Rapid river channel convergence calculation method and system for distributed hydrological model

Abstract

The invention discloses a rapid river channel confluence calculation method for a distributed hydrological model. The method comprises the following steps: acquiring a to-be-analyzed river channel and a remote sensing image of the to-be-analyzed river channel, and dividing the to-be-analyzed river channel into a plurality of river reaches as a plurality of first river reaches; dividing a remote sensing image of a river channel to be analyzed into remote sensing images corresponding to the first river reaches according to the plurality of first river reaches; selecting one of the plurality of first river reaches as a second river reach; taking the remote sensing image of the selected first river reach as a remote sensing image of a second river reach; according to the remote sensing image of the second river reach, the river channel bottom width, the river channel bottom slope and the side slope angle of the second river reach are obtained through estimation; according to the river channel bottom width, the river channel bottom slope and the side slope angle of the second river reach, the water flow of the second river reach is obtained through hydrodynamic calculation; selecting another river reach in the plurality of first river reaches as a new second river reach; the execution is repeated until all the first river reaches are selected; the obtained water flow of each second river reach is the water flow of the river channel to be analyzed. The river channel confluence calculation method is small in calculation amount and easy to land.

Description

Technical Field

[0001] The present invention relates to the technical field of river confluence calculation, and more specifically, to a method and system for rapid river confluence calculation using a distributed hydrological model. Background Art

[0002] Distributed hydrological models have clear physical mechanisms and use hydrodynamic methods to calculate river confluence, and have the potential to improve the accuracy of flood forecasting.

[0003] Existing distributed hydrological models require gridding. This leads to high computational complexity in densely populated river sections. Furthermore, distributed hydrological models require data on the shape and dimensions of each section. However, due to the large number of river sections and the difficulty obtaining field data upstream of river basins, distributed hydrological models struggle to produce accurate results.

[0004] Prior art discloses a quantitative inversion method for monitoring river flow in mountainous areas, comprising: surveying basic river channel information; modeling river section sections and solving parameter problems; real-time monitoring of water surface width; and quantitative inversion of river flow. This method utilizes telemetry to monitor the flow state of the river in real time. Using the real-time water surface width of a river measured once, it performs an inversion calculation to accurately calculate the current river flow, enabling remote, real-time flow assessment. However, this method is computationally intensive, making it difficult to implement. Summary of the Invention

[0005] The present invention addresses the drawback of the existing technology that the algorithm has a large amount of calculation, and provides a distributed hydrological model rapid river confluence calculation method and system. The performance optimization method has the characteristic of low algorithm calculation.

[0006] The primary purpose of the present invention is to solve the above technical problems, and the technical solutions of the present invention are as follows:

[0007] A method for rapid river confluence calculation in a distributed hydrological model, comprising:

[0008] S1: Acquire a river channel to be analyzed and a remote sensing image of the river channel to be analyzed, divide the river channel to be analyzed into multiple river sections as multiple first river sections; divide the remote sensing image of the river channel to be analyzed into remote sensing images corresponding to the first river sections according to the multiple first river sections;

[0009] S2: selecting one of the plurality of first river sections as the second river section; and using the remote sensing image of the selected first river section as the remote sensing image of the second river section;

[0010] S3: estimating the riverbed width, riverbed slope, and side slope angle of the second river section based on the remote sensing image of the second river section;

[0011] S4: deriving the water flow of the second river section through hydrodynamic calculation based on the riverbed width, riverbed slope, and side slope angle of the second river section;

[0012] S5: Select another river section from the multiple first river sections as a new second river section; execute step S3 until all first river sections are selected; the water flow of each second river section obtained is the water flow of the river channel to be analyzed.

