One-dimensional water dynamic simulation method and device for bifurcation river network diversion process

Abstract

The application provides a bifurcated river network diversion process one-dimensional hydrodynamic simulation method and device, wherein the method comprises the following steps: based on digital elevation model data of a target river basin, a research area of key cross sections of a bifurcated river network is demarcated; hydrological analysis is performed on the research area, a ridge line network is extracted, and candidate cross sections meeting continuity and length restrictions are searched; each candidate cross section is orthogonally projected into a starting point distance-high procedure sequence, the maximum elevation value is retained at the same starting point distance, and standard cross section data representing the maximum water retaining topography are formed; the comprehensive water retaining elevation value of each candidate cross section is calculated according to the standard cross section data, and the candidate cross section with the maximum comprehensive water retaining elevation value is selected as a key control cross section. The method realizes automatic and objective extraction from high-precision topographic data to key control cross sections, effectively avoids subjective deviation and geometric distortion caused by traditional manual line selection, and significantly improves the simulation accuracy and physical consistency of the bifurcated river network hydrodynamic model on the diversion process.

Description

Technical Field

[0001] This invention relates to the field of hydrodynamic simulation technology, and in particular to a one-dimensional hydrodynamic simulation method and apparatus for the diversion process of a bifurcation river network. Background Technology

[0002] With the continuous advancement of computer technology and numerical computation methods, hydrodynamic numerical simulation has been widely applied in key areas such as flood evolution analysis, water resource optimization and scheduling, and flood control and disaster reduction decision support. In the one-dimensional hydrodynamic model system, due to its advantages such as high computational efficiency, flexible modeling, relatively low data requirements, and applicability to long-distance rivers and complex river network systems, it has become the mainstream technical means for river network water resource scheduling, river flood process simulation, and real-time flood forecasting.

[0003] However, existing one-dimensional hydrodynamic simulation methods reveal significant limitations when dealing with river network systems with bifurcation structures. As a common complex topology in natural or artificial water systems, bifurcation networks exhibit significant three-dimensional flow characteristics and local hydraulic disturbances at the bifurcation points. One-dimensional models, essentially based on the assumption of mean flow along the course, struggle to fully reflect these complex local flow patterns. To improve simulation accuracy, engineering practice often employs denser cross-sections to more precisely characterize river geometry and hydraulic changes. However, in bifurcation areas, limited levee length, dramatic topographic relief of the floodplains, and irregular boundaries mean that simply increasing cross-section density not only fails to effectively capture the hydraulic processes near the bifurcation points but may also introduce additional errors due to improper cross-section layout.

[0004] More importantly, the current selection of cross-section locations relies heavily on the experience and judgment of modelers, lacking unified and objective technical standards, and exhibiting strong subjectivity and uncertainty. This non-standardized modeling approach easily leads to the model's inability to accurately reproduce the actual diversion ratio and water level connection at bifurcation nodes, resulting in a series of problems such as distorted diversion flow allocation and deviations in upstream and downstream water level calculations. These problems not only weaken the predictive reliability of the model but may also mislead the formulation of downstream flood control scheduling plans, and in severe cases, even cause the failure of water conservancy project operation and scheduling decisions, threatening the flood control safety of the basin.

[0005] Therefore, there is an urgent need for a technical solution that can overcome the defects of existing modeling generalization methods and accurately characterize the local hydraulic characteristics of bifurcation river networks, so as to improve the simulation accuracy and engineering applicability of one-dimensional hydrodynamic models under complex river network conditions. Summary of the Invention

[0006] This invention provides a one-dimensional hydrodynamic simulation method and apparatus for the diversion process of a bifurcation river network. It addresses the technical problem in the prior art where the subjective and generalized cross-section layout fails to accurately capture local hydraulic characteristics, leading to distortion of the diversion ratio and deviation in water level calculation, which in turn affects the accuracy of flood simulation and the reliability of flood control scheduling. This invention improves the simulation accuracy of the diversion process and provides reliable data support and scientific basis for the simulation scheduling and flood control safety of complex water network systems.

[0007] On one hand, this invention provides a one-dimensional hydrodynamic simulation method for the diversion process of a bifurcation river network, comprising: delineating the study area of ​​key cross-sections of the bifurcation river network based on digital elevation model data of the target watershed; performing hydrological analysis on the study area, extracting a ridge network, and searching for candidate cross-sections that meet continuity and length constraints based on the ridge network; orthogonally projecting each candidate cross-section into a starting distance-elevation sequence, retaining the maximum elevation value at the same starting distance, forming standard cross-section data representing the maximum water-blocking topography; calculating the comprehensive water-blocking elevation value of each candidate cross-section based on the standard cross-section data, selecting the candidate cross-section with the largest comprehensive water-blocking elevation value as the key control cross-section, and using the key control cross-section for one-dimensional hydrodynamic simulation of the diversion process of the bifurcation river network.

[0008] Furthermore, the delineation of the research area for key sections of the bifurcation river network based on the digital elevation model data of the target watershed includes: extracting the river centerline, main channel boundary line, and levee lines on both banks of the target watershed based on the digital elevation model data; identifying the main channel centerline and the centerlines of each bifurcation channel from the main channel centerline, and determining the intersection of the main channel centerline and the centerlines of each bifurcation channel as the diversion node; calculating the average width of the main channel and the main channel of each bifurcation channel based on the main channel boundary line; extending a control distance proportional to the average width of the main channel along the main channel centerline and the centerlines of each bifurcation channel downstream from the diversion node to obtain the corresponding feature control point; drawing a perpendicular line to the corresponding river centerline through the feature control point, and the research area is formed by the perpendicular line, the levee lines on both banks, and the main channel boundary line.

[0009] Furthermore, the hydrological analysis of the study area and the extraction of the ridge network include: filling depressions in the digital elevation model data of the study area to generate depression-free digital elevation model data; calculating flow direction and flow grids based on the depression-free digital elevation model data; and extracting watershed watersheds based on the flow direction and flow grids to obtain the ridge network.

[0010] Furthermore, the step of searching for candidate cross sections that meet the continuity and length constraints based on the ridge network includes: in the ridge network, starting from the left bank and ending at the right bank, using a path search algorithm to traverse all continuous paths from the left bank to the right bank, and removing paths that contain duplicate nodes or whose length exceeds a preset threshold, to obtain a set of candidate cross sections.

[0011] Further, the step of orthogonally projecting each candidate cross-section into a sequence of starting point distances and elevations, retaining the maximum elevation value at the same starting point distance, and forming standard cross-section data representing the maximum water-blocking terrain includes: for each candidate cross-section, using the direction of the line connecting its starting point and ending point as the projection reference direction, orthogonally projecting each node on the candidate cross-section onto the projection reference direction to obtain the projection distance and corresponding elevation of each node relative to the starting point; based on the projection distance and corresponding elevation, constructing an equidistant starting point distance sequence, and mapping the line segment interpolation between each node to the equidistant starting point distance sequence; in the case where there are multiple line segment interpolation corresponding to elevation values ​​at each equidistant starting point distance position, retaining the maximum elevation value among them, and generating standard cross-section data representing the maximum water-blocking terrain.

