Automatic calculation method for flood level of tidal river reach based on tidal-flood separation and real-time calibration

Abstract

The invention relates to a tidal river reach flood level automatic calculation method based on tidal-flood separation and real-time calibration, and solves the problems that the current tidal river reach water level forecast and quality control precision is limited, and the practicability is insufficient. According to the method, the flood level of a tidal river section is separated into a tidal control water level and a flood control water level, calculation models are established for effective propagation coefficients of a tidal control low tide level, a tidal control rising tide range, the flood control water level and a flood period tidal range by utilizing historical hydrological data, and erosion and deposition sensitive factors are calibrated in real time according to recent hydrological data. And obtaining measured values or predicted values of the daily average flow of the research section and the flood tide range of the lower boundary, and calculating the flood period low tide level, the flood period flood tide range and the flood period high tide level. The method is simple and practical, needed data are easy to obtain, model construction, real-time calibration and automatic calculation can be completed only through conventional hydrological data such as the tide level and the flow, and the accuracy and the automation level of flood level forecasting and quality control of the frequent erosion and deposition tidal river reach can be improved.

Description

Technical Field

[0001] The invention belongs to the field of hydrology, relates to a river section water level measurement method, and in particular to a tidal river section flood level automatic calculation method based on tide-flood separation and real-time calibration. Background Art

[0002] Reliable hydrological data is the foundation of digital twin water conservancy and a key support for preventing and resolving flood and drought risks. Floods in tidal river sections are influenced by both upstream runoff and downstream tides. When floods and tides overlap, water levels rise dramatically, easily triggering flood disasters. Therefore, flood level forecasting and water level data quality control for tidal river sections are crucial. However, tidal river sections often experience variable erosion and siltation, with steep rises and falls in water levels and unpredictable flow directions, making water level forecasting difficult. Conventional quality control methods, such as setting upper and lower limits for water level fluctuations, maximum rate of rise, establishing a water level-flow relationship, and correlating upstream and downstream water levels, make it difficult to achieve refined quality control of water levels in tidal river sections.

[0003] One effective approach to forecasting and quality control water levels in tidal river sections is to construct a water level calculation model for these sections and perform forecasts or quality control based on the calculated water level values. Domestic experts and scholars have actively explored and technically verified the feasibility of the flood-tide separation theory. However, tidal river sections often experience frequent erosion and sedimentation, and riverbed changes can be significant daily during flood season. The frequency of underwater topography surveys makes it difficult to accurately reflect these changes, limiting the accuracy of the model and reducing its practicality.

[0004] Comprehensive analysis shows that existing technologies for calculating flood levels in tidal river sections all require underwater topography monitoring data or stable riverbed conditions, which limits their use in river sections with frequent scouring and silting. There is no method for automatically calculating flood levels in tidal river sections based on tidal-flood separation and real-time calibration that does not require underwater topography monitoring data and is suitable for river sections with frequent scouring and silting. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems of limited accuracy and insufficient practicality of current water level forecasting and quality control in tidal river sections, and to provide a method for automatic calculation of flood levels in tidal river sections based on tide-flood separation and real-time calibration; to solve the problem that the water level calculation model in tidal river sections with frequent scouring and siltation is often affected by the difficulty in obtaining the required data, and to improve the practicality and calculation accuracy of flood level calculation in tidal river sections.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a method for automatically calculating the flood level of a tidal river section based on tide-flood separation and real-time calibration, comprising the following steps:

[0007] S1, Tide-flood separation, which separates the flood level in the tidal river section into tide-controlled water level and flood-controlled water level;

[0008] S2. Construct a tide-controlled low-tide operator model based on historical hydrological data;

[0009] S3. Based on historical hydrological data, construct a tide control and tidal range operator model;

[0010] S4. Construct a flood control water level operator model based on historical hydrological data;

[0011] S5. Based on historical hydrological data, construct an empirical model of the effective coefficient of tidal range propagation during flood season;

[0012] S6. Determine the scour and sedimentation sensitivity factor in real time based on recent hydrological data;

[0013] S7. Obtain the measured value or predicted value of the model input, and calculate the low tide level during the flood period, the tidal range during the flood period, and the high tide level during the flood period.

[0014] The measured or predicted values ​​of the average daily flow and the tidal range of the lower boundary of the research section are obtained as the input conditions of the automatic calculation model; when the measured values ​​are used as the input conditions, the calculation is mainly based on the past or current water level data for data quality control; when the predicted values ​​are used as the input conditions, the calculation is mainly based on the future water level data for water level forecasting.

[0015] As a preferred method, in S1, a research section is selected in the tidal river section, and the low tide level ZL of the research section is separated into the tide-controlled low tide level ZL′ and the flood-controlled water level ZF, that is:

[0016] ZL=ZL′+ZF

[0017] The high tide level ZH of the study section is separated into the tide-controlled low tide level ZL′, the high tide tidal range ΔZ, and the flood-controlled water level ZF. The high tide tidal range ΔZ is equal to the tide-controlled high tide tidal range ΔZ′ multiplied by the effective coefficient of tidal range propagation α during the flood period, that is:

[0018] ZH=ZL′+ΔZ′×α+ZF.

[0019] As a preferred option, in S2, the tidal level of the coastal section of the downstream estuary is not affected by the upstream runoff and can truly reflect the tidal level changes, which serves as the lower boundary condition for separating the tidal-controlled water level; the tidal range ΔZB of the upper half of the lower boundary is set as i-1 As a separation tide control low tide level ZL′ i Boundary conditions; calibrate the tide-controlled low tide level ZL′ of the research section i The tidal difference ΔZB from the upper half of the lower boundary i-1 The correlation model proposes a comprehensive line and two outer lines. The comprehensive line reflects the overall law of the correlation between the two, and the outer lines reflect the maximum deviation under the influence of erosion and deposition changes in the river channel.

[0020] As a preferred method, in S2, based on historical hydrological data, the low tide level ZL of the research section under different runoff conditions is analyzed. i The tidal difference ΔZB from the upper half of the lower boundary i-1 As the upstream runoff gradually increases, the correlation will gradually decrease. A correlation threshold is set. When the correlation drops to the threshold, the runoff of this magnitude is determined as the maximum allowable runoff for tide control low tide level calculation. When the upstream runoff is less than the maximum allowable runoff, the low tide level ZL of the research section is calibrated. i The tidal difference ΔZB from the upper half of the lower boundary i-1 Correlation model, ignoring the flood control water level, studying the low tide level ZL of the section i Tide-controlled low tide level ZL′ i .

