H-adcp installation position optimization method based on cross-section traversal scanning

Abstract

The application discloses an H-ADCP installation position optimization method based on cross-section traversal scanning, which comprises the following steps: 1) selecting a cross-section to be installed, using a sailing ADCP to measure flow and synchronously observing water level under different water level stages or flow velocity stages, and calculating the average flow velocity of each cross-section; 2) importing the flow velocity data into a cross-section terrain model, dividing candidate units, traversing and extracting representative flow velocities, and generating a flow field and a standard deviation distribution diagram; and 3) comprehensively analyzing and determining the final position through multi-dimensional quantitative evaluation of flow velocity standard deviation, random uncertainty and correlation coefficient, combined with on-site conditions such as terrain adaptability and interference degree. The method disclosed by the application has high site selection efficiency and is suitable for H-ADCP installation site selection in rivers, lakes and other water areas, and is helpful to improve the online monitoring accuracy of river flow.

Description

Technical Field

[0001] This invention belongs to the field of hydrological monitoring technology, specifically relating to a method for optimizing the installation location of H-ADCP based on cross-sectional traversal scanning. Background Technology

[0002] The Acoustic Doppler Current Profiler (ADCP) is currently the most effective instrument for measuring current velocity profiles. In recent years, the horizontal acoustic Doppler current profiler (H-ADCP) has also matured in the application of hydrological surveys in rivers and lakes. The working principle of the H-ADCP is to install the Doppler current velocity measurement sensor probe at a certain depth near the shore, ensuring that the acoustic sensors on the probe are on the same plane. The ultrasonic sensors emit sound at a certain angle towards the opposite bank. When the ultrasonic waves encounter suspended objects in the water, they are reflected. Part of the reflected sound waves are received by the acoustic Doppler current velocity measurement sensor at the transmitting end. The frequency of the reflected sound waves changes with the magnitude of the current velocity. Based on the frequency, the two-dimensional vector velocity at each point on a certain section of the water flow can be calculated.

[0003] To achieve automatic and real-time flow measurement, online river flow monitoring primarily employs the indirect method of measuring the average cross-sectional velocity, known as the index velocity method. The index velocity method establishes a correlation between the index velocity (i.e., the H-ADCP measured velocity) and the average cross-sectional velocity; it is also called the correlation analysis method or regression method. First, the average cross-sectional velocity is measured using a traditional current meter or a mobile ADCP, then the velocity at a specific river layer (i.e., the index velocity) is measured using an H-ADCP, and the correlation between the two is established. To reduce flow measurement errors, the cross-sectional area is borrowed from the measured large cross-sectional area based on the basic water gauge level; the flow rate for each time period can then be calculated from the velocity and area.

[0004] Therefore, the selection of the H-ADCP installation location is crucial to the accuracy of online river flow monitoring. Currently, in practice, the determination of H-ADCP installation locations is usually based on on-site river conditions combined with manual measurement experience. However, this method relies too heavily on manual experience, lacks data support, and cannot standardize the site selection criteria. The quality of site selection varies among different personnel and cross-sections, making it difficult to choose the most suitable installation location. If the selected location is unsuitable, it will significantly impact the measurement accuracy, failing to meet the accuracy requirements of relevant specifications and negatively affecting the continuity and consistency of hydrological data. Furthermore, it will necessitate the selection of a new installation location, causing significant economic losses to the construction team. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies, such as reliance on manual experience in H-ADCP installation site selection, lack of quantitative standards, insufficient data support, difficulty in ensuring monitoring accuracy, and high construction costs. It provides an efficient, standardized, quantitative, and highly reproducible method for optimizing H-ADCP installation locations, achieving the goal of optimal flow velocity representativeness and lowest construction and maintenance costs throughout the entire hydrological cycle.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A method for optimizing the installation location of an H-ADCP based on cross-sectional traversal scanning includes the following steps:

[0008] Step S1: Measurement of cross-sectional flow field data and calculation of average cross-sectional velocity, specifically including:

[0009] Step S1.1: Select the cross section in the target river that meets the flow monitoring requirements, acquire the topographic data of the river cross section using topographic surveying equipment, and establish the cross section topographic model.

[0010] Step S1.2: Based on the historical water level and velocity data of the target river channel, divide the water level or velocity level, and use a mobile ADCP to measure the flow rate of the section to be installed at each water level or velocity level. Simultaneously record the real-time water level data of each measurement through the water level observation equipment to obtain at least 30 mobile profile velocity data.

