Dynamic control method of reservoir operation water level during flood season based on forecast availability

Abstract

This invention discloses a method for dynamic control of reservoir operating water level during the flood season based on forecast availability. It includes analysis of basic hydrological and meteorological laws, analysis of water level-discharge relationship, analysis of meteorological and hydrological forecast levels, interval flow analysis, calculation of the reservoir's operating water level float limit during the flood season, and calculation combining simulation and actual inflow results. For each combination of forecast period and pre-discharge flow, the lowest allowable float value is taken as the reservoir's operating water level fluctuation result under that forecast period and pre-discharge scenario. This invention significantly improves the scientific rigor, safety, and practicality of dynamic control of reservoir operating water level during the flood season by constructing a closed-loop control system from basic hydrological and meteorological law analysis to actual inflow verification.

Description

Technical Field

[0001] This invention relates to a dynamic water level control method, specifically a dynamic water level control method for reservoir operation during the flood season based on forecast availability, belonging to the field of reservoir scheduling technology. Background Technology

[0002] Dynamic control of reservoir flood control levels is an inevitable choice for coordinating "water security, water resources, water ecology, and water economy." It marks a profound transformation in reservoir management from "passive defense" to "active regulation," and from "experience-based decision-making" to "intelligent decision-making," and has become a cutting-edge direction in global reservoir management. Given the uneven spatial and temporal distribution of water resources and the intensifying climate change in my country, its promotion and implementation are of strategic significance for ensuring national water security.

[0003] Currently, reservoir flood season water level control has two aspects: static and dynamic. The former calculates the flood limit water level characteristic value based on the worst-case combination of design floods, taking a conservative approach. This flood limit water level does not consider current inflow conditions, future rainfall and flood forecasts, etc., requiring the reservoir to be prepared for even the smallest floods at all times, leading to problems such as "empty reservoirs" during the flood season, wasting flood resources, and low comprehensive utilization efficiency of flood resources. The latter, by analyzing the accuracy and lead time of rainfall and flood forecasts, combined with the water storage and discharge capacity of the cascade reservoir group, determines the dynamic control range of the flood season water level. This flood limit water level can better realize the utilization of flood resources.

[0004] In the prior art, 1) a method and device for dynamic scheduling of flood control water level of a large plain reservoir disclosed in CN118036992A, the method determines the applicable target weather type based on historical weather forecast information and calculates the maximum and minimum values ​​of dynamic scheduling of flood control water level, and performs dynamic adjustment of water level when the forecast weather is the target type. Although this scheme introduces weather forecast information, its water level fluctuation mainly depends on qualitative weather type classification, without quantitatively evaluating the accuracy and available forecast period of the forecast information, and without fully considering the influence of water inflow between the reservoir and the downstream flood control section, which may lead to insufficient flood control safety margin or insufficient exploitation of floating potential in its dynamic scheduling range in practical applications; 2) a method and device for dynamic scheduling of flood control water level of a large plain reservoir disclosed in CN118036992A, the method determines the applicable target weather type based on historical weather forecast information and calculates the maximum and minimum values ​​of dynamic scheduling of flood control water level, and performs dynamic adjustment of water level when the forecast weather is the target type. The method disclosed in 0852525A, which is a dynamic adjustment method for reservoir flood control limit water level based on forecast error and tiered defense, divides precipitation forecast levels and determines the threshold for tiered control rainfall. Based on the future precipitation forecast level, it back-calculates the safe limit water level and broadens the possible range of precipitation values ​​to increase the utilization of flood resources. However, this method mainly focuses on precipitation forecast itself and emphasizes the judgment of precipitation level for a single event. It does not incorporate the accuracy of hydrological forecasts into the comprehensive analysis system, and it lacks refined calculations for the dynamic decline of water level under complex inflow situations such as continuous rising water processes. Furthermore, it does not use actual historical inflow processes to fully verify the determined rising water level. Therefore, the accuracy and safety of water level control still need to be improved when dealing with complex and changeable hydrological situations.

[0005] In summary, existing technologies generally suffer from problems such as extensive use of forecast information, lack of quantitative differentiation of forecast accuracy and availability of forecast period, neglect of the dynamic impact of water inflow in the region, and lack of reverse safety calculation and real-world verification for continuous water rise processes. Summary of the Invention

[0006] The purpose of this invention is to provide a dynamic control method for reservoir operation water level during the flood season based on forecast availability in order to solve at least one of the above-mentioned technical problems. This method starts from the analysis of basic hydrological and meteorological laws, and determines the boundary conditions for reservoir flood regulation calculation by quantifying the relationship between flood control water level and flow, analyzing the available limits of rainfall and water forecast lead time and accuracy, and determining the inflow process of the interval. It adopts the reverse calculation approach, from the design scenario to the actual calculation, and fully verifies the upper limit of reservoir operation water level during the flood season from the perspective of flood control safety.

