A method for calculating water volume in a river's composite cross-section based on remote sensing data

Abstract

The present invention relates to a method for calculating the water volume of a river channel compound section based on remote sensing data, and belongs to the field of river section water volume measurement and remote sensing application technology. The steps are to obtain basic survey data of the river channel compound section, obtain remote sensing images covering the required river channel section through satellite, pre-process and set the image resolution to R×R; extract the river channel water body by calculating the normalized water body index of the pre-processed image; according to the water body extraction result, calculate the number of pixels of the upstream and downstream river channel width and calculate the upstream and downstream river surface width; calculate the water depth based on the survey basic data of the upstream and downstream river channel compound section and the river surface width, and then calculate the river section water volume based on the water depth and volume formula. The present invention can not only effectively reduce the investment of manpower and material resources, but also realize the normalized monitoring of the river channel compound section and improve the efficiency of water resource management.

Description

Technical Field

[0001] The present invention relates to a method for calculating water volume, in particular to a method for calculating water volume in a river composite section based on remote sensing data, and belongs to the technical field of river channel measurement and remote sensing application. Background Art

[0002] In-stream water volume refers to the amount of water within a given length of a river. Calculating in-stream water volume and understanding water resource dynamics can help strengthen water resource management and provide a basis for decision-makers regarding water resource allocation and utilization. Furthermore, calculating in-stream water volume can promote a balanced ecological cycle of water resources and play a vital role in their development and protection. Currently, in-stream water volume measurement is primarily divided into direct recording and indirect observation. Direct observation involves manually reading water level data from a gauge and calculating it based on actual river survey data. This method is simple and easy to use, but requires significant labor and material resources. Indirect observation calculates in-stream water volume based on real-time hydrological station data and basic river survey data. While this method is faster and less labor-intensive, it is complex and requires a robust network, power, and other infrastructure. This leads to high maintenance costs and a significant capital investment. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above-mentioned shortcomings and provide a method for calculating the water volume of a river complex section based on remote sensing data, which can effectively reduce the waste of manpower and material resources and realize the normalized monitoring of the river complex section.

[0004] The technical solution adopted by the present invention is:

[0005] A method for calculating water volume at a composite cross-section of a river based on remote sensing data comprises the following steps:

[0006] (1) Obtain basic survey data of the river channel composite section, including the parameters of the upstream river channel section: the riverbed width B1 of the lower section of the river channel composite section, the riverbed width B2 of the upper section of the river channel composite section, the slope coefficient m of the right bank of the lower section of the river channel composite section 右1 , the slope coefficient of the left bank of the lower section of the river channel compound section m 左1 , the slope coefficient of the right bank of the upper section of the river channel composite section m 右2 The slope coefficient of the left bank of the upper section of the river channel composite section is m 左2 , the maximum water depth h of the lower section of the river channel composite section 1最高 , the maximum width of the lower section of the river channel composite section D 1最 , the maximum width of the upper section of the river channel composite section D 2最; Parameters of the downstream river section: the riverbed width B1′ of the lower section of the river channel compound section, the riverbed width B2′ of the upper section of the river channel compound section, the slope coefficient m of the right bank of the lower section of the river channel compound section 右1 ′, slope coefficient of the left bank of the lower section of the river channel composite section m 左1 ′, slope coefficient of the right bank of the upper section of the river channel composite section m 右2 ′, the slope coefficient of the left bank of the upper section of the river channel composite section is m 左2 ′, the maximum water depth h of the lower section of the river channel composite section 1最高 ′, the maximum width of the lower section of the river channel composite section D 1最 ′, the maximum width of the upper section of the river channel composite section D 2最 ′, the distance L between the upstream section and the downstream section of the river section to be measured;

[0007] (2) Obtain a remote sensing image covering the required river section, set the image resolution to R × R, perform preprocessing, and extract the river water body based on the preprocessed remote sensing image using the improved normalized difference water index;

[0008] (3) Based on the extracted water body, the number of pixels of the upstream and downstream river widths is calculated as n and n′, respectively, and the upstream and downstream river widths D and D′ are obtained:

[0009] D = n × R;

[0010] D′=n′×R ;

[0011] (4) Calculate the water depth of the upper and lower sections of the river according to the river width:

[0012] Upstream river section,

[0013] When D <D 1最 When h1= , h2=0;

