DEM-based method and system for quickly generating temporary inundation area of reservoir flood control regulation

Abstract

The application discloses a reservoir flood control scheduling temporary inundated area rapid generation method and device based on DEM, relates to the temporary inundated area definition field of water conservancy and hydropower engineering. The method obtains or generates the reservoir river section DEM, the river section line, the normal storage level inundated area range and the backwater table under different working conditions, divides the river channel higher than the reservoir inundated area into multiple units; the inverse distance weighted interpolation method is used to calculate the grid water level of each unit, and the DEM elevation is compared to determine the grid that meets the condition; after the boundary tracking and smoothing treatment, the units are combined, and the normal storage level inundated area is erased, so that the temporary inundated area is obtained. It solves the problems of time-consuming and insufficient precision of the existing method, considers the efficiency and precision, and provides reliable support for flood control scheduling decision, inundated loss evaluation and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of temporary inundation area definition of water conservancy and hydropower engineering, and particularly relates to a method and system for quickly generating a temporary inundation area of reservoir flood control scheduling based on DEM. BACKGROUND

[0002] During a flood or reservoir flood control scheduling, the reservoir is operated according to the flood control requirements, the water level is adjusted between the flood control limit water level and the flood control high water level, the reservoir water level is higher than the normal storage water level, and the area originally not belonging to the reservoir inundation area is temporarily inundated, which is the temporary inundation area of reservoir flood control scheduling. The definition of the temporary inundation area of reservoir flood control scheduling is related to the scientific rationality of the flood control scheduling scheme, plays an important role in issuing inundation early warning, and is directly related to the assessment and compensation of inundation losses. Due to the uncertainty of the flood, when defining the temporary inundation area, the influence of flood backwater needs to be considered, and factors such as inflow and reservoir water level need to be considered, and often multiple different working conditions of temporary inundation need to be analyzed in a short time.

[0003] In the prior art, in order to meet the requirement of multiple scheme calculation in a short period of time, the method usually adopted in the past is to select part of representative working conditions, extract contour lines manually by using GIS software according to the cross section and backwater calculation results, then connect the lines and perform topological processing to form the inundation range under the working condition, and obtain the temporary inundation area range line after superimposing the reservoir inundation area space. Due to time reasons, other working conditions often do not form actual inundation area range lines, but obtain influence indexes through interpolation or manual analysis of key sections. In recent years, in the field of flood reservoir inundation area definition, a water surface grid file is fitted according to the flood water level, and a grid calculator is used to perform algebraic operation on the water surface grid file and the DEM file to determine the inundation area grid file, and the grid is converted into a plane and then combined and processed into a reservoir inundation area plane file.

[0004] The existing method mainly has the following problems: 1) representative working conditions are selected, contour lines are extracted manually by using GIS software, which is time-consuming and difficult to meet the requirement of quickly generating the range under the current situation, and the temporary inundation indexes obtained by interpolation of other working conditions have limited accuracy and are difficult to meet the requirement of flood control scheduling decision; 2) the method of fitting a water surface grid file according to the flood water level and performing algebraic operation on the DEM file to determine the inundation area, and then converting the grid into a plane and combining and processing it into a reservoir inundation area plane file can be used in the simulation analysis of the flood range of a medium or small river, but for a wide area and high-precision DEM, the calculation is time-consuming.

[0005] Therefore, a method and system for quickly generating the temporary inundation area of reservoir flood control scheduling are needed, which takes into account the calculation efficiency and accuracy. SUMMARY

[0006] In view of the deficiencies in the prior art, the purpose of the present application is to provide a DEM-based method and system for quickly generating temporary inundation areas for reservoir flood control scheduling, to solve at least one of the above technical problems in the prior art.

[0007] To solve the above technical problems, the technical solution adopted by the present application is as follows:

[0008] In a first aspect, the present application provides a DEM-based method for quickly generating temporary inundation areas for reservoir flood control scheduling, comprising:

[0009] S1: Obtain or generate a digital elevation model (DEM) for the river section where the reservoir is located;

[0010] S2: Obtain the river cross-section line of the river section where the reservoir is located and perform data preprocessing;

[0011] S3: Obtain the inundation area range of the normal water level and the specific water level of the reservoir;

[0012] S4: Obtain the backwater table of each section under different working conditions predicted by flood control scheduling and perform data preprocessing;