[0013] Furthermore, step S1 of dividing the river to be analyzed into multiple river sections includes:

[0014] S101: setting a plurality of nodes in the river channel according to preset conditions;

[0015] S102: Divide the river into multiple river sections based on the nodes;

[0016] The preset conditions include:

[0017] a. Set the intersection of two or more rivers in the river channel to be analyzed as a node;

[0018] b. According to the remote sensing image of the river to be analyzed, when the river width is less than the first preset threshold, set the node;

[0019] c. Calculate the centerline of the river to be analyzed; based on the centerline of the river to be analyzed, use the principles of calculus to calculate the angle between each centerline and the adjacent centerline; if the angle is greater than a second preset threshold, set the node;

[0020] d. Set nodes where tributaries of the river to be analyzed merge into the main stream;

[0021] e. If the cumulative flow change in the river is greater than the third preset threshold, set the node;

[0022] f. If the change in the low slope of the river channel is greater than the fourth preset threshold, set the node.

[0023] Furthermore, the river bottom width is the water surface width of the second river section;

[0024] The riverbed slope is the elevation difference between the water surfaces at both ends of the second river section;

[0025] The side slope angle is the side slope angle adjacent to the second river section.

[0026] Furthermore, the formula for the hydrodynamic calculation in step S4 is as follows:

[0027]

[0028] n is a constant, R is the wetted perimeter of the water-passing section, S fIt represents the friction resistance ratio, Q represents the flow rate of the water section, A represents the area of the water section, and v represents the water flow velocity in the river.

[0029] Furthermore, the formula for the wetted perimeter R of the water-passing section is as follows:

[0030]

[0031] R represents the wetted perimeter of the water flow section, A represents the area of the water flow section, and χ represents the intermediate calculation amount.

[0032] Furthermore, the formula for the intermediate calculation amount χ is as follows:

[0033]

[0034] w represents the width of the riverbed, h represents the water depth, β represents the side slope angle, A represents the cross-sectional area of the water flow, and sec and csc represent trigonometric functions.

[0035] Furthermore, the formula for the water flow cross-sectional area is as follows:

[0036] A=w·h+h·h / tanβ

[0037] h represents the water depth, w represents the width of the riverbed, and A represents the cross-sectional area of the water flow.

[0038] Furthermore, the formula for the water depth is as follows:

[0039]

[0040] w represents the width of the riverbed, β represents the side slope angle, A represents the cross-sectional area of the water flow, and h represents the water depth.

[0041] Furthermore, the formula for friction ratio drop is as follows:

[0042]

[0043] S0 represents the river bottom slope, It represents the differential expression of water depth and length along the flow direction, and t represents the sequence number.

[0044] A distributed hydrological model rapid river confluence calculation system, applied to the calculation method according to any one of claims 1 to 9, comprising:

[0045] A river section division module: obtaining a river channel to be analyzed and a remote sensing image of the river channel to be analyzed, dividing the river channel to be analyzed into a plurality of river sections as a plurality of first river sections; dividing the remote sensing image of the river channel to be analyzed into remote sensing images corresponding to the first river sections according to the plurality of first river sections;

[0046] A river section selection module: selects one of the plurality of first river sections as the second river section;

[0047] River section estimation module: obtains the riverbed width, riverbed slope and side slope angle of the second river section by estimation based on the remote sensing image of the second river section;

[0048] Water flow calculation module: obtains the water flow of the second river section through hydrodynamic calculation based on the riverbed width, riverbed slope and side slope angle of the second river section;

[0049] Circular processing module: select another river section from multiple first river sections as a new second river section; repeat the process until all first river sections are selected; the water flow of each second river section obtained is the water flow of the river to be analyzed.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] The river confluence calculation method of the present invention divides the river in the entire basin into multiple river sections and applies hydrodynamic calculations to each of these sections, simplifying the computational complexity of hydrodynamic calculations. Therefore, the river confluence calculation method requires little computation and is easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a flow chart of a method for rapid river confluence calculation using a distributed hydrological model provided in Example 1.

[0053] Figure 2 The flowchart provided in Example 1 is for dividing the river channel to be analyzed into multiple river sections.