[0007] This invention achieves the above objective through the following technical solution: a method for dynamic control of reservoir operating water level during the flood season based on forecast availability, comprising the following steps: S1. Analysis of basic hydrological and meteorological patterns: Collect historical typical rainstorm and flood events, and use statistical methods to conduct analysis of basic hydrological and meteorological patterns; S2. Analysis of water level and flow rate relationship: For the same year, plot the water level and flow rate relationship of the downstream control section of the reservoir to determine whether the multi-year water level and flow rate relationship line is a single current distribution and whether it has consistency. S3. Analysis of meteorological and hydrological forecasting level: Collect hydrological and meteorological forecasting products and conduct analysis of the meteorological and hydrological forecasting level of the watershed; S4. Inter-regional flow analysis: If a major tributary flows into the interval, the inflow of that tributary is used as the inflow process of the interval; if no major tributary flows into the interval, but there is a long series of hydrological data at the reservoir dam site and the downstream flood control section, the inflow process of the interval is calculated using the flow difference; if no major tributary flows into the interval, but there is a long series of hydrological data at the reservoir dam site and no long series of hydrological data downstream, the inflow process of the interval is calculated using the area ratio method. S5. Calculation of the maximum upward movement of reservoir operating water level during the flood season: If the inflow process during the forecast period is stable, the degree of upward movement of the reservoir operating water level is determined by reverse calculation; if the inflow process during the forecast period is rising, the water level that the reservoir can rise under the continuous rising process is calculated; from the perspective of the actual inflow of the reservoir, it is verified whether the reservoir can release water to the flood limit level under different forecast periods and different pre-discharge flows; S6. Combining the simulation and actual inflow calculation results, for each combination of forecast period and pre-discharge flow, the lowest value that the reservoir is allowed to float is taken as the result of the reservoir's operating water level fluctuation under this forecast period and pre-discharge scenario.

[0008] As a further aspect of the present invention: In S1, the analysis of basic hydrological and meteorological laws specifically includes: Analysis of Rainstorm Patterns: The causes of rainstorms are analyzed from the aspects of upper-level troughs, low-level vortices, shear lines, low-level jet streams and surface cold air, and the characteristics of rainstorms are analyzed from the aspects of spatiotemporal distribution, intensity and frequency. Hydrological pattern analysis: The flood pattern is analyzed from the aspects of the development process of typical historical floods, the composition of flood areas, the flood encounter situation, the composition of long-term runoff, and the annual distribution.

[0009] As a further aspect of the present invention: In S2, the difference in flow rate at the same water level corresponding to the upper and lower envelopes of the multi-year water level-flow rate relationship cannot exceed a threshold: ; If consistency is achieved, a comprehensive curve based on multi-year water level-discharge relationships should be adopted. This serves as the water level-discharge relationship line for the control station, and the target water level at the downstream flood control section of the reservoir is determined based on this water level-discharge relationship line. The corresponding traffic ; In the formula: This line represents the relationship between water level and flow rate in that year. This represents a curve showing the relationship between water level and flow rate for a given year other than the current year. Indicates a certain water level. This represents the difference in flow rate at the same water level under different water level-flow relationships. The threshold representing the difference in flow rates. This represents the relationship between water level and flow rate. This indicates the control flow rate corresponding to the same water level below the composite line.

[0010] As a further aspect of the present invention: In S3, the meteorological and hydrological forecast level analysis specifically includes: Rainfall forecast accuracy: the accuracy of precipitation forecasts for a specific period. and different forecast periods ( Precipitation forecast accuracy Conduct an assessment, if and Then the forecast period under that period The rainfall forecast is highly usable; Hydrological forecasting level: For different lead times within the same period as rainfall forecasting ( Hydrological forecast Conduct an assessment, if Then the forecast period under that period The hydrological forecasts are highly usable; Based on the analysis results of the rainfall forecast level and hydrological forecast level, As a lead time for calculating the fluctuation of the flood control limit water level of the reservoir; In the formula: Indicates the accuracy of precipitation events over a certain period. Indicates the lead time Precipitation forecast accuracy Indicates the lead time Hydrological forecast accuracy Indicates the lead time The forecasted flow value, Indicates the lead time The actual traffic volume.

[0011] As a further aspect of the present invention: the method for dynamic control of reservoir operating water level during the flood season collects and organizes reservoir characteristic parameters and water level-capacity curves. The dynamic control of the reservoir's flood control limit water level was analyzed based on the discharge capacity curve and the reservoir's flood control scheduling method. The reservoir's characteristic parameters include the normal storage water level, the flood control high water level, the dead water level, and their corresponding reservoir capacity and full discharge.

[0012] As a further aspect of the present invention: In S4, the inflow process of the interval is calculated using the following formula:

[0013] In the formula, Indicates interval flow. This indicates the flow rate at the downstream flood control section. This indicates the flow rate at the upstream flood control section.

[0014] As a further aspect of the present invention: In S4, the water inflow process of the interval is calculated using the area ratio method by the following formula:

[0015] In the formula: This indicates the catchment area represented by the downstream flood control section. This indicates the catchment area represented by the reservoir dam site; Considering the maximum inflow of water between the reservoir and the flood control section Calculate the maximum outflow from the reservoir. Combined with the full discharge flow of the reservoir Determine the range of reservoir pre-discharge flow: when At that time, the reservoir's pre-discharge flow rate Otherwise, the reservoir should try to maintain the discharge level. ; In the formula: This represents the maximum value in the interval flow series. Indicates the pre-discharge flow rate of the reservoir. This indicates the maximum outflow from the reservoir.

