Method for analyzing influence of engineering on hydrologic monitoring capacity of hydrologic station located in tidal river reach and recovery evaluation method of hydrologic station

Abstract

The invention relates to the technical field of hydrological monitoring, and discloses a method for analyzing the influence of engineering on the hydrological monitoring capacity of a hydrological station in a tidal river reach and a recovery evaluation method of the hydrological station. The engineering influence is identified by utilizing a two-dimensional hydrodynamic model, water level comparison monitoring and flow velocity comparison monitoring are respectively carried out on a target hydrologic station in the front stage, the middle stage and the rear stage of engineering construction, the actual measurement influence of the engineering on the target hydrologic station is continuously monitored and analyzed, and a remedy scheme is dynamically adjusted according to the influence degree. And checking and correcting the water level and flow data of the target hydrological station. On the basis of actual measurement influence evaluation, consistency correction is carried out on the water level by establishing a correction method, a flow velocity monitoring scheme is remedied by adopting a newly installed flow measurement system according to the calibrated flow velocity representative line precision condition, and the remedied monitoring capability recovery condition of the observation station is evaluated.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrological monitoring, and particularly relates to a method for analyzing the impact of engineering on the hydrological monitoring ability of a hydrological station located in a tidal reach and a method for evaluating its recovery. Background Art

[0002] Hydrological monitoring is a basic work for understanding and mastering the variation law of water regime, and is the basis for scientific and reasonable decision-making such as flood control and drought relief, project planning, and water resources development and management. However, with the development of social economy, the construction of a large number of water-related projects has profoundly changed the natural hydrological characteristics and measurement conditions of rivers, bringing many difficulties to the calculation, reporting, and adjustment work of hydrological stations.

[0003] Xue Qinglan et al. used the grey system theory to study the relationship between various influencing factors of Qubei Shibuzhi Hydrological Station and the change of river sediment, and quantitatively analyzed the influence degree of human factors; Liang Guisheng et al. analyzed the influence of the reinforcement and maintenance project of Qingtongxia Yellow River Iron Bridge on hydrological measurement of Qingtongxia Hydrological Station at different frequencies, and proposed remedial measures; Chen Apeng studied the influence of the regulation project of the left bank floodplain of Yinghe River on Fuyang Sluice Hydrological Station through the analysis of the distribution law of flow velocity, sediment concentration and river characteristics and the calculation of scour and backwater, and proposed remedial suggestions for hydrological monitoring to ensure the continuity of station data; Gao Chen took the main channel impounding project of Laolicun as an example to calculate the riverbed scour depth and sediment deposition after the project, and comprehensively analyzed the river regime to discuss the influence of the impounding project on hydrological measurement of Beihedian Hydrological Station, in order to provide reference for the formulation of the measurement plan after completion; Zheng Can calculated the magnitude division and scour depth of medium, high and low water by using hydrological measured data to find out the influence degree of the construction of ecological construction projects on hydrological monitoring of Duya Hydrological Station.

[0004] However, the current research mainly focuses on the engineering impact assessment and remedial countermeasure research, lacking the continuous monitoring and measured impact analysis after the completion of the project, and the research on the recovery evaluation of the hydrological station monitoring ability after the remedial measures, and most of them focus on Qingshuihe Station, with less research on tidal reach stations. Summary of the Invention

[0005] To solve the above-mentioned problems in the prior art, the present invention provides a method for analyzing the impact of engineering on the hydrological monitoring ability of a hydrological station located in a tidal reach.

[0006] Another object of the present invention is to provide a method for evaluating the recovery of the hydrological monitoring ability of a hydrological station located in a tidal reach affected by engineering. To solve the above technical problems, the technical solution of the present invention is as follows:

[0007] A method for analyzing the impact of engineering on the hydrological monitoring ability of a hydrological station located in a tidal reach, which uses a two-dimensional hydrodynamic model to identify the engineering impact. By conducting water level comparison monitoring and flow velocity comparison monitoring on the target hydrological station at three stages before, during, and after the engineering construction, the actual impact of the engineering on the target hydrological station is continuously monitored and analyzed.

[0008] Furthermore, the basic equation of the two-dimensional hydrodynamic model adopts the Navier-Stokes equation, and four groups of typical hydrological combinations, namely flood, medium water, low water, and storm surge, are used for calculating the hydrological conditions, so as to obtain the water level and flow velocity change ranges of the target hydrological station and the waters near its representative line before and after the engineering.

[0009] Furthermore, the water level comparison monitoring is analyzed by comparing the changes in the water level characteristic values of adjacent stations; a temporary water level station is set up at the upstream of the target hydrological station where there is no engineering impact, and a pressure water level gauge is installed, and the water level comparison monitoring before, during, and after the construction is carried out between the temporary water level station and the target hydrological station.

