Method, system and terminal for analyzing spatial transfer change of sediment flux in river-lake network

Abstract

This invention belongs to the field of lake sediment change data identification technology, and discloses a method, system, and terminal for analyzing the spatial transfer and change of sediment flux in river networks. The method for analyzing the spatial transfer and change of sediment flux in river networks includes: constructing a sediment transport correlation matrix for the middle and lower reaches of the Yangtze River based on a directed graph; dividing the analysis time series into multiple time stages based on certain major natural evolution events and the construction time of certain water conservancy projects; comparing and analyzing the changes in scour and deposition volumes and the correlation matrix in different river sections during different periods; and clarifying the contribution ratio of different stage nodes to the sediment volume changes in river sections. This invention can systematically sort out the evolutionary history and pattern changes of river-lake relationships, providing a reliable scientific basis and reference for obtaining the optimal state of river-lake relationships and river-lake governance strategies.

Description

Technical Field

[0001] This invention belongs to the field of lake sediment change data identification technology, and in particular relates to a method, system and terminal for analyzing the spatial transfer and change of sediment flux in river networks. Background Technology

[0002] Lakes connected to the Yangtze River are an important component of the river system. [1] It constantly exchanges matter, energy, and biological flows with rivers, leading to continuous changes in river and lake topography. The Yangtze River's middle and lower reaches are interwoven with rivers and lakes, and the relationship between them has undergone significant changes in the past 70 years under the combined influence of natural and human activities. In particular, the construction and operation of the upstream cascade reservoirs and the Three Gorges Dam have altered the water and sediment transport conditions in the middle and lower reaches of the Yangtze, thus changing the characteristics of water and sediment fluxes in the river and lake systems. Extensive research has been conducted on the river-lake relationship in the middle and lower reaches of the Yangtze River, focusing on the patterns of water and sediment transport. [2-8] Analysis of the mechanism and influencing factors of water and sediment exchange between rivers and lakes [9-12] Intrinsic mechanical mechanism

[13] and its subsequent impact [14-16] In-depth research was conducted on multiple aspects, yielding fruitful results. Overall, the construction of the Jingjiang River bend reduction project, the Gezhouba Dam, and the Three Gorges Dam is considered a crucial turning point in the changes in the river-lake sediment relationship since 1950. [3] Therefore, based on the aforementioned time points, different periods were divided, and the patterns of water and sediment transport changes in the main stream of the middle and lower reaches of the Yangtze River and Dongting Lake and Poyang Lake were statistically analyzed. Existing research has shown that the construction and operation of reservoir groups have not had a significant impact on the runoff of the river network in the middle and lower reaches, but the sediment transport has undergone significant changes. [9] Changes in sediment transport directly affect the properties of connected lakes within the river system (sediment-producing or depositional areas). (Zhang Yuning) [1] Based on measured data, this study analyzed the characteristics of sediment transport in the Yangtze River main stream and the two lakes (Dongting Lake and Poyang Lake) since 1960, and presented the changing patterns of the contribution ratio of the two lakes to the sediment transport in the Yangtze River main stream. However, due to the complexity of the river network, there is currently no unified and standardized analysis of the sediment flux changes in the river network formed by the Yangtze River and the two lakes, which is not conducive to the overall control of the changes in the river network pattern. There is also an urgent need to find a method or theory to provide a unified mathematical description of the structural system of the river network.

[0003] Graph theory is an effective tool for establishing connections between mathematical models and topological structures. [17-18]A graph, in this context, is a graphical representation of a given set of points connected by lines. Such graphs are typically used to describe specific relationships between things and can be categorized into directed and undirected graphs. Directed graphs have been widely applied in various fields. Graph theory can standardize and unify the problems being studied. For river networks, the correlation matrix of a directed graph can be used to describe different types of river networks, such as tree-like and ring-like networks, using the same mathematical form. This provides a clear and intuitive description of changes in river-lake relationships and serves as an effective way to analyze changes in water and sediment transport in river networks.

[0004] References involved:

[0005] [1] Zhang Yuning. A Study on Water and Sediment Exchange in the Middle and Lower Reaches of the Yangtze River [D]. East China Normal University, 2021.

[0006] [2] Sun Zhaohua, Zhou Weixing, Zhou Kun, Zhou Xinyue, Chen Li, Li Yitian. Relationship between sediment transport in rivers and lakes and the bed-forming flow in the middle and lower reaches of the Yangtze River [J]. Journal of Hydraulic Engineering, 2021, 52(05):521-534.