[0013] S5: Extend the cross-section line based on the position of the river cross-section line, and combine the reservoir inundation area range to divide the river channel above the reservoir inundation area into multiple river channel units;

[0014] S6: Based on the river extension cross-section line at the upstream and downstream ends, the reservoir inundation area range, the backwater table, and the DEM of the reservoir river section, for each river channel unit within the reservoir inundation area range and each grid above the reservoir inundation area, when the upstream and downstream water levels are inconsistent, the grid water level value is calculated one by one according to the inverse distance weighted interpolation method, and compared with the DEM elevation value, the grid with water level value ≥ DEM elevation value is marked as temporary inundation area grid meeting the conditions;

[0015] S7: Based on the temporary inundation area grid meeting the conditions, generate a topologically closed contour boundary ordered coordinate sequence through a boundary tracking algorithm, and construct a vector polygon, and simultaneously perform smoothing processing on the polygon boundary using a smoothing algorithm, and finally obtain a closed face domain vector file of the temporary inundation area of the reservoir in each river channel unit;

[0016] S8: Merge the temporary inundation areas of the reservoir in multiple river channel units, and erase the reservoir inundation area corresponding to the normal water level, to obtain the temporary inundation area for flood control scheduling under different working conditions.

[0017] Preferably, the method for generating the DEM of the river section where the reservoir is located in S1 comprises:

[0018] Obtain the contour lines and elevation point data in the topographic map;

[0019] The GIS software is used to generate a digital elevation model DEM by using an irregular triangle network or a Kriging interpolation algorithm.

[0020] Preferably, the data preprocessing of the river channel section line in S2 includes:

[0021] Step 1: Process the section line into shp format vector line data;

[0022] Step 2: Add attribute fields containing section number and section name to the section line data set, and record the relevant information.

[0023] Preferably, the data preprocessing of the backwater table in S4 includes:

[0024] Step 1: Organize the backwater table according to the standard format of section number, section name and different working conditions water level;

[0025] Step 2: Sort out the upstream and downstream relationship of the section and record it in the backwater table.

[0026] Preferably, S5 specifically includes:

[0027] Step 1: Set the expansion multiple, and automatically extend the two ends of the section line to fully intersect with the river bank;

[0028] Step 2: Divide the river channel unit according to the extended section line and the upstream and downstream relationship;

[0029] Step 3: Deduct the reservoir inundation area, and only divide the area above the reservoir inundation area.

[0030] Preferably, the step of inverse distance weighted interpolation in S6 includes:

[0031] Step 1: Determine the known water level on the two end section lines of the adjacent upstream and downstream, assuming that the point on the known section line is Qi(xi,yi), The corresponding water level value is zi;

[0032] Step 2: Determine the point to be interpolated, record its coordinates P(x,y);

[0033] Step 3: Calculate the distance di of the point to be interpolated to each known point Qi(xi,yi), the distance formula is:

[0034] ;

[0035] Step 4: Calculate the weight wi of each known point according to the inverse distance weighted method, the weight formula is

[0036] ;

[0037] Wherein, p is distance weight index, p=2; when di=0, the known point is taken as the accurate value of the point to be interpolated;

[0038] Step 5: Normalization weight, formula is:

[0039] , ;

[0040] Step 6: According to the normalized weight and the water level value of the known point, the water level value Z of the point to be interpolated P(x, y) is calculated, and the interpolation formula is:

[0041] .

[0042] Preferably, the boundary tracking algorithm in S7 comprises extracting the contour boundary coordinate points of the temporary inundated area grid, and the contour boundary coordinate points are selected from any one of the following:

[0043] (a) Grid vertex;

[0044] (b) Grid center point;

[0045] (c) Grid edge center point;

[0046] The smoothing processing algorithm in S7 comprises B-spline curve method and five-point smoothing method.

[0047] In a second aspect, the application provides a DEM-based quick generation system for temporary inundated area of reservoir flood control and regulation, characterized in that it is used to implement the DEM-based quick generation method for temporary inundated area of reservoir flood control and regulation, and comprises:

[0048] An acquisition unit is configured to acquire the section line, the section water level value, the reservoir inundated area range surface and the DEM elevation value;

[0049] A division unit is configured to divide the reservoir into a plurality of river channel units according to the section line and the reservoir inundated area range;

[0050] A calculation unit is configured to calculate the water level value based on the upstream and downstream section backwater table interpolation and based on the DEM grid unit, and to calculate the difference between the water level value and the elevation value;

[0051] A fitting unit is configured to perform smoothing processing on the grid outer boundary meeting the condition to obtain the fitted temporary inundated area;

[0052] An analysis unit is configured to perform merging processing on the plurality of unit data, and to perform spatial overlay analysis on the reservoir inundated area to erase and display the output range result;

[0053] An output unit is configured to display and output the range result.