[0014] D 1最 When ≤D≤B2, h1= h 1最高 , h2=0;

[0015] When D>B2, h1=h 1最高 ,h2= ;

[0016] Downstream river section,

[0017] When D′ <D 1最 ′, h1′= , h2′=0;

[0018] D 1最 When ′≤D′≤B2, h1′= h 1最高′, h2′=0;

[0019] When D′>B2, h1′= h 1最高 ′,h2′= ;

[0020] h1: water depth of the lower section of the upstream river channel composite section,

[0021] h2: water depth of the section on the composite section of the upstream river channel,

[0022] h1′: water depth of the lower section of the downstream river channel composite section,

[0023] h2′: water depth of the cross section on the downstream river channel composite cross section,

[0024] m1 is m 左1 With m 右1 The mean of m2 is m 左2 With m 右2 The mean of m1′ is m 左1 ′ and m 右1 ′, m2′ is the mean of m 左2 ′ and m 右2 The mean of ′;

[0025] (5) Calculate the water volume of the river section to be measured using the obtained water level and prism volume formula:

[0026] ,

[0027] ,

[0028] V1 is D=D 1最 is the water volume in the lower section of the river at that time, and L is the distance between the upstream section and the downstream section of the river section.

[0029] The improved normalized difference water index is used to extract river water bodies in step (2) of the above method. The main principles are as follows:

[0030] MNDWI=(p(Green)-p(MIR)) / (p(Green)+p(MIR)),

[0031] MNDWI: improved normalized difference water index, ρ(Green): green band remote sensing reflectance, ρ(MIR): mid-infrared band remote sensing reflectance.

[0032] The specific calculation process of the water depth of the upper and lower sections in step (4) is as follows:

[0033] Let’s first look at the upstream section. According to the definition of slope coefficient:

[0034] (1),

[0035] (2),

[0036] (3),

[0037] (4),

[0038] According to the river cross-section diagram: (5),

[0039] (6),

[0040] d 左1 : The horizontal projection length of the left slope of the lower section of the upstream river channel compound section,

[0041] d 右1 : The horizontal projection length of the right slope of the lower section of the upstream river channel composite section,

[0042] d 左2 : The horizontal projection length of the slope on the left side of the section on the upstream river channel composite section,

[0043] d 右2 : The horizontal projection length of the slope on the right side of the section on the upstream river channel composite section,

[0044] h1: water depth of the lower section of the upstream river channel composite section,

[0045] h2: water depth of the section on the composite section of the upstream river channel,

[0046] m 左1 : Slope coefficient of the left bank of the lower section of the upstream river channel composite section,

[0047] m 右1 : Slope coefficient of the right bank of the lower section of the upstream river channel composite section,

[0048] m 左2 : Slope coefficient of the left bank of the composite section of the upstream river channel,

[0049] m 右2 : Slope coefficient of the right bank of the composite section of the upstream river channel,

[0050] D1: river width at the lower section of the upstream river channel,

[0051] D2: river width at the upper section of the upstream river;

[0052] Take m1 as m 左1 With m 右1 The mean of m2 is m 左2 With m 右2 The mean of

[0053] Substituting formulas (1)-(4) into formulas (5) and (6), we can obtain: h1= ,

[0054] h2 = ,

[0055] When D <D 1最 When h1= , h2=0;

[0056] D 1最 When ≤D≤B2, h1= h 1最高 , h2=0;

[0057] When D>B2, h1=h 1最高 ,h2= .

[0058] The above water depth calculation formula is also applicable to the downstream river section.

[0059] When D′ <D 1最 ′, h1′= , h2′=0;

[0060] D 1最 When ′≤D′≤B2, h1′= h 1最高 ′, h2′=0;

[0061] When D′>B2, h1′= h 1最高 ′,h2′= ;

[0062] Among them D 1最 ′: the maximum width of the lower section of the downstream river channel composite section,

[0063] D 2最 ′: the maximum width of the upper section of the downstream river channel composite section,

[0064] d 左1 ′: The horizontal projection length of the left slope of the lower section of the downstream river channel compound section,

[0065] d 右1 ′: The horizontal projection length of the right slope of the lower section of the downstream river channel compound section,

[0066] d 左2 ′: The horizontal projection length of the left slope of the cross section on the downstream river channel composite cross section,

[0067] d 右2 ′: The horizontal projection length of the right slope of the cross section on the downstream river channel composite cross section,

[0068] B1′: the riverbed width of the lower section of the downstream river channel composite section,

[0069] B2′: the width of the riverbed on the composite cross section of the downstream river channel,

[0070] m1′ is m 左1 ′ and m 右1 ′, m2′ is the mean of m 左2 ′ and m 右2 The mean of ′.