[0007] [3] Zhang Yunchang, Zhang Yegang, Song Qiuling, Shen Dongliang, Xu Juan. The history and future of Jianghu relations [J]. Journal of Hydraulic Engineering, 2021, 52(10):1183-1192.

[0008] [4] Hu Chunhong, Wang Yangui. Changes in sedimentation and river-lake relationship after the operation of the Three Gorges Project [J]. Journal of Yangtze River Scientific Research Institute, 2014, 31(05):107-116.

[0009] [5] Guo Xiaohu, Qu Geng, Liu Ya, Liu Xinyuan. Changes in sediment transport in the downstream channel after the operation of the Three Gorges Project [J]. Journal of Lake Sciences, 2020, 32(02):564-572.

[0010] [6] Xiao Xiao, Mao Beiping, Wu Shiqiang. Evolution of hydrological characteristics of the confluence of the Yangtze River and Dongting Lake in the past 100 years

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[0012] [7] Zhao Junkai, Li Jiufa, Jiang Chenjuan, et al. Water exchange process in rivers and lakes in the middle and lower reaches of the Yangtze River [J]. Advances in Water Science, 2013, 24(6):12.

[0013] [8] Shi Yong, Luan Zhenyu, Chen Liangang, et al. Numerical simulation of the evolution trend of the relationship between rivers and lakes in the middle and lower reaches of the Yangtze River [J].

[0014] Advances in Water Science, 2010, 21(6):832-839.

[0015] [9] Lu Jinyou, Yao Shiming. Response mechanism of river-lake relationship in the middle and lower reaches of the Yangtze River under the combined action of reservoir groups [J]. Journal of Hydraulic Engineering, 2018, 49(01):36-46.

[0016]

[10] Wang Dayu, Guan Jianchao, Fang Chunming, Mao Jixin. Simulation of the impact of water conservancy hub operation on river-lake relations

[0017] [J]. Sediment Research, 2018, 43(01):1-8+80.

[0018]

[11] Zhu Lingling, Chen Jianchi, Yuan Jing, et al. Characteristics of sediment erosion and deposition in Dongting Lake and Poyang Lake and the impact of the Three Gorges Reservoir on them [J]. Advances in Water Science, 2014, 25(3):10.

[0019]

[12] Bing Jianping, Deng Pengxin, Zhang Dongdong, Liu Xin. The impact of the operation of the Three Gorges Reservoir on the hydrological situation of Poyang Lake [J]. Yangtze River, 2020, 51(03):87-93.

[0020]

[13] Han Qiwei. The intrinsic mechanism of changes in Jianghu relations [J]. Journal of Yangtze River Scientific Research Institute, 2014, 31

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[0022]

[14] Han Qiwei. Changes in the distribution of water flow between rivers and lakes lead to new flood conditions in the middle reaches of the Yangtze River [J]. Sediment Research, 1999(5):1-12.

[0023]

[15] Hu Xiangyang, Liu Jiaming, Xu Xingya. The impact of changes in the relationship between rivers and lakes on flood and drought disaster prevention in the Yangtze River Basin and countermeasures [J]. China Water Resources, 2022(05):28-30+23.

[0024]

[16] Wu Bo, Zhao Qiang, Ma Fangkai. Research on the restoration of the relationship between rivers and lakes in the middle and lower reaches of the Yangtze River [J]. Environmental Science Guide, 2019, 38(05):10-14.

[0025]

[17] Yang Kailin. Sparse matrix technique for unsteady flow in canal networks based on graph theory [J]. Journal of Hydraulic Engineering, 2011, 42

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[0027]

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[0028] Based on the above analysis, the existing technologies have the following problems and shortcomings: They do not consider the spatial transfer and variation of sediment flux as a whole within the river network, and the understanding of large-scale changes in the river network pattern needs further deepening. Furthermore, they lack a sediment transport correlation matrix for the river network based on a directed graph, thus hindering a systematic analysis of the changes in scour and deposition volumes and correlation matrices in different river sections at different times. Summary of the Invention

[0029] To overcome the problems existing in related technologies, the present invention discloses a method, system and terminal for analyzing the spatial transfer and changes of sediment flux in river networks.

