[0075] Table 2 Comparison of Xiangshan Reservoir Inundation Results Before and After Dike Modification
[0076]
[0077] The comparison results show that the proper integration of dikes and river sections not only determines the accurate depiction of the flood inundation range, but also directly affects the reliability of the dam-break flood risk assessment, and plays an important supporting role in subsequent flood control zoning, evacuation route planning and emergency resource deployment.
Claims
1. A two-dimensional hydrodynamic flood inundation modeling method integrating measurement cross-sections, characterized in that, Includes the following steps: Extract the levee vector lines based on remote sensing images of the watershed where the target reservoir is located and the measured cross-sections of the river channel; A two-dimensional grid is constructed in the target reservoir and watershed area. The initial ground elevation of the grid cells is assigned by interpolation using measured elevation data to form a preliminary elevation field. The embankment vector line is converted into an embankment closed loop, and the grid cell edges within the envelope of the embankment closed loop in the preliminary elevation field are extracted as embankment cell edges. The edges of the dike units are connected into a continuous broken line according to the direction of water flow. The dike elevation is interpolated by spatial proximity analysis based on the measured cross-sectional data on the continuous broken line to obtain a continuous dike elevation. Using the river area between adjacent measurement sections as a unit, the river is divided into equal sections at preset intervals according to the thalweg line within each unit to form a densified interpolation section. The measurement section and the densification interpolation section are divided into left and right channels by the thalweg line, and control points are determined for each channel. The elevation of each control point is interpolated based on the measured elevation data to obtain a continuous control point elevation line. The continuous control point elevation lines are interpolated into a two-dimensional grid. Based on the continuous embankment elevations, embankment weir structures are set up, and a two-dimensional hydrodynamic model is established to simulate flood inundation of the target reservoir. After converting the embankment vector line into an embankment closed loop and extracting the grid cell edges within the envelope of the embankment closed loop in the preliminary elevation field as embankment cell edges, the process further includes: performing topological checks and geometric continuity processing on the embankment cell edges to ensure that the embankment cell edges are complete and continuous in the grid. The thalweg line divides the measurement section and the densified interpolation section into left and right channels, respectively, and control points are determined for each channel. Based on the measured elevation data, the elevations of each control point are interpolated to obtain a continuous control point elevation line, including: The number of control points is n, which is the maximum number of measured elevation points for the left and right channels in all cross sections. For cross sections with fewer than n measured elevation points, control points are added according to the principle of spatial equidism. The elevation of each control point is obtained by linear interpolation based on the measured elevation data. Connect the control points with the same serial number in each section in sequence to form n longitudinal broken lines. Smooth the longitudinal broken lines to obtain continuous control point elevation lines.
2. The two-dimensional hydrodynamic flood inundation modeling method based on fused measurement sections according to claim 1, characterized in that, A two-dimensional grid is constructed in the target reservoir and watershed area. Initial ground elevations are assigned to the grid cells using measured elevation data through interpolation, forming a preliminary elevation field including: Increase the grid density in the main channel of the river and the area downstream of the dam, and set a gradual transition in side length at the junction of the river and the boundary.
3. The two-dimensional hydrodynamic flood inundation modeling method based on fused measurement sections according to claim 1, characterized in that, Connecting the edges of the dike units along the direction of water flow into a continuous broken line, and interpolating the dike elevation using spatial proximity analysis based on the measured cross-sections, yields continuous dike elevations including: For the edge of the dike unit with missing elevation data, calculate the cumulative starting point distance along the inflection point of the continuous polyline, and use the cumulative starting point distance as the independent variable to perform linear interpolation to complete the data using the measured elevation data before and after the edge of the dike unit. For missing values at the beginning and end of a continuous broken line, the missing values are filled by extending outwards from the nearest measured elevation data.
4. The two-dimensional hydrodynamic flood inundation modeling method based on fused measurement sections according to claim 1, characterized in that, Using the river area between adjacent river measurement sections as units, the river is divided equally within each unit according to the thalweg line at preset intervals to form a denser interpolation section, including: Within each unit, several equidistant perpendicular lines are drawn along the thalweg line at preset intervals. Each perpendicular line intersects with the left and right embankment lines, dividing the river area within the unit into several densified interpolation sections.
5. The two-dimensional hydrodynamic flood inundation modeling method based on fused measurement sections according to claim 1, characterized in that, The vector lines of the dikes are extracted based on remote sensing images and measurement cross sections of the watershed where the target reservoir is located, including: The dike lines of the watershed are extracted from the remote sensing images, and the dike lines are checked using measurement cross-section data to obtain continuous dike vector lines.
6. A two-dimensional hydrodynamic flood inundation modeling system based on the fusion measurement cross-section of the method described in claim 1, characterized in that, include: The levee vector line extraction unit is used to extract levee vector lines based on remote sensing images of the watershed where the target reservoir is located and the measured cross-sections of the river channel. The preliminary topographic field construction unit is used to construct a two-dimensional grid in the target reservoir and watershed area. The grid unit is assigned an initial ground elevation by interpolation using measured elevation data to form a preliminary elevation field. The levee elevation extraction unit is used to convert the levee vector line into a levee closed loop and extract the grid cell edges within the envelope of the levee closed loop in the preliminary elevation field as levee cell edges. The edges of the dike units are connected into a continuous broken line according to the direction of water flow. The dike elevation is interpolated by spatial proximity analysis based on the measured cross-sectional data on the continuous broken line to obtain a continuous dike elevation. The encrypted interpolation section generation unit is used to divide the river channel into equally spaced sections according to the thalweg line within each unit, taking the river channel area between adjacent measurement sections as the unit, and forming an encrypted interpolation section. The continuous control point elevation line establishment unit is used to divide the measurement section and the densification interpolation section into left and right channels with the thalweg as the boundary, and determine the control points respectively; the elevation of each control point is interpolated based on the measured elevation data to obtain the continuous control point elevation line; The flood inundation simulation unit is used to interpolate the continuous control point elevation lines into a two-dimensional grid, set up dike and weir structures according to the continuous dike elevations, and establish a two-dimensional hydrodynamic model to simulate flood inundation of the target reservoir.
7. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the two-dimensional hydrodynamic flood inundation modeling method based on the fusion measurement cross section as described in any one of claims 1-5.
8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the computer program is loaded into the processor, it implements the two-dimensional hydrodynamic flood inundation modeling method based on the fusion measurement cross section as described in any one of claims 1-5.