[0010] Furthermore, both the temporary water level station and the target hydrological station are affected by tides. By using the tidal range and the tidal level difference between upstream and downstream to analyze the relative change of the tidal level difference, the water level change amplitude at the target hydrological station affected by the engineering is analyzed in different time periods to evaluate the actual impact caused by the engineering.

[0011] Furthermore, the tidal level conditions of the temporary water level station and the target hydrological station are different during the flood period and the low water period. During the two stages of the flood period and the low water period before and after the construction, the tidal level change amplitudes of high and low tides are analyzed respectively; Using the water level observation data of the temporary water level station and the target hydrological station to calculate the tidal level differences and means of high and low tides of the two stations during the flood period and the low water period before and after the construction, and comparing them with the corresponding tidal differences of the target hydrological station before the construction, the change amplitudes under various working conditions are obtained, and the engineering impact degrees are judged respectively according to the methods in SL710-2015 "Guidelines for Hydrological Measurement Methods Affected by Engineering".

[0012] Furthermore, a correlation analysis of high and low tidal levels is established: during the flood period and the low water period before, during, and after the construction, the high and low tidal levels of the temporary water level station and the target hydrological station are respectively subjected to correlation fitting to obtain the relationship formula of the tidal levels of the temporary water level station and the target hydrological station, and the tidal level changes before, during, and after the construction are analyzed.

[0013] Furthermore, the analysis of the influence of the maximum tidal level rise and fall rate: analyze the maximum tidal differences, occurrence times, durations, and tidal level rise rates before and after the construction to obtain the difference values of the maximum flood tide rate and the maximum ebb tide rate.

[0014] Furthermore, the flow velocity comparison monitoring is analyzed by whether the cross-sectional flow velocity distribution is changed by the engineering impact and by verifying whether the relationship of the representative flow velocities before and after the engineering construction changes; Before, during, and after the project construction, the representative velocity relationships of the original ADCP flow measurement system are calibrated respectively to obtain the calibrated representative velocity and the relationship between the cross-sectional average velocity (V m ~V cp ), the random uncertainty and systematic error values of the relationship calibration, and the impact degree of the project is judged by referring to the calibration accuracy of the hydraulic factor relationship in the Specification for Hydrological Data Compilation SL / T 247-2020.

[0015] Further preferably, several sets of ADCP flow measurement systems are additionally installed at the project site to monitor the representative velocity simultaneously with the original V-ADCP flow measurement system of the target hydrological station, and the relationship of the representative velocity is calibrated. Before, during, and after the project construction, the representative velocity relationships of the original ADCP flow measurement system are calibrated respectively, and the newly installed ADCP flow measurement systems are calibrated, etc.

[0016] A method for evaluating the restoration of the hydrological monitoring ability of a hydrological station affected by a project in a tidal reach. According to the method for analyzing the impact of a project on the hydrological monitoring ability of a hydrological station in a tidal reach, the actual impact of the project on the target hydrological station is analyzed, and the remedial plan is dynamically adjusted according to the impact degree to check and correct the water level and flow data of the target hydrological station.

[0017] Further, the method for evaluating the restoration of the water level monitoring ability: According to the relationship formulas of the water levels of the temporary water level station and the target hydrological station before, during, and after the construction, the water level relationship formula between the water levels of the target hydrological station without being affected and affected during and after the construction is established through the monitoring data of the temporary water level station. That is, the water level after the project construction can be corrected to the value without being affected by the project through the correction coefficient and the water level relationship formula, so as to keep the data before and after the project construction consistent and restore the water level monitoring ability; The corrected data and the water level data of the target hydrological station before the construction are used to form a series and perform a relationship line fitting with the water level data of the temporary water level station to obtain the correlation coefficients under various working conditions to evaluate the restoration of the consistency of the corrected data.

[0018] Further, the method for evaluating the restoration of the flow velocity monitoring ability: The relationship of the representative line velocity is calibrated before, during, and after the project construction. ADCP flow measurement systems are additionally installed at the project site and the relationship of the representative velocity is calibrated to restore the flow velocity monitoring accuracy; And according to the random uncertainty and systematic error values of the relationship calibration between the calibrated representative velocity and the cross-sectional average velocity (V m ~V cp ), the restoration of the hydrological monitoring ability is evaluated by referring to the calibration accuracy of the hydraulic factor relationship in the Specification for Hydrological Data Compilation SL / T 247-2020. Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0019] Based on the law of tidal movement, the present invention objectively evaluates the impact of the project on water level by calculating the variable amplitude of relative tidal level difference, and further analyzes the measured impact of the project from multiple perspectives by analyzing the upstream and downstream water level relationship curves and the changes in the tidal rise and fall rates before and after construction; analyzes the impact of the project on the calibration accuracy of the velocity relationship and even the monitoring scheme through the calibration of the representative velocity relationship.