[0012] Furthermore, the step of calculating the comprehensive water-blocking elevation value of each candidate section based on the standard cross-section data, and selecting the candidate section with the largest comprehensive water-blocking elevation value as the key control section, includes: calculating the comprehensive water-blocking elevation value of each candidate section based on the equidistant starting point distance-elevation sequence in the standard cross-section data; and selecting the candidate section with the largest comprehensive water-blocking elevation value as the key control section for one-dimensional hydrodynamic simulation of the bifurcation process of the river network.

[0013] Secondly, the present invention also provides a one-dimensional hydrodynamic simulation device for the diversion process of a bifurcation river network, comprising: a study area delineation module for delineating the study area of ​​key cross-sections of the bifurcation river network based on digital elevation model data of the target watershed; a candidate cross-section generation module for performing hydrological analysis on the study area, extracting a ridge network, and searching for candidate cross-sections that meet continuity and length constraints based on the ridge network; a standard cross-section construction module for orthogonally projecting each candidate cross-section into a starting point distance-elevation sequence, retaining the maximum elevation value at the same starting point distance, and forming standard cross-section data representing the maximum water-blocking topography; and a key control cross-section selection module for calculating the comprehensive water-blocking elevation value of each candidate cross-section based on the standard cross-section data, selecting the candidate cross-section with the largest comprehensive water-blocking elevation value as the key control cross-section, and using the key control cross-section for one-dimensional hydrodynamic simulation of the diversion process of the bifurcation river network.

[0014] Thirdly, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the one-dimensional hydrodynamic simulation method for the bifurcation process of a river network as described above.

[0015] Fourthly, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the one-dimensional hydrodynamic simulation method for the bifurcation process of a river network as described above.

[0016] Fifthly, the present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the one-dimensional hydrodynamic simulation method for the bifurcation process of a river network as described above.

[0017] The present invention provides a one-dimensional hydrodynamic simulation method for the diversion process of a bifurcation river network. Based on digital elevation model data of the target watershed, the method delineates the study area of ​​key sections of the bifurcation river network, performs hydrological analysis on the study area, extracts a ridge network, and searches for candidate sections that meet continuity and length constraints based on the ridge network. Then, each candidate section is orthogonally projected into a sequence of starting point distances and elevations, retaining the maximum elevation value at the same starting point distance to form standard section data representing the maximum water-blocking topography. Based on the standard section data, the comprehensive water-blocking elevation value of each candidate section is calculated, and the candidate section with the largest comprehensive water-blocking elevation value is selected as the key control section. This key control section is then used for the one-dimensional hydrodynamic simulation of the diversion process of the bifurcation river network. This method enables automated and objective extraction and optimization of key control sections from high-precision topographic data, effectively avoiding subjective bias and geometric distortion caused by traditional manual route selection. The generated standard sections more realistically reflect the topographic features with the greatest water obstruction, significantly improving the simulation accuracy and physical consistency of the bifurcation river network hydrodynamic model for the diversion process, and providing reliable technical support for flood control scheduling and water resource management. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a flowchart illustrating the one-dimensional hydrodynamic simulation method for the bifurcation process of a river network provided in this embodiment of the invention.

[0020] Figure 2 This is a schematic diagram of feature control point extraction for the one-dimensional hydrodynamic simulation method of the bifurcation process of a river network provided in this embodiment of the invention.

[0021] Figure 3 This is one of the schematic diagrams illustrating the division of the research area for the one-dimensional hydrodynamic simulation method of the bifurcation process of the river network provided in this embodiment of the invention.

[0022] Figure 4 This is the second schematic diagram of the research area division for the one-dimensional hydrodynamic simulation method of the bifurcation process of the river network provided in this embodiment of the invention.

[0023] Figure 5 This is a schematic diagram of the candidate cross-section projection of the one-dimensional hydrodynamic simulation method for the bifurcation process of the river network provided in the embodiment of the present invention.

[0024] Figure 6 This is a distribution map of the key control section screening results of the one-dimensional hydrodynamic simulation method for the bifurcation process of the river network provided in this embodiment of the invention.

[0025] Figure 7 This is a schematic diagram of the starting point distance-elevation of the key control section in the one-dimensional hydrodynamic simulation method for the bifurcation process of the river network provided in this embodiment of the invention.

[0026] Figure 8 This is a comparison chart of downstream flood flow in a bifurcation channel simulated by the one-dimensional hydrodynamic simulation method for the bifurcation process of a river network provided in this embodiment of the invention and by traditional methods.

[0027] Figure 9 This is a comparison chart of the one-dimensional hydrodynamic simulation method for the bifurcation process of the river network provided in this embodiment of the invention and the downstream flood flow of the main channel simulated by the traditional method.

[0028] Figure 10 This is a schematic diagram of the overall process of the one-dimensional hydrodynamic simulation method for the bifurcation process of a river network provided in this embodiment of the invention.

[0029] Figure 11 This is a schematic diagram of the structure of the one-dimensional hydrodynamic simulation device for the bifurcation process of a river network provided in an embodiment of the present invention.

[0030] Figure 12 This is a schematic diagram of the physical structure of the electronic device provided in the embodiment of the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0032] With the development of computer technology, hydrodynamic simulation has become an important tool for flood research and management. One-dimensional hydrodynamic simulation, due to its fast computation speed, high flexibility, and wide applicability, has become a crucial method for river network water resource scheduling, river flood simulation, and river flood forecasting. However, bifurcation river networks present a significant challenge in one-dimensional hydrodynamic simulation. Bifurcation river networks are a complex feature of river networks, and in existing one-dimensional hydrodynamic modeling practices, simulation accuracy is often constrained by the generalization method used in modeling. Increasing the number of cross-sections is a common method to improve simulation accuracy in hydrodynamic simulations; however, in bifurcation river networks, the finite length of dikes and the complex floodplains make it difficult to improve accuracy simply by increasing the number of cross-sections. Furthermore, the selection of cross-section locations is subjective and uncertain, which can lead to the model's inability to accurately capture the local hydraulic characteristics at the bifurcation points, resulting in problems such as distorted bifurcation ratio simulations and water level calculation errors. This limits the application of the model and may increase the risk of downstream flood control scheduling, even leading to the failure of water conservancy project scheduling decisions.

[0033] In view of this, the present invention proposes a one-dimensional hydrodynamic simulation method for the diversion process of bifurcation river networks. By using deterministic methods to identify key control sections, the method objectively describes the impact of river channels and floodplains on the diversion process of bifurcation rivers, improves the simulation accuracy of the diversion process, and provides reliable data support and scientific basis for the simulation scheduling and flood control safety of complex water network systems.

[0034] Specifically, Figure 1 A flowchart illustrating the one-dimensional hydrodynamic simulation method for the bifurcation process of a river network provided in an embodiment of the present invention is shown.

[0035] like Figure 1 As shown, the method includes: S110, delineating the study area of ​​key cross-sections of the bifurcation river network based on digital elevation model data of the target watershed; S120, performing hydrological analysis on the study area, extracting the ridge network, and searching for candidate cross-sections that meet the continuity and length constraints based on the ridge network; S130, orthogonally projecting each candidate cross-section into a starting distance-elevation sequence, retaining the maximum elevation value at the same starting distance, forming standard cross-section data representing the maximum water-blocking topography; S140, calculating the comprehensive water-blocking elevation value of each candidate cross-section based on the standard cross-section data, selecting the candidate cross-section with the largest comprehensive water-blocking elevation value as the key control cross-section, and using the key control cross-section for one-dimensional hydrodynamic simulation of the bifurcation process of the river network.