[0011] Step S1.3: For each measurement, based on the flow data obtained by the mobile ADCP and the cross-sectional area corresponding to the water level of that measurement (obtained from the cross-sectional topographic model), calculate the average cross-sectional velocity according to the following formula: Average cross-sectional velocity = Flow rate of measurement / Cross-sectional area corresponding to the measurement, to obtain the average cross-sectional velocity of each measurement.

[0012] Step S2: H-ADCP installation location traversal simulation analysis, specifically including:

[0013] Step S2.1: Determine the technical parameters of the proposed H-ADCP, including the measurement range, measurement angle, and the proposed installation water level elevation range;

[0014] Step S2.2: Import the velocity data from each measurement's transit profile obtained in Step S1.2 into the cross-sectional topographic model established in Step S1.1. Combine this with the real-time water level of each measurement to identify the spatial distribution of velocity data for each cross-sectional unit within the cross-section. This ensures that the discrete velocity data has clear spatial coordinates of the starting point distance and elevation, achieving spatial anchoring of the velocity data for each cross-sectional unit. The specific implementation process is as follows:

[0015] 1) Data preprocessing: The velocity data of each measurement's navigation profile are standardized in format, retaining core fields (measurement number, distance from the starting point of the collection point, measured water depth, stratified velocity, and collection time), and invalid data (such as underwater virtual points caused by depth measurement errors and abnormal velocity values) are removed.

[0016] 2) Elevation conversion: Combining the real-time water level data of each measurement, the measured water depth of each velocity collection point is converted into the elevation of the velocity measurement point. The conversion formula is: Elevation of velocity measurement point = Real-time water level elevation of this measurement - Measured water depth of the measurement point, generating a three-dimensional original dataset of "starting point distance - elevation - velocity" for each measurement.

[0017] 3) Model import: Through the numerical model interface of the hydrological data processing software, the standardized three-dimensional flow velocity datasets of each measurement are imported into the cross-sectional topographic model. The model has stored the continuous correspondence between the "starting point distance - riverbed elevation" of the cross section to be installed.

[0018] 4) Spatial Matching and Recognition: Based on the two-dimensional rectangular coordinate system of starting distance-elevation, the software accurately matches each velocity measurement point in the three-dimensional velocity dataset to the corresponding spatial location of the cross-sectional terrain model. At the same time, it identifies the cross-sectional unit to which each velocity measurement point belongs (the basic grid unit preset in the cross-sectional terrain model, which is the spatial carrier of the velocity data). Finally, it realizes the accurate identification of the spatial distribution of velocity data in each cross-sectional unit in the cross-section, forming a correlation database of "cross-sectional unit-multiple velocity measurement data". The database can trace the measurement, water level, spatial coordinates and other attributes of each velocity data.

[0019] Step S2.3: Divide candidate location units according to a preset interval, and use a traversal scanning method to extract the transit profile velocity data of each candidate location unit in all measurements (as the representative velocity of H-ADCP) to form a cross-sectional flow field distribution map; at the same time, calculate the velocity standard deviation of each candidate location unit to generate a cross-sectional standard deviation distribution map. The specific implementation process is as follows:

[0020] 1) Candidate location unit division

[0021] Scope of division: Strictly limited to the H-ADCP measurement range (starting point distance interval) determined in step S2.1 and the range of the proposed installation water level elevation, without exceeding the effective monitoring area of ​​the equipment;

[0022] Grid division: Based on the two-dimensional rectangular coordinate system of starting distance-elevation of the cross-sectional terrain model, the grid is divided into equal intervals according to the preset intervals to form candidate location units with seamless connection, no overlap and full coverage. Each unit has a unique spatial identifier (starting distance interval - elevation interval) as a potential evaluation unit for H-ADCP installation.

[0023] 2) Extraction of flow velocity data at candidate locations

[0024] Using a full-test traversal scanning method, taking candidate location units as units, the velocity data of each test run profile of all cross-sectional units within the coverage area of ​​each candidate location unit are extracted from the "cross-sectional unit-multi-test velocity data" association database formed in step S2.2. This data is used as the H-ADCP representative velocity of the candidate location unit, forming a dedicated "test-representative velocity" dataset for each candidate location unit. This ensures that the dataset covers all tests in step S1.2 without any test omissions.