[0021] As a preference, in S3, the high tide difference ΔZB of the same half tide at the lower boundary is i As a separation of the tide-controlled high and low tide range ΔZ′ i Boundary conditions; calibration of the tidal range ΔZ′ of the tidal-controlled high tide in the research section i The tidal range ΔZB at the same half tide as the lower boundary i Correlation model; due to the influence of changes in river scouring and silting, a long time span will lead to a decrease in correlation, while a short time span will result in insufficient sample data and will also lead to a decrease in correlation. The optimal time span varies depending on the frequency of river scouring and silting. The time span with the best correlation is selected as the optimal time span for tide control high tide and tidal range calculation; the hydrological data of the optimal time span are selected for parameter calibration in sections.

[0022] As a preferred method, in S3, based on historical hydrological data, the tidal range ΔZ of the research section under different runoff conditions is analyzed. i The tidal range ΔZB at the same half tide as the lower boundary i As the upstream runoff gradually increases, the correlation will gradually decrease. A correlation threshold is set. When the correlation drops to the threshold, the runoff of this magnitude is determined as the maximum allowable runoff for tide control tidal range calculation. When the upstream runoff is less than the maximum allowable runoff, the tidal range ΔZ of the research section is determined. i is the tidal range ΔZ′ controlled by the tide i .

[0023] As a preferred method, in S4, the tide-controlled low-tide operator model is used to calculate the high tide difference ΔZB of the half tide on the lower boundary. i-1 As input, select the comprehensive line and calculate the tide-controlled low tide level ZL′ of the half tide of the research section. i , the low tide level ZL of the half tide of the research section i Subtract the tide-controlled low tide ZL′ i , is the flood control water level ZF corresponding to the semi-tidal low tide level of the research section i,Right now:

[0024] ZF i =ZL i -ZL′ i

[0025] The average daily flow rate Q of the research section D As the boundary condition for flood control water level routing, the average daily flow Q of the study section is established. D and daily average flood control water level D Correlation model; calibration of the average daily flow rate Q of the research section D and daily average flood control water level D A correlation model is proposed, and a comprehensive line and two outer lines are drawn up. The comprehensive line reflects the overall law of the correlation between the two, and the outer lines reflect the maximum deviation affected by the changes in river channel scouring and deposition.

[0026] As a preferred method, in S4, the average daily flow Q is analyzed based on historical hydrological data. D and daily average flood control water level D When the average daily flow is small, the water level of the study section is mainly the tide-controlled water level, which has a poor correlation with the average daily flow. A correlation threshold is set. When the average daily flow is greater than a certain level, the correlation is greater than the threshold. The average daily flow of this level is determined as the minimum runoff determined by the flood control water level.

[0027] As a preferred method, in S5, the calibrated tide control tide range operator model is used to calculate the tide range ΔZB at the same half tide of the following boundary. i As input, calculate the tidal range ΔZ′ of the half tide at the study section. i ; The measured high tide range ΔZ at the half tide of the study section i Divide by the tidal range ΔZ′ i , is the effective coefficient α of the tidal range of the study section i ,Right now:

[0028]

[0029] The average daily flow rate Q of the research section D As the influencing factor of the effective coefficient of tidal range propagation during flood period, the average daily flow rate Q of the research section is calibrated. D Correlation model with the effective coefficient α of tidal range propagation during flood period;

[0030] Rating Q D When the correlation model with α is used, the correlation between the average daily flow and the effective coefficient of tidal range propagation during the flood period is analyzed, and a correlation threshold is set. When the average daily flow is greater than a certain level, the correlation is greater than the threshold, and the average daily flow of this level is determined as the minimum runoff for tidal range attenuation during the flood period.

[0031] As a preferred method, in S6, a time span of N days is selected, with the calibration day minus N days as the start time and the calibration day as the end time. The hydrological data when the upstream runoff is less than the maximum allowable runoff within the time span are selected to form a real-time calibration sample set, and the tidal range ΔZ′ of the study section is automatically calibrated in real time. i The tidal range ΔZB at the same half tide as the lower boundary i Correlation model;

[0032] The comprehensive line and outer line of the tide-controlled low-tide level operator model are used to deduce the tide-controlled low-tide level of the study section, and the average deviation between the derived tide-controlled low-tide level and the measured low-tide level is calculated. The comprehensive line of the tide-controlled low-tide level operator model is offset in real time.

[0033] The comprehensive line and outer line of the flood control water level operator sub-model are used to deduce the daily average flood control water level of the research section, and the average deviation between the derived daily average flood control water level and the measured daily average flood control water level is calculated, and the comprehensive line of the flood control water level operator sub-model is offset in real time.

[0034] Based on flood-tide separation, the present invention separates the complex flood levels in tidal river sections into flood-controlled water levels influenced by upstream runoff and tide-controlled water levels influenced by downstream tidal levels. A data-driven model is established based on a long series of historical hydrological data. The scouring and silting sensitivity factor is calibrated in real time based on recent hydrological data. The flood levels in tidal river sections are automatically calculated based on upstream runoff and downstream tidal levels, enabling automatic forecasting of future flood levels and refined quality control of current flood levels in tidal river sections. This method is simple and practical, and the required data is easily accessible. Only conventional hydrological data such as tidal level and flow rate are required to complete model construction, real-time calibration, and automatic calculation. This method is beneficial for improving the accuracy and automation of flood level forecasting and quality control in tidal river sections with frequent scouring and silting. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention will be further described below with reference to the accompanying drawings.

[0036] Figure 1 It is a schematic diagram of a calculation step of the present invention.

[0037] Figure 2 This is a schematic diagram of the model calibration process of S1-6 in Example 1 of the present invention.

[0038] Figure 3 This is a schematic diagram of the automatic calculation process of the model of S7-10 in Example 1 of the present invention.

[0039] Figure 4 is the comprehensive rating ZL′ in Example 1 of the present invention i and ΔZB i-1 Plot of the correlation model.

[0040] Figure 5is the monthly calibrated ΔZ′ in Example 1 of the present invention i and ΔZB i Plot of the correlation model.

[0041] Figure 6 The comprehensive rating Q in Example 1 of the present invention is D with ZF D A graph of the correlation model.

[0042] Figure 7 The Q is determined in Example 1 of the present invention. D Plot of the correlation model with α.

[0043] Figure 8 The real-time automatic calibration ΔZ′ in Example 1 of the present invention i and ΔZB i Plot of the correlation model.