[0036] The following will provide a detailed description of steps S110-S140 and related steps.

[0037] S110, based on digital elevation model data of the target watershed, delineates the research area of ​​key cross sections of the bifurcation river network.

[0038] In practical hydrological simulation or flood control planning projects, the target watershed must first be clearly defined. In this application, the target watershed refers to a catchment area containing at least one river bifurcation structure, such as the network of rivers in the Pearl River Delta. The target watershed is the object of subsequent diversion process simulation, and its scope is usually determined by project requirements, such as a controlling bifurcation section upstream of a flood control protection zone.

[0039] Next, digital elevation model (DEM) data for the target watershed is acquired. Here, DEM data refers to surface elevation information stored in a regular raster format, typically derived from satellite remote sensing (such as ASTER GDEM), aerial photogrammetry, or lidar mapping, with a spatial resolution generally ranging from 1 to 30 meters. DEM data is used to accurately depict topographic features such as riverbeds, floodplains, and levees.

[0040] Based on this, key cross-sections of the bifurcation network within the target watershed are identified. It should be noted that in this embodiment, key cross-sections of the bifurcation network are not pre-designated artificial cross-sections, but rather refer to potential topographic barriers located near bifurcation nodes that have a controlling influence on water flow distribution. The specific shape and location of the key cross-sections of the bifurcation network are unknown and need to be automatically identified through subsequent steps; the purpose of step S110 is to delineate a reasonable search range, i.e., the study area.

[0041] In this embodiment, the study area specifically refers to the local geographical area surrounding the bifurcation nodes, encompassing the inflow section of the main channel and the initial sections of each bifurcation channel. The delineation of the study area is based on objective geometric rules: using the intersection of the centerlines of the main channel and the bifurcation channels (i.e., the bifurcation node) as a reference, the study area is extended upstream and downstream along each channel centerline by several times the average width of the main channel (e.g., 20–30 times), and enclosed by perpendicular lines drawn to the levee line and the channel boundary. This delineated study area covers key topographic features affecting the bifurcation ratio (such as side bars, mid-channel bars, and local highlands) while avoiding the introduction of irrelevant areas, thereby improving the efficiency and focus of subsequent cross-sectional searches.

[0042] S120, perform hydrological analysis on the study area, extract the ridge network, and search for candidate cross sections that meet the continuity and length constraints based on the ridge network.

[0043] After completing the delineation of the study area in step S110, the automatic cross-section search stage begins. The core of this step S120 is to identify the topographic elevation boundaries that may control water flow distribution within the study area and generate a series of reasonable cross-section candidate schemes from them.

[0044] Specifically, standard hydrological analysis was first performed on the digital elevation model (DEM) data of the study area. This hydrological analysis refers to using hydrological processing tools in a Geographic Information System (GIS) (such as ArcGIS's Hydrology module or the open-source TauDEM toolset) to sequentially perform depression filling, flow direction, and flow accumulation calculations. Depression filling eliminates flow interruptions in the DEM caused by data errors or actual depressions; flow direction determines the flow destination of each raster cell; and flow accumulation reflects the intensity of the runoff.

[0045] Based on the above standard hydrological analysis results, a ridge network is further extracted. In this embodiment, the ridge network refers to a linear topological structure formed by topographic watersheds, representing a set of lines connecting local elevation maxima, where water flows split to either side and cannot cross. In practice, ridges can be obtained by inverting the flow accumulation grid to extract a virtual river network, or by directly identifying watershed boundaries based on the flow direction grid. The ridge network is stored as a vector polyline for subsequent path searching.

[0046] Subsequently, candidate cross-sections are searched based on the ridge network. Specifically, a starting point is set in the set of left bank boundary nodes of the ridge network, and an ending point is set in the set of right bank boundary nodes. A path search algorithm (such as depth-first search) is called to automatically generate all connected paths from the left bank to the right bank. To ensure that the paths are reasonable and effective, two key constraints are imposed: (1) Continuity constraint: adjacent nodes in the path must be directly connected by ridge line segments to ensure geometric continuity; (2) Length constraint: the total length of the path does not exceed a preset threshold (e.g., 1-5 times the average width of the main channel) to prevent invalid cross-sections from excessive detours due to terrain noise.

[0047] Each path that satisfies the above constraints is a candidate cross-section. In this embodiment, the candidate cross-section is not a straight cross-section in the traditional sense, but a broken line that extends naturally along the topographic ridge. It can truly reflect the potential obstruction effect of landforms such as beaches and embankments on water flow, and provide sufficient samples for subsequent screening of the most controllable cross-section.

[0048] S130, each candidate cross section is orthogonally projected into a sequence of starting point distance-elevation, and the maximum elevation value is retained at the same starting point distance to form standard cross section data representing the maximum water-blocking terrain.

[0049] After obtaining multiple candidate cross sections, they need to be uniformly transformed into a standardized terrain representation that can be used as input for hydrodynamic models. The core objective of this step is to convert the spatially varied polygonal candidate cross sections into one-dimensional, equidistant elevation profiles that reflect the most unfavorable water-blocking terrain.

[0050] First, for each candidate cross-section (i.e., the polyline path from the left bank to the right bank generated by the ridge network), orthogonal projection processing is performed. Specifically, using the line connecting the start and end points of the candidate cross-section as the reference axis, i.e., the local cross-section direction, all vertices on the cross-section are projected onto this reference axis along a direction perpendicular to the reference axis. After projection, each original point corresponds to a one-dimensional position along the reference axis (called the start distance) and its original elevation value, thus forming a set of discrete start distance-elevation sequence. Here, the start distance refers to the distance from the start point of the cross-section along the reference axis to the projection point, usually in meters.

[0051] Because the number and distribution of vertices vary among different candidate cross-sections, their starting point distance sequences are usually non-equidistant and do not correspond to each other. To facilitate subsequent comparison and fusion, a unified standard starting point distance grid needs to be constructed. For example, with a step size of 0.5m or 1m, equally spaced starting point distance sets can be generated over the entire cross-section length.

[0052] Next, at each standard starting point distance, the elevation values ​​obtained by linear interpolation of all candidate cross-sections near that location are compared and the highest elevation value is retained. That is, at the same lateral position, the highest topographic point among all possible paths is selected to construct a synthetic topographic profile with the most unfavorable or greatest water obstruction, so as to effectively capture the comprehensive obstruction effect of landforms such as beaches, sand ridges, and embankments on water flow.

[0053] The final standard cross-section data is an array of equidistant starting point distances and their corresponding maximum elevation values, which can be directly used as the river cross-section input in a one-dimensional hydrodynamic model (such as HEC-RAS, MIKE11) to simulate the diversion resistance caused by the beach topography at the bifurcation node.

[0054] S140, calculate the comprehensive water-blocking elevation value of each candidate section based on the standard section data, select the candidate section with the largest comprehensive water-blocking elevation value as the key control section, and use the key control section for one-dimensional hydrodynamic simulation of the bifurcation process of the river network.

