River section optimization processing method in one-dimensional hydrodynamic model modeling process

Abstract

The invention discloses a riverway section optimization processing method in a one-dimensional hydrodynamic model modeling process, which comprises the following steps: extracting section topographic data from a riverway topographic map, drawing an image of each section based on the section topographic data, and determining a riverway slope through the lowest point elevation of each section diagram; an L-shaped and / or linear cross section is presented for the overtopping, and the cross section of the river channel is linearly extended; inserting a certain number of new river channel sections into two adjacent river channel sections of which the elevation difference is greater than a preset elevation difference; and simulating the corresponding water level of the river channel section at the end moment specified by the model through the original river channel section data, extracting the extended and interpolated river channel section data based on the corresponding water level of the river channel section, and retaining effective river channel section data. The method has the advantages that the river section optimization efficiency is effectively improved, the operation is simple, the labor cost and the time cost of data optimization are greatly saved, and the requirement of efficiently and accurately constructing a model can be well met.

Description

Technical Field

[0001] The present invention relates to the technical field of one-dimensional hydrodynamic modeling in water conservancy projects, and particularly relates to a method for optimizing river cross-sections during the modeling process of a one-dimensional hydrodynamic model. Background Art

[0002] As a mathematical model describing the interaction between the forces and motion of water flow, a hydrodynamic model establishes a mathematical model based on the basic equations of fluid mechanics to numerically simulate the dynamic process of flowing water. The flow rate and water level of the river cross-section are observed through a one-dimensional model, and the water level and flow rate of each key cross-section are calculated through the one-dimensional hydrodynamic model, mainly using the river cross-section information for simulation.

[0003] At present, one-dimensional hydrodynamics plays an irreplaceable role in runoff simulation. The data status of the river cross-section often has a decisive impact on whether the hydrodynamic model can accurately simulate the runoff result. At present, the river cross-section information is mostly obtained by detecting the river terrain with an unmanned aerial vehicle and extracting the river cross-section from the DEM through GIS. The directly obtained cross-section often cannot be directly used for the modeling of the one-dimensional hydrodynamic model.

[0004] When the hydrodynamic model simulates the actual river flow through the river cross-section, when the elevation difference between the bottom of the river cross-section and the elevation of both banks is small in areas such as floodplains, the hydrodynamic model cannot accurately identify the river channel, resulting in the flow rate deviating from the river channel and causing calculation errors in the model; if the elevation difference between the upper and lower cross-sections is too large, the model calculation will collapse; if there are too many data points for collecting the river cross-section data, including most topographic cross-section data points of mountainous forests and other terrains unrelated to the river channel, it will slow down the model calculation rate. Therefore, how to optimize the river cross-section so that the one-dimensional hydrodynamic model can run more accurately and efficiently has become an urgent problem to be solved. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for optimizing river cross-sections during the modeling process of a one-dimensional hydrodynamic model, so as to solve the foregoing problems existing in the prior art.

[0006] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A method for optimizing river cross-sections during the modeling process of a one-dimensional hydrodynamic model includes the following steps:

[0008] S1. Draw a river cross-section diagram: Extract the cross-section terrain data from the river topographic map, draw the image of each cross-section based on the cross-section terrain data, and determine the river slope through the elevation of the lowest point of each cross-section diagram;

[0009] S2. Extension and interpolation of river channel sections: For floodplain sections that present an "L" shape and / or an "I" shape, the river channel section is linearly extended to make the bottom part of the river channel section present a "V" shape; for two adjacent river channel sections whose elevation difference is greater than the preset elevation difference parameter, a certain number of new river channel sections are inserted between the two river channel sections;

[0010] S3. Screening of effective river section data: The corresponding water level of the river section at the end time specified by the model is simulated through the original river section data, and the extended and interpolated river section data are extracted based on the corresponding water level of the river section to retain the effective river section data.