[0071] The specific process of calculating the water volume of the river section to be measured in step (5) above is as follows:

[0072] According to the volume formula of a prism:

[0073] ,

[0074] Substituting the cross-sectional area and river distance calculated based on the water depth into the above formula,

[0075] When D <D 1最 And D′ <D 1最 'hour,

[0076] River section water volume V 水 = ,

[0077] When D 1最 ≤D≤B2 when the water volume of the river section V 水 =V1= ,

[0078] When D> B2 and D′> B2′, the water volume of the river section is V 水 = .

[0079] The beneficial effects of the present invention are:

[0080] This method uses complex river section survey data and remote sensing imagery to analyze and calculate the river width at these sections, then calculates the water volume within the river. This method not only effectively reduces human and material investment but also enables regular monitoring of complex river sections, improving water resource management efficiency. It can be applied to a variety of fields, including river flow monitoring, flood control management, and dispatch management. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Figure 1 is a flow chart of the method of the present invention;

[0082] Figure 2 This is a schematic diagram of the upstream river section;

[0083] Figure 3 This is a schematic diagram of the downstream river section;

[0084] Figure 4 is a certain section survey data in an embodiment of the present invention;

[0085] Figure 5 is a satellite remote sensing image covering the river section in an embodiment of the present invention (the box represents the section);

[0086] Figure 6 This is a diagram of the water body extraction results in an embodiment of the present invention (the box represents the section). DETAILED DESCRIPTION

[0087] The present invention is further described below with reference to specific implementation methods and examples.

[0088] A method for calculating water volume at a composite cross-section of a river based on remote sensing data comprises the following steps:

[0089] (1) Obtain basic survey data of the river channel composite section, including the parameters of the upstream river channel section: the riverbed width B1 of the lower section of the river channel composite section, the riverbed width B2 of the upper section of the river channel composite section, the slope coefficient of the right bank of the lower section of the river channel composite section

[0090] m 右1 , the slope coefficient of the left bank of the lower section of the river channel compound section m 左1 , the slope coefficient of the right bank of the upper section of the river channel composite section m 右2 The slope coefficient of the left bank of the upper section of the river channel composite section is m 左2 , the maximum water depth h of the lower section of the river channel composite section 1最高 , the maximum width of the lower section of the river channel composite section D 1最 , the maximum width of the upper section of the river channel composite section D 2最 ; Parameters of the downstream river section: the riverbed width B1′ of the lower section of the river channel compound section, the riverbed width B2′ of the upper section of the river channel compound section, the slope coefficient m of the right bank of the lower section of the river channel compound section 右1 ′, slope coefficient of the left bank of the lower section of the river channel composite section m 左1 ′, slope coefficient of the right bank of the upper section of the river channel composite section m 右2 ′, the slope coefficient of the left bank of the upper section of the river channel composite section is m 左2 ′, the maximum water depth h of the lower section of the river channel composite section 1最高 ′, the maximum width of the lower section of the river channel composite section D 1最 ′, the maximum width of the upper section of the river channel composite section D 2最 ′, the distance L between the upstream section and the downstream section of the river section to be measured.

[0091] (2) Obtain a remote sensing image covering the required river section, set the image resolution to R × R (m × m), perform image registration, orthorectification and other preprocessing, and extract the river water body based on the preprocessed remote sensing image using the improved normalized difference water index:

[0092] The main principles are as follows:

[0093] MNDWI=(p(Green)-p(MIR)) / (p(Green)+p(MIR)) ,

[0094] MNDWI: improved normalized difference water index, ρ(Green): green band remote sensing reflectance, ρ(MIR): mid-infrared band remote sensing reflectance.

[0095] (3) Based on the extracted water body, the number of pixels of the upstream and downstream river widths is calculated as n and n′, respectively, and the upstream and downstream river widths D (m) and D′ (m) are obtained:

[0096] D = n × R;

[0097] D′=n′×R.