[0055] After obtaining standard cross-sectional data representing the most water-blocking topography, it is necessary to further quantify the potential impact of each candidate cross-section on water flow distribution and identify the cross-section with the greatest controlling effect. This step introduces the comprehensive water-blocking elevation value as an index to achieve objective ranking and selection of candidate cross-sections.

[0056] Specifically, the comprehensive water-blocking elevation value is not simply the highest point or average elevation of the cross-section, but a weighted evaluation index constructed based on hydraulic principles. In a typical implementation, the comprehensive water-blocking elevation value can be defined as follows: at a preset design water level (such as the frequent flood level or the multi-year average high water level), the water-blocking area formed by all elevation points in the standard cross-section above that water level (i.e., the elevation-width integral) is calculated, and then divided by the total width of the cross-section to obtain the equivalent water-blocking height per unit width.

[0057] For each candidate cross-section, its comprehensive water-blocking elevation value was calculated using the method described above. Then, the comprehensive water-blocking elevation values ​​of all candidate cross-sections were compared, and the candidate cross-section with the largest comprehensive water-blocking elevation value was selected as the key control cross-section. Here, the key control cross-section is the topographically controlled location near the bifurcation node that plays a dominant role in flow distribution; its shape best represents the actual riverbed's constraint on the diversion process.

[0058] Finally, the selected key control sections are embedded into one-dimensional hydrodynamic models (such as HEC-RAS, MIKE11, etc.) as internal boundary conditions or local resistance elements at bifurcation nodes to simulate the flow distribution process of the bifurcation river network. For example, in the model, it is set as an internal section connecting the main channel and the tributary, and the flow distribution of each channel is automatically adjusted through its elevation-flow relationship, thereby more realistically reflecting the dynamic influence of the floodplain topography on the flow distribution ratio.

[0059] In this embodiment, the study area of ​​key cross-sections of the bifurcation river network is delineated based on digital elevation model data of the target watershed. Hydrological analysis is performed on the study area to extract a ridge network. Candidate cross-sections that meet continuity and length constraints are searched based on the ridge network. Each candidate cross-section is then orthogonally projected into a sequence of starting point distances and elevations, retaining the maximum elevation value at the same starting point distance to form standard cross-section data representing the maximum water-blocking topography. The comprehensive water-blocking elevation value of each candidate cross-section is calculated based on the standard cross-section data. The candidate cross-section with the largest comprehensive water-blocking elevation value is selected as the key control cross-section, which is then used for one-dimensional hydrodynamic simulation of the bifurcation process of the river network. This method achieves automated and objective extraction and optimization from high-precision topographic data to key control cross-sections, effectively avoiding subjective bias and geometric distortion caused by traditional manual route selection. The generated standard cross-sections more realistically reflect the characteristics of the maximum water-blocking topography, significantly improving the simulation accuracy and physical consistency of the bifurcation river network hydrodynamic model for the diversion process, providing reliable technical support for flood control scheduling and water resource management.

[0060] Based on the above embodiments, the process of delineating the study area in step S110 will be described in detail below.

[0061] Based on the digital elevation model data of the target watershed, the study area of ​​key sections of the bifurcation river network is delineated, including: extracting the river centerline, main channel boundary line, and levee lines on both banks of the target watershed based on the digital elevation model data; identifying the main channel centerline and the centerlines of each bifurcation channel from the main channel centerline, and determining the intersection of the main channel centerline and the centerlines of each bifurcation channel as the diversion nodes; calculating the average width of the main channel and the main channel of each bifurcation channel based on the main channel boundary line; starting from the diversion nodes, extending control distances proportional to the average width of the main channel along the main channel centerline and the centerlines of each bifurcation channel downstream to obtain the corresponding characteristic control points; drawing perpendicular lines to the corresponding river centerline through the characteristic control points, and forming the study area by the perpendicular lines, the levee lines on both banks, and the main channel boundary line.

[0062] It is easy to understand that in this embodiment, the delineation of the study area is completed in collaboration with high-precision digital elevation model data (DEM) and geographic information system (GIS) platform to ensure the objectivity of the boundary determination and hydraulic representativeness.

[0063] First, based on the DEM data of the target watershed, the river network is extracted using hydrological analysis tools (such as the Hydrology module or Whitebox Tools in ArcGIS), and a smooth river centerline is generated. At the same time, the main channel boundary line is identified by combining the DEM topographic curvature, slope and inundation analysis, and the dike lines on both banks are extracted based on the artificial dike vector data or topographic abrupt change features.

[0064] Subsequently, in the centerline network, the upstream main stream segment without branching is identified as the main channel centerline, and several tributary segments branching off from its downstream end are identified as the centerlines of each branching channel. The geometric intersection of the main channel centerline and any branching channel centerline is explicitly defined as the diversion node, which is the key location where the spatial distribution of water flow begins.

[0065] Next, based on the extracted main channel boundary line, the average lateral distance between the two channel boundaries is calculated within a certain length range (e.g., 500m–2km) along the center line of the main channel using the spatial measurement function of the GIS platform, thus obtaining the average width D of the main channel. Similarly, the average width d of the main channel is calculated for each branch channel.

[0066] Based on this, starting from the branching node, extend downstream along the centerline of the main channel by a distance N×D (where N is a preset multiple, typically 15–40) to determine the characteristic control points on the main channel; similarly, extend downstream along the centerline of each branch channel by n×d (n can also be 15–40) to determine the corresponding characteristic control points for each branch channel. The process for extracting characteristic control points can be found in [link to documentation]. Figure 2 , Figure 2The diagram illustrates the feature control point extraction of the one-dimensional hydrodynamic simulation method for the bifurcation process of a river network provided in this embodiment of the invention.

[0067] Finally, through each feature control point, draw an orthogonal perpendicular line to the centerline of the river channel. This perpendicular line, together with the dike lines on both banks and the main channel boundary line of the corresponding river segment, encloses a locally closed area, which is the study area used for key section extraction. Typically, this can be divided into the main channel area S1, the bifurcation channel area S2, and the upstream confluence area S3; S3, since it does not participate in the diversion process, can be excluded from subsequent analysis. A typical division of the study area can be found in [reference needed]. Figure 3 , Figure 3 This illustration shows one of the schematic diagrams of the research area division for the one-dimensional hydrodynamic simulation method for the bifurcation process of a river network provided in an embodiment of the present invention.

[0068] If the bifurcation is adjacent to the levee and has no independent floodplain, then only a single study area S1 is formed to accommodate the special river type. For details on the special division of the study area, please refer to [link to relevant documentation]. Figure 4 , Figure 4 The second schematic diagram shows the division of the research area for the one-dimensional hydrodynamic simulation method of the bifurcation process of the river network provided in the embodiment of the present invention.

[0069] The delineation method provided in this embodiment is entirely driven by topographic geometry and hydraulic scale (river width multiple), avoiding the subjectivity and redundancy of traditional delineation that relies on experience or visual observation. It accurately covers the diversion influence area and effectively controls the scale of the computational domain, laying a reliable spatial foundation for subsequent ridge line extraction, cross-section search and high-precision hydrodynamic simulation.