[0025] 3) Generation of cross-sectional flow field distribution map

[0026] Based on the representative flow velocity of each candidate location unit, the average value of the representative flow velocity of each candidate location unit is calculated. Using the cross-sectional topographic model as the base map, the average flow velocity of each candidate location unit is visualized by using the color gradient method (e.g., the greater the flow velocity, the darker the color) through hydrological data processing software, generating a cross-sectional flow field distribution map, which intuitively reflects the flow velocity distribution characteristics of each potential installation location within the cross-section to be installed.

[0027] 4) Calculation of flow velocity standard deviation and generation of standard deviation distribution map

[0028] Flow velocity standard deviation calculation: For each candidate location unit, the flow velocity standard deviation is calculated using a dedicated dataset of "measurement-representative flow velocity" to characterize the stability of the flow velocity of the candidate location unit under multiple measurements.

[0029] Standard deviation distribution map generation: The flow velocity standard deviation of each candidate location unit is spatially matched with the cross-sectional topographic model. The standard deviation distribution map of the cross section is generated by using the color gradient method (e.g., the smaller the standard deviation, the lighter the color) through hydrological data processing software. This visually reflects the flow velocity stability characteristics of each potential installation location within the cross section to be installed.

[0030] Based on the output results of step S2: the proposed H-ADCP technical parameter table, candidate location unit spatial distribution table, cross-sectional flow field distribution map, cross-sectional standard deviation distribution map, "measurement-representative flow velocity" dataset and flow velocity standard deviation quantification index for each candidate location unit will provide a comprehensive basis for the optimal installation location in step S3.

[0031] Step S3: Optimize the installation location, specifically including:

[0032] Step S3.1: Calculate the random uncertainty and correlation coefficient between the representative velocity of each candidate location unit and the average velocity of the corresponding measurement section;

[0033] Step S3.2: Based on the random uncertainty and correlation coefficient, candidate positions that meet the preset accuracy threshold are selected;

[0034] Step S3.3: Based on the actual site conditions, select the position with the optimal flow velocity representativeness from the candidate positions that meet the accuracy threshold, and use it as the final installation position of H-ADCP.

[0035] Further optimization involves selecting a straight section of the target river channel without significant bends or tributary inflows for installation to ensure a stable flow field and minimize terrain interference. A combination of a total station and an echo sounder, or an unmanned surface-to-water multibeam echo sounder, is used to measure the section's topographic data. Based on the measurement data, a section topographic model is established to clarify the correspondence between the section elevation and the distance from the starting point.

[0036] Further optimization is achieved in step S1.2, where water level or velocity levels are classified based on historical hydrological data of the target river channel. Specifically, this is done by analyzing the changes in flow rate and corresponding velocity at the station based on historical hydrological data of the target river channel section, distinguishing different water level and velocity levels for comparison, with no fewer than 15 levels. Each water level and velocity level is compared 3 to 5 times, and at least 2 times if conditions are insufficient.

[0037] The specific parameters for flow measurement using a mobile ADCP should be set according to the cross-sectional conditions, the maximum possible flow velocity, the power of the measuring vessel, and the test requirements; the water level observation equipment should have a measurement accuracy of ≤ ±0.01m and a data sampling interval of less than 1min.

[0038] To further optimize, the H-ADCP technical parameters determined in step S2.1 must meet the following requirements:

[0039] 1) The measurement range is determined based on the width of the section to be installed, and the measurement range covers 60%-90% of the width of the mainstream area of ​​the section, ensuring that the flow velocity characteristics of the mainstream area of ​​the section can be captured.

[0040] 2) The measurement angle is the angle between the H-ADCP probe and the direction of water flow, and the value range is 80°-100°.

[0041] 3) The proposed installation water level elevation range is determined based on the water level data of the section to be installed over the past 5 years, covering more than 75% of the water level occurrence frequency of the section, that is, excluding extreme high water levels and extreme low water levels.

[0042] Further optimization is achieved in step S2.3 by dividing the candidate position units by a preset interval as follows: the interval between the candidate position units is no greater than 1 / 2 of the H-ADCP beam resolution; if the H-ADCP beam resolution is 0.5m, then the interval between the candidate position units is ≤0.25m, ensuring that no key positions are missed during the traversal scan.