[0020] Based on the evaluation of the measured impact, a correction formula is established to correct the water levels during and after construction for consistency. Depending on the degree of impact, a new flow measurement system is installed to remedy the velocity monitoring scheme, and the recovery of the monitoring ability of the gauging station after the remedy is evaluated.

[0021] The target hydrological station of the present invention uses a two-dimensional hydrodynamic model to identify the project impact, analyzes and evaluates the measured impact on the gauging station through continuous monitoring before and after the project implementation, and evaluates the recovery of the monitoring ability of the gauging station after the remedial measures. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for the implementation manners will be briefly introduced below. Obviously, the drawings in the following description are only some implementation manners of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0023] Figure 1 It is a comparison chart of the correlation between the high tide levels of the temporary water level stations and the target hydrological station during the flood season before, during, and after construction; Figure 2 It is a comparison chart of the correlation between the high tide levels of the temporary water level stations and the target hydrological station during the dry season before, during, and after construction; Figure 3 It is a comparison chart of the correlation between the low tide levels of the temporary water level stations and the target hydrological station during the flood season before, during, and after construction; Figure 4 It is a comparison chart of the correlation between the low tide levels of the temporary water level stations and the target hydrological station during the dry season before, during, and after construction. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions of the present application will be clearly and completely described below with reference to the drawings of the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the described embodiments belong to the scope of protection of the present application.

[0025] Unless otherwise defined, technical terms or scientific terms used in this application shall have the ordinary meanings understood by those of ordinary skill in the art to which this application pertains. The terms "first", "second" and similar terms used in this application do not denote any order, quantity or importance, but are only used to distinguish different components. Words such as "including" or "comprising" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. Words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. Words such as "upper", "lower", "left", "right" are only used to indicate relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly. Example 1

[0026] This example discloses a method for analyzing the impact of a project on the hydrological monitoring ability of a hydrological station located in a tidal reach. The two-dimensional hydrodynamic model is used to identify the project impact. By conducting water level comparison monitoring and flow velocity comparison monitoring on the target hydrological station at three stages before, during and after the project construction, and calculating the variation range of the relative tidal level difference based on the tidal movement law, the actual impact of the project on the target hydrological station is continuously monitored and analyzed.

[0027] The basic equation of the two-dimensional hydrodynamic model adopts the Navier-Stokes equation. Four sets of typical hydrological combinations, namely flood, medium water, low water and storm surge, are used for calculating hydrological conditions to obtain the water level and flow velocity variation ranges of the target hydrological station and the waters near its representative line before and after the project.

[0028] The water level comparison monitoring is analyzed by comparing the variation of water level characteristic values of adjacent stations; a temporary water level station is set up at an unaffected location upstream of the target hydrological station, and a pressure water level gauge is installed to conduct water level comparison monitoring on the temporary water level station and the target hydrological station before, during and after the construction.

[0029] Both the temporary water level station and the target hydrological station are affected by tides. By analyzing the relative variation of the tidal level difference using the tidal range and the upstream and downstream tidal level differences, the water level variation amplitude at the target hydrological station affected by the project is analyzed in different time periods to evaluate the actual impact caused by the project.

[0030] The tidal level conditions of the temporary water level station and the target hydrological station are different during the flood period and the low water period. During the two stages of the flood period and the low water period before and after the construction, the variation ranges of the high and low tide levels are analyzed respectively; Calculate the differences and means of the high and low tide levels between the temporary water level station and the target hydrological station during the flood season and the dry season before and after construction using the water level observation data of the two stations, and compare them with the corresponding tidal differences of the target hydrological station before construction to obtain the change ranges under various working conditions. Then, judge the degree of project influence respectively according to the methods in SL710-2015 "Guidelines for Hydrological Measurement Methods Affected by Projects".

[0031] Establish a correlation analysis of high and low tide levels: Fit the high and low tide levels of the temporary water level station and the target hydrological station during the flood season and the dry season before, during, and after construction respectively to obtain the relationship formula between the tide levels of the temporary water level station and the target hydrological station, and analyze the tide level changes before, during, and after construction.

[0032] Analysis of the influence of the maximum tide level rise and fall rate: Analyze the maximum rise and fall tidal differences, occurrence times, durations, and tide level rise rates before and after construction to obtain the difference values of the maximum flood tide rate and the maximum ebb tide rate.

