A length-adaptive watershed coding method and system for flood forecasting

Abstract

The present invention relates to a length-adaptive watershed coding method and system for flood forecasting, which comprises: dividing the watershed into a multi-layer structure according to the upstream and downstream topological relationship of the watershed, and each layer of the structure is a sub-watershed unit; taking the sub-watershed unit containing the watershed exit point as the last layer, confirming whether each layer of sub-watershed units meets the dynamic adjustment conditions, and if not, coding each layer of sub-watersheds from bottom to top layer by layer; if the dynamic adjustment conditions are met, the sub-watershed units of this layer are dynamically adjusted and coded, and the codes of the sub-watershed units of the remaining layers remain unchanged. The present invention can realize the minimum range of flood forecast coding adjustment, can quickly locate the watershed that needs to be adjusted according to the dynamic coding, and the watershed coding adjustment is concise and efficient. The present invention can be widely used in the field of flood forecasting.

Description

Technical Field

[0001] The present invention relates to the technical field of flood forecasting, and in particular to a length-adaptive watershed coding method and system for flood forecasting. Background Art

[0002] The water flow network in the physical watershed is complex and changeable, including natural rivers and changes due to subsequent artificial water conservancy projects such as diversion and drainage ditches, reservoir sluices, etc. As my country's hydrological monitoring station network system and water conservancy project facilities continue to improve, how to fully reflect the topological relationship between sub-basins under the dynamic changes of flood reporting stations and reservoir nodes is crucial to improving the foresight period and execution efficiency of flood forecasting.

[0003] The division of watershed units mainly includes two parts, namely, the determination of sub-basin scope and sub-basin coding, which characterizes the hydraulic connection between different regions and is a pre-work and an important part of flood forecasting. The determination of the sub-basin scope is to unify the river section as the basic condition, and define the area where the water flows into the river section as a sub-basin. Therefore, the sub-basin corresponds to the river section one by one, which is also a recognized determination principle in flood forecasting. The key is how to encode the sub-basin. The coding not only represents the topological relationship between sub-basins, but also determines the order and efficiency of calculation in the flood forecasting process. It needs to meet the application needs such as the confluence of multiple river sections, large-scale watershed division, and the establishment of upstream and downstream relationships of river sections. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide a length-adaptive watershed coding method and system for flood forecasting, which can achieve the minimum range of flood forecast coding adjustment, can quickly locate the watershed that needs to be adjusted according to dynamic coding, and the watershed coding adjustment is concise and efficient.

[0005] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a length-adaptive watershed coding method for flood forecasting, which includes: according to the upstream and downstream topological relationship of the watershed, the watershed is divided into a multi-layer structure, and each layer of the structure is a sub-watershed unit; the sub-watershed unit containing the watershed exit point is taken as the last layer, and it is confirmed whether each layer of sub-watershed units meets the dynamic adjustment conditions. If not, each layer of sub-watersheds is coded layer by layer from bottom to top; if the dynamic adjustment conditions are met, the sub-watershed units of this layer are dynamically adjusted and coded, and the coding of the sub-watershed units of other layers remains unchanged.

[0006] Furthermore, each sub-basin is coded layer by layer from bottom to top, including:

[0007] Taking the exit point of the last layer of sub-basin as the starting point, the first level coding is performed on the last layer of sub-basin units;

[0008] For the sub-basin unit located upstream of the exit point of the last sub-basin unit, a 2-bit sequence code is added after the exit point of the last sub-basin unit has been coded;

[0009] For each subsequent layer of sub-basin units, a 2-bit sequence code is added to the end of the sub-basin unit code of the previous layer each time a level is added.

[0010] Further, the first level of coding includes:

[0011] The first level of coding uses Arabic letters to encode the natural watershed, and the exit point of the last level of sub-watershed units is coded by adding a 3-digit sequential code after the natural watershed code.