[0043] Further optimization is achieved by using the following formula in step S2.3 to calculate the standard deviation of the flow velocity for each candidate location unit:

[0044]

[0045] Among them, S j For the first j The standard deviation of the flow velocity in each candidate location unit. n For the number of measurements, v ji For the first j Unit 1 i The representative flow velocity of each measurement, It represents the average value of the representative flow velocity from multiple measurements in this unit; the smaller the standard deviation, the stronger the flow velocity stability at that location.

[0046] Further optimization involves the following step, S3.1, where the calculation of random uncertainty is performed using a Type A uncertainty assessment method. The calculation formula is as follows:

[0047]

[0048] in, u j For the first j The standard uncertainty of each candidate location element, S j For the first j The standard deviation of the flow velocity in each candidate location unit. n For the number of measurements, k U is the coverage factor (taken as 2, corresponding to a confidence probability of 95%). j For the first j The expanded uncertainty of each candidate location unit, i.e. the final random uncertainty.

[0049] Further optimization involves the following step, S3.1, where the correlation coefficient is calculated as follows: using the Pearson product-moment correlation coefficient formula, the linear correlation coefficient between the representative velocity sequence of the candidate location unit and the cross-sectional average velocity sequence of the corresponding measurement is calculated. r j The formula is:

[0050]

[0051] in, r j The correlation coefficient has a value range of [-1, 1]. For the first i The cross-sectional average flow velocity of each measurement, This represents the average flow velocity across multiple cross-sections; r ji The closer the value is to 1, the stronger the linear correlation between the two.

[0052] Further optimization is achieved in step S3.2, referring to the requirement of "relative error of online monitoring flow ≤ ±5%" in the "Specification for River Flow Measurement" (GB50179-2015). The preset accuracy threshold is set as follows: random uncertainty U ≤ 5%; correlation coefficient r ≥ 0.9; the candidate positions that meet the above two thresholds are the positions that meet the accuracy requirements.

[0053] Further optimization involves the following evaluation indicators for the actual on-site layout conditions of small- to medium-sized river cross-sections in step S3.3:

[0054] 1) Terrain adaptability: The riverbed slope at the installation location is ≤15°, with no protruding reefs or silt-filled pits;

[0055] 2) Degree of water flow disturbance: The velocity variation coefficient at this location is ≤10%, and the distance from disturbance sources such as bends and backflows is ≥3 times the cross-sectional width;

[0056] 3) Convenience of construction and operation and maintenance: The horizontal distance between the installation location and the shore is ≤5m, the water depth is ≥1.0m, and there are no high-voltage lines or strong electromagnetic interference sources in the vicinity.

[0057] The evaluation indicators for the actual on-site layout conditions of ultra-wide river channel sections with multiple piers include:

[0058] 1) Terrain adaptability: The transverse slope of the riverbed is ≤5%, there are no protruding rocks with a height greater than 0.8m or siltation pits with a depth greater than 1.0m, and the bearing capacity of the riverbed in the installation area is ≥50kN / m²;

[0059] 2) Degree of water flow interference: The coefficient of variation of flow velocity is ≤10%, the distance from the interference source is ≥1 times the distance between adjacent bridge piers, and the H-ADCP beam angle avoids the ultrasonic reflection zone of the bridge piers;

[0060] 3) Convenience of construction and operation and maintenance: The installation platform anchoring system meets the requirements of a 5-year return period water flow impact load, water depth 1.5m-5m, data transmission signal strength ≥-85dBm, and connection time with the shore operation and maintenance base ≤30 minutes.

[0061] Further optimization includes step S3.4: specific implementation steps for installation location verification: at the selected final installation location, a temporary H-ADCP is deployed for 72 hours of continuous monitoring, and three comparative measurements are carried out simultaneously using a mobile ADCP; if the relative error of the flow rate in the comparative measurement is ≤±3%, then the location is confirmed as the final installation location; if the error exceeds ±3%, then return to step S2 to readjust the candidate location unit interval, and perform traversal scanning and selection again.

[0062] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0063] 1. Significantly improved site selection accuracy: Supported by flow field data from multiple water levels and multiple measurements, and combined with quantitative indicators such as standard deviation, random uncertainty, and correlation coefficient, installation locations with strong flow velocity stability and high correlation with the cross-sectional average flow velocity throughout the entire hydrological cycle are selected, ensuring that the relative error of flow monitoring is small.