[0044] Figure 9 The points in ZL' in the last 30 days in Example 1 of the present invention are i and ΔZB i-1 Distribution plot on the correlation model.

[0045] Figure 10 The data in the last 30 days in Example 1 of the present invention is D with ZF D Distribution plot on the correlation model. DETAILED DESCRIPTION

[0046] The present invention will be further described below through specific embodiments in conjunction with the accompanying drawings.

[0047] Example 1: A method for automatically calculating flood levels in tidal river sections based on tide-flood separation and real-time calibration, the main steps are as follows: Figure 1 This method is divided into three parts: model construction, real-time calibration and water level calculation. S1 to S6 are the model construction and real-time calibration process, as shown in Figure 2 As shown; S7 ~ S10 water level calculation process, such as Figure 3 The details are as follows.

[0048] S1. Tide-flood separation: the flood level in the tidal river section is separated into tide-controlled water level and flood-controlled water level.

[0049] S1.1. The tide-controlled water level is a virtual water level formed in the study section assuming that it is not affected by upstream runoff. The flood-controlled water level is a virtual water level formed in the study section assuming that it is not affected by downstream tidal propagation. The characteristic values ​​of the tide-controlled water level include the tide-controlled low tide level, the tide-controlled high tide level, and the tide-controlled high tide range.

[0050] S1.2. Separate the low tide level ZL of the study section into the tide-controlled low tide level ZL′ and the flood-controlled water level ZF, that is:

[0051] ZL=ZL′+ZF

[0052] S1.3. Separate the high tide level ZH of the study section into the tide-controlled low tide level ZL′, the high tide tidal range ΔZ, and the flood-controlled water level ZF. The high tide tidal range ΔZ is equal to the tide-controlled high tide tidal range ΔZ′ multiplied by the effective coefficient of tidal range propagation α during the flood period, that is:

[0053] ZH=ZL′+ΔZ′×α+ZF

[0054] S2. Based on historical hydrological data, a tide-controlled low-tide operator model is constructed.

[0055] S2.1. Determine the boundary conditions for calculating the tide-controlled low tide level. The tide level of the coastal section of the downstream estuary is not affected by the upstream runoff and can truly reflect the changes in the tide level. This serves as the lower boundary condition for separating the tide-controlled water level. Specifically, the tide-controlled low tide level ZL′ of the study section i Mainly affected by the upper half tide, the tidal difference ΔZB between the upper half tide and the lower boundary i-1 The correlation is better, and the high tide difference ΔZB of the upper half of the lower boundary is i-1 As a separation tide control low tide level ZL′ i boundary conditions.

[0056] S2.2, determine the maximum allowable runoff for tide-controlled low-tide calculation. Based on historical hydrological data, analyze the low-tide level ZL of the study section under different runoff conditions. i The tidal difference ΔZB from the upper half of the lower boundary i-1 As the upstream runoff gradually increases, the correlation will gradually decrease. A correlation threshold is set. When the upstream runoff is greater than a certain level, the correlation drops to the threshold. The runoff of this level is determined as the maximum allowable runoff for tide control low tide level calculation. When the upstream runoff is less than the maximum allowable runoff, the flood control water level is close to zero. The low tide level ZL of the research section i Tide-controlled low tide level ZL′ i .

[0057] S2.3. Comprehensive calibration of tide-controlled low-tide operator model. Select historical hydrological data when upstream runoff is less than the maximum allowable runoff to calibrate the low-tide level ZL of the study section. i The tidal difference ΔZB from the upper half of the lower boundary i-1 Correlation model, namely, tide-controlled low tide level ZL′ i The tidal difference ΔZB from the upper half of the lower boundary i-1The correlation model proposes a comprehensive line and two outer lines. The comprehensive line reflects the overall law of the correlation between the two, and the outer lines reflect the maximum deviation affected by the changes in river channel erosion and deposition.

[0058] In this example, the Zhijiang Hydrological Station at the Qiantang River estuary was used as the study section. Located downstream from the confluence of the Fuchun and Puyang Rivers, Zhijiang Station controls 75% of the Qiantang River basin and serves as a key flow control station. Furthermore, the station is located in a high-tidal section of the Qiantang River estuary, approximately 130 km from the sea. As the only tidal flow monitoring station on the Qiantang River, its water level is influenced by a combination of upstream runoff and downstream strong tides. The Zhapu Tide Station, located downstream along the coastal section of the estuary, is located just outside the Qiantang River's vent. Its tidal range is largely unaffected by upstream runoff, serving as the lower boundary condition for separating the tidal-controlled water level at Zhijiang Station. The average daily discharge at Zhijiang Station reflects the magnitude of upstream runoff.

[0059] According to the hydrological data from 2015 to 2019, the low tide level ZL of Zhijiang Station under different runoff conditions was analyzed. i The tidal difference ΔZB from the upper half of the tide at Zhapu station i-1 The correlation is that the average daily flow at Zhijiang Station is greater than 200m 3 / s, the correlation is significantly reduced, and the 200m 3 / s is determined as the tide-controlled low tide level ZL′ i The maximum daily average flow calculated. The daily average flow of Zhijiang Station is less than 200m 3 / s hydrological data, comprehensive calibration ZL′ i and ΔZB i-1 Correlation model, propose one integrated line and two outsourced lines respectively, such as Figure 4 shown.

[0060] Comprehensive line: ZL′ i =-0.054×ΔZB i-1 2 +1.0841×ΔZB i-1 -0.7896

[0061] Upper envelope: ZL′ i =0.0398×ΔZB i-1 3 -0.7961×ΔZB i-1 2 +5.419×ΔZB i-1 -8.1662

[0062] Lower envelope: ZL′ i =0.0769×ΔZB i-1 2 -0.3341×ΔZB i-1 +2.4483

[0063] The correlation coefficient R of the comprehensive line is 0.86, indicating that there is a certain offset in the correlation relationship under different conditions of river channel erosion and deposition, and the maximum offset is determined by the upper and lower envelope lines.

[0064] S3. Based on historical hydrological data, a tide control and tidal range operator model is constructed.

[0065] S3.1. Determine the boundary conditions for the calculation of the tide-controlled tidal range. The tidal level of the coastal section of the downstream estuary is not affected by the upstream runoff and serves as the lower boundary condition for separating the tide-controlled water level. Specifically, the tide-controlled tidal range ΔZ′ of the section is studied. i Mainly affected by the magnitude of the tidal force of the half tide, the tidal difference ΔZB with the same half tide at the lower boundary i The correlation is better, and the high tide difference ΔZB of the same half tide at the lower boundary is i As a separation of the tide-controlled high and low tide range ΔZ′ i boundary conditions.