[0012] Furthermore, the dynamic adjustment conditions are as follows: when the relationship between the flow generation and confluence of the watershed changes, the sub-watershed units are redivided to obtain a new hydraulic topological relationship, and then the re-divided sub-watershed units are dynamically adjusted and encoded.

[0013] Furthermore, the sub-basin units of this layer are dynamically adjusted and coded using two methods: a new coding dynamic adjustment method and a deletion coding dynamic adjustment method.

[0014] Furthermore, a new encoding dynamic adjustment method is added, including:

[0015] The sub-basins that meet the dynamic adjustment conditions are divided, and the newly added projects and monitoring stations are used as cutting nodes. The division is interrupted at the cutting nodes, and the sub-basin units of this layer are divided into two levels: the bottom layer and the top layer.

[0016] The cutting node is used as the exit point of the bottom sub-basin unit, the original code is kept unchanged, the top sub-basin unit code is based on the bottom sub-basin code, and a 2-bit sequence code is added to the end of the bottom sub-basin code.

[0017] Furthermore, the deletion coding dynamic adjustment method includes:

[0018] Determine the node to be deleted, merge the upper and lower level codes of the node, delete the lower level code, retain the upper level code, and keep the rest of the codes unchanged.

[0019] A length-adaptive watershed coding system for flood forecasting includes: a first processing module, which divides the watershed into a multi-layer structure according to the upstream and downstream topological relationship of the watershed, and each layer of the structure is used as a sub-watershed unit; a second processing module, which takes the sub-watershed unit containing the watershed exit point as the last layer, and confirms whether each layer of sub-watershed units meets the dynamic adjustment conditions. If not, each layer of sub-watersheds is coded layer by layer from bottom to top; a dynamic adjustment module, which dynamically adjusts the coding of the sub-watershed units of this layer if the dynamic adjustment conditions are met, and the coding of the sub-watershed units of other layers remains unchanged.

[0020] A computer-readable storage medium storing one or more programs, wherein the one or more programs include instructions, which, when executed by a computing device, cause the computing device to perform any of the above methods.

[0021] A computing device comprises: one or more processors, a memory and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include instructions for executing any of the above methods.

[0022] The present invention adopts the above technical solution, which has the following advantages:

[0023] 1. The present invention takes into account the dynamic changing characteristics of natural watersheds and water conservancy projects, supports dynamic expansion of coding length, and is suitable for the construction of flood forecasting schemes for watersheds of different sizes.

[0024] 2. The present invention simplifies the topological relationship between watersheds and can directly perform hierarchical parallel calculations without traversing the database or determining the topological relationship and confluence calculation order through other attribute fields, thereby improving the efficiency of flood forecasting calculations. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a flow chart of a length-adaptive flood forecasting watershed coding method according to an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of dynamic coding of watersheds in an embodiment of the present invention;

[0027] Figure 3 is a schematic diagram of a newly added encoding dynamic adjustment method in an embodiment of the present invention;

[0028] Figure 4 It is a schematic diagram of a method for dynamic adjustment of erasure coding in an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0030] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0031] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0032] At present, there are many methods for basin unit coding, which can be roughly divided into five categories: topological attribute table method, binary tree coding, multi-tree coding, Pfafstetter method, and trunk-branch topological coding. Among them, the topological attribute table method is a method to set a unique natural number code for each sub-basin randomly or according to a certain algorithm, and then establish topological attributes according to the upstream and downstream relationship of the river network, which is used for the river network confluence calculation of the hydrological model; binary tree and multi-tree coding are methods for coding based on binary tree and multi-tree theory respectively; Pfafstetter coding is a method of coding the four first-level tributaries with the largest catchment area in the sub-basin from downstream to upstream and dividing them, and the five main stream sections are coded from bottom to top; trunk-branch topological coding is a Pfafstetter-like coding system. The above methods have their own characteristics, but the defects are also obvious. First, most methods cannot directly calculate the codes of adjacent upstream and downstream sub-basins, and need to be obtained by searching the entire coding system; second, the topological attributes are relatively fixed. Once the change is sent, it needs to be re-traversed and updated according to the algorithm, and local adjustments cannot be made.