[0064] 2. Standardized and reproducible process: Key technical details such as equipment parameters, measurement accuracy, division intervals, and threshold standards are clearly defined, replacing the traditional experience-based site selection method. This avoids fluctuations in site selection quality caused by differences in personnel experience. Those skilled in the art can directly reproduce the process, which is applicable to different river scenarios.

[0065] 3. High site selection efficiency and low cost: Through traversal scanning and simulation analysis, there is no need for repeated on-site trial installations, which greatly shortens the site selection cycle; at the same time, it avoids secondary construction caused by site selection errors, and reduces costs such as equipment disassembly and material loss.

[0066] 4. High adaptability: The process parameters, such as the candidate location interval and the number of water level levels, can be flexibly adjusted according to the terrain features, water level variation range, and H-ADCP equipment parameters of different rivers. It is suitable for H-ADCP installation and site selection in various water areas such as plain rivers, mountain rivers, and lakes. Attached Figure Description

[0067] Figure 1 A flowchart of an efficient method for optimizing H-ADCP installation location based on cross-sectional traversal scanning;

[0068] Figure 2 This is a diagram illustrating data extraction.

[0069] Figure 3 This is a schematic diagram of the standard deviation distribution of the cross section. Detailed Implementation

[0070] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0071] This embodiment takes a flow monitoring section of a mountain river as an example, and describes in detail the implementation process of the present invention for the optimal installation location of H-ADCP in a wide-section river with multiple bridge piers.

[0072] This embodiment is applied to an online flow monitoring project in a large, wide, and shallow river (including bridges spanning the river). The river hydrological and equipment parameters are as follows:

[0073] Cross-sectional parameters: The downstream straight section of the bridge was selected, with the starting point ranging from 0m to 800m and the elevation ranging from 0m to 40m; the section has 4 piers (piers 1-4), with the distance between adjacent piers being 80m, 80m, and 50m respectively; the water level variation range over the past 5 years is 15m-25m, with an average water level of 16m during the dry season, 20m during the normal water season, and 24m during the wet season.

[0074] Equipment parameters: H-ADCP beam resolution 0.5m, measurement range 200m-700m (covering the core watershed of the cross section), measurement angle 90°; mobile ADCP sampling frequency 2Hz, 15 profile layers.

[0075] Accuracy requirements: The relative error of flow monitoring should be ≤ ±3%, and the area affected by water flow interference around bridge piers should be avoided.

[0076] In this embodiment, as Figure 1 As shown, the implementation steps of the H-ADCP installation location optimization method based on cross-sectional traversal scanning are as follows:

[0077] Step S1: Measurement of cross-sectional flow field data and calculation of average cross-sectional velocity

[0078] Cross-sectional terrain modeling: An unmanned surface-to-surface (USS) multibeam echo sounder was used to measure the cross-sectional terrain, controlling the elevation accuracy to ±0.1m and the starting point distance accuracy to ±1.0m. A cross-sectional terrain model was established with a starting point distance of 0m-800m and an elevation of 0m-40m. For example... Figure 2 Black outline in the middle.

[0079] Multi-level flow field acquisition:

[0080] Water level levels are divided into 15.0m, 15.7m, 16.4m, 17.1m, 17.8m, 18.5m, 19.2m, 19.9m, 20.6m, 21.3m, 22.0m, 22.7m, 23.4m, 24.1m, and 24.8m, covering the core water level range of 15m-25m; two flow measurements are conducted for each level, for a total of 30 measurements.

[0081] Flow measurement setup: A mobile ADCP is used to measure the flow along the full width of the cross-section, with a sampling frequency of 2Hz and a sampling time of 20s per layer; the water level is recorded simultaneously using a radar level gauge with an accuracy of ±0.01m.

[0082] Calculation of average cross-sectional velocity: Based on the large cross-sectional area corresponding to the water level of each measurement (e.g., when the water level is 20m during the normal water period, the cross-sectional area is about 12000m²), the average cross-sectional velocity is calculated according to the formula. Typical measurement data are shown in Table 1.

[0083] Table 1 Calculation results of average flow velocity at cross-section

[0084]

[0085] Step S2: Simulation analysis of H-ADCP installation location traversal

[0086] Technical parameters determined: H-ADCP measurement range 200m-700m, planned installation water level elevation range 17m-23m, covering 85% of daily water levels.