[0011] Preferably, the cross-sectional data includes a starting distance X and an elevation Y; in step S1, a curve graph of each cross section of the river channel is drawn with the starting distance X as the x-axis and the elevation Y as the y-axis, and the curve graph is output as an image in png format.

[0012] Preferably, step S2 comprises,

[0013] S21. River section extension: determine the lowest point of the river section, move the lowest point of the river section downward by a certain distance, and then extend it linearly to the preset range on both sides;

[0014] S22. River section interpolation: When the elevation difference between the lowest point elevations of two adjacent river sections is greater than a preset elevation difference parameter, the number of new river sections to be inserted is calculated based on the elevation difference between the two adjacent river sections and the preset elevation difference parameter, and the new river sections of that number are inserted between the two adjacent river sections.

[0015] Preferably, step S21 specifically includes the following contents:

[0016] S211, identify the coordinates of the lowest point of the river (X min ,Y min );

[0017] S212, the lowest point elevation of the river Y min Subtract a certain value S to move the lowest point of the river section downward;

[0018] S213, the cross-sectional coordinates of the river after displacement (X min ,Y min -S) as the reference point, extending to the left and right sides by a certain width F to modify the river section data;

[0019] S214. Save and output the modified cross-section data.

[0020] Preferably, step S213 is specifically to use a For loop to filter data points to the left, when |X min -X (min-Q)Stop screening when it is greater than or equal to F, record the Q value, and use Y min Replace Y with +i*E1 min-i ; Use a For loop to screen data points to the right. When the Wth data point |X (min+w) -X min Stop screening when it is greater than or equal to F, record the W value, and use Y min Replace Y with +j*E2 min+j ;

[0021] Where, E1 = (Y (min-Q) -Y min ) / Q; i is a positive integer from 0 to Q; X (min-Q) is the x-axis distance of the Qth data point; Y min-i is the y-axis distance of the ith data point; Y (min-Q) is the y-axis distance of the Qth data point; E2 = (Y( (min+w) -Y min ) / W; j is a positive integer from 0 to W; X (min+W) is the x-axis distance of the Wth data point; Y min+j is the y-axis distance of the jth data point; Y (min+w) is the y-axis distance of the Wth data point.

[0022] Preferably, step S22 specifically includes the following contents,

[0023] S221. Statistically calculate the elevation of the lowest point of all river channel cross-sections;

[0024] S222. Put all river channel cross-sections into the cross-section data function sequence in sequence according to the front and back order;

[0025] S223. Judge whether the elevation difference D between the lowest point elevations of every two adjacent river channel cross-sections in the cross-section data function sequence is greater than the preset elevation difference parameter E. If so, calculate the interpolation number C according to the elevation difference D and the preset elevation difference parameter E, and subtract t*(D / C) from the larger elevation value of the two data points with similar x-axis numerical differences from the lowest point elevation of the river channel on the left and right sides of the two adjacent river channel cross-sections in turn. t is a positive integer from 1 to C, and the two-dimensional array formed by the result after each subtraction and the corresponding x-axis numerical value is used as the new cross-section data and put into the cross-section data function sequence in sequence; otherwise, directly put the original river channel cross-section order into the cross-section data function sequence;

[0026] S224. Save and output the new cross-section data function sequence including the original river channel cross-section and the new river channel cross-section.

[0027] Preferably, step S223 is specifically as follows. For any two adjacent river channel cross-sections in the cross-section data function sequence, judge the lowest point elevation Y of the previous river channel cross-section 1minand the elevation difference D between it and the lowest point Y of the adjacent next river channel section. If so, determine the number C of interpolations by rounding up C = int(D / E), and use the elevation Y of the lowest point of the river channel 2min as the center point of the river channel, traverse the cross-section data points to both sides, and respectively correspond one by one to the data points with similar lateral differences from the center point of the river channel on the left and right sides of two adjacent river channel cross-sections. Compare the elevation values of the two data points, and successively subtract t*(D / C) from the larger elevation value. Each time the value t*(D / C) is subtracted, the result and the corresponding x-axis value are respectively saved in different two-dimensional arrays until any dataset on the left and right sides of two adjacent river channel cross-sections has been traversed. Use the two-dimensional array data as the new cross-section data and sequentially put it into the cross-section data function sequence; otherwise, directly put the original river channel cross-section into the cross-section data function sequence in sequence. min