[0066] S3.2. Determine the maximum allowable runoff for the tidal range calculation. Based on historical hydrological data, analyze the tidal range ΔZ′ of the study section under different runoff conditions. i The tidal range ΔZB at the same half tide as the lower boundary i As the upstream runoff gradually increases, the correlation will gradually decrease. A correlation threshold is set. When the upstream runoff is greater than a certain level, when the correlation drops to the threshold, the runoff of this level is determined as the maximum allowable runoff for tide control tidal range calculation. When the upstream runoff is less than the maximum allowable runoff, the tide range ΔZ of the research section is determined. i is the tidal range ΔZ′ controlled by the tide i .

[0067] S3.3. Determine the optimal time span for calculating the tidal range of tide control. Select historical hydrological data when the upstream runoff is less than the maximum allowable runoff, and analyze the tidal range of tide control ΔZ′ at the study section with different time spans. i The tidal range ΔZB at the same half tide as the lower boundary i Due to the influence of changes in river scouring and silting, a long time span will lead to a decrease in correlation, while a short time span will result in insufficient sample data, which will also lead to a decrease in correlation. The optimal time span varies with the frequency of river scouring and silting. The time span with the best correlation is selected as the optimal time span for tide control high tide range calculation.

[0068] S3.4, Segment-wise calibration of the tide control tidal range operator model. Select historical hydrological data when the upstream runoff is less than the maximum allowable runoff, and calibrate the tidal range ΔZ of the study section. i The tidal range ΔZB at the same half tide as the lower boundary iCorrelation model, namely, the tide-controlled tidal range ΔZ′ i The tidal range ΔZB at the same half tide as the lower boundary i Correlation model, the hydrological data with the best time span are selected for parameter calibration.

[0069] In this example, based on the hydrological data from 2015 to 2019, the tidal range ΔZ at Zhijiang Station under different runoff conditions is analyzed. i The tidal range ΔZB at the same half tide as that at Zhapu Station i The correlation is that the average daily flow at Zhijiang Station is greater than 2000m 3 / s, the correlation is significantly reduced, and the 2000m 3 / s is determined as the tidal range ΔZ′ i The maximum daily average flow calculated. The daily average flow of Zhijiang Station is less than 2000m 3 The hydrological data at 1000 s were used to analyze the correlation between the tidal range at Zhijiang Station and the tidal range at Zhapu Station at the same half tide in different time spans, and the tidal range ΔZ′ was determined to be the tidal range controlled by the tide. i The best time span for calculation is one month. ΔZ′ is determined monthly. i and ΔZB i The correlation model was calibrated monthly in 2017, and the correlation coefficient R was 0.82 to 0.99. Figure 5 shown.

[0070] S4. Construct a flood control water level operator model based on historical hydrological data.

[0071] S4.1. Calculate the flood control water level. Use the tide control low tide level operator model to calculate the high tide difference ΔZB at the half tide on the lower boundary. i-1 As input, select the comprehensive line and calculate the tide-controlled low tide level ZL′ of the half tide of the research section. i , the low tide level ZL of the half tide of the research section i Subtract the tide-controlled low tide ZL′ i , is the flood control water level ZF corresponding to the semi-tidal low tide level of the research section i ,Right now:

[0072] ZF i =ZL i -ZL′ i

[0073] S4.2. Determine the boundary conditions for flood control water level calculation. The flood control water level is mainly affected by upstream runoff, and upstream runoff is used as the boundary condition for flood control water level calculation. Specifically, the average daily flow of the study section can reflect the changes in upstream runoff. The average daily flow of the study section Q D As the boundary condition for flood control water level routing, the average daily flow Q of the study section is established.D and daily average flood control water level D The correlation model.

[0074] S4.3. Determine the minimum runoff for flood control water level. Analyze the average daily flow Q based on historical hydrological data. D and daily average flood control water level D When the average daily flow is small, the water level of the study section is mainly the tide-controlled water level, which has a poor correlation with the average daily flow. A correlation threshold is set. When the average daily flow is greater than a certain level, the correlation exceeds the threshold, and the average daily flow of this level is determined as the minimum runoff determined by the flood control water level.

[0075] S4.4. Comprehensive calibration of flood control water level operator model. Select historical hydrological data when the average daily flow is greater than the minimum runoff, and calibrate the average daily flow Q of the study section. D and daily average flood control water level D A correlation model is proposed, and a comprehensive line and two outer lines are drawn up. The comprehensive line reflects the overall law of the correlation between the two, and the outer lines reflect the maximum deviation affected by the changes in river channel scouring and deposition.

[0076] In this example, the calibrated ZL′ is used. i and ΔZB i-1 Correlation model, based on the tidal range ΔZB of the upper half of the tide at Zhapu station i-1 As input, select the comprehensive line and calculate the tide-controlled low tide level ZL′ of each half tide at Zhijiang Station from 2015 to 2019 i , that is: ZL′ i =-0.054×ΔZB i-1 2 +1.0841×ΔZB i-1 -0.7896, the measured low tide level ZL at each half tide at Zhijiang Station i Subtract the tide-controlled low tide ZL′ i , get the flood control water level ZF corresponding to each half-tide low tide level of Zhijiang Station i According to the hydrological data from 2015 to 2019, the average daily flow Q of Zhijiang Station was analyzed. D and daily average flood control water level D The correlation is that the average daily flow at Zhijiang Station is greater than 2000m 3 / s, the correlation shows an upward trend, and 2000m 3 / s is determined as the minimum daily average flow rate for flood control water level. The daily average flow rate of Zhijiang Station is greater than 2000m 3 / s hydrological data, comprehensive rate q D with ZF D The correlation model of , proposes one integrated line and two outsourced lines, such as Figure 6 shown.

[0077] Comprehensive line: ZF D =-0.0075×q D 2 +0.3122×Q D

[0078] Upper envelope: ZF D =-0.0075×Q D 2 +0.3122×Q D +0.7056

[0079] Lower envelope: ZF D =-0.0075×Q D 2 +0.3122×Q D -0.5944

[0080] Where Q D The unit is 10 3 m 3 The correlation coefficient R of the integrated line is 0.74, indicating that there is a certain offset in the correlation relationship under different river channel erosion and deposition conditions, and the maximum offset is determined by the upper and lower envelope lines.

[0081] S5. Based on historical hydrological data, construct an empirical model of the effective coefficient of tidal range propagation during flood season.