[0033] However, in actual application, natural river basins are often affected by human activities, especially the construction, relocation and demolition of water conservancy projects (such as reservoirs, sluices, hydrological stations, etc.), which will lead to major changes in the topological relationship of water flow in the river basin. In order to meet the needs of river basin flood forecasting under changing conditions, it is necessary to consider and dynamically update the existing river basin coding system to reflect the latest water flow relationship. There is a need for an efficient and convenient coding algorithm that is different from traditional natural river basins and takes into account the impact of water conservancy projects, especially to provide technical support for distributed hydrological simulation, river basin division, display and runoff calculation in digital twin scenarios.

[0034] In order to solve the above problems, the present invention provides a length-adaptive watershed coding method and system for flood forecasting, which realizes the minimum range of flood forecast coding adjustment, can quickly locate the watershed that needs to be adjusted according to dynamic coding, and the watershed coding adjustment is concise and efficient.

[0035] In one embodiment of the present invention, taking into account practical problems such as water conservancy project isolation, the present invention combines the existing general principles of water conservancy object classification and coding and the national watershed boundary data set division method to provide a length-adaptive watershed coding method for flood forecasting, which can provide support for parallel calculation of watershed flow generation and support business needs such as dynamic adjustment of water flow networks. In this embodiment, Figure 1 As shown, the method comprises the following steps:

[0036] 1) According to the topological relationship between the upstream and downstream of the basin, the basin is divided into a multi-layer structure, and each layer of the structure is regarded as a sub-basin unit;

[0037] 2) Take the sub-basin unit containing the basin outlet point as the last layer, and confirm whether each layer of sub-basin units meets the dynamic adjustment conditions. If not, code each layer of sub-basin from bottom to top;

[0038] 3) If the dynamic adjustment conditions are met, the sub-basin unit of this layer will be dynamically adjusted and coded, while the codes of the sub-basin units of other layers remain unchanged.

[0039] In the above step 1), the watershed is divided into a multi-layer structure, specifically: the watershed is divided into multiple layers according to the relationship between the main and tributary rivers of the water system, each layer contains a river section and corresponding entry points, exit points and watershed areas, and the river section and the corresponding entry points, exit points and watershed areas constitute the sub-basin unit of this layer.

[0040] In the above step 2), each layer of sub-basin is coded layer by layer from bottom to top, including the following steps:

[0041] 2.1) Taking the exit point of the last layer of sub-basin as the starting point, the first level encoding is performed on the last layer of sub-basin units;

[0042] In this embodiment, the first-level coding uses Arabic letters (AZ) to encode the natural watershed (i.e. the entire watershed. This embodiment refers to the first-level area code in Appendix C-Watershed System Code Table in SL / T 213-2020, and mainly assigns values ​​to the existing watershed codes). The exit point of the last-level sub-watershed unit is coded by adding a 3-digit sequential code (001-999) after the natural watershed code, for example A001.

[0043] 2.2) The sub-basin unit located upstream of the exit point of the last sub-basin unit indicates a deeper level than the unit where the exit point of the last sub-basin unit is located. In this case, a 2-digit sequence code (01-99) is added after the exit point of the last sub-basin unit has been coded, for example, A00101.

[0044] 2.3) Each subsequent layer of sub-basin units follows the above step 2.2), and a 2-bit sequence code is automatically added to the end of the sub-basin unit code of the previous layer for each additional level.

[0045] In this embodiment, since the hierarchical depths of different watershed unit sizes are different, the maximum length of the watershed code is 256 characters, which can support up to 128 layers. Compared with other algorithms, it can meet the needs of more detailed watershed division, and the reason why 2-bit sequence codes are added in the second level and later is that the deeper the level, the fewer possible branches there are, avoiding excessive occupation of storage bits.