[0030] The technical solution is as follows: A method for analyzing the spatial transfer and change of sediment flux in river networks includes the following steps:

[0031] S1, Constructing a sediment transport correlation matrix for the river network based on a directed graph;

[0032] S2, based on certain major natural evolution events and the construction time of certain water conservancy projects, divides the analyzed time series into multiple time stages;

[0033] S3. Compare and analyze the changes in scour and sedimentation volume and sediment transport correlation matrix of different river sections at different time stages to obtain the sediment contribution ratio of different stage nodes to the changes in scour and sedimentation volume of the river section.

[0034] In one embodiment, in step S1, G represents a directed graph, mathematically defined as G = (V, E), where V and E are the sets of nodes and directed edges, respectively, and G is a pair of V and E.

[0035] In one embodiment, in step S1, the river network includes a tree diagram and a circular directed graph. The tree diagram consists only of branches, and the circular directed graph contains closed loops. For node j within the river network, the sediment transport equation is:

[0036]

[0037] In the formula, |E| in W is the total number of inflow channels at node j, including point sources; j It is the total amount of sand coming into each node j; s i Q represents the sediment concentration when river segment i enters node j. i Indicates flow rate.

[0038] In one embodiment, in step S1, when describing different types of river network structures using directed graphs, a river network correlation matrix can be constructed. This matrix reflects the river network topology information. Based on the directed graph, a sediment transport equation is constructed, and its correlation matrix reflects the contribution of nodes to the sediment transport volume of the river reach. The equation can be expressed as:

[0039]

[0040] In the formula, the element a in the matrix i，j W represents the contribution of node j to the sediment load of river segment i. i ΔW represents the amount of sediment transported at node i; i This indicates the change in scouring and sedimentation in river segment i.

[0041] Among them, a i，j W j +a i，k W k =ΔW i

[0042] In the formula, a i，j W j It refers to the amount of sediment injected into or out of river segment i through node j, a i，j W j A positive value indicates that there is a. i，j W j The amount of sediment flows into river segment i through node j, a i，j W j A negative value indicates that there exists a value of |a|. i，j W j The amount of sediment flows out from node j in river segment i;

[0043] ΔW i This means that the net sediment load of river segment i, represented by the two endpoints, nodes j and j', is equal to the scouring and deposition volume of river segment i obtained according to the sediment transport method, which represents the change in scouring and deposition volume of river segment i. The above formula can be further expressed as:

[0044]

[0045] Analysis for different time periods as well as The study aims to understand the patterns of riverbed evolution and the impact of different nodes at the bifurcation points on the scouring and sedimentation of the corresponding river sections.

[0046] In one embodiment, dividing the analyzed time series into multiple time phases in step S2 includes the following steps:

[0047] Based on the identified object, select the time series for analysis. Within the selected time series, identify major natural events or the construction of water conservancy projects that have a significant impact on the selected river network water and sediment transport. Using the time of occurrence of river network water and sediment transport as nodes, divide the time series into n time stages.

[0048] In step S3, the contribution ratio of sediment volume to the changes in scouring and deposition in the river section at different stage nodes is obtained, including:

[0049] Based on the time period determined in step S2, for each period, a sediment transport correlation matrix is ​​constructed based on step S1. The characteristics of scour and deposition changes in different river sections are analyzed based on the right-hand side of the sediment transport correlation matrix. Based on the correlation matrix on the left side of the sediment transport correlation matrix, the contribution ratio of nodes to the sediment volume changes in river section scour and deposition is analyzed.

[0050] Another objective of this invention is to provide a system for analyzing the spatial transfer and variation of sediment flux in river networks, comprising:

[0051] The sediment transport correlation matrix construction module is used to construct sediment transport correlation matrices for river networks based on directed graphs.

[0052] The module for dividing time into multiple time phases is used to divide the analyzed time series into multiple time phases based on certain major natural evolution events and the construction time of certain water conservancy projects.

[0053] The sediment contribution ratio acquisition module is used to compare and analyze the changing patterns of scour and sedimentation volume and sediment transport correlation matrix in different river sections at different time stages, and to obtain the sediment contribution ratio of different stage nodes to the scour and sedimentation changes in the river section.

[0054] Another object of the present invention is to provide a computer device, the computer device including a memory and a processor, the memory storing a computer program, which, when executed by the processor, causes the processor to perform the method for analyzing the spatial transfer and change of sediment flux in river networks.

[0055] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the method for analyzing the spatial transfer and changes of sediment flux in river networks.