[0098] (4) Calculate the water depth of the upper and lower sections of the river according to the river width:

[0099] Let’s first look at the upstream section. According to the definition of slope coefficient:

[0100] (1) ,

[0101] (2),

[0102] (3),

[0103] (4),

[0104] According to the river cross-section diagram: (5) ,

[0105] (6),

[0106] d 左1 : Projection length in the horizontal direction of the left slope of the lower section of the upstream river channel compound section (m),

[0107] d 右1 : Projection length in the horizontal direction of the right slope of the lower section of the upstream river channel compound section (m),

[0108] d 左2: Projection length in the horizontal direction of the slope on the left side of the section on the upstream river channel composite section (m),

[0109] d 右2 : Projection length in the horizontal direction of the slope on the right side of the upstream river channel composite section (m),

[0110] h1: water depth of the lower section of the upstream river channel composite section (m),

[0111] h2: water depth of the section on the composite section of the upstream river channel (m),

[0112] m 左1 : Slope coefficient of the left bank of the lower section of the upstream river channel composite section,

[0113] m 右1 : Slope coefficient of the right bank of the lower section of the upstream river channel composite section,

[0114] m 左2 : Slope coefficient of the left bank of the composite section of the upstream river channel,

[0115] m 右2 : Slope coefficient of the right bank of the composite section of the upstream river channel,

[0116] D1: river width at the lower section of the upstream river (m),

[0117] D2: river width of the upper section of the upstream river (m);

[0118] Take m1 as m 左1 With m 右1 The mean of m2 is m 左2 With m 右2 The mean of

[0119] Substituting formulas (1)-(4) into formulas (5) and (6), we can obtain: h1= ,

[0120] h2 = ,

[0121] When D <D 1最 When h1= , h2=0;

[0122] When D>B2, h1=h 1最高 ,h2= .

[0123] The above water depth calculation formula is also applicable to the downstream river section.

[0124] When D′ <D 1最 ′, h1′= , h2′=0;

[0125] D 1最 When ′≤D′≤B2, h1′= h 1最高 ′, h2′=0;

[0126] When D′>B2, h1′= h 1最高 ′,h2′= ;

[0127] Among them D 1最 ′: the maximum width of the lower section of the downstream river channel composite section (m),

[0128] D 2最 ′: Maximum width of the upper section of the downstream river channel composite section (m),

[0129] d 左1 ′: Projection length of the left slope of the lower section of the downstream river channel compound section in the horizontal direction (m),

[0130] d 右1 ′: Projection length of the right slope of the lower section of the downstream river channel compound section in the horizontal direction (m),

[0131] d 左2 ′: Projection length of the left slope of the cross section on the downstream river channel composite cross section in the horizontal direction (m),

[0132] d 右2 ′: Projection length of the right slope of the cross section on the downstream river channel composite cross section in the horizontal direction (m),

[0133] B1′: riverbed width of the lower section of the downstream river channel composite section (m),

[0134] B2′: the width of the riverbed on the composite cross section of the downstream river channel (m),

[0135] m1′ is m 左1 ′ and m 右1 ′, m2′ is the mean of m 左2 ′ and m 右2 The mean of ′.

[0136] (5) Calculate the water volume of the river section to be measured (m 3 ):

[0137] According to the volume formula of a prism:

[0138] ,

[0139] Substituting the cross-sectional area and river distance calculated based on the water depth into the above formula,

[0140] When D <D 1最 And D′ <D1最 'hour,

[0141] River section water volume V 水 = ,

[0142] When D 1最 ≤D≤B2 when the water volume of the river section V 水 =V1= ,

[0143] When D> B2 and D′> B2′, the water volume of the river section is V 水 = .