[0016] As a further aspect of the present invention: In S5, if the inflow process of the reservoir during the forecast period is stable, the determination of the degree of rise in the reservoir's operating water level using a reverse calculation approach specifically includes: Assuming the reservoir water level rises above the flood control limit. If the water level is meters, then the reservoir water level is... The corresponding storage capacity difference is ; If the forecast period is ( ), then the reservoir's inflow rate during the forecast period is On this basis, it is also necessary to increase purging ; like This indicates that the water level in the reservoir has risen to [a certain level]. ; In the formula: Indicates the flood control limit water level of the reservoir. This indicates the degree to which the water level rises above the flood control limit of the reservoir. Indicates the rising water level of the reservoir. This indicates the reservoir capacity corresponding to the flood control limit water level. This indicates the reservoir capacity corresponding to the rising water level. This represents the difference between the reservoir capacity corresponding to the rising water level and the reservoir capacity corresponding to the flood control limit water level. This indicates that if it is to be in the foreseeable period The water level will be pre-released to the flood control limit level, which requires an additional discharge on top of the existing inflow.

[0017] As a further aspect of the present invention: In S5, if the inflow of water into the reservoir shows an upward trend during the forecast period, the calculation of the reservoir's potential water level during the continuous rise specifically includes: Assuming the foresight period is ( ), pre-discharge flow rate at Between presets Class; If the pre-discharge flow rate is When, set Current reservoir inflow and The maximum expected inflow at the end of the period are respectively Choose either the current inbound flow rate or the projected maximum inbound flow rate at the end of the period. and And must meet To conduct floating calculations; Pre-discharge volume during the forecast period Based on the reservoir water level and storage capacity curve Calculate the rising water level. ; Traverse all Combine and calculate the reservoir's rising water level for each combination. From a safety perspective, each combination... Under this combination, the highest water level that the reservoir is allowed to rise to is ; In the formula: This indicates the several discharge options set between the full discharge flow rate and the maximum discharge flow rate. This indicates that the pre-discharge flow rate is The j-th type of current reservoir inflow rate is set below. This indicates that the pre-discharge flow rate is The k-th type of predicted maximum inbound flow at the end of the period is set below. This indicates the amount of water that can be pre-released within the forecast period. This indicates the water level at which the water can be raised.

[0018] As a further aspect of the present invention: In S5, from the perspective of the actual inflow of water into the reservoir, the verification of whether the reservoir can release water to the flood control limit level under different forecast periods and different pre-discharge flows specifically includes: Based on the actual hourly water inflow data of the reservoir over many years, several maximum inflow values ​​were set. Based on different forecast periods ( ), from the maximum inbound flow value Counting backwards to the start of the forecast period, the inbound flow rate Several actual water inflow processes were obtained. ; Using different pre-leakage flow rates Calculate the amount of water that can be pre-discharged within the forecast period, and calculate the floating water level based on the reservoir water level and capacity curve; Traverse all Combined calculations are performed to determine the reservoir's floating water level under each combination in actual water inflow scenarios. , From a safety perspective, each Under this combination, the highest water level that the reservoir is allowed to rise to is ; In the formula: This represents a certain maximum inbound flow rate. express The forecast period is calculated by counting backwards from the maximum inbound flow rate to the inbound flow rate at the start of the forecast period. This indicates the amount of water that can be pre-released within the forecast period. This indicates the water level at which the water can be raised.

[0019] The beneficial effects of this invention are: (1) This invention significantly improves the scientific, safe, and practical nature of dynamic water level control during the flood season by constructing a closed-loop control system that integrates basic hydrological and meteorological law analysis with actual inflow verification. Specifically, firstly, this method reveals the fundamental correlation mechanism between runoff generation and flood control targets in the basin through in-depth statistical analysis of historical rainstorm and flood characteristics and consistency verification of water level-discharge relationships at downstream flood control sections. This lays a solid hydrological foundation for subsequent dynamic control and avoids blind decision-making due to unclear understanding of basin characteristics. Secondly, this method innovatively introduces a quantitative assessment of meteorological and hydrological forecasting levels. By setting multiple thresholds for rainfall forecast accuracy, hydrological forecast accuracy, and process accuracy, this method scientifically selects usable forecast lead times, achieving a leap from "empirical use of forecasts" to "quantitative screening of forecasts based on availability," effectively avoiding flood control risks caused by blindly adopting low-precision forecast information. Finally, for the inflow between the reservoir and the downstream flood control section, this method provides multiple refined analysis approaches based on measured data or the area ratio method. Based on this, and combined with the maximum inflow between the section and the full discharge of the reservoir, the feasible range of pre-discharge flow is reasonably delineated, solving the technical problem of misjudging downstream flood control pressure due to ignoring the dynamic changes of inflow between the section.

[0020] (2) This invention adopts the reverse calculation approach and the multi-scenario traversal combination calculation method for two typical situations: stable water inflow and continuous water rise. From the perspective of flood control safety, it fully verifies the water level rise limit under different pre-discharge capacity and water inflow combination. Furthermore, it uses the actual hourly water inflow process over many years for empirical verification. Finally, the lowest safe value is taken as the final floating result by combining the simulation and actual results. This dual insurance mechanism of "design scenario deduction" and "actual process verification" greatly enhances the robustness and credibility of the dynamic control scheme and ensures that the reservoir can still safely fall back to the flood limit water level under extreme working conditions.