[0082] S5.1. Calculate the effective coefficient of propagation of the high tide range. Use the calibrated tide control high tide range operator model to calculate the high tide range ΔZB at the same half tide of the following boundary. i As input, calculate the tidal range ΔZ′ of the half tide at the study section. i The measured high tide range ΔZ at the half tide of the study section i Divide by the tidal range ΔZ′ i , is the effective coefficient α of the tidal range of the study section i ,Right now:

[0083]

[0084] S5.2. Determine the factors affecting the effective coefficient of tidal range propagation during flood season. The effective coefficient of tidal range propagation during flood season is mainly affected by upstream runoff. Specifically, the average daily flow of the study section can reflect the changes in upstream runoff. The average daily flow of the study section Q D As the influencing factor of the effective coefficient of tidal range propagation during flood period, the daily average flow rate Q of the research section is established. D Correlation model with the effective coefficient α of tidal range propagation during flood period.

[0085] S5.2.1. Determine the minimum runoff for tidal range attenuation during flood season. Based on historical hydrological data, analyze the correlation between the average daily flow and the effective coefficient of tidal range propagation during flood season. Set a correlation threshold. When the average daily flow exceeds a certain level, the correlation is greater than the threshold. The average daily flow of this level is determined as the minimum runoff for tidal range attenuation during flood season.

[0086] S5.2.2. Comprehensively calibrate the empirical model for the effective coefficient of tidal range propagation during flood season. Select historical hydrological data when the average daily flow is greater than the minimum runoff, and calibrate the average daily flow Q of the study section. D Correlation model with the effective coefficient α of tidal range propagation during flood period.

[0087] In this example, based on the hydrological data from 2015 to 2019, the ΔZ′ calibrated monthly is used. i and ΔZB i Correlation model, based on the tidal range ΔZB at the same half tide of Zhapu station i As input, calculate the tidal range ΔZ′ of the half tide at Zhijiang Station. i The measured high tide range ΔZ at the half tide at Zhijiang Station i Divide by the tidal range ΔZ′ i , is the effective coefficient α of the propagation of the tidal range of this high tide i ,Right now The average daily flow at Dangzhijiang Station is greater than 6000m 3 / s, the correlation is better, and 6000m 3 / s is determined as the minimum daily average flow for tidal range attenuation during flood season. The daily average flow of Zhijiang Station is greater than 6000m 3 / s hydrological data, calibrate Q D The correlation model with α, such as Figure 7 shown.

[0088] α=0.0079×Q D 2 -0.2346×Q D +2.3569

[0089] Where Q D The unit is 10 3 m 3 / s.

[0090] S6. Based on recent hydrological data, scour and sedimentation sensitivity factors are determined in real time.

[0091] S6.1. Perform real-time calibration on the tide-controlled high tide and tidal range operator model. Select the recent hydrological data with the best time span for real-time calibration. When the best time span is N days, the calibration date minus N days is used as the start time, and the calibration date is used as the end time. Select the hydrological data within this time span when the upstream runoff is less than the maximum allowable runoff to form a real-time calibration sample set, and automatically calibrate the tide-controlled high tide and tidal range ΔZ′ of the study section in real time. i The tidal range ΔZB at the same half tide as the lower boundary i Correlation model.

[0092] S6.2. Real-time offset of the integrated line of the tide-controlled low-tide level operator sub-model. Select the recent hydrological data when the upstream runoff is less than the maximum allowable runoff, and the tidal range ΔZB of the upper half of the lower boundary i-1 As the model input, the comprehensive line of the tide-controlled low tide level operator model is used to deduce the tide-controlled low tide level ZL′ of the research section. 综 , calculate the comprehensive line to deduce the tide-controlled low tide level ZL′ 综 Average deviation from the measured low tide level ZL If E 综 <0, the upper envelope of the tide-controlled low-tide level operator model is used to deduce the tide-controlled low-tide level ZL′ of the research section. 上包 Calculate the upper envelope to deduce the tide-controlled low tide level ZL′ 上包 Average deviation from the measured low tide level ZL The deviation coefficient of the integrated line upward envelope is If E 综 >0, the lower envelope of the tide-controlled low-tide level operator model is used to deduce the tide-controlled low-tide level ZL′ of the research section. 下包 Calculate the lower envelope to deduce the tide-controlled low tide level ZL′ 下包 Average deviation from the measured low tide level ZL The deviation coefficient of the comprehensive line to the downward envelope is

[0093] S6.3. Real-time offset of the integrated line of the flood control water level routing sub-model. Select the recent hydrological data when the average daily flow is greater than the minimum runoff to study the average daily flow Q of the section. D As the model input, the comprehensive line of the flood control water level operator model is used to deduce the daily average flood control water level ZF D综 , calculate the comprehensive line to deduce the daily average flood control water level ZF D综 Compared with the measured daily average flood control water level ZF D The average deviation If E 综 <0, the upper envelope of the flood control water level operator model is used to deduce the daily average flood control water level ZF D上包 , calculate the upper envelope to deduce the daily average flood control water level ZF D上包Compared with the measured daily average flood control water level ZF D The average deviation The deviation coefficient of the integrated line upward envelope is If E 综 >0, the lower envelope of the flood control water level operator model is used to derive the daily average flood control water level ZF D下包 Calculate the lower envelope to derive the daily average flood control water level ZF D下包 Compared with the measured daily average flood control water level ZF D The average deviation The deviation coefficient of the comprehensive line to the downward envelope is

[0094] In this example, the maximum flow rate measured at Zhijiang Station on June 26, 2017 was 18,300 m 3 / s, and the measured maximum water level was 7.89m, both of which are the highest values ​​since the station was established. Taking the recalculation of the maximum flood level on that day as an example, assuming June 26, 2017 is the current date.

[0095] The tidal range operator model for tide control is calibrated in real time. The calibration period is 30 days, and the average daily flow at Zhijiang Station from May 27 to June 26, 2017 is less than 2000m 3 / s hydrological data, real-time automatic calibration of the tide control tidal range ΔZ′ of the Zhijiang station i The tidal range ΔZB at the same half tide as that at Zhapu Station i Correlation model, ΔZ′ i =0.0543×ΔZB i 2 -0.3194×ΔZB i +0.5194, the correlation coefficient R is 0.95, such as Figure 8 shown.