[0087] Spatial matching of flow velocity data: Flow velocity data from 30 transect measurements were imported into the cross-sectional topographic model. Combined with real-time water levels from each measurement, the specific spatial location of the flow velocity data for each cross-sectional unit within the cross-section was determined through 'distance from starting point to elevation' coordinate matching. Figure 2 As shown in the figure, the colored flow velocity data is superimposed on the black terrain curve. Based on this matching result, flow velocity data of the same spatial location in different measurements can be accurately extracted.

[0088] Traversal scanning and data processing: 30 representative flow velocities were extracted from each cell, and the standard deviation distribution of the flow velocity for each candidate cell was calculated, such as... Figure 3 As shown, the standard deviation is smallest in the downstream area of ​​pier 4 (500m-700m from the starting point), at 6.2%.

[0089] Step S3: Optimization and Verification of Installation Location

[0090] Quantitative evaluation: For candidate locations with a starting point distance of 600m and an elevation of 20m, the calculated random uncertainty is 4.1% (≤5%) and the correlation coefficient is 0.94 (≥0.9), which meets the accuracy threshold.

[0091] Site suitability: The location is 100m horizontally away from pier 4, avoiding interference from the pier; the riverbed slope is 8° (≤15°) and the water depth is 4m (≥1.0m), which is suitable for construction and operation and maintenance requirements.

[0092] Verification: A temporary H-ADCP was deployed for 72 hours of monitoring, with three simultaneous mobile comparative measurements. The relative errors of the flow rate were 2.2%, 1.9%, and 2.6%, respectively, all ≤ ±3%.

[0093] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for optimizing the installation location of H-ADCP based on cross-sectional traversal scanning, characterized in that, Includes the following steps: Step S1: Measurement of cross-sectional flow field data and calculation of average cross-sectional velocity, specifically including: Step S1.1: Select the cross section in the target river that meets the flow monitoring requirements, acquire the topographic data of the cross section using topographic surveying equipment, and establish the cross section topographic model. Step S1.2: Based on the historical water level and velocity data of the target river channel, divide the water level level or velocity level, and use a mobile ADCP to measure the flow rate of the section to be installed at each water level level or velocity level. Simultaneously record the real-time water level data of each measurement through the water level observation equipment to obtain at least 30 mobile profile velocity data. The specific implementation of classifying water level or flow velocity levels based on historical hydrological data of the target river channel is as follows: Based on historical hydrological data of the target river channel section, analyze the flow changes and corresponding flow velocity changes at the station, distinguish different water level levels and flow velocity levels for comparative testing, with a total of no less than 15 levels, and each water level level and flow velocity level is compared 3 to 5 times, and at least 2 times if conditions are insufficient. The specific parameters for flow measurement using a mobile ADCP should be set according to the cross-sectional conditions, the maximum possible flow velocity, the power of the measuring vessel, and the test requirements. Step S1.3: For each measurement, based on the flow rate data obtained by the mobile ADCP and the cross-sectional area corresponding to the real-time water level of that measurement, calculate the average cross-sectional velocity according to the following formula: Average cross-sectional velocity = Flow rate of measurement / Cross-sectional area corresponding to the measurement, to obtain the average cross-sectional velocity of each measurement. Step S2: H-ADCP installation location traversal simulation analysis, specifically including: Step S2.1: Determine the technical parameters of the proposed H-ADCP, including the measurement range, measurement angle, and the proposed installation water level elevation range; Step S2.2: Import the velocity data of each measurement of the underway profile obtained in step S1.2 into the cross-sectional terrain model established in step S1.1, and combine it with the real-time water level of each measurement to identify the spatial distribution of the velocity data of each cross-sectional unit in the cross-section. Step S2.3: Divide the candidate location units according to the preset interval, and use the traversal scanning method to extract the flow velocity data of each candidate location unit in all measurements to form a cross-sectional flow field distribution map; at the same time, calculate the flow velocity standard deviation of each candidate location unit to generate a cross-sectional standard deviation distribution map. Step S3: Optimize the installation location, specifically including: Step S3.1: Calculate the random uncertainty and correlation coefficient between the representative velocity of each candidate location unit and the average velocity of the corresponding measurement section; Step S3.2: Based on the random uncertainty and correlation coefficient, candidate positions that meet the preset accuracy threshold are selected; Step S3.3: Based on the actual site conditions, select the position with the optimal flow velocity representativeness from the candidate positions that meet the accuracy threshold, and use it as the final installation position of H-ADCP.