[0021] (3) This invention effectively resolves the contradiction between the waste of flood resources caused by traditional static control and the extensive forecasting and utilization and the single verification method in existing dynamic control methods. It realizes the maximum exploitation potential of flood resources without increasing the downstream flood control risk. Its implementation process is simple and easy to carry out, and the output results are intuitive and clear. It has extremely high engineering promotion and application value. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall control flow of the present invention; Figure 2 This is a diagram showing the relationship between water level and flow rate at a certain station in Embodiment 3 of the present invention; Figure 3 This is a schematic diagram of the continuously rising water flow process during the forecast period in Embodiment 3 of the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1, as Figure 1 As shown in the figure, this embodiment provides a method for dynamic control of reservoir operating water level during the flood season based on forecast availability. This method includes the following steps: First, analysis of basic hydrological and meteorological patterns: collect historical typical rainstorm and flood events, and use statistical methods to conduct analysis of basic hydrological and meteorological patterns.

[0025] The analysis of basic hydrological and meteorological laws specifically includes: Analysis of Rainstorm Patterns: The causes of rainstorms are analyzed from the aspects of upper-level troughs, low-level vortices, shear lines, low-level jet streams and surface cold air, and the characteristics of rainstorms are analyzed from the aspects of spatiotemporal distribution, intensity and frequency. Hydrological pattern analysis: The flood pattern is analyzed from the aspects of the development process of typical historical floods, the composition of flood areas, the flood encounter situation, the composition of long-term runoff, and the annual distribution.

[0026] Second, water level-discharge relationship analysis: For the same year, plot the water level-discharge relationship at the downstream control section of the reservoir to determine whether the multi-year water level-discharge relationship line shows a single current distribution and whether it has consistency.

[0027] The difference in flow rate at the same water level corresponding to the upper and lower envelopes of the multi-year water level-flow relationship must not exceed a threshold: ; If consistency is achieved, a comprehensive curve based on multi-year water level-discharge relationships should be adopted. This serves as the water level-discharge relationship line for the control station, and the target water level at the downstream flood control section of the reservoir is determined based on this water level-discharge relationship line. The corresponding traffic ; In the formula: This line represents the relationship between water level and flow rate in that year. This represents a curve showing the relationship between water level and flow rate for a given year other than the current year. Indicates a certain water level. This represents the difference in flow rate at the same water level under different water level-flow relationships. The threshold representing the difference in flow rates. This represents the relationship between water level and flow rate. This indicates the control flow rate corresponding to the same water level below the composite line.

[0028] Third, analysis of meteorological and hydrological forecasting level: collect hydrological and meteorological forecast products and conduct analysis of the meteorological and hydrological forecasting level of the basin.

[0029] The analysis of meteorological and hydrological forecasting levels specifically includes: Rainfall forecast accuracy: the accuracy of precipitation forecasts for a specific period. and different forecast periods ( Precipitation forecast accuracy Conduct an assessment, if and Then the forecast period under that period The rainfall forecast is highly usable; Hydrological forecasting level: For different lead times within the same period as rainfall forecasting ( Hydrological forecast Conduct an assessment, if Then the forecast period under that period The hydrological forecasts are highly usable; Based on the analysis results of the rainfall forecast level and hydrological forecast level, The forecast period for calculating the fluctuation of the flood control limit water level of the reservoir is in hours; In the formula: Indicates the accuracy of precipitation events over a certain period. Indicates the lead time Precipitation forecast accuracy Indicates the lead time Hydrological forecast accuracy Indicates the lead time The forecasted flow value, Indicates the lead time The actual traffic volume.

[0030] The method for dynamic water level control during the flood season of this reservoir involves collecting and organizing reservoir characteristic parameters and water level-capacity curves. The dynamic control of the reservoir's flood control limit water level was analyzed based on the discharge capacity curve and the reservoir's flood control scheduling method. The reservoir's characteristic parameters include the normal storage water level, the flood control high water level, the dead water level, and their corresponding reservoir capacity and full discharge.

[0031] Fourth, interval flow analysis: If a major tributary flows into the interval, the inflow of that tributary is used as the inflow process of the interval; if no major tributary flows into the interval, but there is a long series of hydrological data at the reservoir dam site and the downstream flood control section, the inflow process of the interval is calculated using the flow difference; if no major tributary flows into the interval, but there is a long series of hydrological data at the reservoir dam site and no long series of hydrological data downstream, the inflow process of the interval is calculated using the area ratio method.

[0032] If no major tributaries flow into the interval, but there is a long series of hydrological data at the reservoir dam site and downstream flood control section, the inflow process of the interval is calculated using the flow difference, specifically using the following formula:

[0033] In the formula, Indicates interval flow. This indicates the flow rate at the downstream flood control section. This indicates the flow rate at the upstream flood control section.