[0096] The integrated line of the tide-controlled low-tide level operator model is offset in real time. The calibration time span is 30 days, and the average daily flow of Zhijiang Station from May 27 to June 26, 2017 is less than 200m 3 / s hydrological data, there are 2 data that meet the conditions, ΔZB i-1 They are 5.03m and 4.69m respectively. Figure 9 The red dots are shown. i-1 As the model input, use ZL′ i and ΔZB i-1 The comprehensive line of the correlation model is used to deduce the tide-controlled low tide level ZL′ at Zhijiang Station 综 The measured low tide levels ZL are 2.98m and 3.06m respectively. The tide-controlled low tide level ZL′ is deduced by calculating the comprehensive line. 综The average deviation E from the measured low tide level ZL 综 =0.18m. Using ZL′ i and ΔZB i-1 The lower envelope of the correlation model is used to deduce the tide-controlled low tide level ZL′ at Zhijiang Station 下包 The values ​​are 2.71m and 2.57m respectively. The lower envelope is calculated to deduce the tide-controlled low tide level ZL′. 下包 The average deviation E from the measured low tide level ZL 下包 =-0.38m. The deviation coefficient of the integrated line to the downward envelope is

[0097] The flood control water level routing sub-model integrated line is offset in real time. The calibration time span is 30 days, and the average daily flow of Zhijiang Station from May 27 to June 26, 2017 is greater than 2000m 3 / s hydrological data, there are 6 data that meet the conditions, Q D 2870m respectively 3 / s、5560m 3 / s、3470m 3 / s、2710m 3 / s、3010m 3 / s、2350m 3 / s, such as Figure 10 The red dots are shown. D As the model input, use Q D with ZF D The comprehensive line of the correlation model is used to deduce the daily average flood control water level ZF of Zhijiang Station D综 They are 0.83m, 1.50m, 0.99m, 0.79m, 0.87m and 0.69m respectively. The measured daily average flood control water level ZF D They are 1.28m, 1.65m, 1.20m, 1.07m, 1.24m and 0.89m respectively. The daily average flood control water level ZF is calculated by the comprehensive line. D综 Compared with the measured daily average flood control water level ZF D The average deviation E 综 =-0.27m. Use Q D with ZF D The upper envelope of the correlation model is used to deduce the daily average flood control water level ZF of Zhijiang Station D上包 They are 1.54m, 2.21m, 1.70m, 1.50m, 1.58m and 1.40m respectively. The upper envelope is calculated to deduce the daily average flood control water level ZF D上包 Compared with the measured daily average flood control water level ZF D The average deviation E 上包 =0.43m. The deviation coefficient of the integrated line upward envelope is

[0098] S7. Obtain measured or predicted values ​​for model input. Obtain measured or predicted values ​​for the average daily discharge and the tidal range at the lower boundary of the study section as inputs for the automatic calculation model. When using measured values ​​as inputs, the calculation primarily focuses on past or current water level data and can be used for data quality control. When using predicted values ​​as inputs, the calculation primarily focuses on future water level data and can be used for water level forecasting. See the calculation steps in S8-10 for details.

[0099] S8. Use the automatic calculation model to calculate the low tide level during the flood period.

[0100] S8.1. Use the tide-controlled low-tide level operator sub-model to generate the tide-controlled low-tide level calculation value. The high tide tidal range ΔZB of the half tide on the following boundary i-1 As the model input, the comprehensive line of the tide-controlled low-tide level operator model is used to deduce the low-tide level ZL′ of the study section. 综 ; If E 综 <0, the upper envelope of the tide-controlled low-tide operator model is used to deduce the low-tide level ZL′ of the study section. 上包 , the offset coefficient of the integrated line upward envelope Calculated value of low tide level ZL′ at the tide-controlled section 演 =ZL′ 综 +(ZL′ 上包 -ZL′ 综 )×β; if E 综 >0, the lower envelope of the tide-controlled low-tide operator model is used to deduce the low-tide level ZL′ of the research section. 下包 , the deviation coefficient of the integrated line to the downward envelope Calculated value of low tide level ZL′ at the tide control section 演 =ZL′ 综 -(ZL′ 综 -ZL′ 下包 )×β, calculate the daily average tide-controlled low tide value.

[0101] S8.2. Use the flood control water level calculation model to generate the flood control water level calculation value. D As the model input, the comprehensive line of the flood control water level operator model is used to deduce the daily average flood control water level ZF of the study section. D综 ; If E 综 <0, the upper envelope of the flood control water level operator model is used to deduce the daily average flood control water level ZF D上包 , the offset coefficient of the integrated line upward envelope is The calculated value of the daily flood control water level of the research section is ZF D演 =ZF D综 +(ZF D上包 -ZF D综 )×β; if E 综>0, the lower envelope of the flood control water level operator model is used to derive the daily average flood control water level ZF D下包 , the deviation coefficient of the comprehensive line to the downward envelope is The calculated value of the daily flood control water level of the research section is ZF D演 =ZF D综 -(ZF D综 -ZF D下包 )×β.

[0102] S8.3. Generate the calculated low tide value during flood period. The calculated daily average tide-controlled low tide value ZL′ of the research section 演 Compared with the calculated value of daily flood control water level ZF of the research section D演 Add them together to get the calculated value of the daily average low tide level during the flood period ZL of the research section. 演 ,Right now:

[0103] ZL 演 =ZL′ 演 +ZF D演

[0104] In this example, the measured value is used as the input condition to calculate the past water level data, assuming that June 26, 2017 is the current date. On June 26, 2017, the average daily flow at Zhijiang Station was 14800m 3 / s, the measured high tide range ΔZB at the upper half of the tide at Zhapu station i-1 The measured high tide difference ΔZB at the same half tide of Zhapu Station is 6.01m and 7.53m respectively. i They are 7.53m and 6.10m respectively.

[0105] Use the tide control low tide level operator model to generate tide control low tide level calculation value. i-1 As the model input, use ZL′ i and ΔZB i-1 The comprehensive line of the correlation model is used to deduce the tide-controlled low tide level ZL′ at Zhijiang Station 综 They are 3.78m and 4.31m respectively, using ZL′ i and ΔZB i-1 The lower envelope of the correlation model is used to deduce the tide-controlled low tide level ZL′ at Zhijiang Station 下包 They are 3.22m and 4.29m respectively. The offset coefficient of the integrated line to the downward envelope is β=0.33. The calculated value of the low tide level ZL′ of the Zhijiang station is 演 =ZL′ 综 -(ZL′ 综 -ZL′ 下包 )×β, the calculated values ​​are 3.59m and 4.31m respectively, and the calculated value of the daily average tide-controlled low tide level ZL′ of the Zhijiang station is obtained. 演 It is 3.95m.