[0070] Based on the above embodiments, the process of generating candidate cross sections in step S120 will be described in detail below.

[0071] Hydrological analysis of the study area was conducted to extract the ridge network, including: filling depressions in the digital elevation model data of the study area to generate depression-free digital elevation model data; calculating flow direction and flow rate grids based on the depression-free digital elevation model data; and extracting watershed watersheds based on the flow direction and flow rate grids to obtain the ridge network.

[0072] The method for searching candidate cross sections based on ridge network to meet the continuity and length constraints includes: in the ridge network, starting from the left bank and ending at the right bank, using a path search algorithm to traverse all continuous paths from the left bank to the right bank, and removing paths containing duplicate nodes or exceeding a preset threshold in length, to obtain a set of candidate cross sections.

[0073] In this embodiment, the search for key curve sections is based on the hydrological analysis function of a high-precision digital elevation model (DEM) and a GIS platform, and a systematic process is used to achieve full and unbiased extraction of candidate sections.

[0074] First, import the DEM raster data corresponding to the study area delineated in step S110 into a GIS platform (such as ArcGIS or QGIS), and use its hydrological analysis module to perform depression filling processing in sequence to eliminate false catchment areas caused by data noise or local depressions, and generate a depression-free DEM; then, calculate the flow direction raster and flow accumulation raster based on the depression-free DEM.

[0075] Next, based on the flow direction and flow rate grid, a watershed segmentation method was used to identify the watershed line within the study area. Specifically, by tracing the boundaries of high-flow paths in reverse, a linear network of structures composed of local elevation maxima, namely the ridge network, was extracted. The ridge network accurately depicts the topological connections of the topographic uplifts such as beaches and sandbars on both sides of the river channel.

[0076] Based on this ridge network, define the set of left bank endpoints. With the set of right bank endpoints (Usually determined by the intersection of the levee line or the boundary of the main channel with the ridge line), and the depth-first search (DFS) algorithm is invoked to traverse all possible paths from the left bank to the right bank.

[0077] During the search process, several constraints are introduced to ensure the effectiveness of the path: (1) Boundary constraints: Path starting point Must belong to Path endpoint Must belong to (2) Continuity constraint: There must be a valid edge connection in the ridge network between any adjacent nodes in the path, i.e. (3) Non-repetition constraint: The path must not contain duplicate nodes to prevent the formation of loops; (4) Length threshold constraint: The total length of the path It must not exceed the preset upper limit ( The maximum topology traversal depth is set (e.g., 5–8 times the average width of the main channel) to allow the cross-section to moderately detour according to the actual beach and channel topography, while eliminating redundant divergent paths caused by local complex micro-topography.

[0078] All paths satisfying the above constraints are determined to be valid continuous polyline sections, and their node sequence is used as follows (e.g., The data is stored in a candidate cross-section set. Finally, the three-dimensional coordinates of all nodes corresponding to each candidate cross-section are extracted. This forms the original dataset used for subsequent orthogonal projection and water-blocking elevation calculations. To determine the validity of the generated continuous polyline cross-section; The intermediate adjacent nodes to be searched.

[0079] This embodiment implements controlled full-path search on the ridge network, which not only preserves the non-linear cross-sectional morphological characteristics of natural river channels caused by sandbars, shoals, etc., but also ensures the hydraulic rationality and computational feasibility of candidate cross-sections through strict topological and length constraints, providing a high-quality and comprehensive candidate sample library for the subsequent construction of standard cross-sections adapted to one-dimensional hydrodynamic models.

[0080] Based on the above embodiments, the process of constructing standard cross-sectional data in step S130 will be described in detail below.

[0081] Each candidate cross-section is orthogonally projected into a sequence of starting point distances and elevations. The maximum elevation value is retained at the same starting point distance to form standard cross-section data representing the terrain with the greatest water obstruction. This includes: for each candidate cross-section, the direction of the line connecting its starting point and ending point is used as the projection reference direction. Each node on the candidate cross-section is orthogonally projected onto the projection reference direction to obtain the projected distance and corresponding elevation of each node relative to the starting point; based on the projected distance and corresponding elevation, an equidistant starting point distance sequence is constructed, and the line segment interpolation between each node is mapped to the equidistant starting point distance sequence; when there are multiple line segment interpolation corresponding to elevation values ​​at each equidistant starting point distance position, the maximum elevation value is retained to generate standard cross-section data representing the terrain with the greatest water obstruction.

[0082] In this embodiment, in order to transform the candidate cross-sections obtained in step S120 into standard cross-section data suitable for a one-dimensional hydrodynamic model, a dimensionality reduction processing method based on orthogonal projection and maximum elevation preservation mechanism is adopted.

[0083] First, for each candidate section, extract the coordinates of the starting point on the left bank. Coordinates of the right bank endpoint Construct a projection baseline vector pointing from the starting point to the ending point. For the projection baseline vector After normalization, the unit vector of the projection direction is obtained. .

[0084] Subsequently, for each node on the candidate cross section (in Construct a local vector pointing from the starting point to the node. Based on the principle of orthogonal projection of vector dot product, calculate the projected distance of the node on the projection reference direction. At the same time, the original absolute elevation value of the node is preserved. This results in a set of discrete projected distance-elevation data pairs. Accordingly, the projection process of the candidate cross-section can be found in [reference needed]. Figure 5 , Figure 5 The diagram shows a candidate cross-section projection schematic of the one-dimensional hydrodynamic simulation method for the bifurcation process of a river network provided in an embodiment of the present invention.

[0085] Furthermore, to eliminate the projection regression or folding phenomenon caused by the curvature of the original ridge line (i.e., non-monotonic changes in the projection distance of some nodes), the above discrete projection distance-elevation data pairs are... Perform resampling.

[0086] Specifically, first determine the minimum value among all projected distances. With the maximum value And set a reasonable resampling step size. (Typically 0.5–2 meters, depending on the DEM resolution), construct a one-dimensional equidistant starting point distance sequence. .

[0087] Next, traverse the spatial line segment formed by each adjacent node in the candidate cross-section. Linear interpolation is performed along its projection axis to map it to... Within the corresponding interval. During the interpolation process, if a certain segment is equidistant from the starting point position... If the elevation is covered by multiple line segments, meaning there are multiple interpolated elevation values, then the maximum elevation preservation mechanism is activated. .in, For a certain segment of the equidistant starting point distance sequence, the position of the equidistant starting point distance is... The final retained elevation value; The position of the current traversed line segment at an equidistant starting point. The interpolated elevation at each location. The maximum elevation retention mechanism ensures that only the maximum water-blocking elevation is retained at each lateral position, accurately reflecting the terrain's ability to impede water flow.

[0088] Finally, the generated one-dimensional equidistant starting point distance The starting point is zeroed out to form an equidistant sequence of starting point distance-elevation parameters, which constitutes a one-dimensional standard river cross-section data set representing the maximum water-blocking topography. .

[0089] This embodiment effectively transforms naturally complex, non-linear ridge cross-sections into standard cross-sections that conform to the input specifications of one-dimensional hydrodynamic models through a strict orthogonal projection and maximum elevation screening strategy. This not only fully preserves the maximum water-blocking characteristics of the riverbed and channel structure, but also avoids the exaggeration of width and distortion of hydraulic parameters caused by cross-sectional geometric distortion.