[0034] If no major tributaries flow into the interval, and there is a long series of hydrological data at the reservoir dam site but no long series of hydrological data downstream, then the area ratio method is used to calculate the inflow process of the interval, specifically using the following formula:

[0035] In the formula: This indicates the catchment area represented by the downstream flood control section. This indicates the catchment area represented by the reservoir dam site; Considering the maximum inflow of water between the reservoir and the flood control section Calculate the maximum outflow from the reservoir. Combined with the full discharge flow of the reservoir Determine the range of reservoir pre-discharge flow: when At that time, the reservoir's pre-discharge flow rate Otherwise, the reservoir should try to maintain the discharge level. ; In the formula: This represents the maximum value in the interval flow series. Indicates the pre-discharge flow rate of the reservoir. This indicates the maximum outflow from the reservoir.

[0036] Fifth, calculation of the upper limit of reservoir operating water level during the flood season: If the inflow process of the reservoir is stable during the forecast period, the degree of water level rise during the reservoir operation is determined by the reverse calculation approach; if the inflow process of the reservoir is rising during the forecast period, the water level that the reservoir can rise during the continuous rise process is calculated; from the perspective of the actual inflow of the reservoir, it is verified whether the reservoir can release water to the flood limit level under different forecast periods and different pre-discharge flows.

[0037] If the inflow to the reservoir is stable during the forecast period, the degree of rise in the reservoir's operating water level is determined using a reverse calculation approach, specifically including: Assuming the reservoir water level rises above the flood control limit. If the water level is meters, then the reservoir water level is... The corresponding storage capacity difference is ; If the forecast period is ( ), then the reservoir's inflow rate during the forecast period is On this basis, it is also necessary to increase purging ; like This indicates that the water level in the reservoir has risen to [a certain level]. ; In the formula: Indicates the flood control limit water level of the reservoir. This indicates the degree to which the water level rises above the flood control limit of the reservoir. Indicates the rising water level of the reservoir. This indicates the reservoir capacity corresponding to the flood control limit water level. This indicates the reservoir capacity corresponding to the rising water level. This represents the difference between the reservoir capacity corresponding to the rising water level and the reservoir capacity corresponding to the flood control limit water level. This indicates that if it is to be in the foreseeable period The water level will be pre-released to the flood control limit level, which requires an additional discharge on top of the existing inflow.

[0038] If the inflow to the reservoir shows an upward trend during the forecast period, the specific water level that the reservoir can rise under a sustained rise includes: Assuming the foresight period is ( ), pre-discharge flow rate at Several levels are preset between them, that is Class; If the pre-discharge flow rate is When, set Current reservoir inflow and The maximum expected inflow at the end of the period are respectively Choose either the current inbound flow rate or the projected maximum inbound flow rate at the end of the period. and And must meet To conduct floating calculations; Pre-discharge volume during the forecast period Based on the reservoir water level and storage capacity curve Calculate the rising water level. ; Traverse all Combine and calculate the reservoir's rising water level for each combination. From a safety perspective, each combination... Under this combination, the highest water level that the reservoir is allowed to rise to is ; In the formula: This indicates the several discharge options set between the full discharge flow rate and the maximum discharge flow rate. This indicates that the pre-discharge flow rate is The j-th type of current reservoir inflow rate is set below. This indicates that the pre-discharge flow rate is The k-th type of predicted maximum inbound flow at the end of the period is set below. This indicates the amount of water that can be pre-released within the forecast period. This indicates the water level at which the water can be raised.

[0039] From the perspective of actual reservoir inflow, the verification of whether the reservoir can release water to the flood control limit level under different forecast periods and different pre-discharge flows specifically includes: Based on the actual hourly water inflow data of the reservoir over many years, several maximum inflow values ​​were set. Based on different forecast periods ( ), from the maximum inbound flow value Counting backwards to the start of the forecast period, the inbound flow rate Several actual water inflow processes were obtained. ; Using different pre-leakage flow rates Calculate the amount of water that can be pre-discharged within the forecast period, and calculate the floating water level based on the reservoir water level and capacity curve; Traverse all Combined calculations are performed to determine the reservoir's floating water level under each combination in actual water inflow scenarios. , From a safety perspective, each Under this combination, the highest water level that the reservoir is allowed to rise to is ; In the formula: This represents a certain maximum inbound flow rate. express The forecast period is calculated by counting backwards from the maximum inbound flow rate to the inbound flow rate at the start of the forecast period. This indicates the amount of water that can be pre-released within the forecast period. This indicates the water level at which the water can be raised.

[0040] Sixth, combining the simulation and actual inflow calculation results, for each combination of forecast period and pre-discharge flow, the lowest value that the reservoir is allowed to float is taken as the result of the reservoir's operating water level fluctuation under this forecast period and pre-discharge scenario.

[0041] Example 2, as Figures 2 to 3 As shown, this embodiment takes a certain station as an example and provides a method for dynamic control of reservoir operation water level during the flood season based on forecast availability, including the following steps: (1) Conduct basic analysis of hydrological and meteorological laws.

[0042] (2) Analysis of the relationship between water level and flow rate at the downstream flood control point of the reservoir.