[0054] In a third aspect, the present application provides an electronic device comprising:

[0055] a memory for storing a computer program;

[0056] a processor for implementing the DEM-based temporary inundated area generation method for reservoir flood control scheduling when executing the computer program.

[0057] In a fourth aspect, the present application provides a computer program product comprising a computer program for implementing the DEM-based temporary inundated area generation method for reservoir flood control scheduling when executed by a processor.

[0058] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0059] The present application provides a DEM-based temporary inundated area generation method and system for reservoir flood control scheduling, which divides the river channel above the reservoir inundated area into multiple river channel units according to the backwater table under different working conditions of the reservoir inundated area range surface and flood scheduling prediction, interpolates according to the inverse distance weighted method, calculates the water level value of each grid in the river channel unit, determines the grid meeting the condition by comparing with the DEM grid elevation value, constructs a vector polygon through the contour boundary ordered coordinate sequence, and obtains the segmented temporary inundated area of reservoir flood after smoothing processing. The temporary inundated area under different working conditions is simulated accurately based on high-resolution DEM for the reservoir with flood control storage capacity set above the normal storage level during the early stage of the project scheme demonstration, which provides a reference for statistical investigation and analysis of temporary inundation impact, flood control high water level demonstration, and engineering scheme comparison. During flood control scheduling, the temporary inundated area under different working conditions is simulated quickly and accurately combined with high-resolution DEM, the temporary inundation range is predicted in real time, reliable data support is provided for formulating the scheduling scheme and scheduling decision, scientific basis is provided for long-term planning and scheduling of the reservoir, data basis is provided for formulating the resettlement scheme in advance, which helps to reduce the inundation loss, and more accurate range is provided for timely issuing early warning information, thereby improving the emergency response efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0060] Figure 1 The flow chart of the reservoir construction land acquisition range generation method of the present application.

[0061] Figure 2 The block diagram of the reservoir construction land acquisition range generation system of the present application.

[0062] Figure 3 The digital elevation model (DEM) of a certain reservoir river channel.

[0063] Figure 4The original cross-section line arrangement diagram.

[0064] Figure 5 The reservoir inundation area backwater table.

[0065] Figure 6 The extended cross-section river section division diagram.

[0066] Figure 7 The grid water level calculation and comparison diagram in the river channel unit.

[0067] Figure 8 The grid boundary extraction and smoothing processing diagram.

[0068] Figure 9 The different working condition inundation area line diagram generated according to DEM. DETAILED DESCRIPTION

[0069] In order for those skilled in the art to better understand the technical solutions of the present application, the preferred embodiments of the present application will be described below in combination with specific examples, but it should be understood that the drawings are only used for illustrative description and cannot be understood as a limitation of the present patent; in order to better illustrate the present embodiment, some components in the drawings will be omitted, enlarged or reduced, and do not represent the actual product size; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings can be omitted. The positional relationship described in the drawings is only used for illustrative description and cannot be understood as a limitation of the present patent.

[0070] Example 1

[0071] As shown in the flow chart of a reservoir flood control scheduling temporary inundation area rapid generation method based on high-precision DEM, the method comprises the following steps S1-S8, specifically: Figure 1 S1: Obtain or generate a digital elevation model DEM of the river section where the reservoir is located.

[0072] In one possible implementation, the digital elevation model DEM of the river section where the reservoir is located is obtained in S1, comprising:

[0073] The DEM of the river channel range downloaded or collected through various channels.

[0074] In one possible implementation, the method for generating the digital elevation model DEM of the river section where the reservoir is located in S1 comprises:

[0075] Obtain the contour lines, elevation points, etc. in the topographic map;

[0076] Generate a digital elevation model DEM using spatial interpolation algorithms such as irregular triangle network or Kriging interpolation with GIS software.