[0028] Preferably, step S3 is specifically as follows: By performing runoff simulation on a large flow rate, obtain the cross-section water level data at the last moment set by the model. Through the cross-section water level data Z corresponding to each cross-section at the last moment, screen the extended and interpolated river channel cross-section data points; start from the lowest point of the river channel cross-section and screen the data points to the left and right. Stop screening when the y-axis elevation value of the river channel cross-section data point is greater than the cross-section water level data Z, and retain the screened valid river channel cross-section data.

[0029] The beneficial effects of the present invention are: 1. The method of the present invention effectively improves the optimization efficiency of the river channel cross-section. It is not only simple to operate, but also greatly saves the labor cost and time cost of data optimization, and can well meet the requirements of efficiently and accurately constructing a model. 2. The method of the present invention adopts automatic judgment and recognition, and adjusts simply according to the modeling needs of the staff in a timely manner. Optimizing the river channel cross-section is more suitable for the needs of water conservancy modeling, and greatly reduces the workload of later manual intervention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a flowchart of the method in the embodiment of the present invention

[0031] Figure 2 is an image of the river channel cross-section of the Yanghe River Gorge section in the upper reaches of the Yongding River drawn in the embodiment of the present invention;

[0032] Figure 3 is a schematic diagram of the river channel cross-section data of the Yanghe River Gorge section in the upper reaches of the Yongding River before and after interpolation using the method of the present invention in the embodiment of the present invention;

[0033] Figure 4 is a schematic diagram of the river channel cross-section data of the Yanghe River Gorge section in the upper reaches of the Yongding River before and after extension using the method of the present invention in the embodiment of the present invention;

[0034] Figure 5 ​It is a schematic diagram of the effective river channel cross-section data of the Yanghe River Gorge section in the upper reaches of the Yongding River before and after screening using the method of the present invention in the embodiments of the present invention. Detailed implementation manners

[0035] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific implementation manners described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] Embodiment 1

[0037] When performing one-dimensional hydrodynamic modeling, the collected river channel cross-section data often includes floodplain terrain data, too large elevation differences between the upper and lower levels, and too many invalid data points, resulting in the inability of the hydrodynamic model to correctly, effectively and quickly simulate the actual water flow rate. Based on this, a method for optimizing river channel cross-sections and its application in one-dimensional hydrodynamic modeling are provided to solve the problems that the existing methods for optimizing river channel cross-sections have low accuracy, require a large amount of manual intervention, and cannot meet the requirements of efficient measurement. As Figure 1 shown, the method specifically includes the following parts.

[0038] I. Drawing of river channel cross-section diagrams

[0039] Extract cross-section terrain data from the river channel topographic map, draw an image of each cross-section based on the cross-section terrain data, and determine the river channel slope through the elevation of the lowest point of each cross-section diagram.

[0040] Specifically: the cross-section data includes the starting distance X and the elevation Y; taking the starting distance X as the x-axis and the elevation Y as the y-axis, draw a curve graph of each cross-section of the river channel and output it as an image in png format to help users quickly view the river channel cross-section and understand the general situation of the river channel cross-section.

[0041] II. Extension and interpolation of river channel cross-sections

[0042] For floodplains presenting "L"-shaped and / or "-"-shaped cross-sections, linearly extend the river channel cross-section so that the bottom part of the river channel cross-section presents a "V" shape; for two adjacent river channel cross-sections with an elevation difference greater than a preset elevation difference, insert a certain number of new river channel cross-sections between these two river channel cross-sections.