[0054] Figure 3 Schematic diagram of river channel parameters provided in Example 1. DETAILED DESCRIPTION

[0055] The accompanying drawings are for illustrative purposes only and are not to be construed as limiting this patent;

[0056] In order to better illustrate this embodiment, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product size;

[0057] It is understandable to those skilled in the art that some well-known structures and descriptions thereof may be omitted in the drawings.

[0058] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0059] Example 1

[0060] like Figure 1 As shown in FIG, a method for calculating rapid river confluence using a distributed hydrological model includes:

[0061] S1: Acquire a river channel to be analyzed and a remote sensing image of the river channel to be analyzed, divide the river channel to be analyzed into multiple river sections as multiple first river sections; divide the remote sensing image of the river channel to be analyzed into remote sensing images corresponding to the first river sections according to the multiple first river sections;

[0062] S2: selecting one of the plurality of first river sections as the second river section; and using the remote sensing image of the selected first river section as the remote sensing image of the second river section;

[0063] S3: estimating the riverbed width, riverbed slope, and side slope angle of the second river section based on the remote sensing image of the second river section;

[0064] S4: deriving the water flow of the second river section through hydrodynamic calculation based on the riverbed width, riverbed slope, and side slope angle of the second river section;

[0065] S5: Select another river section from the multiple first river sections as a new second river section; execute step S3 until all first river sections are selected; the water flow of each second river section obtained is the water flow of the river channel to be analyzed.

[0066] Furthermore, if Figure 2 As shown, step S1 divides the river to be analyzed into multiple river sections, including:

[0067] S101: setting a plurality of nodes in the river channel according to preset conditions;

[0068] S102: Divide the river into multiple river sections based on the nodes;

[0069] The preset conditions include:

[0070] a. Set the intersection of two or more rivers in the river channel to be analyzed as a node;

[0071] b. According to the remote sensing image of the river to be analyzed, when the river width is less than the first preset threshold, set the node;

[0072] c. Calculate the centerline of the river to be analyzed; based on the centerline of the river to be analyzed, use the principles of calculus to calculate the angle between each centerline and the adjacent centerline; if the angle is greater than a second preset threshold, set the node;

[0073] d. Set nodes where tributaries of the river to be analyzed merge into the main stream;

[0074] e. If the cumulative flow change in the river is greater than the third preset threshold, set the node;

[0075] f. If the change in the low slope of the river channel is greater than the fourth preset threshold, set the node.

[0076] It should be noted that the present invention adopts the concept of river sections, and the river channel between two nodes is the river section. When setting the nodes, they are set in the order of going upstream along the main trunk of the river from the outlet of the basin. The cross-sectional changes of the river channel are gradual, and drastic changes rarely occur. The shape of the river channel is similar to a rectangle, especially in the upper reaches of the basin, this shape is highly consistent with the actual situation. The present invention generalizes the river channel of the entire basin into a moderate number of river sections, and assumes that the shape and size of each section in the river section are the same. In this way, only the size of one section needs to be measured for the same river section; further, the cross-sectional shape of the river channel is generalized to a rectangle, and the cross-sectional size of each river section has only one parameter, the width of the river section, and then satellite remote sensing images can be used to estimate the width of this river section.

[0077] Furthermore, if Figure 3 As shown, the river bottom width is the water surface width of the second river section;

[0078] The riverbed slope is the elevation difference between the water surfaces at both ends of the second river section;

[0079] The side slope angle is the side slope angle adjacent to the second river section.

[0080] It should be noted that for river sections with few people and inconvenient transportation, it is very difficult to measure the cross-sectional dimensions of the river on site. Therefore, this patent simplifies the calculation conditions, and the cross-sectional dimensions of the river can be estimated using the above parameters. These parameters are relatively easy to obtain, making the implementation of the patented method more convenient.

[0081] Furthermore, the formula for the hydrodynamic calculation in step S4 is as follows:

[0082]

[0083] n is a constant, R is the wetted perimeter of the water-passing section, S f It represents the friction resistance ratio, Q represents the flow rate of the water section, A represents the area of the water section, and v represents the water flow velocity in the river.