[0046] In the above step 2), the dynamic adjustment condition is: when the flow generation and confluence relationship of the basin changes, the sub-basin units are re-divided to obtain a new hydraulic topological relationship, and the re-divided sub-basin units are dynamically adjusted and encoded.

[0047] For example, the construction of new water conservancy projects, the relocation of measuring stations, the downgrading and scrapping of water conservancy projects will change the original basin runoff generation and confluence relationship, and the sub-basin units will need to be redivided. At this time, dynamic adjustments are needed to provide accurate boundary ranges for hydrological forecasts.

[0048] In the above step 3), the coding of the sub-watershed unit of this layer is dynamically adjusted. In this embodiment, two methods can be used for dynamic adjustment, specifically: a dynamic adjustment method of adding coding and a dynamic adjustment method of deleting coding.

[0049] In this embodiment, when there is a newly built water conservancy project or hydrological monitoring station, it is necessary to make additional coding adjustments, mainly to make more detailed divisions of the sub-basin units that can be predicted / controlled to meet the needs of flood forecasting. Specifically, the method for dynamic adjustment of the additional coding is: adopting the principle of minimization adjustment, when dividing the sub-basin that meets the dynamic adjustment coding, only the sub-basin and related basins are re-encoded, and the coding of unrelated sub-basins remains unchanged. Among them, the sub-basins that have hydraulic connections with the sub-basins that meet the dynamic adjustment coding and affect the order of flood forecast calculation are related basins, and those without hydraulic connections are unrelated sub-basins.

[0050] A new encoding dynamic adjustment method is added, which specifically includes the following steps:

[0051] 3.1) Segment the sub-basins that meet the dynamic adjustment conditions, use the newly added projects and monitoring stations as cutting nodes, interrupt the segmentation at the cutting nodes, and divide the sub-basin units into two levels: the bottom layer and the top layer;

[0052] 3.2) The cutting node is used as the exit point of the bottom sub-basin unit, the original code is kept unchanged, the top sub-basin unit code is based on the bottom sub-basin code, and a 2-bit sequence code is added to the end of the bottom sub-basin code.

[0053] For example, Figure 2For example, assuming that the sub-basin A00102 needs to be split, it is interrupted at the cutting node, and a 2-digit sequence code (A0010201) is added based on the sub-basin code. The upstream sub-basin A001 and the surrounding sub-basin A00101 do not need to be changed. The entire dynamic adjustment process only requires adding one sub-basin code, such as Figure 3 shown.

[0054] In this embodiment, when a water conservancy project is scrapped or demolished, or when a sub-basin needs to be simplified according to flood forecasting to improve calculation efficiency, dynamic adjustment of deletion coding is performed. The dynamic adjustment method of deletion coding is specifically as follows:

[0055] Determine the node to be deleted, merge the upper and lower level codes of the node, delete the lower level code, retain the upper level code, and keep the rest of the codes unchanged.

[0056] For example, taking the above-mentioned newly added sub-basin as an example for deletion, if the node is deleted, then the upper and lower levels of the node are merged (A00102, A0010201), the lower level code is deleted, and the upper level code A00102 remains unchanged (such as Figure 4 As shown in Figure 2.2, if you need to delete the node between A00101 and A0010101 to merge two sub-basins, you only need to keep the code of A00101 unchanged and delete the code of the lower layer, i.e. A0010101. The codes of A0010102 and its downstream sub-basin remain unchanged.

[0057] When in use, since the encoding in this embodiment adopts a hierarchical adaptive structure containing upstream and downstream topological relationships, when adjusting the watershed division, the watershed units involved in the adjustment can be quickly located according to the regional water flow connections, and adjustments can be made quickly and targetedly through the local traversal algorithm.