[0043] 2.1. Extension of river channel cross-sections: For floodplains presenting an "L" or even a "-" shape cross-section, it is difficult for the hydrodynamic model to accurately simulate the flow rate within the river channel. Then it is necessary to automatically identify the lowest point of the river channel cross-section, move the lowest point of the river channel cross-section down a certain distance, and linearly extend it within a preset range on both the left and right sides, so that the bottom part of the river channel cross-section presents a "V" shape, so that the hydrodynamic model can accurately identify the river channel and run within the river channel when simulating the water flow.

[0044] (1) Identify the coordinates (X min , Y min ) of the lowest point of the river channel.

[0045] (2) Subtract a certain value S from the elevation Y of the lowest point of the river channel to lower the lowest point of the river channel cross-section. min

[0046] (3) Using the coordinates (X min , Y min - S) of the lowered river channel cross-section as the reference point, extend a certain width F to both the left and right to modify the river channel cross-section data.

[0047] Specifically: Use a For loop to filter data points on the left side. When |X min - X (min-Q) | is greater than or equal to F, stop filtering, record the Q value, and replace Y min with Y min-i + i * E1; Use a For loop to filter data points on the right side. When the |X (min+W) - X min of the Wth data point is greater than or equal to F, stop filtering, record the W value, and replace Y min with Y min+j + j * E2;

[0048] Among them, E1 = (Y (min-Q) - Y min ) / Q; i is a positive integer from 0 to Q; X (min-Q) is the x-axis distance of the Qth data point; Y min-i is the y-axis distance of the ith data point; Y (min-Q) is the y-axis distance of the Qth data point; E2 = (Y (min+W) - Y min ) / W; j is a positive integer from 0 to W; X (min+W) is the x-axis distance of the Wth data point; Y min+j is the y-axis distance of the jth data point; Y (min+W) is the y-axis distance of the Wth data point.

[0049] (4) Save and output the modified cross-section data.

[0050] 2.2 River channel cross-section interpolation: When performing hydrodynamic modeling with river channel data, since some river channels are located in valleys and the elevation difference between the upper and lower cross-sections is large, resulting in an excessive slope of the river channel cross-section. Therefore, when the elevation difference between the lowest point elevations of two adjacent river channel cross-sections is greater than the preset elevation difference, calculate the number of new river channel cross-sections to be inserted based on the elevation difference between the two adjacent river channel cross-sections and the preset elevation difference, and insert that number of new river channel cross-sections between the two adjacent river channel cross-sections.

[0051] ​(1) Statistically calculate the elevation of the lowest point of all river cross-sections;

[0052] (2) Sequentially place all river cross-sections into a sequence of cross-section data functions in the order of front and back;

[0053] (3) Determine whether the elevation difference D between the elevations of the lowest points of every two adjacent river cross-sections in the sequence of cross-section data functions is greater than a preset elevation difference parameter E. If so, calculate the number of interpolation points C according to the elevation difference D and the preset elevation difference parameter E. Subtract t*(D / C) from the larger elevation value of the two data points on the left and right sides of the adjacent two river cross-sections with x-axis numerical differences similar to the elevation of the lowest point of the river in turn, where t is a positive integer from 1 to C, and form a two-dimensional array with the results after each subtraction and the corresponding x-axis numerical values as new cross-section data and sequentially place them into the sequence of cross-section data functions; otherwise, directly place the original river cross-section order into the sequence of cross-section data functions.

[0054] Specifically: For any two adjacent river cross-sections in the sequence of cross-section data functions, judge the elevation difference D between the elevation Y of the lowest point of the previous river cross-section 1min and the elevation Y of the lowest point of the adjacent next river cross-section 2min If so, determine the number of interpolation points C by rounding up C = int(D / E). Use the elevation Y of the lowest point of the river min as the center point of the river and traverse the cross-section data points to both sides. Respectively, correspond one by one to the data points on the left and right sides of the adjacent two river cross-sections with lateral differences similar to the center point of the river. Compare the elevation values of the two data points, and subtract t*(D / C) from the larger elevation value in turn. Each time the value t*(D / C) is subtracted, the results and the corresponding x-axis numerical values are saved in different two-dimensional arrays until any data set on the left and right sides of the adjacent two river cross-sections has been traversed. Use the two-dimensional array data as new cross-section data and place it into the sequence of cross-section data functions in order; otherwise, directly place the original river cross-section order into the sequence of cross-section data functions.