[0043] Based on the analysis of compiled data from a certain station from 2017 to 2023, a water level-discharge relationship curve for recent years was plotted. Figure 2 As can be seen from Table 1, the water level-discharge relationship does not change much throughout the year, and the water level-discharge relationship in each year is a single linear distribution. From the perspective of interannual distribution, the water level-discharge relationship line in the high water part is basically stable, while the water level-discharge relationship line in the medium and low water parts has a certain rightward skew, that is, the corresponding flow rate increases at the same water level.

[0044] Table 1 shows the statistical table of corresponding flow rate changes at a certain station's warning water level and guaranteed water level (unit: m³). 3 / s)

[0045] (3) Analysis of the meteorological and hydrological forecasting level of the basin.

[0046] We collected hydrological and meteorological forecast products from many years and conducted an analysis of the basin's meteorological and hydrological forecasting capabilities.

[0047] Regarding the accuracy of rainfall forecasts, see Tables 2 and 3: Table 2 shows the 24-hour forecast scores for a certain river during the flood season from May to October 2022-2023.

[0048] Table 3 shows the 48-hour forecast scores for a certain river during the flood season from May to October 2022-2023.

[0049] Regarding the accuracy of hydrological forecasts, a total of 184 short-term hydrological forecasts were issued from May to October 2024. The accuracy of short-term forecasts at various cross-sections was assessed, and the results for a specific station are shown in Table 4. Analysis of the accuracy assessment table shows that the 48-hour forecast accuracy at a certain station on the main cross-section of the Dadu River ranged from 92.0% to 96.7%. While the accuracy gradually decreased with increasing lead time, the 48-hour short-term forecast accuracy at this station remained above 90%, meeting the relevant requirements.

[0050] Table 4 shows the accuracy assessment of short-term forecasts for a certain station in 2024.

[0051] (4) Analysis of factors affecting the dynamic control of reservoir flood control water level.

[0052] Collect and organize reservoir characteristic parameters and water level-capacity curves. Data such as discharge capacity curves and reservoir flood control scheduling methods.

[0053] (5) Conduct interval flow analysis.

[0054] Considering the inflow from the Shuangjiangkou Dam site to the Dajin section during the flood season, the drainage area of ​​this section accounts for 2.86% of the Dajin station's total drainage area. Using the maximum daily average flow from May to October during the flood season at the Dajin station from 2008 to 2024, and employing the hydrological area analogy method, the maximum inflow from the Shuangjiangkou Dam site to the Dajin section is calculated to be Q_interval_max = 100 m³ / s.

[0055] (6) If the inflow process of the reservoir is stable during the forecast period, the degree of rise of the reservoir operating water level shall be determined by the reverse calculation approach.

[0056] Based on the analysis of the forecast period Tp, the pre-discharge flow Qf, and the forecast flow Qp, when the forecast inflow within the forecast period Tp is greater than Qp, the reservoir uniformly pre-discharges Qr in a uniform manner, so as to lower the reservoir level to the flood control limit level within the forecast period without increasing the downstream flood control pressure as much as possible. The Shuangjiangkou Reservoir pre-discharged its water level from 2481-2500m to 2480m within 12h, 24h, and 48h. The increased discharge flow rates required for the reservoir level to drop to the flood control limit level within different forecast periods are shown in Table 5.

[0057] Table 5 shows the increased discharge flow rates as the reservoir water level drops to the flood control limit level during different forecast periods.

[0058] (7) If the inflow of water to the reservoir shows an upward trend during the forecast period, calculate the water level that the reservoir can rise during the continuous rise.

[0059] Taking a less favorable scenario, for a continuously rising inflow during the forecast period, the rise in water level is analyzed as a linear change. Therefore, different inflow conditions (Qin), different forecast flow rates (Qp) (1000–3000 m³ / s), pre-release flow rates (600–3000 m³ / s), and a pre-lowering water level of 2480 m are considered. The corresponding pre-release volume and upward displacement space are also considered for different forecast periods (12h, 24h, 48h).

[0060] Assuming a lead time of 24 hours, and the pre-release flow rate is 1000 m³ / h 3 / s, 1400m 3 / s, 1800m 3 / s、2200m 3 / s, 2600m 3 / s, 3000m 3 / s, 3400m 3 At a flow rate of / s, the potential for water level rise in the Shuangjiangkou Hydropower Station reservoir under different forecast flow rates was calculated, and the results are shown in Tables 6 to 11: Table 6 shows the calculation of reservoir upwelling space for different inflow and pre-discharge rates (pre-discharge rate 1000m³). 3 / s, forecast period 24h) Water volume: 100 million m³ 3 Water level: m

[0061] Table 7 shows the calculation of reservoir upwelling space for different inflow and pre-discharge rates (pre-discharge rate 1400m³). 3 / s, forecast period 24h) Water volume: 100 million m³ 3 Water level: m Table 8 shows the calculation of reservoir upwelling space for different inflow and pre-discharge rates (pre-discharge rate 1800 m³ / s). 3 / s, forecast period 24h) Water volume: 100 million m³ 3 Water level: m

[0062] Table 9 shows the calculation of reservoir upwelling space for different inflow and pre-discharge rates (pre-discharge rate 2200 m³ / s). 3 / s, forecast period 24h) Water volume: 100 million m³ 3 Water level: m

[0063] Table 10 shows the calculation of reservoir upwelling space for different inflow and pre-discharge rates (pre-discharge rate 2600 m³ / s).3 / s, forecast period 24h) Water volume: 100 million m³ 3 Water level: m

[0064] Table 11 shows the calculation of reservoir upwelling space for different inflow and pre-discharge rates (pre-discharge rate 3000 m³ / h). 3 / s, forecast period 24h) Water volume: 100 million m³ 3 Water level: m

[0065] (8) From the perspective of the actual inflow of water into the reservoir, verify whether the reservoir can release water to the flood limit level under different forecast periods and different pre-discharge flows.