[0144] Example: This example calculates and analyzes the water resources of a certain section of the Si River. First, obtain the basic hydrological survey data of the section, such as Figure 4 According to the drawings of the cross-section survey, the width of the riverbed of the lower cross-section of the upstream river channel is B1, which is 40m, and the width of the riverbed of the upper cross-section of the upstream river channel is B2, which is 275m. The maximum width of the riverbed of the lower cross-section of the upstream river channel is D 1最 The maximum width of the upper section of the upstream river channel is 200m. 2最 The slope coefficient of the right bank of the lower section of the upstream river channel composite section is m 右1 is 2.5, and the slope coefficient of the left bank of the lower section of the upstream river channel composite section is m 左1 is 2.5, the slope coefficient of the right bank of the upper section of the upstream river channel composite section is m 右2 is 3, and the slope coefficient of the left bank of the upper section of the upstream river channel composite section is m 左2 =3, the maximum water depth h of the lower section of the upstream river channel composite section 1最高 The width of the riverbed of the lower section of the downstream river channel compound section is B1′, which is 40m. The width of the riverbed of the upper section of the downstream river channel compound section is B2′, which is 275m. The maximum width of the riverbed of the lower section of the downstream river channel compound section is

[0145] D 1最 ′ is 200m, and the maximum width of the upper section of the downstream river channel is D 2最 ′ is 340 meters, and the slope coefficient of the right bank of the lower section of the downstream river channel composite section is m 右1 ′ is 2.5, and the slope coefficient of the left bank of the lower section of the downstream river channel composite section is m 左1 ′ is 2.5, the slope coefficient of the right bank of the upper section of the downstream river channel composite section is m 右2 ′ is 3, the slope coefficient of the left bank of the upper section of the downstream river channel composite section is m 左2 ′ is 3, the maximum water depth h of the lower section of the downstream river channel composite section 1最高 ′ is 8m and the river length L is 200m.

[0146] Obtain satellite remote sensing images covering the Si River section. The resolution of the acquired images is 40×40m. Figure 5 , extract the water body of the image, and the extraction result is as follows Figure 6 .

[0147] The number of river cross-section pixels n is calculated to be 8, then the upstream river width D = 8 × 40 = 320m, the downstream river width D′ = 8 × 40 = 320m, D> B2, D′> B2′, and the water volume V is calculated using the above water volume calculation formula. 水 =9.517 million m 3 .

[0148] The above description is only one embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for calculating water volume in a river complex section based on remote sensing data, characterized by: The steps are as follows: (1) Obtain basic survey data of the river channel composite section, including the parameters of the upstream river channel section: the riverbed width B1 of the lower section of the river channel composite section, the riverbed width B2 of the upper section of the river channel composite section, the slope coefficient m of the right bank of the lower section of the river channel composite section 右1 , the slope coefficient of the left bank of the lower section of the river channel compound section m 左1 , the slope coefficient of the right bank of the upper section of the river channel composite section m 右2 The slope coefficient of the left bank of the upper section of the river channel composite section is m 左2 , the maximum water depth h of the lower section of the river channel composite section 1最高 , the maximum width of the lower section of the river channel composite section D 1最 , the maximum width of the upper section of the river channel composite section D 2最 ; Parameters of the downstream river section: the riverbed width B1′ of the lower section of the river channel compound section, the riverbed width B2′ of the upper section of the river channel compound section, the slope coefficient m of the right bank of the lower section of the river channel compound section 右1 ′, slope coefficient of the left bank of the lower section of the river channel composite section m 左1 ′, slope coefficient of the right bank of the upper section of the river channel composite section m 右2 ′, the slope coefficient of the left bank of the upper section of the river channel composite section is m 左2 ′, the maximum water depth h of the lower section of the river channel composite section 1最高 ′, the maximum width of the lower section of the river channel composite section D 1最 ′, the maximum width of the upper section of the river channel composite section D 2最 ′, the distance L between the upstream section and the downstream section of the river section to be measured; (2) Obtain a remote sensing image covering the required river section, set the image resolution to R × R, perform preprocessing, and extract the river water body based on the preprocessed remote sensing image using the improved normalized difference water index; (3) Based on the extracted water body, the number of pixels of the upstream and downstream river widths is calculated as n and n′, respectively, and the upstream and downstream river widths D and D′ are obtained: D = n × R; D′=n′×R ; (4) Calculate the water depth of the upper and lower sections of the river according to the river width: Upstream river section, When D <D 1最 When h1= , h2=0; D 1最 When ≤D≤B2, h1= h 1最高 , h2=0; When D>B2, h1=h 1最高 ,h2= ; Downstream river section, When D′ <D 1最 ′, h1′= , h2′=0; D 1最 When ′≤D′≤B2, h1′= h 1最高 ′, h2′=0; When D′>B2, h1′= h 1最高 ′,h2′= ; h1: water depth of the lower section of the upstream river channel composite section, h2: water depth of the section on the composite section of the upstream river channel, h1′ is the water depth of the lower section of the downstream river channel composite section, h2′ The water depth of the cross section on the downstream river channel composite section, m1 is m 左1 With m 右1 The mean of m2 is m 左2 With m 右2 The mean of m1′ is m 左1 ′ and m 右1 ′, m2′ is the mean of m 左2 ′ and m 右2 The mean of ′; (5) Calculate the water volume of the river section to be measured using the obtained water level and prism volume formula: ， ， V1 is D=D 1最 is the water volume in the lower section of the river at that time, and L is the distance between the upstream section and the downstream section of the river section.