[0077] ​

[0078] In this embodiment, a 2*2m grid digital elevation model of the area where the reservoir is located is pre-established according to the contour lines of the reservoir, and the contour lines are preferably derived from the topography in the dry season, the minimum elevation is lower than the normal water level value of the current section, and the maximum elevation is higher than the backwater level value. The digital elevation model generated in this way can clearly record the elevation data near the reservoir river channel and can cover the required calculation area. The DEM is shown in Figure 3 .

[0079] It should be noted that the higher the grid accuracy of the DEM, the higher the accuracy of the generated result, but the slower the calculation speed.

[0080] S2: Obtain the river section line of the river section where the reservoir is located, and perform data preprocessing.

[0081] In one possible implementation, the river section line preprocessing in S2 includes:

[0082] Step 1: Process the section line into shp format vector line data;

[0083] Step 2: Add attribute fields to the section line data set, which should include the section number and section name fields, and enter the relevant information.

[0084] It should be noted that the coverage of the section line can include the entire main stream and the main tributaries. The arrangement of the river section line is shown in Figure 4 .

[0085] S3: Obtain the submerged area range surface of the normal water level or a specific water level of the reservoir.

[0086] In one possible implementation, the submerged area of the normal water level or a specific water level of the reservoir in S3 usually refers to the submerged area corresponding to the design flood water level of the reservoir. The source of the reservoir submerged area can be the previously drawn reservoir submerged area range, the submerged area range surface generated according to the corresponding tool, the land acquisition range determined after the field staking and delimiting, or even the submerged range of a certain characteristic water level during the normal water level, flood control high water level, etc. The blue area shown in Figure 4 .

[0087] S4: Obtain the backwater table of each section under different working conditions predicted by flood control scheduling, and perform preprocessing.

[0088] In one possible implementation, the data preprocessing in S4 includes:

[0089] Step 1: Organize the backwater table according to the section number, section name, and different working condition water level in a standard format;

[0090] Step 2: Sort out the upstream and downstream relationship of the section and record it in the backwater table.

[0091] In a specific example, the collated backwater table data is as shown in Figure 5 .

[0092] It should be noted that the section number and section name should be noted in correspondence with the section number and section name in the section line.

[0093] S5: Based on the location of the river section line, the extended section line is extended; based on the extended section line and the reservoir inundation area, the river above the reservoir inundation area is divided into multiple river units. As shown in Figure 6 .

[0094] In one possible implementation, the method of dividing the river unit based on the section line and the reservoir inundation area in S5 includes:

[0095] Step 1: After setting the extended section multiple, the ends of the section line are automatically extended to avoid the situation that the section line is sometimes too short to intersect with the river bank;

[0096] Step 2: Divide the river unit according to the extended section line and the upstream and downstream relationship;

[0097] Step 3: Deduct the reservoir inundation area range, and only divide the area above the reservoir inundation area.

[0098] It should be noted that deducting the reservoir inundation area can greatly reduce the number of calculation grids and improve the calculation efficiency.

[0099] S6: Based on the river extended section line at the upstream and downstream ends, the reservoir inundation area range, the backwater table, and the reservoir river section digital elevation model DEM, for each grid in the reservoir inundation area range and above the reservoir inundation area in each river unit, when the upstream and downstream water levels are inconsistent, the inverse distance weighted interpolation method is used to calculate the grid water level value one by one, and compared with the DEM elevation value, the reservoir temporary inundation area grid in each river unit is determined according to the grid that meets the conditions.

[0100] In one possible implementation, the step of the inverse distance weighted interpolation method in S6 is:

[0101] Step 1: Determine the known water level on the adjacent upstream and downstream section lines, assuming that the point on the known section line is Qi(xi, yi), , and the corresponding water level value is zi;

[0102] Step 2: Determine the point to be interpolated, record its coordinates P(x, y);

[0103] Step 3: Calculate the distance di of the point to be interpolated to each known point Qi(xi, yi), the distance formula is:

[0104] ;

[0105] Step 4: Calculate the weight wi of each known point according to the inverse distance weighting method, and the weight formula is

[0106] ;

[0107] where p is the distance weight index, usually p = 2, that is, the inverse of the square of the distance as the weight; when di = 0, in order to avoid division by zero error, the known point is taken as the exact value of the point to be interpolated;

[0108] Step 5: Normalize the weight, and the formula is:

[0109] , ;

[0110] Step 6: According to the normalized weight and the water level value of the known point, the water level value Z of the point to be interpolated P(x, y) is calculated, and the interpolation formula is: .