[0033] The flow velocity comparison monitoring is analyzed by whether the cross-sectional flow velocity distribution is changed by the project and by verifying whether the relationship of the representative flow velocity before and after the project construction changes; Before, during, and after the project construction, the relationship of the representative flow velocity of the original ADCP flow measurement system is calibrated respectively to obtain the calibrated representative flow velocity and the random uncertainty and systematic error values of the relationship calibration between the cross-sectional average flow velocity (V m ~V cp ). Then, judge the degree of project influence respectively according to the calibration accuracy of the hydraulic factor relationship in SL / T247-2020 "Hydrological Data Compilation Specification". Example 2

[0034] This example discloses a method for evaluating the restoration of the hydrological monitoring ability of a hydrological station affected by a project in a tidal reach. According to the method for analyzing the influence of a project on the hydrological monitoring ability of a hydrological station in a tidal reach in Example 1, analyze the actual influence of the project on the target hydrological station, and dynamically adjust the remedial plan according to the influence degree to check and correct the water level and flow data of the target hydrological station.

[0035] Method for evaluating the restoration of water level monitoring ability: According to the relationship formula of the tide levels of the temporary water level station and the target hydrological station before, during, and after construction, establish a water level relationship formula between the water level without influence and the water level with influence during and after construction of the target hydrological station through the monitoring data of the temporary water level station. That is, the water level after the project construction can be corrected to the value without being affected by the project through the correction coefficient and the water level relationship formula, so as to keep the data before and after the project construction consistent and restore the water level monitoring ability; Use the corrected data and the water level data of the target hydrological station before construction to form a series and perform a relationship line fitting with the water level data of the temporary water level station to obtain the correlation coefficients under various working conditions to evaluate the restoration of the consistency of the corrected data.

[0036] Method for evaluating the recovery of flow velocity monitoring ability: calibrate the relationship of representative line flow velocity before, during, and after engineering construction; install several sets of ADCP flow measurement systems at the engineering site and calibrate the representative flow velocity relationship to restore the flow velocity monitoring accuracy; and evaluate the recovery of hydrological monitoring ability according to the random uncertainty and systematic error values of the calibration representative flow velocity and cross-section average flow velocity (Vm~Vcp) relationship line, in comparison with the calibration accuracy of hydraulic factor relationship lines in the "Hydrological Data Compilation Specification" SL / T247-2020. Application example

[0037] This embodiment uses a two-dimensional hydrodynamic model to identify the engineering impact, analyzes the measured impact on the gauging station through continuous monitoring and evaluation before and after the engineering implementation, and evaluates the recovery of the monitoring ability of the gauging station after the remedial measures.

[0038] 1 Situation of the target hydrological station The measurement items of the target hydrological station include water level, flow rate, saltwater intrusion, precipitation, etc., and two float-type water level gauges, two ADCPs (mounted on floating drums), a salinometer, and a tipping bucket self-recording rain gauge are used for automatic on-line monitoring respectively.

[0039] The anti-collision project is located about 600 m upstream of the water level self-recording platform of the target hydrological station.

[0040] 2 Method for analyzing the impact of the project and implementation of the remedial plan 2.1 Identification of the impact of the anti-collision project The anti-collision project is located at the confluence of river runoff and tides. The hydrodynamic conditions are jointly controlled by the upstream discharging runoff and the external sea tides and tidal currents. The impact of the project on the gauging station is analyzed by constructing a one-dimensional and two-dimensional coupled tidal current mathematical model. The one-dimensional tidal current mathematical model in the river network area adopts the one-dimensional Saint-Venant equations, and the basic equations of the two-dimensional mathematical model near the project adopt the Navier-Stokes equations. Four groups of typical hydrological combinations are used for calculating the hydrological conditions. After calculation, under the four hydrological combination conditions, the water level change range of the gauging station and the waters near its representative line before and after the project is -0.005 m to 0.017 m, the flow velocity change range is -0.045 m / s to 0.027 m / s, and the flow direction change range is -1.513° to 1.127°. The blocking cable of the anti-collision project's auxiliary facilities is only 238 m away from the nearest floating drum of the gauging station. The engineering construction operation has aggravated the interference to the water flow near the gauging station and affected the current measurement scheme.

[0041] 2.2 Method for restoring the hydrological monitoring ability of the hydrological station, that is, the remedial plan and implementation situation (1) Remedial plan To restore the water level and flow velocity monitoring functions of the target hydrological station, in accordance with the requirements of specifications such as the "Tidal Hydrological Survey Code" (SL732-2015) and the "Guidelines for Hydrological Survey Methods Affected by Projects" (SL710-2015), and in combination with the actual situation of the project, a remedial plan is proposed: ① Conduct comparative monitoring of water level and flow velocity at the target hydrological station in the three stages before, during, and after construction, analyze the actual measured impacts caused by the project, and dynamically adjust the remedial plan according to the degree of impact to verify the water level and flow data of the target hydrological station; ② After the comparative monitoring, evaluate the restoration of the monitoring function of the target hydrological station by establishing the relationship between the hydrological data before and after construction.