[0106] Use the flood control water level routing sub-model to generate flood control water level routing values. D As the model input, use Q D with ZF D The comprehensive line of the correlation model is used to deduce the daily average flood control water level ZF of Zhijiang Station D综 is 2.98m, using Q D with ZF D The upper envelope of the correlation model is used to deduce the daily average flood control water level ZF of Zhijiang Station D上包 is 3.68m, the upward envelope deviation coefficient of the comprehensive line is β=0.39, and the daily average flood control water level calculation value ZF D演 =ZF D综 +(ZF D上包 -ZF D综 )×β, calculate ZF D演 is 3.25m.

[0107] Generate the low tide routing value during flood period. The daily average tide-controlled low tide routing value ZL′ of Zhijiang Station 演 The calculated value of the daily flood control water level at Zhijiang Station is ZF D演 The sum of the two is the daily average low tide level calculated value ZL at Zhijiang Station 演 , calculate ZL 演 It is 7.20m.

[0108] S9. Use the automatic calculation model to calculate the tidal range during flood season.

[0109] S9.1. Use the tide-controlled high tide and tidal range operator sub-model to generate the tide-controlled high tide and tidal range calculation value. Take the tide-controlled high tide and tidal range ΔZB at the same half tide of the lower boundary as the model input, and use the tide-controlled high tide and tidal range operator sub-model calibrated in real time to generate the tide-controlled high tide and tidal range calculation value ΔZ′ for the study section. 演 .

[0110] S9.2. Use the empirical model of the effective coefficient of tidal range propagation during flood season to generate the effective coefficient of tidal range propagation during flood season. D When the runoff is greater than the minimum runoff of the tidal range attenuation during the flood period, the average daily flow of the study section Q D As the model input, the effective coefficient of tidal range propagation during flood period is generated by using the empirical model of effective coefficient of tidal range propagation during flood period; the average daily flow Q D When the runoff is less than the minimum runoff for tidal range attenuation during flood season, the effective coefficient of tidal range propagation during flood season α=1.

[0111] S9.3. Generate the calculated value of the high tide range during the flood period. The calculated value of the high tide range ΔZ′ of the tide-controlled section 演 Multiply by the effective coefficient of tidal range propagation during flood season α to get the calculated value of tidal range during flood season ΔZ of the research section. 演 ,Right now:

[0112] ΔZ 演 =ΔZ′ 演 ×α

[0113] In this example, the tide-controlled high tide range operator model is used to generate the tide-controlled high tide range calculation value. The measured high tide range ΔZB at the same half tide of Zhapu Station is used as the model input. ΔZB is 7.53m. The real-time calibrated ΔZ′ is used. i and ΔZB i Correlation model, generating the calculated value ΔZ′ of the tide control tide at Zhijiang Station 演 It is 1.19m.

[0114] The effective coefficient of tidal range propagation during flood season is generated by using the empirical model of effective coefficient of tidal range propagation during flood season. D As the model input, use Q D The correlation model with α generates an effective coefficient α of 0.615 for tidal range propagation during flood season.

[0115] Generate the calculated value of high tide range during flood season. The calculated value of high tide range ΔZ′ at Zhijiang Station 演 Multiplying by the effective coefficient of tidal range propagation during flood season α, we get the calculated value of tidal range during flood season ΔZ at Zhijiang Station. 演 It is 0.73m.

[0116] S10. Use the automatic calculation model to calculate the high tide level during the flood period. The calculated value of the daily low tide level of the research section is ZL. 演 Calculated value of high tide difference ΔZ of the research section 演 Add them together to calculate the high tide level ZH during the flood period of the research section. 演 ,Right now:

[0117] ZH 演 =ZL 演 +ΔZ 演 =ZL′ 演 +ZF D演 +ΔZ′ 演 ×α

[0118] In this example, the automatic calculation model is used to calculate the high tide level during the flood period. The daily average low tide level calculation value ZL at Zhijiang Station 演 The calculated value of the high tide range ΔZ at Zhijiang Station 演 Add them together to get the high tide level calculation value ZH of Zhijiang Station 演 It is 7.93m.

[0119] Accuracy Assessment: On June 26, 2017, the measured high tide level at Zhijiang Station was 7.89m, with an estimated absolute error of 0.04m. This meets the requirements for tide forecast accuracy assessment in the "Specifications for Hydrological Information Forecasting" (GB / T 22482-2008).

Claims

1. A method for automatically calculating flood levels in tidal river sections based on tide-flood separation and real-time calibration, characterized in that: The following steps are involved: S1, Tide-flood separation, which separates the flood level in the tidal river section into tide-controlled water level and flood-controlled water level; S2. Construct a tide-controlled low-tide operator model based on historical hydrological data; S3. Based on historical hydrological data, construct a tide control and tidal range operator model; S4. Construct a flood control water level operator model based on historical hydrological data; S5. Based on historical hydrological data, construct an empirical model of the effective coefficient of tidal range propagation during flood season; S6. Determine the scour and sedimentation sensitivity factor in real time based on recent hydrological data; S7. Obtain the measured values ​​or predicted values ​​of the model input and calculate the low tide level during the flood period, the tidal range during the flood period, and the high tide level during the flood period; The measured or predicted values ​​of the average daily flow and the tidal range of the lower boundary of the research section are obtained as the input conditions of the automatic calculation model; when the measured values ​​are used as the input conditions, the calculation is mainly based on the past or current water level data for data quality control; when the predicted values ​​are used as the input conditions, the calculation is mainly based on the future water level data for water level forecasting.

2. The method for automatically calculating flood levels in tidal river sections based on tide-flood separation and real-time calibration according to claim 1 is characterized in that: In S1, a research section is selected in the tidal river section, and the low tide level ZL of the research section is separated into the tide-controlled low tide level ZL′ and the flood-controlled water level ZF, that is: ZL=ZL′+ZF The high tide level ZH of the study section is separated into the tide-controlled low tide level ZL′, the high tide tidal range ΔZ, and the flood-controlled water level ZF. The high tide tidal range ΔZ is equal to the tide-controlled high tide tidal range ΔZ′ multiplied by the effective coefficient of tidal range propagation α during the flood period, that is: ZH=ZL′+ΔZ′×α+ZF.