[0090] Based on the above embodiments, the process of selecting key control sections in step S140 will be described in detail below.

[0091] The comprehensive water-blocking elevation value of each candidate section is calculated based on the standard section data. The candidate section with the largest comprehensive water-blocking elevation value is selected as the key control section. This includes: calculating the comprehensive water-blocking elevation value of each candidate section based on the equidistant starting point distance-elevation sequence in the standard section data; and selecting the candidate section with the largest comprehensive water-blocking elevation value as the key control section for one-dimensional hydrodynamic simulation of the bifurcation process of the river network.

[0092] In this embodiment, one-dimensional standard cross-sectional data of each candidate cross-section is generated in step S130. Based on this, a quantitative evaluation mechanism is used to further screen out key control sections that play a dominant role in water flow distribution.

[0093] Specifically, for each candidate cross-section, the standard cross-section data (equidistant starting point distance - height sequence) is used. (), where the distance between adjacent nodes is a fixed resampling step size. The comprehensive water-blocking elevation value was calculated using a weighted summation method. The calculation formula is: , For comprehensive water-blocking elevation; and These are the distances from the starting point of the one-dimensional equidistant point to the first... The and the first The absolute elevation of each grid node; The starting point is the resampling step size (i.e., the fixed distance between adjacent nodes). The denominator is the total number of nodes in this one-dimensional standard river cross-section. This is the total flood discharge width of the cross section.

[0094] Comprehensive water-blocking elevation value The calculation essentially involves calculating the area-weighted average elevation of the cross-sectional topography along the transverse direction (i.e., the flood discharge direction). The numerator is calculated by multiplying the arithmetic mean of the elevations of two adjacent nodes by the distance. The approximate value of the cross-sectional elevation-width integral is obtained by summing the values; the denominator is the sum of all spacings, which is the total flood discharge width of the cross-section. Therefore, It represents the average resistance of the cross section to water flow. The larger the value, the stronger its overall water-blocking effect.

[0095] After completing all candidate cross-sections After calculation, the comprehensive water-blocking elevation values ​​of each candidate section are automatically compared, and one of them is selected. The largest candidate cross section is selected as the key control section. This key control section best represents the topographic control features that play a decisive role in the distribution of water flow in the bifurcation area, and in particular, it can reflect the constraint effect of complex shoal and channel structures (such as side shoals, river islands, and local highlands) on the mainstream path.

[0096] Finally, the geometric and elevation data of key control sections are input into a one-dimensional hydrodynamic model (such as HEC-RAS, MIKE11, etc.) to simulate the diversion ratio, water level response and flood discharge capacity of the bifurcation river network under different inflow conditions.

[0097] This embodiment introduces a weighted summation formula based on clear physical meaning to construct an objective, quantifiable, and reproducible key section screening mechanism. It effectively overcomes the problem of insufficient representativeness caused by traditional methods relying on manual experience or simply taking the maximum elevation point. It significantly improves the simulation accuracy of the bifurcation river network hydrodynamic model for the spatial allocation process of water flow, and provides a scientific and reliable decision-making basis for flood risk assessment, river regulation planning, and refined water resource scheduling.

[0098] In some embodiments, taking a certain watershed A as an example, the entire process of one-dimensional hydrodynamic simulation of the bifurcation process of the river network in a one-dimensional hydrodynamic model is described.

[0099] Specifically, assuming a one-dimensional hydrodynamic model is needed to simulate the bifurcation process of a river network in a certain watershed A, DEM raster data of the watershed needs to be acquired before the simulation. Using a GIS platform, the average main channel widths d=201m and D=72m are obtained from the river centerline. Diversion nodes are identified from the intersection of the river centerlines. Using predetermined multiples n=20 and N=40, corresponding control distances are extended along the diversion nodes to each river channel to determine the characteristic control points of each channel. A perpendicular line from each characteristic control point to the centerline intersects the levee. Since the bifurcation channels are adjacent to the levee, the study area is divided according to the special case described in S110. Then, using GIS, the study area is analyzed for filling and excavating depressions, flow direction, and cumulative discharge to obtain the watershed of the study area.

[0100] Subsequently, the watershed of the study area was processed using a GIS platform to obtain a three-dimensional coordinate set of the ridge network composed of interconnected polyline segments. The projection resampling step size was then set. and the maximum length threshold for topology search .

[0101] This bifurcation channel meets the special case in S204. A series of cross-sectional paths are searched in the S1 region by the path search algorithm, and the left endpoint of each cross-sectional path is filled with a perpendicular line to the embankment to obtain a series of candidate cross-sections.

[0102] Then, the nodal projection distance is calculated using the orthogonal projection principle of vector dot product. Then, through orthogonal projection and resampling of the maximum water-blocking elevation, a "starting point distance-elevation" sequence for each candidate section is generated. The comprehensive water-blocking elevation of each candidate section is quantitatively calculated using the following formula to obtain the comprehensive water-blocking elevation of the key control section: .

[0103] Figure 6 This diagram illustrates the distribution of key control section screening results for the one-dimensional hydrodynamic simulation method for bifurcation river network processes provided in this embodiment of the invention. According to... Figure 6 As can be seen, after adopting the one-dimensional hydrodynamic simulation method for the bifurcation process of the river network provided by this invention, the code can automatically extract the key control section (red part) with the largest comprehensive water-blocking elevation value from the ridge network (light-colored part). The starting distance and elevation data of the key control section are as follows: Figure 7 As shown, Figure 7 This diagram illustrates the key control section starting point distance-elevation of the one-dimensional hydrodynamic simulation method for the bifurcation process of a river network provided in this embodiment of the invention.

[0104] The selected key control sections are input into the one-dimensional hydrodynamic model. Figure 8 This diagram shows a comparison of downstream flood discharge in bifurcation channels between the one-dimensional hydrodynamic simulation method for the bifurcation process of river networks provided in this embodiment of the invention and the traditional method. Figure 9 This diagram illustrates a comparison between the one-dimensional hydrodynamic simulation method for the bifurcation process of a river network provided in this embodiment of the invention and the downstream flood discharge of the main channel simulated by a traditional method. Figure 8-9 As shown, the peak flow ratio between the downstream bifurcation channel and the main channel was optimized from 962:2721 to 780:2886. After objectively selecting key control sections in this invention, the diversion ratio of the bifurcation channel is more accurate, and the flood simulation is closer to reality. This has a positive impact on correcting the distortion in the simulation of complex diversion ratios and the deviation in water level calculations for this basin. Furthermore, it demonstrates that the high-precision simulation method provided by this invention can objectively describe the impact of riverbeds and floodplains on the diversion process, and has significant implications for basin flood control and drainage planning, refined water resource allocation, and reducing flood risks.

[0105] In other embodiments, Figure 10 The diagram shows the overall process of the one-dimensional hydrodynamic simulation method for the bifurcation process of a river network provided in this embodiment of the invention, clearly demonstrating the complete process from the delineation of the study area to the selection of key control sections.