[0055] (4) Save and output the new sequence of cross-section data functions containing the original river cross-sections and the new river cross-sections.

[0056] III. Screening of effective river cross-section data

[0057] Simulate the water level corresponding to the river cross-section at the specified end time of the model through the original river cross-section data, and extract the extended and interpolated river cross-section data based on the water level corresponding to the river cross-section, and retain the effective river cross-section data.

[0058] Specifically: By simulating the runoff of a large flow rate, the cross-section water level data at the last moment of the model setting is obtained. Through the cross-section water level data Z corresponding to each cross-section at the last moment, the data points of the extended and interpolated river channel cross-section are screened. Starting from the lowest point of the river channel cross-section, the data points are screened to the left and right. When the y-axis elevation value of the river channel cross-section data point is greater than the cross-section water level data Z, the screening stops, and the effective river channel cross-section data selected is retained.

[0059] Embodiment 2

[0060] In this embodiment, taking the river channel cross-section of the Yanghe River Gorge section in the upper reaches of the Yongding River as an example, the execution process of the method of the present invention is specifically described.

[0061] I. Drawing of river channel cross-section diagram

[0062] The river channel cross-section of the Yanghe River Gorge section in the upper reaches of the Yongding River is processed. Through the river channel cross-section data points, with the data point position as the x-axis coordinate and the data point elevation as the y-axis coordinate, a river channel cross-section image is drawn. As Figure 2 shown.

[0063] II. River channel extension and interpolation

[0064] 2.1 River channel cross-section interpolation: All cross-section data of the Yanghe River Gorge section are placed in a sequence in order. The elevation of the lowest point of all cross-sections is counted. Taking the preset elevation difference parameter E as an evaluation index, it is traversed whether the elevation difference D between every two adjacent cross-sections is greater than the preset elevation difference parameter E. If there are two cross-sections with an elevation difference D greater than the E value, the number of inserted cross-sections C is determined by the formula C = int(D / E); and taking the lowest point Ymin of the river channel as the center point of the river channel, the data points are traversed to both sides. For the left and right sides of the adjacent cross-sections respectively, the data points with similar horizontal differences to the center point are corresponded one by one, and the elevation values of the two data points are compared. Subtract t*(D / C) (t is a positive integer from 1 to C) from the higher value, and save it with the corresponding x-axis data value in different two-dimensional arrays until any data set on both the left and right sides of the adjacent two cross-section data has been traversed. Using the two-dimensional array data as the new cross-section data, and sequentially putting it into the cross-section data sequence. If the elevation difference D between two cross-sections is less than the E value, the original cross-section data is directly put into the sequence in order. Finally, a sequence containing the original cross-sections and the interpolated cross-sections in order can be obtained. By reprocessing the sequence, the cross-section data is extracted into an Excel file in the order of the corresponding row numbers according to the numbers. The slope of the whole-process river channel cross-section is compared and rechecked in the order of the lowest point of the cross-section. The comparison result is as Figure 3 shown.

[0065] 2.2 River channel section extension: In the floodplain depression area of the Yanghe River, identify the elevation of the lowest point of the river channel. Subtract the set difference, such as 2 meters, from the elevation of the lowest point of the river channel. Then, according to the set width, such as 5 meters, screen data points from the lowest point to both sides. Stop screening when the absolute value of the x-axis distance between the data points on the left and right sides and the x-axis distance of the lowest point is greater than or equal to 5 meters. Calculate the value through relevant formulas and replace the original data point values. As Figure 4 shown.