3. The method for automatically calculating flood levels in tidal river sections based on tide-flood separation and real-time calibration according to claim 1 is characterized in that: In S2, the tidal level of the coastal section of the downstream estuary is not affected by the upstream runoff and can truly reflect the tidal level changes, which serves as the lower boundary condition for separating the tidal-controlled water level. The tidal range ΔZB of the upper half of the lower boundary is i-1 As a separation tide control low tide level ZL′ i Boundary conditions; calibrate the tide-controlled low tide level ZL′ of the research section i The tidal difference ΔZB from the upper half of the lower boundary i-1 The correlation model proposes a comprehensive line and two outer lines. The comprehensive line reflects the overall law of the correlation between the two, and the outer lines reflect the maximum deviation affected by the changes in river channel erosion and deposition.

4. The method for automatically calculating flood levels in tidal river sections based on tide-flood separation and real-time calibration according to claim 3 is characterized in that: In S2, based on historical hydrological data, the low tide level ZL of the research section under different runoff conditions was analyzed. i The tidal difference ΔZB from the upper half of the lower boundary i-1 As the upstream runoff gradually increases, the correlation will gradually decrease. A correlation threshold is set. When the correlation drops to the threshold, the runoff of this magnitude is determined as the maximum allowable runoff for tide control low tide level calculation. When the upstream runoff is less than the maximum allowable runoff, the low tide level ZL of the research section is calibrated. i The tidal difference ΔZB from the upper half of the lower boundary i-1 Correlation model, ignoring the flood control water level, studying the low tide level ZL of the section i Tide-controlled low tide level ZL′ i .

5. The method for automatically calculating flood levels in tidal river sections based on tide-flood separation and real-time calibration according to claim 1 is characterized in that: In S3, the tidal range ΔZB of the same half tide at the lower boundary is i As a separation of the tide-controlled high and low tide range ΔZ′ i Boundary conditions; calibration of the tidal range ΔZ′ of the tidal-controlled high tide in the research section i The tidal range ΔZB at the same half tide as the lower boundary i Correlation model; due to the influence of changes in river scouring and silting, a long time span will lead to a decrease in correlation, while a short time span will result in insufficient sample data and will also lead to a decrease in correlation. The optimal time span varies depending on the frequency of river scouring and silting. The time span with the best correlation is selected as the optimal time span for tide control high tide and tidal range calculation; the hydrological data of the optimal time span are selected for parameter calibration in sections.

6. The method for automatically calculating flood levels in tidal river sections based on tide-flood separation and real-time calibration according to claim 5 is characterized in that: In S3, based on historical hydrological data, the tidal range ΔZ of the study section under different runoff conditions is analyzed. i The tidal range ΔZB at the same half tide as the lower boundary i As the upstream runoff gradually increases, the correlation will gradually decrease. A correlation threshold is set. When the correlation drops to the threshold, the runoff of this magnitude is determined as the maximum allowable runoff for tide control tidal range calculation. When the upstream runoff is less than the maximum allowable runoff, the tidal range ΔZ of the research section is determined. i is the tidal range ΔZ′ controlled by the tide i .

7. The method for automatically calculating flood levels in tidal river sections based on tide-flood separation and real-time calibration according to claim 1 is characterized in that: In S4, the tide-controlled low-tide operator model is used to calculate the high tide difference ΔZB of the half tide on the lower boundary. i-1 As input, select the comprehensive line and calculate the tide-controlled low tide level ZL′ of the half tide of the research section. i , the low tide level ZL of the half tide of the research section i Subtract the tide-controlled low tide ZL′ i , is the flood control water level ZF corresponding to the semi-tidal low tide level of the research section i ,Right now: ZF i =ZL i -ZL′ i The average daily flow rate Q of the research section D As the boundary condition for flood control water level routing, the average daily flow Q of the study section is established. D and daily average flood control water level D Correlation model; calibration of the average daily flow rate Q of the research section D and daily average flood control water level D A correlation model is proposed, and a comprehensive line and two outer lines are drawn up. The comprehensive line reflects the overall law of the correlation between the two, and the outer lines reflect the maximum deviation affected by the changes in river channel scouring and deposition.

8. The method for automatically calculating flood levels in tidal river sections based on tide-flood separation and real-time calibration according to claim 7 is characterized in that: In S4, based on historical hydrological data, the average daily flow Q D and daily average flood control water level D When the average daily flow is small, the water level of the study section is mainly the tide-controlled water level, which has a poor correlation with the average daily flow. A correlation threshold is set. When the average daily flow is greater than a certain level, the correlation is greater than the threshold. The average daily flow of this level is determined as the minimum runoff determined by the flood control water level.

9. The method for automatically calculating flood levels in tidal river sections based on tide-flood separation and real-time calibration according to claim 1 is characterized in that: In S5, the calibrated tide-controlled high tide range operator model is used to calculate the high tide range ΔZB at the same half tide of the following boundary. i As input, calculate the tidal range ΔZ′ of the half tide at the study section. i ; The measured high tide range ΔZ at the half tide of the study section i Divide by the tidal range ΔZ′ i , is the effective coefficient α of the tidal range of the study section i ,Right now: The average daily flow rate Q of the research section D As the influencing factor of the effective coefficient of tidal range propagation during flood period, the average daily flow rate Q of the research section is calibrated. D Correlation model with the effective coefficient α of tidal range propagation during flood period; Rating Q D When the correlation model with α is used, the correlation between the average daily flow and the effective coefficient of tidal range propagation during the flood period is analyzed, and a correlation threshold is set. When the average daily flow is greater than a certain level, the correlation exceeds the threshold, and the average daily flow of this level is determined as the minimum runoff for tidal range attenuation during the flood period.

10. The method for automatically calculating flood levels in tidal river sections based on tide-flood separation and real-time calibration according to claim 1, characterized in that: In S6, the time span is selected as N days, the calibration day minus N days is used as the start time, and the calibration day is used as the end time. The hydrological data when the upstream runoff is less than the maximum allowable runoff within this time span are selected to form a real-time calibration sample set, and the tidal range ΔZ′ of the study section is automatically calibrated in real time. i The tidal range ΔZB at the same half tide as the lower boundary i Correlation model; The comprehensive line and outer line of the tide-controlled low-tide level operator model are used to deduce the tide-controlled low-tide level of the study section, and the average deviation between the derived tide-controlled low-tide level and the measured low-tide level is calculated. The comprehensive line of the tide-controlled low-tide level operator model is offset in real time. The comprehensive line and outer line of the flood control water level operator sub-model are used to deduce the daily average flood control water level of the research section, and the average deviation between the derived daily average flood control water level and the measured daily average flood control water level is calculated, and the comprehensive line of the flood control water level operator sub-model is offset in real time.

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