[0111] Further, the grid in the river unit is based on the DEM grid, for example, if the DEM is 2*2m, then the grid unit for calculating the water level value is also 2*2m.

[0112] It should be noted that generally the calculation starts from the end section (upstream) and gradually spreads to the downstream section. For the reservoir flat section, when the backwater levels of the upstream and downstream sections are the same, do not perform interpolation calculation, directly take the section water level value to reduce the calculation amount and improve the calculation efficiency.

[0113] In one possible implementation, the method for determining the grid that meets the condition in S6 is as follows:

[0114] Step 1: Extract the elevation value of the DEM where the grid is located;

[0115] Step 2: Compare the calculated grid water level value with the elevation value in the DEM;

[0116] Step 3: Mark all the areas where the water level value is equal to and higher than the DEM elevation value as the areas that meet the condition.

[0117] The principle of grid calculation and marking is shown in Figure 7 , and the grid in the figure is only for illustration and does not represent the actual division.

[0118] S7: Based on the grid unit that meets the submergence condition, the topologically closed contour boundary ordered coordinate sequence is generated by the boundary tracking algorithm, and the vector polygon is constructed, and the polygon boundary is smoothed by using the smoothing algorithm, and finally the closed surface domain vector file of the temporary submergence area of the reservoir in each river unit is obtained.

[0119] In one possible implementation, in S7, based on the grid cells meeting the submergence condition, the contour boundary coordinate sequence of topological closure is generated by a boundary tracking algorithm, and a vector polygon is constructed, so that the one-step submergence area vectorization is directly realized in the grid topological space, effectively avoiding the bottleneck problem of merging calculation after grid vectorization, and avoiding the time-consuming of extracting the boundary line and then performing topological processing, and obviously improving the processing efficiency. Among them, there are three ways to extract the contour boundary coordinate points, one is the grid vertex, which has a little more smoothing processing workload; the second is the grid center point, which usually calculates the submergence area slightly smaller, but the efficiency is slightly higher; the third is the midpoint of the grid edge line.

[0120] In one possible implementation, the smoothing algorithm in S7 includes B-spline curve method and five-point smoothing method, which can effectively eliminate the jagged fluctuation. Among them, the B-spline curve method is more suitable for the scenario of giving priority to accuracy, and the five-point smoothing method has low calculation complexity and is suitable for the scenario of giving priority to efficiency. The smoothing processing result is shown in Figure 8 .

[0121] S8: Merge the temporary submergence areas of the reservoirs of the multiple river channel units, and erase the reservoir submergence area corresponding to the normal storage level, so as to obtain the temporary submergence area under different working conditions.

[0122] In one possible implementation, after the temporary submergence areas of the reservoirs of the multiple river channel units are merged in S8, since the lower edge line is obtained by smoothing the grid boundary, in order to ensure the consistency of the boundary line, the reservoir submergence area is erased to ensure the accuracy of the lower edge line of the temporary submergence area. As shown in Figure 8 .

[0123] The following is described with specific embodiments.

[0124] Taking a certain reservoir flood submergence influence analysis scheme as an example. Obtain the high-precision DEM of the reservoir river section with a grid size of 2*2m, as shown in Figure 3 . According to the above steps, arrange the section line, and upload the reservoir submergence area range as shown in Figure 4 . After preprocessing the backwater table under different working conditions, the result is shown in Figure 5 . After obtaining the above data through the program page, the reservoir river is segmented after extending the section line, and the segmentation result is shown in Figure 6 . After comparing the interpolation calculation with the DEM elevation, the boundary meeting the condition is extracted, and the process is shown in Figure 7 . The smoothing processing result is shown in Figure 8 . After merging the multi-segment data and erasing the reservoir submergence area range, the temporary submergence area under different working conditions (working condition 1, working condition 2) is obtained, as shown in Figure 9 .

[0125] The method is simple and easy to operate, and can quickly generate temporary inundation ranges of large and medium-sized reservoir areas under different working conditions under the condition that the DEM precision is high, shorten the range drawing time, and is beneficial to the promotion of project decision-making, and provides rapid data support for reservoir flood control scheduling decision-making.