[0056] Combining all the above technical solutions, the advantages and positive effects of this invention are as follows: This invention constructs a sediment transport correlation matrix for river networks based on directed graphs. Based on certain major natural evolution events and the construction time of certain water conservancy projects, the analyzed time series is divided into multiple time stages. By comparing and analyzing the changes in scour and sedimentation volumes and the correlation matrix in different river sections during different periods, it clarifies the contribution ratio of different stage nodes to the sediment volume changes in river sections. This invention can systematically trace the evolutionary history of river-lake relationships, providing a reliable scientific basis and reference for obtaining the optimal state of river-lake relationships and river-lake governance strategies. Attached Figure Description

[0057] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0058] Figure 1 This is a flowchart of a method for analyzing the spatial transfer and changes of sediment flux in river networks, provided by an embodiment of the present invention.

[0059] Figure 2(a) is a tree diagram provided in an embodiment of the present invention;

[0060] Figure 2(b) is a circular directed graph provided in an embodiment of the present invention;

[0061] Figure 3 This is a schematic diagram of the generalized river network in the middle and lower reaches of the Yangtze River provided in an embodiment of the present invention;

[0062] Figure 4 This is a correlation matrix diagram for Phase 1 (2003-2018) provided in an embodiment of the present invention;

[0063] Figure 5 This is a schematic diagram of a system for analyzing the spatial transfer and change of sediment flux in river networks, provided by an embodiment of the present invention.

[0064] In the figure: 1. Sediment transport correlation matrix construction module; 2. Multiple time stage division module; 3. Sediment contribution ratio acquisition module. Detailed Implementation

[0065] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0066] I. Explanation of the Implementation Example:

[0067] like Figure 1 As shown in the embodiments of the present invention, the method for analyzing the spatial transfer and change of sediment flux in river networks includes:

[0068] S101, Constructing a sediment transport correlation matrix for the river network of the Yangtze River from Yichang to Datong in the middle and lower reaches based on a directed graph;

[0069] S102, which covers the period from 1956 to 2018, can be divided into 5 time phases based on the construction time of the Jingjiang River bend reduction project, the Gezhouba Dam, and the Three Gorges Dam.

[0070] S103. Compare and analyze the variation patterns of scour and sedimentation volume and sediment transport correlation matrix in different river sections at different time stages, and obtain the sediment contribution ratio of different stage nodes to the scour and sedimentation changes in the river section.

[0071] As a preferred embodiment, dividing the analyzed time series into multiple time stages in step S102 includes the following steps:

[0072] Based on the identified object, select the time series for analysis. Within the selected time series, identify major natural events or the construction of water conservancy projects that have a significant impact on the selected river network water and sediment transport. Using the time of occurrence of river network water and sediment transport as nodes, divide the time series into n time stages.

[0073] In step S103, the contribution ratio of sediment volume to the scouring and deposition changes of different stage nodes is obtained, including:

[0074] Based on the time period determined in step S102, for each period, a sediment transport correlation matrix for that period is constructed based on step S101. The characteristics of scour and deposition changes in different river sections are analyzed based on the right-hand side of the sediment transport correlation matrix. Based on the correlation matrix on the left side of the sediment transport correlation matrix, the contribution ratio of nodes to the sediment volume changes in river section scour and deposition is analyzed.

[0075] Example 1

[0076] Directed graphs in graph theory represent the relationships between objects. Let G represent a directed graph, and its mathematical definition can be written as G = (V, E), where V and E are the sets of nodes and directed edges, respectively, and G is a pair of V and E. River networks involve tree graphs and circular directed graphs. Directed graphs can be represented as shown in Figures 2(a) and 2(b), where a tree graph consists only of branches, while a circular directed graph contains closed loops. For node j within the river network, the sediment transport equation can be expressed as...

[0077]

[0078] In the formula, |E| in W is the total number of inflow channels (including point sources) at node j; j It is the total amount of sand coming into each node j; s i Q represents the sediment concentration when river segment i enters node j. i This represents flow rate. When describing different types of river network structures using directed graphs, a sediment transport correlation matrix can be constructed, which reflects the river network topology information.

[0079] A sediment transport equation is constructed based on a directed graph. Its correlation matrix reflects the contribution of each node to sediment transport in a river section. The equation can be expressed as follows:

[0080]

[0081] In the above formula, the element a in the matrix i，j , representing the contribution of node j to the sediment load of river segment i, i.e., a i，j W jIt refers to the amount of sediment injected into or out of river segment i through node j, a i，j W j A positive value indicates that there is a. i，j W j The amount of sediment flows into river segment i through node j, a i，j W j A negative value indicates that there exists a value of |a|. i，j W j The sediment flow originates from node j in river segment i. Consider the following equation as an example:

[0082] a i，j W j +a i，k W k =ΔW i (3)

[0083] The above formula means that the net sediment contribution of the two endpoints of river segment i, namely node j and node k, to river segment i is equal to the amount of scouring and deposition obtained by river segment i according to the sediment transport method.