[0106] like Figure 10 As shown, the overall process is divided into five main levels, from top to bottom: study area division → hydrological and topographic analysis → candidate cross-section generation → cross-section dimensionality reduction modeling → comprehensive evaluation and selection. The entire process is supported by a GIS platform and relies on digital elevation model (DEM) data to achieve automated conversion and scientific selection from two-dimensional topography to one-dimensional standard cross-sections.

[0107] First, deterministic rules (such as those based on the river centerline, diversion nodes, and levee boundaries) are used to delineate the study area to be analyzed. Then, standard hydrological preprocessing is performed on the DEM of the study area in the GIS environment, including filling depressions (eliminating false catchment areas), calculating flow direction, and performing cumulative flow analysis, thereby extracting the watershed watershed network, i.e., the ridge network.

[0108] Subsequently, based on the ridge network, the left bank endpoints are set as the starting set and the right bank endpoints as the ending set. A path search algorithm (such as depth-first search) is invoked to traverse all continuous paths from the left bank to the right bank. Three constraints are imposed during the process: the beginning and end of the path must be located on the left and right banks respectively; adjacent nodes must be connected by ridge lines (to ensure terrain continuity); duplicate nodes are prohibited (to prevent loops), and the total length must not exceed a preset threshold. (To avoid invalid detours). Paths that meet the conditions constitute the "candidate ridge section data set", that is, the candidate section set.

[0109] Next, orthogonal projection is performed on each candidate section, using the direction of the line connecting the start and end points as the projection reference axis. After normalization, the projection direction vector is obtained. Each node on the section is orthogonally projected along this direction to obtain the projected distance of each node relative to the start point. and its original elevation To eliminate projection folding caused by terrain curvature (such as the projection distance of later nodes being smaller than that of earlier nodes), a fixed-step, equidistant starting point distance sequence is constructed. The original polyline segment is linearly interpolated and mapped to this sequence; if multiple segments cover the same starting point distance, the highest elevation value (reflecting the maximum water-blocking capacity) is retained, ultimately generating one-dimensional "starting point distance - elevation" standard cross-section data. .

[0110] Furthermore, based on standard cross-sectional data Calculate the comprehensive water-blocking elevation value for each standard cross section. The calculation method is as follows: average the elevations of adjacent elevation points, multiply by the distance between them, sum them up, and divide by the total width. Essentially, this is a weighted average of the cross-sectional elevations along the transverse direction. (Comprehensive water-blocking elevation value) The overall resistance strength of the cross-section to water flow was quantified.

[0111] Ultimately, selected The largest candidate section is used as the key control section to represent the dominant topographic control effect at the bifurcation node, supporting the diversion simulation and flood control assessment in the subsequent hydrodynamic model.

[0112] Corresponding to the one-dimensional hydrodynamic simulation method for the bifurcation process of river networks described in the above embodiments, this invention also proposes a one-dimensional hydrodynamic simulation device for the bifurcation process of river networks. Specifically, Figure 11A schematic diagram of the structure of the one-dimensional hydrodynamic simulation device for the bifurcation process of a river network provided in an embodiment of the present invention is shown.

[0113] like Figure 11 As shown, the device includes: a study area delineation module 1110, used to delineate the study area of ​​key cross sections of the bifurcation river network based on digital elevation model data of the target watershed; a candidate cross section generation module 1120, used to perform hydrological analysis on the study area, extract the ridge network, and search for candidate cross sections that meet the continuity and length constraints based on the ridge network; a standard cross section construction module 1130, used to orthogonally project each candidate cross section into a starting point distance-elevation sequence, retain the maximum elevation value at the same starting point distance, and form standard cross section data representing the maximum water-blocking topography; and a key control cross section selection module 1140, used to calculate the comprehensive water-blocking elevation value of each candidate cross section based on the standard cross section data, select the candidate cross section with the largest comprehensive water-blocking elevation value as the key control cross section, and use the key control cross section for one-dimensional hydrodynamic simulation of the bifurcation process of the river network.

[0114] In this embodiment, the study area division module 1110 delineates the study area of ​​key cross sections of the bifurcation river network based on the digital elevation model data of the target watershed. The candidate cross section generation module 1120 performs hydrological analysis on the study area, extracts the ridge network, and searches for candidate cross sections that meet the continuity and length constraints based on the ridge network. Then, the standard cross section construction module 1130 orthogonally projects each candidate cross section into a starting distance-elevation sequence, retains the maximum elevation value at the same starting distance, and forms standard cross section data representing the maximum water-blocking topography. Then, the key control cross section selection module 1140 calculates the comprehensive water-blocking elevation value of each candidate cross section based on the standard cross section data, selects the candidate cross section with the largest comprehensive water-blocking elevation value as the key control cross section, and uses the key control cross section for one-dimensional hydrodynamic simulation of the bifurcation process of the river network. This device enables automated and objective extraction and optimization of high-precision topographic data into key control sections, effectively avoiding subjective bias and geometric distortion caused by traditional manual route selection. The generated standard sections more realistically reflect the topographic features with the greatest water obstruction, significantly improving the simulation accuracy and physical consistency of the bifurcation river network hydrodynamic model for the diversion process, and providing reliable technical support for flood control scheduling and water resource management.

[0115] It should be noted that the one-dimensional hydrodynamic simulation device for the bifurcation process of the river network provided in this embodiment of the invention can be referred to in correspondence with the one-dimensional hydrodynamic simulation method for the bifurcation process of the river network described in the above embodiments, and will not be repeated here.

[0116] Figure 12 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 12As shown, the electronic device may include: a processor 1210, a communications interface 1220, a memory 1230, and a communication bus 1240, wherein the processor 1210, the communications interface 1220, and the memory 1230 communicate with each other through the communication bus 1240. The processor 1210 can call logic instructions in the memory 1230 to execute a one-dimensional hydrodynamic simulation method for the bifurcation process of a river network. This method includes: delineating the study area of ​​key cross-sections of the bifurcation network based on digital elevation model data of the target watershed; performing hydrological analysis on the study area, extracting a ridge network, and searching for candidate cross-sections that meet continuity and length constraints based on the ridge network; orthogonally projecting each candidate cross-section into a starting point distance-elevation sequence, retaining the maximum elevation value at the same starting point distance to form standard cross-section data representing the maximum water-blocking topography; calculating the comprehensive water-blocking elevation value of each candidate cross-section based on the standard cross-section data, selecting the candidate cross-section with the largest comprehensive water-blocking elevation value as the key control cross-section, and using the key control cross-section for one-dimensional hydrodynamic simulation of the bifurcation process of the river network.

[0117] Furthermore, the logical instructions in the aforementioned memory 1230 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part 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 the present 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.

[0118] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the one-dimensional hydrodynamic simulation method for the bifurcation process of the above-mentioned methods. The method includes: delineating the study area of ​​key cross sections of the bifurcation network based on digital elevation model data of the target watershed; performing hydrological analysis on the study area, extracting a ridge network, and searching for candidate cross sections that meet the continuity and length constraints based on the ridge network; orthogonally projecting each candidate cross section into a starting distance-elevation sequence, retaining the maximum elevation value at the same starting distance, forming standard cross section data representing the maximum water-blocking topography; calculating the comprehensive water-blocking elevation value of each candidate cross section based on the standard cross section data, selecting the candidate cross section with the largest comprehensive water-blocking elevation value as the key control cross section, and using the key control cross section for one-dimensional hydrodynamic simulation of the bifurcation process of the bifurcation network.