[0042] (2)Implementation situation ① Implementation situation of water level comparison measurement The impact on the water level observation accuracy can be analyzed by comparing the changes in the water level characteristic values of adjacent stations. Through on-site investigation, considering factors such as terrain and water flow conditions, a temporary water level station was set up 4.5 km upstream of the target hydrological station (i.e., the place not affected by the project), a pressure-type water level gauge was installed, and water level comparison observations were carried out between the temporary water level station and the target hydrological station before, during, and after construction.

[0043] ② Implementation situation of flow velocity comparison measurement The impact on the flow velocity observation can be analyzed from whether the cross-sectional flow velocity distribution is affected by the project construction and changes, and whether the relationship between the representative flow velocities before and after the project is verified. The relationship between the representative line flow velocities was calibrated before, during, and after the project construction. During the remedial process, the remedial measures (hereinafter referred to as the functional restoration remedial plan) were adjusted according to the actual impact situation. Two sets of H-ADCP flow measurement systems were newly installed at the main bridge pier in advance, and the representative flow velocities were monitored simultaneously with the original flow measurement system, and the relationship between the representative flow velocities was calibrated.

[0044] 3 Methods for analyzing the actual measured impacts of the project on the target hydrological station, methods for restoring the hydrological monitoring capabilities, and methods for evaluating the restoration situation 3.1 Analysis of actual measured impacts of the project (1)Water level impact ① Analysis of the impact of water level amplitude change The water level of the target hydrological station in the tidal reach is affected by both project construction and estuarine tides. Although the water level in the tidal reach rises and falls with the tides, the tidal rise and fall are regular. The tidal type in the area of the target hydrological station is an irregular semi-diurnal tide, that is, the tide level shows two high tides and two low tides within a lunar day. The water level difference between adjacent high tide levels and low tide levels within a cycle is called the tidal range. The size of the tidal range is affected by the combined influence of the tide-generating force, the coast, and the seabed topography. The average value of the tidal range within a certain period is called the mean tidal range.

[0045] Therefore, the change of tides is basically restricted by astronomical conditions. The average tidal range at the same location within a certain period is relatively stable under the same hydrological conditions and is not greatly affected by the project. However, the tidal level difference between different positions upstream and downstream may change significantly due to the project. Therefore, the present invention analyzes the relative change of the tidal level difference by using the tidal range and the tidal level difference between upstream and downstream, and analyzes the water level change amplitude at the measuring station affected by the project in different time periods by this method to objectively evaluate the actual impact caused by the project.

[0046] Both the temporary water level station and the target hydrological station are affected by tides, and the tidal level conditions are different during the flood period and the dry period. Therefore, the present invention analyzes the tidal range change of high and low tides in two stages before and after construction during the flood period and the dry period respectively. The water level observation data of the two stations are used to calculate the tidal level differences and means of high and low tides at the two stations before and after construction during the flood period and the dry period, and compare them with the corresponding tidal range of the target hydrological station before construction to obtain the change amplitude under various working conditions, and judge the influence degree respectively by referring to the method in the "Guidelines for Hydrological Measurement Methods Affected by Projects" (SL710-2015). The analysis and statistical results are shown in Tables 1 and 2.

[0047] Affected by the project, the average change amplitude of high tides at the measuring station during the flood period before and after construction is 4.25%, and the average change amplitude of low tides is 6.38%. The average change amplitude of high tides and low tides during the dry period is both 1.0%. The influence during the flood period is greater than that during the dry period. The average change amplitude of high and low tides in different periods is within 10%, and the overall belongs to slight influence. According to the statistics of different intervals of the change amplitude of high and low tides in different periods, about 77.3% of the high tidal levels during the flood period belong to slight influence, about 18.8% belong to medium influence, and about 3.9% belong to severe influence; about 74.7% of the low tidal levels during the flood period belong to slight influence, about 22.9% belong to medium influence, and about 2.4% belong to severe influence; about 96.5% of the high tidal levels during the dry period belong to slight influence, and about 3.5% belong to medium influence; about 90.0% of the low tidal levels during the dry period belong to slight influence, and about 0.6% belong to medium influence.

[0048] Table 1 Statistical Table of Average Tidal Range of the Target Hydrological Station during the Flood and Dry Periods before Construction

[0049] Table 2 Statistical Table of Tidal Level Differences and Change Amplitudes between the Temporary Water Level Station and the Target Hydrological Station before and after Construction

[0050] Note: Change amplitude = change value / tidal difference before construction; due to space limitations, the change amplitude is presented in the form of interval statistical results in this table.