[0066] Based on a preliminary analysis of the graded fluctuation space of the operating water level of a reservoir during the flood season, this section uses the hourly flow process of a certain station during the main flood season from 2010 to 2025 to analyze the dynamic pre-release of the operating water level under different forecast conditions. Different floating schemes and forecasted inflow rates (1000 m³ / s) are calculated and statistically analyzed. 3 / s, 1400m 3 / s, 1800m 3 / s、2200m 3 / s, 2600m 3 / s, 3000m 3 Analysis of the pre-discharge situation with a safe pre-discharge to the flood control limit level of 2480m ( / s), with a pre-discharge flow not exceeding 3000m³ / s. 3 / s verifies the safety pre-leakage of the proposed buoyancy space.

[0067] Based on a 24-hour forecast period and a predicted inflow of 1800 m³ / h 3 For example, / s: Based on the measured inflow flood process, if it is necessary to safely pre-discharge to the flood control limit level of 2480m within the forecast period, and the operating water level rises to 2481m, the pre-discharge flow rate needs to be 1800m³. 3 / s or higher; when the operating water level rises to 2482m, the pre-release flow rate needs to be 2200m³ / s. 3 / s or higher; when the operating water level rises to 2483m, the pre-discharge flow rate needs to be 2600m³ / s. 3 / s or higher; when the operating water level rises to 2484m, the pre-discharge flow rate needs to be 3000m³. 3 / s or more. As shown in Tables 12 to 14.

[0068] Table 12 shows the predicted inflow rate of 1800 m³ / h. 3 Statistical table of pre-discharge situations under different pre-discharge flow rates and rising water levels in the / s scenario, with a forecast period of 12 hours.

[0069] Table 13 shows the predicted inflow rate of 1800 m³ / h. 3 Statistical table of pre-discharge situations under different pre-discharge flow rates and rising water levels in the / s scenario, with a 24-hour lead time.

[0070] Table 14 shows the predicted inflow rate of 1800 m³ / h. 3 Statistical table of pre-discharge situations under different pre-discharge flow rates and rising water levels in the / s scenario, with a forecast period of 48 hours.

[0071] (9) Combining simulation and actual inflow calculation results, for each type The minimum allowable rise of the reservoir is taken as the result of the reservoir's operating water level fluctuation under this forecast period and pre-release scenario.

[0072] As shown in Tables 15 to 17, the simulated water inflow conditions are as follows: Table 15 compares the calculation of reservoir upwelling space under different inflow rates 12 hours ahead of the warning date, assuming no downstream warning level is caused. Flow rate: m³ 3 / s Water level: m

[0073] Table 16 compares the calculations of reservoir upwelling space under different inflow rates 24 hours ahead of the forecast period, assuming no downstream warning level is triggered. Flow rate: m³ 3 / s, water level: m

[0074] Table 17 compares the calculations of reservoir uplift space under different inflow rates 48 hours ahead of the warning level, assuming no downstream warning level is triggered. Flow rate: m³ 3 / s Water level: m

[0075] As shown in Tables 18 to 20, under actual water inflow conditions: Table 18 compares the calculation of reservoir upwelling space under different inflow rates 12 hours ahead of the warning time, assuming no downstream warning level is caused. Flow rate: m³ 3 / s Water level: m

[0076] Table 19 compares the calculations of reservoir uplift space under different inflow rates 24 hours ahead of the warning date, assuming no downstream warning level is triggered. Flow rate: m³ 3 / s, water level: m

[0077] Table 20 compares the calculation of reservoir upwell space under different inflow rates 48 hours ahead of the warning date, without causing downstream warning levels to exceed the warning level. Flow rate: m³ 3 / s Water level: m

[0078] The fluctuations resulting from the combined analysis of both factors are shown in Tables 21 to 23: Table 21 compares the calculation of reservoir upwelling space under different inflow rates 12 hours ahead of the warning time, assuming no downstream warning level is caused. Flow rate: m³ 3 / s, water level: m

[0079] Table 22 compares the calculated reservoir uplift space under different inflow rates 24 hours ahead of the warning date, assuming no downstream warning level is triggered. Flow rate: m³ 3 / s, water level: m

[0080] Table 23 compares the calculation of reservoir upwelling space under different inflow rates 48 hours ahead of the warning time, assuming no downstream warning level is caused. Flow rate: m³ 3 / s, water level: m