[0084] It should be noted that this formula is derived based on the Manning formula:

[0085]

[0086] Furthermore, the formula for the wetted perimeter R of the water-passing section is as follows:

[0087]

[0088] R represents the wetted perimeter of the water flow section, A represents the area of the water flow section, and χ represents the intermediate calculation amount.

[0089] Furthermore, the formula for the intermediate calculation amount χ is as follows:

[0090]

[0091] w represents the width of the riverbed, h represents the water depth, β represents the side slope angle, A represents the cross-sectional area of the water flow, and sec and csc represent trigonometric functions.

[0092] Furthermore, the formula for the water flow cross-sectional area is as follows:

[0093] A=w·h+h·h / tanβ

[0094] h represents the water depth, w represents the width of the riverbed, and A represents the cross-sectional area of the water flow.

[0095] Furthermore, the formula for the water depth is as follows:

[0096]

[0097] w represents the width of the riverbed, β represents the side slope angle, A represents the cross-sectional area of the water flow, and h represents the water depth.

[0098] Furthermore, the formula for friction ratio drop is as follows:

[0099]

[0100] S0 represents the river bottom slope, It represents the differential expression of water depth and length along the flow direction, and t represents the sequence number.

[0101] When calculating water flow, the Newton iteration method can be used for iterative calculation. The specific formula is as follows:

[0102]

[0103] represents the inflow of the second river reach at time t+1; is the outflow of the adjacent river section of the second river section at time t+1; q is the lateral recharge of the unit.

[0104] Among them, c represents the intermediate calculation amount:

[0105] The formula can be derived from the following formula:

[0106]

[0107] b is the coefficient.

[0108] A distributed hydrological model rapid river confluence calculation system, applied to the calculation method according to any one of claims 1 to 9, comprising:

[0109] A river section division module: obtaining a river channel to be analyzed and a remote sensing image of the river channel to be analyzed, dividing the river channel to be analyzed into a plurality of river sections as a plurality of first river sections; dividing the remote sensing image of the river channel to be analyzed into remote sensing images corresponding to the first river sections according to the plurality of first river sections;

[0110] A river section selection module: selects one of the plurality of first river sections as the second river section;

[0111] River section estimation module: obtains the riverbed width, riverbed slope and side slope angle of the second river section by estimation based on the remote sensing image of the second river section;

[0112] Water flow calculation module: obtains the water flow of the second river section through hydrodynamic calculation based on the riverbed width, riverbed slope and side slope angle of the second river section;

[0113] Circular processing module: select another river section from multiple first river sections as a new second river section; repeat the process until all first river sections are selected; the water flow of each second river section obtained is the water flow of the river to be analyzed.

[0114] The same or similar reference numerals correspond to the same or similar components;

[0115] The terms used in the drawings to describe positional relationships are for illustrative purposes only and should not be construed as limiting this patent;

[0116] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A method for rapid river confluence calculation using a distributed hydrological model, characterized in that: include: S1: Acquire a river channel to be analyzed and a remote sensing image of the river channel to be analyzed, and divide the river channel to be analyzed into multiple river sections as multiple first river sections; Dividing the remote sensing image of the river to be analyzed into remote sensing images corresponding to the first river sections according to the plurality of first river sections; S2: selecting one of the plurality of first river sections as the second river section; and using the remote sensing image of the selected first river section as the remote sensing image of the second river section; S3: estimating the riverbed width, riverbed slope, and side slope angle of the second river section based on the remote sensing image of the second river section; S4: deriving the water flow of the second river section through hydrodynamic calculation based on the riverbed width, riverbed slope, and side slope angle of the second river section; S5: Select another river section from the multiple first river sections as a new second river section; execute step S3 until all first river sections are selected; the water flow of each second river section obtained is the water flow of the river channel to be analyzed.