[0126] Embodiment 2

[0127] Further illustrated in combination with Embodiment 1, Figure 2 is a structural schematic diagram of a reservoir flood control scheduling temporary inundation area rapid generation method and device provided by an embodiment of the application, and the device comprises:

[0128] An acquisition unit is configured to acquire a section line, a section water level value, a reservoir inundation area range surface, and a DEM elevation value.

[0129] A division unit is configured to divide the reservoir into a plurality of river channel units according to the section line and the reservoir inundation area range.

[0130] A calculation unit is configured to calculate a water level value based on an upstream and downstream section backwater table interpolation and based on a DEM grid unit, and to calculate a difference value between the water level value and the elevation value.

[0131] A fitting unit is configured to perform smoothing processing on a grid outer boundary that meets a condition, to obtain a fitted temporary inundation area.

[0132] An analysis unit is configured to perform merging processing on a plurality of unit data, and to perform spatial overlay analysis on the plurality of unit data and the reservoir inundation area, to erase and display output range results.

[0133] An output unit is configured to display and output the range results.

[0134] Embodiment 3

[0135] Further illustrated in combination with Embodiment 1, an electronic device provided by an embodiment of the application comprises a memory and a processor.

[0136] The memory is configured to store a computer program.

[0137] The processor is configured to, when executing the computer program, implement the mountainous river channel type reservoir inundation area rapid generation method of Embodiment 1, wherein the computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.

[0138] For example, the memory can include, but is not limited to, random access memory (RAM), read-only memory (ROM), flash memory, first-in-first-out memory (FIFO), and / or first-in-last-out memory (FILO), etc.; the processor can be, but is not limited to, a microprocessor of STM32F105 series, an ARM (Advanced RISC Machines) processor, an X86 architecture processor, or a processor integrated with NPU (neural-network processing units).

[0139] Embodiment 4

[0140] Further illustrated in combination with Embodiment 1, the embodiment of the present application provides a computer program product, when the computer program product is executed by a processor, a high-precision DEM-based fast generation method of a mountainous river-type reservoir inundation area is realized. The program product can execute the operations of each step and obtain the range result.

[0141] Embodiment 5

[0142] Further illustrated in combination with Embodiment 1, the embodiment of the present application provides a computer readable storage medium, and instructions are stored on the computer readable storage medium, when the instructions are run on a computer, a high-precision DEM-based fast generation method of a mountainous river-type reservoir inundation area is executed. The above instructions can be realized in the form of a software function unit and sold or used as an independent product, and can be stored in a computer readable storage medium.

[0143] Through the above description of the embodiments, those skilled in the art can clearly understand the software and hardware required by each embodiment. Based on such understanding, the technical solutions of the present application or the part of the technical solutions that essentially contribute to the prior art can be embodied in the form of a software product, which is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium refers to a carrier storing data, which can include, but is not limited to, a floppy disk, an optical disc, a hard disk, a flash memory, a USB flash disk, etc., and the computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.

[0144] The above embodiments are merely preferred technical solutions of the present application and should not be regarded as a limitation on the present application; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A DEM-based method for quickly generating temporary inundation areas in reservoir flood control scheduling, characterized in that, The method comprises the following steps: S1: obtaining or generating a digital elevation model DEM of a river section where the reservoir is located; S2: obtaining a river section line of the river section where the reservoir is located, and performing data preprocessing; S3: obtaining a submerged area range surface of the reservoir at a normal water storage level and a specific water level; S4: obtaining a backwater table of each section under different working conditions predicted by flood control scheduling, and performing data preprocessing; S5: extending and lengthening the section line based on the position of the river section line, and combining the reservoir submerged area range to divide the river channel higher than the reservoir submerged area into a plurality of river channel units; S6: based on the river channel extension section line at the upstream and downstream ends, the reservoir submerged area range, the backwater table and the reservoir river section digital elevation model DEM, for each river channel unit, when the upstream and downstream water levels are inconsistent, the grid water level value is calculated one by one according to the inverse distance weighted interpolation, and compared with the DEM elevation value, the grid which meets the condition of water level value ≥ DEM elevation value is marked as a temporary submerged area grid; S7: based on the temporary submerged area grid meeting the condition, the topologically closed contour boundary ordered coordinate sequence is generated by the boundary tracking algorithm, and the vector polygon is constructed, and the polygon boundary is smoothed by using the smoothing algorithm, and finally the closed surface domain vector file of the temporary submerged area of the reservoir in each river channel unit is obtained; S8: merging the temporary submerged area of the reservoir in the plurality of river channel units, and erasing the reservoir submerged area corresponding to the normal water storage level, so that the temporary submerged area of the reservoir under different working conditions for flood control scheduling is obtained.