[0051] ② Correlation Analysis of High and Low Tidal Levels Before, during, and after construction, the correlation between the high and low tide levels of the temporary water level station and the target hydrological station is relatively good, and the two show a linear relationship, as shown in Figures 1 to 4 . It can be seen from the comparison chart that the impact of the project on the correlation between the water levels of the temporary water level station and the target hydrological station during the flood period is relatively obvious. Whether it is the high tide level or the low tide level, the relationship lines during and after the construction period deviate significantly from those before construction, and the overall relationship curve shifts upward. During the dry period, the relationship curves before and after construction basically overlap, and the impact of the project on the correlation between the water levels of the temporary water level station and the target hydrological station is slight. Therefore, the impact during the flood period is greater than that during the dry period.

[0052] ③ Analysis of the influence of the maximum tidal level rise and fall rate The statistics of the maximum flood tide and ebb tide differences, occurrence times, durations, and tidal level rise rates before and after construction are shown in Table 3. According to the statistical results, affected by the project, the difference in the maximum flood tide rate before and after construction is 5.55%, and the difference in the maximum ebb tide rate is 12.82%.

[0053] Table 3 Statistical table of the maximum tidal level rise and fall rates before and after construction

[0054] (2) Influence on flow velocity Before the construction of the anti-collision project at the target hydrological station, the real-time monitoring of the flow by V-ADCP had good results, and using V-ADCP to represent the flow velocity for flow derivation could meet the accuracy requirements of relevant hydrological measurement specifications. After the construction of the anti-collision project, due to the influence of the anti-collision facilities on the water flow, the flow regime of the flow measurement section at the target hydrological station changed, and the relationship of the representative flow velocity also changed accordingly. In the remedial measures, the relationship of the representative flow velocity before, during, and after construction was calibrated in two periods respectively, and the newly installed H-ADCP flow measurement system in the functional recovery remedial plan was calibrated in one period. In the calibration of each stage, the statistical situation of the random uncertainty and systematic error when the confidence level is 95% is shown in Table 4.

[0055] According to the "Hydrological Data Compilation Specification" (SL / T 247-2020), for Class II and Class III accuracy hydrological stations, the calibration accuracy of the hydraulic factor relationship of tidal current (including tidal influence) stations should meet the requirements that the random uncertainty is within 16% and 20% respectively, and the systematic error is within ±3%.

[0056] It can be seen from the error statistics that before the construction of the anti-collision project at the target hydrological station, the representativeness of the flow velocity monitored by V-ADCP was relatively high, and the random uncertainty and systematic error of the calibrated relationship between the V-ADCP representative flow velocity and the cross-section average flow velocity (V m ~V cp ) were 13.8%, 9.8% and 1.6%, -1.2% respectively, meeting the requirements of Class II accuracy for hydrological (tidal current) stations; During the project construction period, the calibrated V m ~V cpThe random uncertainties of the relationship calibration are 16.8% and 18.6% respectively, both exceeding the accuracy requirements of Class II for hydrological (tidal current) stations, indicating that with the construction of the project, the measurement accuracy of the representative flow velocity relationship line at the target hydrological station has decreased; The two calibration periods of V m ~V cp The statistical uncertainties of the relationship calibration errors are 17.2% and 24% respectively, and the measurement accuracies exceed the flow measurement accuracies of Class II and Class III hydrological (tidal current) stations respectively. This indicates that the anti-collision project has had an obvious impact on the original representative flow velocity monitoring scheme at the target hydrological station; After the project was completed, a functional restoration and remedial plan was adopted. Two sets of H-ADCP flow measurement systems were newly installed at the main bridge piers to monitor the representative flow velocity. The calibrated V m ~V cp The random uncertainty of the relationship calibration is 14.0%, which is less than 16.0%. The measurement accuracy meets the accuracy requirements of Class II for hydrological (tidal current) stations, indicating that the adopted restoration and remedial measures are reasonable and effective, and the measurement accuracy of the relationship calibration has been improved.

[0057] Table 4 Statistical table of representative flow velocity relationship errors for each period

[0058] 3.2 Methods for restoring hydrological monitoring capabilities and evaluation methods for restoration status Method for correcting water level observation data: According to the above-mentioned measured impact analysis, due to the project impact, the consistency of the water level observation data at the target hydrological station during the construction period and after construction has been damaged to a certain extent, especially significantly affected during the flood period. Therefore, it is necessary to correct the water level observation data after construction so that the corrected water level is consistent with the historical water level observation values of this station, and thus the historical data of several decades can continue to be used, maintaining the continuity of the data.

[0059] According to the above-mentioned measured impact analysis in Section 3.1, water level characteristic values, namely high tide level and low tide level, are selected from the observation samples for analysis. The tide levels ( 、 、 )of the target hydrological station before, during, and after construction and the tide levels ( )of the temporary water level station have good correlation. Therefore, through the temporary water level station, a water level relationship formula (correction formula) can be established between the water levels ( 、 )of the target hydrological station during and after construction without being affected and the water levels ( 、 )affected by the project. That is, the water level after project construction can be corrected to the value without being affected by the project through the correction coefficient and the correction formula, so as to keep the data before and after construction consistent.