2. A method for rapid river confluence calculation based on a distributed hydrological model according to claim 1, characterized in that: Step S1 divides the river to be analyzed into multiple river sections, including: S101: setting a plurality of nodes in the river channel according to preset conditions; S102: Divide the river into multiple river sections based on the nodes; The preset conditions include: a. Set the intersection of two or more rivers in the river channel to be analyzed as a node; b. According to the remote sensing image of the river to be analyzed, when the river width is less than the first preset threshold, set the node; c. Calculate the centerline of the river to be analyzed; based on the centerline of the river to be analyzed, use the principles of calculus to calculate the angle between each centerline and the adjacent centerline; if the angle is greater than a second preset threshold, set the node; d. Set nodes where tributaries of the river to be analyzed merge into the main stream; e. If the cumulative flow change in the river is greater than the third preset threshold, set the node; f. If the change in the low slope of the river channel is greater than the fourth preset threshold, set the node.

3. A method for rapid river confluence calculation based on a distributed hydrological model according to claim 1, characterized in that: The river bottom width is the water surface width of the second river section; The riverbed slope is the elevation difference between the water surfaces at both ends of the second river section; The side slope angle is the side slope angle adjacent to the second river section.

4. A method for rapid river confluence calculation using a distributed hydrological model according to claim 1, characterized in that: The formula for the hydrodynamic calculation in step S4 is as follows: n is a constant, R is the wetted perimeter of the water-passing section, S f It represents the friction resistance ratio, Q represents the flow rate of the water section, A represents the area of the water section, and v represents the water flow velocity in the river.

5. A method for rapid river confluence calculation based on a distributed hydrological model according to claim 4, characterized in that: The formula for the wetted perimeter R of the water-passing section is as follows: R represents the wetted perimeter of the water flow section, A represents the area of the water flow section, and χ represents the intermediate calculation amount.

6. A method for rapid river confluence calculation using a distributed hydrological model according to claim 5, characterized in that: The formula for the intermediate calculation quantity χ is as follows: w represents the width of the riverbed, h represents the water depth, β represents the side slope angle, A represents the cross-sectional area of the water flow, and sec and csc represent trigonometric functions.

7. A method for rapid river confluence calculation based on a distributed hydrological model according to any one of claims 4 to 6, characterized in that: The formula for the water flow cross-sectional area is as follows: A=w·h+h·h / tanβ h represents the water depth, w represents the width of the riverbed, and A represents the cross-sectional area of the water flow.

8. A method for rapid river confluence calculation based on a distributed hydrological model according to claim 7, characterized in that: The formula for the water depth is as follows: w represents the width of the riverbed, β represents the side slope angle, A represents the cross-sectional area of the water flow, and h represents the water depth.

9. A method for rapid river confluence calculation using a distributed hydrological model according to claim 4, characterized in that: The formula for friction ratio drop is as follows: S0 represents the river bottom slope, It represents the differential expression of water depth and length along the flow direction, and t represents the sequence number.

10. A distributed hydrological model rapid river confluence calculation system, applied to the calculation method according to any one of claims 1 to 9, characterized in that: include: River section division module: obtaining a river channel to be analyzed and a remote sensing image of the river channel to be analyzed, and dividing the river channel to be analyzed into a plurality of river sections as a plurality of first river sections; Dividing the remote sensing image of the river to be analyzed into remote sensing images corresponding to the first river sections according to the plurality of first river sections; A river section selection module: selects one of the plurality of first river sections as the second river section; River section estimation module: obtains the riverbed width, riverbed slope and side slope angle of the second river section by estimation based on the remote sensing image of the second river section; Water flow calculation module: obtains the water flow of the second river section through hydrodynamic calculation based on the riverbed width, riverbed slope and side slope angle of the second river section; Circular processing module: select another river section from multiple first river sections as a new second river section; repeat the process until all first river sections are selected; the water flow of each second river section obtained is the water flow of the river to be analyzed.

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