2. The method according to claim 1, characterized in that, In step S2.1, the specific technical parameters of the determined H-ADCP are as follows: 1) The measurement range is determined based on the width of the section to be installed, ensuring that the measurement range covers 60%-90% of the section width; 2) The measurement angle is the angle between the H-ADCP probe and the direction of water flow, and the value range is 80°-100°; 3) The proposed installation water level elevation range is determined based on the water level data of the section to be installed over the past 5 years, covering more than 75% of the water level occurrence frequency of the section.

3. The method according to claim 2, characterized in that, In step S2.3, the specific implementation of dividing the candidate position units by the preset interval is as follows: the interval of the candidate position units is not greater than 1 / 2 of the H-ADCP beam resolution.

4. The method according to claim 3, characterized in that, In step S2.3, the specific formula for calculating the standard deviation of the flow velocity for each candidate location unit is as follows: ; Among them, S j For the first j The standard deviation of the flow velocity in each candidate location unit. n For the number of measurements, v ji For the first j The candidate location unit is the i The representative flow velocity of each measurement, The average value of the representative flow velocity from multiple measurements at the candidate location unit.

5. The method according to claim 4, characterized in that, In step S3.1, the specific implementation of calculating random uncertainty is as follows: A Type A uncertainty assessment method is used, and the calculation formula is: ; in, u j For the first j The standard uncertainty of each candidate location element, S j For the first j The standard deviation of the flow velocity in each candidate location unit. n For the number of measurements, k As the inclusion factor, U j For the first j The expanded uncertainty of each candidate location unit, i.e. the final random uncertainty.

6. The method according to claim 5, characterized in that, In step S3.1, the correlation coefficient is calculated as follows: using the Pearson product-moment correlation coefficient formula, the linear correlation coefficient between the representative velocity sequence of the candidate location unit and the cross-sectional average velocity sequence of the corresponding measurement is calculated. r j The formula is: ; in, r j For the first j The correlation coefficients of the candidate location units range from [-1, 1]. For the first i The cross-sectional average flow velocity of each measurement, This represents the average flow velocity across multiple cross-sections.

7. The method according to claim 6, characterized in that, In step S3.2, the preset accuracy threshold is: random uncertainty U j ≤5%; correlation coefficient r j ≥0.9; Simultaneously satisfying the random uncertainty U j ≤5% and correlation coefficient r j Candidate positions with two thresholds ≥0.9 are those that meet the accuracy requirements.

8. The method according to claim 7, characterized in that, In step S3.3, the evaluation indicators for the actual on-site layout conditions of small and medium-sized river cross-sections include: 1) Terrain adaptability: The riverbed slope at the installation location is ≤15°, with no protruding reefs or silt-filled pits; 2) Degree of water flow disturbance: The velocity variation coefficient at this location is ≤10%, and the distance from disturbance sources such as bends and backflows is ≥3 times the cross-sectional width; 3) Convenience of construction and operation and maintenance: The horizontal distance between the installation location and the shore is ≤5m, the water depth is ≥1.0m, and there are no high-voltage lines or strong electromagnetic interference sources in the vicinity; The evaluation indicators for the actual on-site layout conditions of ultra-wide river channel sections with multiple piers include: 1) Terrain adaptability: The transverse slope of the riverbed is ≤5%, there are no protruding rocks with a height greater than 0.8m or siltation pits with a depth greater than 1.0m, and the bearing capacity of the riverbed in the installation area is ≥50kN / m²; 2) Degree of water flow interference: The coefficient of variation of flow velocity is ≤10%, the distance from the interference source is ≥1 times the distance between adjacent bridge piers, and the H-ADCP beam angle avoids the ultrasonic reflection zone of the bridge piers; 3) Convenience of construction and operation and maintenance: The installation platform anchoring system meets the requirements of a 5-year return period water flow impact load, water depth 1.5m-5m, data transmission signal strength ≥-85dBm, and connection time with the shore operation and maintenance base ≤30 minutes.

9. The method according to claim 8, characterized in that, Step S3 further includes step S3.4: specific implementation steps for installation location verification: at the selected final installation location, a temporary H-ADCP is deployed for 72 hours of continuous monitoring, and three comparative measurements are carried out simultaneously using a mobile ADCP; if the relative error of the flow rate in the comparative measurement is ≤±3%, then the location is confirmed as the final installation location; if the error exceeds ±3%, then return to step S2 to readjust the candidate location unit interval, and perform traversal scanning and selection again.

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