2. The DEM-based method for quickly generating temporary inundation area in reservoir flood control scheduling according to claim 1, characterized in that, The method for generating the digital elevation model DEM of the river section where the reservoir is located in S1 comprises: obtaining contour lines and elevation point data in a topographic map; generating a digital elevation model DEM by using an irregular triangle network or a Kriging interpolation algorithm through GIS software.

3. The DEM-based method for quickly generating temporary inundation areas for flood control scheduling of a reservoir according to claim 1, characterized in that, The data preprocessing of the river section line in S2 comprises: Step 1: processing the section line into shp format vector line data; Step 2: adding attribute fields containing section number and section name to the section line data set, and entering related information.

4. The DEM-based method for quickly generating temporary inundation area in reservoir flood control scheduling according to claim 1, characterized in that, The data preprocessing of the backwater table in S4 comprises: Step 1: arranging the backwater table according to the standard format of section number, section name and different working condition water level; Step 2: combing the upstream and downstream relationship of the section, and recording in the backwater table.

5. The DEM-based method for quickly generating temporary inundation areas for flood control scheduling of a reservoir according to claim 1, characterized in that, S5 specifically comprises: Step 1: setting an expansion multiple to automatically lengthen the section line to the river bank; Step 2: dividing the river channel unit according to the extended section line and the upstream and downstream relationship; Step 3: excluding the reservoir submerged area range, and only dividing the area higher than the reservoir submerged area.

6. The DEM-based method for quickly generating temporary inundation areas for flood control scheduling of a reservoir according to claim 1, characterized in that, The steps of the inverse distance weighted interpolation in S6 comprise: Step 1: Determine the known water level on the adjacent upstream and downstream cross-section lines, assuming the point on the known cross-section line as Qi(xi, yi), The corresponding water level value is zi; Step 2: determining the point to be interpolated, and recording its coordinates P(x, y); Step 3: calculating the distance di of the point to be interpolated to each known point Qi(xi, yi), and the distance formula is: ； Step 4: calculating the weight wi of each known point according to the inverse distance weighted method, and the weight formula is ； wherein p is the distance weight index, p=2; when di=0, the known point is taken as the exact value of the point to be interpolated; Step 5: normalizing the weight, and the formula is: ， ； Step 6: According to the normalized weight and the water level value of the known points, the water level value Z of the interpolation point P(x, y) is calculated, and the interpolation formula is: 。 7. The DEM-based method for quickly generating temporary inundation areas for flood control scheduling of a reservoir according to claim 1, characterized in that, The boundary tracking algorithm in S7 includes extracting the contour boundary coordinate points of the temporary inundated area grid, and the contour boundary coordinate points are selected from any one of the following: (a) grid vertex; (b) grid center point; (c) grid edge center point; The smoothing algorithm in S7 includes B-spline curve method and five-point smoothing method.

8. A DEM-based reservoir flood control scheduling temporary inundation area rapid generation system, characterized in that, The method for implementing the DEM-based quick generation of temporary inundated area for reservoir flood control scheduling according to any one of claims 1-7 comprises: An acquisition unit is configured to acquire a section line, a section water level value, a reservoir inundated area range surface, and DEM elevation values. A division unit is configured to divide the reservoir into a plurality of river channel units according to the section line and the reservoir inundated area range. A calculation unit is configured to calculate water level values based on upstream and downstream section backwater table interpolation and DEM grid unit, and to calculate the difference between the water level values and the elevation values. A fitting unit is configured to perform smoothing processing on the grid outer boundary that meets the conditions to obtain a fitted temporary inundated area. An analysis unit is configured to perform merging processing on the plurality of unit data, and to perform spatial overlay analysis with the reservoir inundated area to erase and display the output range results. An output unit is configured to display and output the range results.

9. An electronic device, comprising: It comprises: A memory is configured to store a computer program. A processor is configured to execute the computer program to implement the DEM-based quick generation of temporary inundated area for reservoir flood control scheduling according to any one of claims 1-7.

10. A computer program product, characterised in that, It comprises a computer program, which, when executed by a processor, implements the DEM-based quick generation of temporary inundated area for reservoir flood control scheduling according to any one of claims 1-7.

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