[0058] In summary, in the actual flood forecast calculation process of the present invention, the information such as basin confluence relationship, basin level and division is all contained in the coding system (for example, the code A001010202 indicates that this basin is a 4th-level basin, its superior is A0010102, the superior is A00101, the next superior is A001, and the highest level is A. Its water eventually flows into the exit point of A step by step according to the level. The same level is A001010201 - because of the sequential code), which can support the parallel and synchronous calculation of basin flow generation and convergence. Figure 2As shown, for example, when the runoff generation and confluence process of the 8 sub-basins of the basin needs to be calculated, the traditional method needs to be calculated from top to bottom according to the water flow sequence, and the 8 sub-basins are traversed and calculated in turn; while the present invention can be used according to the hierarchy, the same hierarchy (10 bits) is calculated first, and the next hierarchy (8 bits) is calculated, and the 2 bits are decreased, and finally only 4 steps are needed to complete the original 8-step calculation, and the efficiency is doubled, as shown in Table 1.

[0059] Table 1 Comparison of flow calculations of watershed dynamic calculation codes

[0060]

[0061] Furthermore, in the actual flood forecasting process, sub-basins are often divided or merged, and this process involves changes in the original topological relationship of each sub-basin. However, since the forecasting scheme has been constructed, re-adjusting the coding on a large scale obviously does not meet the requirements. Therefore, the dynamic adjustment method of adding and deleting coding of the present invention can effectively solve this problem. Moreover, when applying flood forecasting, all sub-basins above / below a certain sub-basin can be called at any time through the basin coding. Figure 2 For example, if you need to extract the watershed range above A00101, you only need to search for all sub-watersheds with the prefix A00101 through the code, instead of extracting according to the upstream and downstream codes through the database attribute table, which greatly improves efficiency.

[0062] In one embodiment of the present invention, a length-adaptive flood forecasting watershed coding system is provided, which comprises:

[0063] The first processing module divides the watershed into a multi-layer structure according to the upstream and downstream topological relationship of the watershed, and each layer of the structure is regarded as a sub-watershed unit;

[0064] The second processing module takes the sub-basin unit containing the basin exit point as the last layer, and confirms whether each layer of sub-basin units meets the dynamic adjustment conditions. If not, each layer of sub-basin units is coded layer by layer from bottom to top;

[0065] The dynamic adjustment module dynamically adjusts the coding of the sub-basin unit of the layer if the dynamic adjustment conditions are met, and the coding of the sub-basin units of the other layers remains unchanged.

[0066] In the above embodiment, coding is performed layer by layer on each sub-watershed from bottom to top, including:

[0067] Taking the exit point of the last layer of sub-basin as the starting point, the first level coding is performed on the last layer of sub-basin units;

[0068] For the sub-basin unit located upstream of the exit point of the last sub-basin unit, a 2-bit sequence code is added after the exit point of the last sub-basin unit has been coded;

[0069] For each subsequent layer of sub-basin units, a 2-bit sequence code is added to the end of the sub-basin unit code of the previous layer each time a level is added.

[0070] The first level of coding includes:

[0071] The first level of coding uses Arabic letters to encode the natural watershed, and the exit point of the last level of sub-watershed units is coded by adding a 3-digit sequential code after the natural watershed code.

[0072] In the above embodiment, the dynamic adjustment condition is: when the relationship between the flow generation and confluence of a watershed changes, the watershed unit is redefined and then the dynamic adjustment coding is performed.

[0073] In the above embodiment, two methods are used to dynamically adjust the coding of the sub-watershed unit of this layer: a dynamic adjustment method of adding coding and a dynamic adjustment method of deleting coding.

[0074] In this embodiment, a new encoding dynamic adjustment method is added, including:

[0075] The sub-basins that meet the dynamic adjustment conditions are divided, and the newly added projects and monitoring stations are used as cutting nodes. The division is interrupted at the cutting nodes, and the sub-basin units of this layer are divided into two levels: the bottom layer and the top layer.