[0119] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements a one-dimensional hydrodynamic simulation method for the bifurcation process of a river network provided by the methods described above. This method includes: delineating the study area of ​​key cross-sections of the bifurcation river network based on digital elevation model data of the target watershed; performing hydrological analysis on the study area, extracting a ridge network, and searching for candidate cross-sections that meet continuity and length constraints based on the ridge network; orthogonally projecting each candidate cross-section into a starting distance-elevation sequence, retaining the maximum elevation value at the same starting distance, forming standard cross-section data representing the maximum water-blocking topography; calculating the comprehensive water-blocking elevation value of each candidate cross-section based on the standard cross-section data, selecting the candidate cross-section with the largest comprehensive water-blocking elevation value as the key control cross-section, and using the key control cross-section for one-dimensional hydrodynamic simulation of the bifurcation process of the river network.

[0120] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0121] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0122] 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 of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A one-dimensional hydrodynamic simulation method for the diversion process of a bifurcation river network, characterized in that, include: Based on the digital elevation model data of the target watershed, the study area of ​​key cross sections of the bifurcation river network was delineated. Hydrological analysis was performed on the study area to extract the ridge network, and candidate cross sections that meet the continuity and length constraints were searched based on the ridge network. Each candidate cross section is orthogonally projected into a sequence of starting point distance-elevation, and the maximum elevation value is retained at the same starting point distance to form standard cross section data representing the maximum water-blocking terrain. The comprehensive water-blocking elevation value of each candidate section is calculated based on the standard cross-section data. The candidate section with the largest comprehensive water-blocking elevation value is selected as the key control section, and the key control section is used for one-dimensional hydrodynamic simulation of the bifurcation process of the river network. The search for candidate sections that satisfy the continuity and length constraints based on the ridge network includes: In the ridge network, starting from the left bank and ending at the right bank, a path search algorithm is used to traverse all continuous paths from the left bank to the right bank, and paths containing duplicate nodes or exceeding a preset threshold in length are removed to obtain a set of candidate cross sections. The process of orthogonally projecting each candidate cross-section into a sequence of starting point distance-elevation parameters, retaining the maximum elevation value at the same starting point distance, and forming standard cross-section data representing the maximum water-blocking terrain includes: For each candidate section, the direction of the line connecting its start point to its end point is used as the projection reference direction. Each node on the candidate section is orthogonally projected onto the projection reference direction to obtain the projection distance and corresponding elevation of each node relative to the start point. Based on the projection distance and corresponding elevation, an equidistant starting point distance sequence is constructed, and the line segment interpolation between each node is mapped to the equidistant starting point distance sequence. When multiple line segment interpolation values ​​exist at each equidistant starting point location, the maximum elevation value is retained to generate standard cross-sectional data representing the terrain with the greatest water obstruction.

2. The one-dimensional hydrodynamic simulation method for the bifurcation process of a river network according to claim 1, characterized in that, The digital elevation model data based on the target watershed is used to delineate the study areas of key sections of the bifurcation river network, including: Based on the digital elevation model data, the river centerline, main channel boundary line, and levee lines on both banks of the target watershed are extracted. Identify the main channel centerline and the centerlines of each branch channel from the channel centerline, and determine the intersection of the main channel centerline and the centerlines of each branch channel as the diversion node. Based on the main channel boundary line, the average width of the main channel and each branch channel is calculated respectively. Starting from the diversion node, control distances proportional to the average width of the main channel are extended downstream along the centerline of the main channel and the centerline of each branch channel to obtain the corresponding characteristic control points. Draw a perpendicular line from the feature control point to the corresponding river centerline. The study area is formed by the perpendicular line, the levee lines on both banks, and the boundary line of the main channel.

3. The one-dimensional hydrodynamic simulation method for the bifurcation process of a river network according to claim 1, characterized in that, The hydrological analysis of the study area and the extraction of the ridge network include: The digital elevation model data of the study area is subjected to depression filling processing to generate depression-free digital elevation model data. Calculate the flow direction and flow grid based on the data from the depression-free digital elevation model; The watershed watershed is extracted based on the flow direction and flow rate grid, resulting in the ridge network.

4. The one-dimensional hydrodynamic simulation method for the bifurcation process of a river network according to claim 1, characterized in that, The step of calculating the comprehensive water-blocking elevation value of each candidate section based on the standard section data, and selecting the candidate section with the largest comprehensive water-blocking elevation value as the key control section, includes: Based on the equidistant starting point distance-elevation sequence in the standard cross-section data, the comprehensive water-blocking elevation value of each candidate cross-section is calculated. The candidate section with the largest comprehensive water-blocking elevation value was selected as the key control section for one-dimensional hydrodynamic simulation of the bifurcation process of the river network.

5. A one-dimensional hydrodynamic simulation device for the diversion process of a bifurcation river network, characterized in that, include: The study area delineation module is used to delineate the study areas of key cross sections of bifurcation river networks based on digital elevation model data of the target watershed. The candidate cross-section generation module is used to perform hydrological analysis on the study area, extract the ridge network, and search for candidate cross-sections that meet the continuity and length constraints based on the ridge network. The standard cross-section construction module is used to orthogonally project each candidate cross-section into a starting point distance-elevation sequence, retaining the maximum elevation value at the same starting point distance, and forming standard cross-section data that characterizes the maximum water-blocking terrain. The key control section selection module is used to calculate the comprehensive water-blocking elevation value of each candidate section based on the standard section data, select the candidate section with the largest comprehensive water-blocking elevation value as the key control section, and use the key control section for one-dimensional hydrodynamic simulation of the bifurcation process of the river network. The search for candidate sections that satisfy the continuity and length constraints based on the ridge network includes: In the ridge network, starting from the left bank and ending at the right bank, a path search algorithm is used to traverse all continuous paths from the left bank to the right bank, and paths containing duplicate nodes or exceeding a preset threshold in length are removed to obtain a set of candidate cross sections. The process of orthogonally projecting each candidate cross-section into a sequence of starting point distance-elevation parameters, retaining the maximum elevation value at the same starting point distance, and forming standard cross-section data representing the maximum water-blocking terrain includes: For each candidate section, the direction of the line connecting its start point to its end point is used as the projection reference direction. Each node on the candidate section is orthogonally projected onto the projection reference direction to obtain the projection distance and corresponding elevation of each node relative to the start point. Based on the projection distance and corresponding elevation, an equidistant starting point distance sequence is constructed, and the line segment interpolation between each node is mapped to the equidistant starting point distance sequence. When multiple line segment interpolation values ​​exist at each equidistant starting point location, the maximum elevation value is retained to generate standard cross-sectional data representing the terrain with the greatest water obstruction.

6. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the one-dimensional hydrodynamic simulation method for the bifurcation process of a river network as described in any one of claims 1 to 4.

7. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the one-dimensional hydrodynamic simulation method for the bifurcation process of a river network as described in any one of claims 1 to 4.

8. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the one-dimensional hydrodynamic simulation method for the bifurcation process of a river network as described in any one of claims 1 to 4.

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