2. The method for calculating water volume in a river composite section based on remote sensing data according to claim 1, wherein: The main principles of using the improved normalized difference water index to extract river water bodies in step (2) are as follows: MNDWI=(p(Green)-p(MIR)) / (p(Green)+p(MIR)) , MNDWI: improved normalized difference water index, ρ(Green): green band remote sensing reflectance, ρ(MIR): mid-infrared band remote sensing reflectance.

3. The method for calculating water volume in a river composite section based on remote sensing data according to claim 1, wherein: The specific calculation process of the water depth of the upper and lower sections in step (4) is as follows: Let’s first look at the upstream section. According to the definition of slope coefficient: （1）， （2）， （3）， （4）， According to the river cross-section diagram: (5), （6）， d 左1 : The horizontal projection length of the left slope of the lower section of the upstream river channel compound section, d 右1 : The horizontal projection length of the right slope of the lower section of the upstream river channel composite section, d 左2 : The horizontal projection length of the slope on the left side of the section on the upstream river channel composite section, d 右2 : The horizontal projection length of the slope on the right side of the section on the upstream river channel composite section, h1: water depth of the lower section of the upstream river channel composite section, h2: water depth of the section on the composite section of the upstream river channel, m 左1 : Slope coefficient of the left bank of the lower section of the upstream river channel composite section, m 右1 : Slope coefficient of the right bank of the lower section of the upstream river channel composite section, m 左2 : Slope coefficient of the left bank of the composite section of the upstream river channel, m 右2 : Slope coefficient of the right bank of the composite section of the upstream river channel, D1: river width at the lower section of the upstream river channel, D2: river width at the upper section of the upstream river; Take m1 as m 左1 With m 右1 The mean of m2 is m 左2 With m 右2 The mean of Substituting formulas (1)-(4) into formulas (5) and (6), we can obtain: h1= , h2 = ， When D <D 1最 When h1= , h2=0; D 1最 When ≤D≤B2, h1= h 1最高 , h2=0; When D>B2, h1=h 1最高 ,h2= ; The above water depth calculation formula is also applicable to the downstream river section. When D′ <D 1最 ′, h1′= , h2′=0; D 1最 When ′≤D′≤B2, h1′= h 1最高 ′, h2′=0; When D′>B2, h1′= h 1最高 ′,h2′= ; Among them D 1最 ′: the maximum width of the lower section of the downstream river channel composite section, D 2最 ′: the maximum width of the upper section of the downstream river channel composite section, d 左1 ′: The horizontal projection length of the left slope of the lower section of the downstream river channel compound section, d 右1 ′: The horizontal projection length of the right slope of the lower section of the downstream river channel compound section, d 左2 ′: The horizontal projection length of the left slope of the cross section on the downstream river channel composite cross section, d 右2 ′: The horizontal projection length of the right slope of the cross section on the downstream river channel composite cross section, B1′: the riverbed width of the lower section of the downstream river channel composite section, B2′: the width of the riverbed on the composite cross section of the downstream river channel, m1′ is m 左1 ′ and m 右1 ′, m2′ is the mean of m 左2 ′ and m 右2 The mean of ′.

4. The method for calculating water volume in a river composite section based on remote sensing data according to claim 1, wherein: The specific process of calculating the water volume of the river section to be measured in step (5) is as follows: According to the volume formula of a prism: ， Substituting the cross-sectional area and river distance calculated based on the water depth into the above formula, When D <D 1最 And D′ <D 1最 ′, the water volume of the river section V 水 = , When D 1最 ≤D≤B2 when the water volume of the river section V 水 =V1= , When D> B2 and D′> B2′, the water volume of the river section is V 水 = .

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