[0076] The cutting node is used as the exit point of the bottom sub-basin unit, the original code is kept unchanged, the top sub-basin unit code is based on the bottom sub-basin code, and a 2-bit sequence code is added to the end of the bottom sub-basin code.

[0077] In this embodiment, the erasure coding dynamic adjustment method includes:

[0078] Determine the node to be deleted, merge the upper and lower level codes of the node, delete the lower level code, retain the upper level code, and keep the rest of the codes unchanged.

[0079] The system provided in this embodiment is used to execute the above-mentioned method embodiments. Please refer to the above-mentioned embodiments for specific processes and detailed contents, which will not be repeated here.

[0080] In the computing device structure provided in one embodiment of the present invention, the computing device may be a terminal, which may include: a processor, a communications interface, a memory, a display screen and an input device. Among them, the processor, the communications interface and the memory communicate with each other through a communication bus. The processor is used to provide computing and control capabilities. The memory includes a non-volatile storage medium and an internal memory, and the non-volatile storage medium stores an operating system and a computer program. When the computer program is executed by the processor, the above method is implemented; the internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a management network, NFC (near field communication) or other technologies. The display screen may be a liquid crystal display screen or an electronic ink display screen, and the input device may be a touch layer covered on the display screen, or a key, trackball or touchpad provided on the housing of the computing device, or an external keyboard, touchpad or mouse, etc. The processor may call the logic instructions in the memory.

[0081] In addition, the logic instructions in the above-mentioned memory can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0082] In one embodiment of the present invention, a computer program product is provided, wherein the computer program product includes a computer program stored on a non-transitory computer-readable storage medium, wherein the computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute the methods provided by the above-mentioned method embodiments.

[0083] In one embodiment of the present invention, a non-transitory computer-readable storage medium is provided, wherein the non-transitory computer-readable storage medium stores server instructions, and the computer instructions enable a computer to execute the methods provided in the above embodiments.

[0084] The above embodiment provides a computer-readable storage medium, whose implementation principle and technical effect are similar to those of the above method embodiment, and will not be repeated here.

[0085] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0086] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0087] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A length-adaptive watershed coding method for flood forecasting, characterized in that: include: According to the topological relationship between the upstream and downstream of the basin, the basin is divided into a multi-layer structure, and each layer of the structure is regarded as a sub-basin unit; The sub-basin unit containing the basin exit point is taken as the last layer to confirm whether each layer of sub-basin units meets the dynamic adjustment conditions. If not, each layer of sub-basin units is coded layer by layer from bottom to top. If the dynamic adjustment conditions are met, the sub-basin unit of the layer is dynamically adjusted and coded, and the sub-basin unit codes of the other layers remain unchanged; Each sub-basin is coded layer by layer from bottom to top, including: Taking the exit point of the last sub-basin as the starting point, the first-level coding is performed on the last sub-basin unit; the first-level coding is: the first-level coding uses Arabic letters AZ to code the natural basin, and the exit point of the last sub-basin unit is coded by adding 3 digits to the natural basin code; For the sub-basin unit located upstream of the exit point of the last sub-basin unit, a 2-bit sequence code is added after the exit point of the last sub-basin unit has been coded; For each subsequent sub-basin unit, a 2-bit sequence code is added to the end of the sub-basin unit code of the previous level. The maximum length of the basin code is 256 characters. The dynamic adjustment conditions are: when the relationship between watershed flow generation and confluence changes, the sub-watershed units are re-divided to obtain new hydraulic topological relationships, and the re-divided sub-watershed units are dynamically adjusted and coded; Dynamically adjust the coding of sub-basin units, using the dynamic adjustment method of adding coding and the dynamic adjustment method of deleting coding; The newly added code dynamic adjustment method is: adopt the principle of minimization adjustment, when dividing the sub-basin that meets the dynamic adjustment code, only the sub-basin and related basins are recoded, and the codes of unrelated sub-basins remain unchanged; among them, the sub-basins that have water conservancy connections with the sub-basins that meet the dynamic adjustment code and affect the flood forecast calculation order are related basins, otherwise the sub-basins without water conservancy connections are unrelated sub-basins; The newly added encoding dynamic adjustment method also includes: The sub-basins that meet the dynamic adjustment conditions are divided, and the newly added projects and monitoring stations are used as cutting nodes. The division is interrupted at the cutting nodes, and the sub-basin units of this layer are divided into two levels: the bottom layer and the top layer. The cutting node is used as the exit point of the bottom sub-basin unit, the original code is kept unchanged, the top sub-basin unit code is based on the bottom sub-basin code, and a 2-bit sequence code is added to the end of the bottom sub-basin code; The erasure coding dynamic adjustment method includes: Determine the node to be deleted, merge the upper and lower level codes of the node, delete the lower level code, retain the upper level code, and keep the rest of the codes unchanged.