[0084] The river section analyzed in this embodiment of the invention is the Yichang to Datong section, with a total length of 1180 km. Upstream from Chenglingji, three outlets (Songzikou, Taipingkou, and Ouchikou) on the south bank of the Jingjiang River flow into Dongting Lake. Dongting Lake then collects water from the Xiang, Zi, Yuan, and Li rivers, converging at Chenglingji before joining the Yangtze River. Poyang Lake collects water from the Gan, Fu, Xin, Rao, and Xiu rivers, converging at Hukou before joining the main stream of the Yangtze River. A generalized river network is constructed for the above-mentioned river section, such as... Figure 3 As shown, this includes the confluence of the Yangtze River main stream at Yichang, Zhicheng, Shashi, Jianli, Luoshan, Hankou, Jiujiang, and Datong hydrological stations, as well as the four rivers of Dongting Lake and the five rivers of Poyang Lake. Figure 3 The schematic diagram of the generalized river network in the middle and lower reaches of the Yangtze River shows a total of 19 nodes (black numbers) and 20 river sections.

[0085] It should be noted that the branching of Dongting Lake at Songzikou and Taipingkou is generally defined as branching off from Zhicheng Station (node ​​2), the branching off at Ouchikou is generally defined as branching off from Shashi Station (node ​​3), the confluence of the four rivers is generally defined as node 4, and the confluence of the main stream is generally defined as node 10 at Luoshan Station; the confluence of Poyang Lake is generally defined as confluence of the main stream at Jiujiang Station (node ​​12), and the confluence of the five rivers is generally defined as node 18.

[0086] Based on the aforementioned river network, equations for scour and sedimentation in different river sections at different time stages can be constructed:

[0087]

[0088] Analysis for different periods as well as The changing patterns can clarify the characteristics of riverbed evolution and the magnitude of the influence of different nodes at the bifurcation points on the scouring and deposition changes of the corresponding river sections. Calculations were performed using measured data from 2003 to 2018, and the resulting key matrix change diagram is shown below. Figure 4 The correlation matrix diagram for Phase 1 (2003-2018) is shown below.

[0089] Example 2

[0090] like Figure 5 As shown, this embodiment of the invention provides a system for analyzing the spatial transfer and variation of sediment flux in river networks, comprising:

[0091] Module 1 for constructing sediment transport correlation matrix is ​​used to construct sediment transport correlation matrix of river network based on directed graph;

[0092] Module 2, which divides the time series under analysis into multiple time stages based on certain major natural evolution events and the construction time of certain water conservancy projects;

[0093] Module 3, which obtains the sediment contribution ratio, is used to compare and analyze the changes in the scouring and deposition volume and sediment transport correlation matrix of different river sections at different time stages, and to obtain the sediment contribution ratio of different stage nodes to the changes in scouring and deposition of river sections.

[0094] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0095] The information interaction and execution process between the above-mentioned devices / units are based on the same concept as the method embodiments of the present invention. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0096] Those skilled in the art will understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the functions described above can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this invention. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0097] II. Application Examples:

[0098] Application Example 1

[0099] The present invention also provides a computer device comprising: at least one processor, a memory, and a computer program stored in the memory and executable on the at least one processor, wherein the processor executes the computer program to implement the steps in any of the above method embodiments.

[0100] Application Example 2

[0101] The present invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, can implement the steps in the above-described method embodiments.

[0102] Application Example 3

[0103] The present invention also provides an information data processing terminal, which is used to provide a user input interface to implement the steps in the above method embodiments when executed on an electronic device. The information data processing terminal is not limited to mobile phones, computers, and switches.

[0104] Application Example 4

[0105] The present invention also provides a server that, when executed on an electronic device, provides a user input interface to implement the steps described in the above method embodiments.

[0106] Application Example 5

[0107] The present invention provides a computer program product that, when run on an electronic device, enables the electronic device to implement the steps described in the various method embodiments.

[0108] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments of the present invention can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include at least: any entity or device capable of carrying the computer program code to a photographing device / terminal device, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium. Examples include USB flash drives, portable hard drives, magnetic disks, or optical disks.