[0060] For example, for the high tide level during the flood period, the relevant relationships between the target hydrological station and the temporary water level station before, during, and after construction are as follows: Before construction = 1.0081 - 0.1277; During construction = 1.0184 - 0.0812; After construction = 1.0106 - 0.0877.

[0061] From the above equations, the water level correction coefficients of the unaffected water levels during and after construction can be deduced, and thus the water level correction relationships of the target hydrological station during and after construction can be obtained: During construction = 1.0081((( + 0.0812) / 1.0184)) - 0.1277 = 0.9899 - 0.0473; After construction = 1.0081((( + 0.0877) / 1.0106)) - 0.1277 = 0.9975 - 0.0402. Similarly, the correction formulas under other working conditions can be deduced, as shown in Table 5.

[0062] According to the "Standard for Water Level Observation" (GBT50138 - 2010), the water level station should conduct a verification and compile a station verification book at the initial stage of station establishment. In case of any changes later, the changed parts should be promptly supplemented and revised in the same year. The impact of the project construction on the water level should be described in the verification book, and the water level correction formula should be attached. The correction formula obtained through the remedial measures can be used to calculate the water level correction value of the unaffected project, so as to maintain consistency with the historical water level data. After verification, the series composed of the corrected data and the water level data of the target hydrological station before construction is used for the relationship line fitting with the water level data of the temporary water level station. The correlation coefficients under each working condition are all around 1.0, indicating that the consistency of the corrected data is restored well.

[0063] Table 5 Statistical Table for Deducing the Water Level Correction Relationships of the Target Hydrological Station Before and After Construction

[0064] Method for Evaluating the Recovery of Flow Velocity Monitoring Ability: The construction of the project has damaged the existing representative flow velocity relationship and affected the measurement of the flow velocity. The remedial measures use the moving - ship ADCP with less impact from the project for flow measurement and then re - calibrate the representative flow velocity relationship, enabling the establishment of a stable relationship.

[0065] According to the basic hydrological station accuracy class division method in the "River Flow Measurement Specification" (GB50179-2015), the target hydrological station belongs to the second-class accuracy station; according to Article A.0.3 of this specification, "When a hydrological measurement station is difficult to meet the original accuracy requirements due to the limitations of the station control and measurement conditions, the accuracy class can be reduced by one level, but it should not be lower than the third class accuracy."

[0066] According to the alignment results in Table 4: Before construction, the alignment results of the two periods met the flow measurement accuracy specification requirements for the second-class hydrological (tidal) stations; during the construction period, due to the influence of the project construction, the measurement accuracy exceeded the second class but was within the specification requirements of the third-class hydrological (tidal) stations. Therefore, after reducing the accuracy class of the hydrological station, the accuracy of the representative velocity relationship calibrated during the construction period still met the requirements of the relevant measurement specifications and could be used for flow measurement during the construction period; The alignment results of the two periods after construction showed that the measurement accuracy exceeded the flow measurement accuracy of the second-class and third-class hydrological (tidal) stations respectively, and did not meet the measurement requirements according to the requirements of the GB50179-2015 specification, and other remedial measures needed to be taken.

[0067] The remedial measure of the present invention is to newly install the H-ADCP flow measurement system earlier to avoid data interruption due to the non-meeting requirements of the later calibration relationship. The representative velocity relationship was calibrated synchronously with the original representative section, and the measurement accuracy was within the specification requirements of the second-class hydrological (tidal) stations. Therefore, this scheme was used as a functional restoration remedial measure to replace the original representative section measurement scheme.

[0068] In summary, after taking the remedial measures, the velocity monitoring ability of the target hydrological station was restored, and the calibrated representative velocity relationship could be used for flow measurement affected by the project.

[0069] Obviously, the above embodiments of the present invention are only examples for clearly explaining the present invention, and are not limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for analyzing the impact of engineering on the hydrological monitoring capability of a hydrological station located in a tidal river section, characterized in that: The two-dimensional hydrodynamic model is used to identify the impact of the project. By conducting water level comparative monitoring and flow velocity comparative monitoring of the target hydrological station before, during and after the construction of the project, the measured impact of the project on the target hydrological station is continuously monitored and analyzed.

2. The method for analyzing the impact of engineering on the hydrological monitoring capability of a hydrological station located in a tidal river section according to claim 1, characterized in that: The basic equation of the two-dimensional hydrodynamic model adopts the Navier-Stokes equation, and the hydrological conditions are calculated using four typical hydrological combinations of flood, moderate water, low water and storm surge to obtain the range of changes in water level and flow velocity in the waters near the target hydrological station and its representative line before and after the project.