[0066] III. Screening of effective river channel section data

[0067] Finally, extract the cross-section data in the obtained excel format. Through runoff simulation of the Yanghe River with a larger flow rate of 50 cubic meters per second (the flow rate of the Yanghe River is generally about 15 cubic meters per second), obtain the cross-section water level curve at the last moment. Screen the cross-section data points through the water level corresponding to each cross-section. Start screening from the lowest point of the river channel cross-section to the data points on both sides. Stop when the y-axis elevation value of the river channel cross-section data point is greater than the water level. Retain the screened river channel cross-section data, as Figure 5 shown.

[0068] By adopting the above technical solutions disclosed in the present invention, the following beneficial effects are obtained:

[0069] The present invention provides a method for optimizing the river channel cross-section in the process of building a one-dimensional hydrodynamic model. The method of the present invention effectively improves the efficiency of optimizing the river channel cross-section. It is not only simple to operate, but also greatly saves the labor cost and time cost of data optimization, and can well meet the requirements of efficiently and accurately building a model. The method of the present invention adopts automatic judgment and recognition, and adjusts simply according to the modeling requirements of the staff in a timely manner. Optimizing the river channel cross-section is more suitable for the needs of hydraulic modeling, and greatly reduces the workload of later manual intervention.

[0070] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for optimizing the river channel cross-section during the modeling process of a one-dimensional hydrodynamic model, characterized in that: It includes the following steps: S1. Draw the river channel cross-section diagram: Extract the cross-section terrain data from the river channel topographic map, draw the image of each cross-section based on the cross-section terrain data, and determine the river channel slope by the elevation of the lowest point of each cross-section diagram; S2. River channel cross-section extension and interpolation: For the floodplain with an "L" shape and / or a "-" shaped cross-section, linearly extend the river channel cross-section so that the bottom part of the river channel cross-section presents a "V" shape; For two adjacent river channel cross-sections with an elevation difference greater than the preset elevation difference parameter, insert a certain number of new river channel cross-sections between these two river channel cross-sections; S3. Screening of effective river channel cross-section data: Simulate the water level corresponding to the river channel cross-section at the end time specified by the model through the original river channel cross-section data, and extract the extended and interpolated river channel cross-section data based on the water level corresponding to the river channel cross-section, and retain the effective river channel cross-section data.

2. The channel cross-section optimization method in the one-dimensional hydrodynamic model modeling process according to claim 1, characterized in that: The cross-section data includes the starting point distance X and the elevation Y; In step S1, with the starting point distance X as the x-axis and the elevation Y as the y-axis, draw the curve graph of each cross-section of the river channel, and output it as an image in png format.

3. The method for optimizing the river channel cross-section in the one-dimensional hydrodynamic model modeling process according to claim 2, characterized in that: Step S2 includes S21. River channel cross-section extension: Determine the lowest point of the river channel cross-section, move the lowest point of the river channel cross-section down a certain distance, and linearly extend it within a preset range to the left and right; S22. River channel cross-section interpolation: When the elevation difference between the lowest point elevations of two adjacent river channel cross-sections is greater than the preset elevation difference parameter, calculate the number of new river channel cross-sections to be inserted according to the elevation difference between the two adjacent river channel cross-sections and the preset elevation difference parameter, and insert the number of new river channel cross-sections between these two adjacent river channel cross-sections.

4. The method for optimizing the river channel cross-section during the one-dimensional hydrodynamic model modeling process according to claim 3, characterized in that: Step S21 specifically includes the following content S211. Identify the coordinates (X min , Y min ) of the lowest point of the river channel; S212. Subtract a certain value S from the elevation Y of the lowest point of the river channel to lower the lowest point of the river channel cross-section; min ​ S213. With the coordinates (X min , Y min -S) of the shifted river channel cross-section as the reference point, extend a certain width F to both the left and right to modify the river channel cross-section data; S214. Save and output the modified cross-section data.