[0109] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention and within the spirit and principles of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for analyzing the spatial transfer and variation of sediment flux in river networks, characterized in that, The method includes the following steps: S1, Constructing a sediment transport correlation matrix for the river network based on a directed graph; S2, based on major natural evolution events and the construction time of water conservancy projects, divides the time series of analysis into multiple time stages; S3. Compare and analyze the changes in the scouring and deposition volume and sediment transport correlation matrix of different river sections at different time stages, and obtain the contribution ratio of sediment volume to the changes in scouring and deposition volume of different stage nodes. In step S1, the river network includes a tree-shaped directed graph and a circular directed graph. The tree-shaped directed graph is composed of branches, and the circular directed graph contains closed loops. For node j within the river network, the sediment transport equation is: ； In the formula, It is a node The total number of inflow channels; It is each node Total amount of sand coming in; Indicates that river segment i enters node The sand content at that time Indicates flow rate; In step S1, when describing different types of river network structures using directed graphs, a river network correlation matrix is ​​constructed. This matrix reflects the river network topology information. Based on the directed graph, a sediment transport equation is constructed, and its correlation matrix reflects the contribution of nodes to the sediment transport of the river section. The equation is expressed as: ； In the formula, the elements in the matrix Represents a node river section The contribution of sand volume, W i Represents a node i The amount of sediment transported; Indicates river section Changes in siltation and sedimentation volume; The correlation matrix of the sediment transport equation is: ; In the formula, Through nodes Inflow or outflow section of the river The amount of sand, A positive value indicates that there is The amount of sand through the nodes Inflow section , A negative value indicates that there is a value of 0. The amount of sediment in the river section From node Outflow; node and nodes river section The net sediment contribution is equal to that of the river section The amount of scouring and silting is determined based on the sediment transport method. Further expressed as: ； In the formula, Represented by element The resulting correlation matrix; Represented by nodes j The column vector formed by the amount of sand coming in; Indicated as river segment i The column vector formed by the scouring and silting volumes; Analysis based on different time stages as well as The study aims to understand the patterns of riverbed evolution and the impact of different nodes at the bifurcation points on the scouring and sedimentation of the corresponding river sections.

2. The method for analyzing the spatial transfer and variation of sediment flux in river networks according to claim 1, characterized in that, In step S1, the directed graph is represented as G, and mathematically defined as G = (V, E), where V and E are the sets of nodes and directed edges, respectively, and G is a pair of V and E.

3. The method for analyzing the spatial transfer and variation of sediment flux in river networks according to claim 1, characterized in that, In step S2, dividing the analyzed time series into multiple time stages includes the following steps: based on the determined object, select the time series to be analyzed; in the selected time series, determine the major natural events or construction of water conservancy projects that have a significant impact on the selected river network water and sediment transport; and divide the time series into n time stages by taking the time of river network water and sediment transport as the node. In step S3, obtaining the contribution ratio of nodes to sediment volume changes in river scour and deposition at different stages includes: based on the time stages determined in step S2, for each stage, constructing the sediment transport correlation matrix for that stage based on step S1; analyzing the characteristics of sediment volume changes in different river sections based on the right-hand side of the sediment transport correlation matrix; and analyzing the contribution ratio of nodes to sediment volume changes in river sections based on the correlation matrix on the left-hand side of the sediment transport correlation matrix.

4. A system for analyzing the spatial transfer and change of sediment flux in river and lake networks, implementing the method for analyzing the spatial transfer and change of sediment flux in river and lake networks as described in any one of claims 1 to 3, characterized in that, The system used to analyze the spatial transfer and change of sediment flux in river networks includes: The sediment transport correlation matrix construction module (1) is used to construct the sediment transport correlation matrix of the river network based on the directed graph; The multiple time-stage segmentation module (2) is used to divide the analyzed time series into multiple time stages based on certain major natural evolution events and the construction time of certain water conservancy projects; The sediment contribution ratio acquisition module (3) is used to compare and analyze the changes in the scouring and deposition volume and sediment transport correlation matrix of different river sections at different time stages, and to obtain the sediment contribution ratio of different stage nodes to the scouring and deposition changes of the river section.

5. A computer device, characterized in that, The computer device includes a memory and a processor. The memory stores a computer program. When the computer program is executed by the processor, the processor performs the method for analyzing the spatial transfer and change of sediment flux in river networks as described in any one of claims 1 to 3.

6. A computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the method for analyzing the spatial transfer and variation of sediment flux in river networks as described in any one of claims 1 to 3.

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