3. The method for analyzing the impact of engineering on the hydrological monitoring capability of a hydrological station located in a tidal river section according to claim 1, characterized in that: The water level comparison monitoring is analyzed by comparing the changes in water level characteristic values ​​of adjacent stations; a temporary water level station is set up at a location upstream of the target hydrological station that is not affected by the project, and a pressure water level gauge is installed to conduct water level comparison monitoring between the temporary water level station and the target hydrological station before, during and after construction.

4. The method for analyzing the impact of engineering on the hydrological monitoring capability of a hydrological station located in a tidal river section according to claim 3 is characterized in that: Both the temporary water level station and the target hydrological station are affected by tides. By using the tidal range and the upstream and downstream tidal level difference to analyze the relative change of the tidal level difference, the water level change amplitude at the target hydrological station affected by the project is analyzed in different time periods to evaluate the actual impact of the project.

5. The method for analyzing the impact of engineering on the hydrological monitoring capability of a hydrological station located in a tidal river section according to claim 4, characterized in that: The tidal conditions of the temporary water level station and the target hydrological station are different during the flood and dry seasons. The high and low tide level fluctuations are analyzed in the flood and dry seasons before and after the construction. The water level observation data of the temporary water level station and the target hydrological station are used to calculate the difference and mean of high and low tide levels of the two stations during the flood and dry seasons before and after construction, and compared with the corresponding tidal range of the target hydrological station before construction to obtain the range of changes under various working conditions, and the degree of impact of the project is judged by comparing with the methods in SL710-2015 "Guidelines for Hydrological Survey Methods Affected by Engineering Projects".

6. The method for analyzing the impact of engineering on the hydrological monitoring capability of a hydrological station located in a tidal river section according to claim 5, characterized in that: Establish correlation analysis of high and low tides: perform correlation fitting on the high and low tides of the temporary water level station and the target hydrological station during the flood and dry seasons before, during and after construction, obtain the relationship between the tidal levels of the temporary water level station and the target hydrological station, and analyze the changes in tidal levels before, during and after construction.

7. The method for analyzing the impact of engineering on the hydrological monitoring capability of a hydrological station located in a tidal river section according to claim 6, characterized in that: Analysis of the impact of maximum tidal rise and fall rate: Analyze the maximum tidal range, occurrence time, duration and tidal rise rate before and after construction to obtain the difference in maximum tidal rate and maximum tidal rate.

8. The method for analyzing the impact of engineering on the hydrological monitoring capability of a hydrological station located in a tidal river section according to claim 7, characterized in that: The velocity comparison monitoring is performed by analyzing whether the velocity distribution of the cross section is changed by the project and verifying whether the representative velocity relationship before and after the project construction changes; The representative line velocity relationship is calibrated before, during and after the construction of the project to obtain the random uncertainty and systematic error value of the line determination between the calibrated representative flow velocity and the average flow velocity of the section. The degree of impact of the project is judged by comparing the accuracy of the line determination of the hydraulic factor relationship in SL / T247-2020 "Specifications for the Compilation of Hydrological Data".

9. A method for assessing the recovery of hydrological monitoring capacity of a hydrological station located in a tidal river section affected by a project, characterized in that: According to the method for analyzing the impact of engineering on the hydrological monitoring capacity of a hydrological station located in a tidal river section as described in claim 8, the measured impact of the engineering on the target hydrological station is analyzed, and the remedial plan is dynamically adjusted according to the degree of impact to verify and correct the water level and flow data of the target hydrological station.

10. The method for restoring and evaluating the hydrological monitoring capability of a hydrological station located in a tidal river section affected by a project according to claim 9, characterized in that: Water level monitoring capacity restoration assessment method: According to the relationship between the temporary water level station and the tidal level of the target hydrological station before, during and after construction, The water level relationship between the unaffected water level and the affected water level of the target hydrological station during and after construction is established through the monitoring data of the temporary water level station. That is, the water level after the project construction can be corrected to the value when it is not affected by the project through the correction coefficient and the water level relationship, so that the data before and after the project construction can be kept consistent and the water level monitoring capability can be restored. The corrected data and the water level data of the target hydrological station before construction are used to form a series and fit the relationship line with the water level data of the temporary water level station to obtain the correlation coefficient under each working condition to evaluate the consistency recovery of the corrected data. Flow rate monitoring capability recovery assessment method: The representative line velocity relationship calibration will be carried out before, during and after the construction of the project. The ADCP flow measurement system will be installed at the project site, and the representative flow velocity relationship calibration will be carried out to restore the flow velocity monitoring accuracy. The random uncertainty and systematic error value of the line determination based on the calibrated representative flow velocity and the average flow velocity of the section will be compared with the line determination accuracy of the hydraulic factor relationship in SL / T247-2020 "Specifications for Hydrological Data Compilation" to evaluate the recovery of the hydrological monitoring capacity.

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