5. The method for optimizing the river channel cross-section in the one-dimensional hydrodynamic model modeling process according to claim 4, characterized in that: Step S213 specifically involves using a For loop to screen data points to the left. When |X min - X (min-Q) | is greater than or equal to F, stop screening, record the Q value, and replace Y with Y min + i * E1 min-i ; use a For loop to screen data points to the right. When the |X of the W-th data point (min+w) - X min | is greater than or equal to F, stop screening, record the W value, and replace Y with Y min + j * E2 min+j ; where, E1 = (Y (min-Q) - Y min ) / Q; i is a positive integer from 0 to Q; X (min-Q) is the x-axis distance of the Qth data point; Y min-i is the y-axis distance of the ith data point; Y (min-Q) is the y-axis distance of the Qth data point; E2 = (Y (min+W) - Y min ) / W; j is a positive integer from 0 to W; X (min+W) is the x-axis distance of the Wth data point; Y min+j is the y-axis distance of the jth data point; Y (min+W) is the y-axis distance of the Wth data point.

6. The method for optimizing the river channel cross-section during the one-dimensional hydrodynamic model modeling process according to claim 5, characterized in that: Step S22 specifically includes the following content S221. Count the elevation of the lowest point of all river channel cross-sections; S222. Put all the river channel cross-sections into the cross-section data function sequence in order; S223. Judge whether the elevation difference D between the lowest point elevations of every two adjacent river channel cross-sections in the cross-section data function sequence is greater than the preset elevation difference parameter E. If so, calculate the interpolation number C according to the elevation difference D and the preset elevation difference parameter E, and subtract t*(D / C) from the large elevation value in the two data points with similar x-axis numerical differences from the lowest point elevation of the river channel on the left and right sides of the two adjacent river channel cross-sections in turn. t is a positive integer from 1 to C, and the two-dimensional array formed by the result after each subtraction and the corresponding x-axis numerical value is used as the new cross-section data and put into the cross-section data function sequence in turn; Otherwise, directly put the original river channel cross-section order into the cross-section data function sequence; S224. Save and output the new cross-section data function sequence including the original river channel cross-section and the new river channel cross-section.

7. The method for optimizing the river channel cross-section during the one-dimensional hydrodynamic model modeling process according to claim 6, characterized in that: Specifically, in step S223, for any two adjacent river channel cross-sections in the cross-section data function sequence, it is determined whether the elevation difference D between the elevation Y of the lowest point of the previous river channel cross-section 1min and the elevation Y of the lowest point of the adjacent next river channel cross-section 2min is greater than the preset elevation difference parameter E. If so, the number of interpolation points C is determined by rounding up C = int(D / E). Starting from the elevation Y of the lowest point of the river channel min as the center point of the river channel, traverse the cross-section data points to both sides, and respectively correspond one by one to the data points with similar lateral differences from the center point of the river channel on the left and right sides of the two adjacent river channel cross-sections. Compare the elevation values of the two data points, and subtract t*(D / C) from the larger elevation value in turn. Each time the value t*(D / C) is subtracted, the result and the corresponding x-axis value are saved in different two-dimensional arrays until any data set on the left and right sides of the two adjacent river channel cross-sections has been traversed. Use the two-dimensional array data as the new cross-section data and sequentially put it into the cross-section data function sequence; otherwise, directly put the original river channel cross-section into the cross-section data function sequence in sequence.

8. The method for optimizing the river channel cross-section in the one-dimensional hydrodynamic model modeling process according to claim 7, characterized in that: Specifically, in step S3, by performing runoff simulation on the large flow rate, the cross-section water level data at the last moment set by the model is obtained. Based on the cross-section water level data Z corresponding to each cross-section at the last moment, the data points of the extended and interpolated river channel cross-section are screened. Starting from the lowest point of the river channel cross-section, data points are screened to the left and right. The screening stops when the y-axis elevation value of the river channel cross-section data point is greater than the cross-section water level data Z, and the effective river channel cross-section data obtained by screening is retained.

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