2. A length-adaptive watershed coding system for flood forecasting, characterized in that: include: The first processing module divides the watershed into a multi-layer structure according to the upstream and downstream topological relationship of the watershed, and each layer of the structure is regarded as a sub-watershed unit; The second processing module takes the sub-basin unit containing the basin exit point as the last layer, and confirms whether each layer of sub-basin units meets the dynamic adjustment conditions. If not, each layer of sub-basin units is coded layer by layer from bottom to top; Dynamic adjustment module: if the dynamic adjustment conditions are met, the sub-basin unit of the layer will be dynamically adjusted, and the codes of the sub-basin units of the other layers will remain unchanged; The dynamic adjustment conditions are: when the relationship between watershed flow generation and confluence changes, the sub-watershed units are re-divided to obtain new hydraulic topological relationships, and the re-divided sub-watershed units are dynamically adjusted and coded; Dynamically adjust the coding of sub-basin units, using the dynamic adjustment method of adding coding and the dynamic adjustment method of deleting coding; The newly added code dynamic adjustment method is: adopt the principle of minimization adjustment, when dividing the sub-basin that meets the dynamic adjustment code, only the sub-basin and related basins are recoded, and the codes of unrelated sub-basins remain unchanged; among them, the sub-basins that have water conservancy connections with the sub-basins that meet the dynamic adjustment code and affect the flood forecast calculation order are related basins, otherwise the sub-basins without water conservancy connections are unrelated sub-basins; Each sub-basin is coded layer by layer from bottom to top, including: Taking the exit point of the last sub-basin as the starting point, the first-level coding is performed on the last sub-basin unit; the first-level coding is: the first-level coding uses Arabic letters AZ to code the natural basin, and the exit point of the last sub-basin unit is coded by adding 3 digits to the natural basin code; For the sub-basin unit located upstream of the exit point of the last sub-basin unit, a 2-bit sequence code is added after the exit point of the last sub-basin unit has been coded; For each subsequent sub-basin unit, a 2-bit sequence code is added to the end of the sub-basin unit code of the previous level. The maximum length of the basin code is 256 characters. The newly added encoding dynamic adjustment method also includes: The sub-basins that meet the dynamic adjustment conditions are divided, and the newly added projects and monitoring stations are used as cutting nodes. The division is interrupted at the cutting nodes, and the sub-basin units of this layer are divided into two levels: the bottom layer and the top layer. The cutting node is used as the exit point of the bottom sub-basin unit, the original code is kept unchanged, the top sub-basin unit code is based on the bottom sub-basin code, and a 2-bit sequence code is added to the end of the bottom sub-basin code; The erasure coding dynamic adjustment method includes: Determine the node to be deleted, merge the upper and lower level codes of the node, delete the lower level code, retain the upper level code, and keep the rest of the codes unchanged.

3. A computer-readable storage medium storing one or more programs, characterized in that: The one or more programs include instructions that, when executed by a computing device, cause the computing device to perform the method of claim 1 .

4. A computing device, characterized in that include: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include instructions for executing the method according to claim 1.

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