[0081] Working Principle: By analyzing hydrological and meteorological patterns, forecast accuracy, and inflow characteristics within a given area, the safe upward fluctuation limit of the reservoir's operating water level during the flood season is calculated in reverse, achieving a dynamic balance between flood control safety and flood resource utilization. First, historical rainstorm and flood data are collected, and statistical methods are used to reveal the causes, spatiotemporal distribution, and evolution patterns of rainstorms, laying the foundation for subsequent analysis. Simultaneously, the water level-discharge relationship at downstream control sections is plotted to verify consistency and determine a comprehensive relationship line to quantify flood control objectives. Second, the basin's meteorological and hydrological forecasting level is assessed. By evaluating the accuracy of rainfall processes, the precision of precipitation forecasts at different lead times, and the precision of hydrological forecasts, lead times with high availability are selected as the basis for water level fluctuation calculations. Next, inter-area flow analysis is conducted: if a tributary flows into the area, the tributary inflow is directly used; if there is no tributary but data is available from both upstream and downstream, the inter-area inflow is calculated using the flow difference; if there is no downstream data, the area ratio method is used for estimation, and the maximum reservoir discharge is determined by combining this with the maximum inflow within the area, thereby defining the pre-discharge range. Based on this, the upward floating limit is calculated for different inflow situations: if the inflow is stable during the forecast period, a reverse calculation is used, assuming the water level rises by a certain margin, to check whether the increased discharge flow can safely pre-release the water to the flood control limit within the forecast period; if the inflow shows an upward trend, a combination of multi-level pre-discharge flow, current inflow, and maximum flow at the end of the forecast period is preset, and the pre-dischargeable water volume is calculated iteratively and the allowable upward floating water level is deduced, taking the lowest value of the safe upper limit among each combination. Finally, using the actual hourly inflow process over many years, pre-discharge scenarios under different forecast periods and pre-discharge flows are simulated, the success rate of safe pre-discharge is verified and statistically analyzed, and the simulation and actual calculation results are combined. For each combination of forecast period and pre-discharge flow, the lowest allowable upward floating water level is selected as the final operating water level fluctuation result, thereby maximizing the potential for flood resource utilization without increasing downstream flood control risks.

[0082] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims. Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This method of description is merely for clarity, and those skilled in the art should consider the specification as a whole. The technical solutions in the various embodiments can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A dynamic control method for reservoir flood season operation water level based on forecast availability, characterized in that The method for dynamic control of reservoir water level during the flood season includes the following steps: S1. Analysis of basic hydrological and meteorological patterns: Collect historical typical rainstorm and flood events, and use statistical methods to conduct analysis of basic hydrological and meteorological patterns; S2. Analysis of water level and flow rate relationship: For the same year, plot the water level and flow rate relationship of the downstream control section of the reservoir to determine whether the multi-year water level and flow rate relationship line is a single current distribution and whether it has consistency. S3. Analysis of meteorological and hydrological forecasting level: Collect hydrological and meteorological forecasting products and conduct analysis of the meteorological and hydrological forecasting level of the watershed; S4. Inter-regional flow analysis: If a major tributary flows into the interval, the inflow of that tributary is used as the inflow process of the interval; if no major tributary flows into the interval, but there is a long series of hydrological data at the reservoir dam site and the downstream flood control section, the inflow process of the interval is calculated using the flow difference; if no major tributary flows into the interval, but there is a long series of hydrological data at the reservoir dam site and no long series of hydrological data downstream, the inflow process of the interval is calculated using the area ratio method. S5. Calculation of the maximum upward movement of reservoir operating water level during the flood season: If the inflow process during the forecast period is stable, the degree of upward movement of the reservoir operating water level is determined by reverse calculation; if the inflow process during the forecast period is rising, the water level that the reservoir can rise under the continuous rising process is calculated; from the perspective of the actual inflow of the reservoir, it is verified whether the reservoir can release water to the flood limit level under different forecast periods and different pre-discharge flows; S6. Combining the simulation and actual inflow calculation results, for each combination of forecast period and pre-discharge flow, the lowest value that the reservoir is allowed to float is taken as the result of the reservoir's operating water level fluctuation under this forecast period and pre-discharge scenario.

2. The method for dynamic control of the operating water level of a reservoir during the flood season according to claim 1, characterized in that: In S1, the analysis of basic hydrological and meteorological laws specifically includes: Analysis of Rainstorm Patterns: The causes of rainstorms are analyzed from the aspects of upper-level troughs, low-level vortices, shear lines, low-level jet streams and surface cold air, and the characteristics of rainstorms are analyzed from the aspects of spatiotemporal distribution, intensity and frequency. Hydrological pattern analysis: The flood pattern is analyzed from the aspects of the development process of typical historical floods, the composition of flood areas, the flood encounter situation, the composition of long-term runoff, and the annual distribution.

3. The method for dynamic control of the operating water level of a reservoir during the flood season according to claim 1, characterized in that: In S2, the flow difference corresponding to the same water level of the upper and lower envelope lines of the multi-year water level-flow relationship cannot exceed a threshold value: ; If there is consistency, adopt the comprehensive line of water level discharge relationship of many years As the water level discharge relationship line of the control station, and based on the water level discharge relationship line, the target water level of the flood control section downstream of the reservoir is determined The corresponding discharge respectively ; In the formula: represents the water level-flow relationship line of the current year, represents the water level-flow relationship line of a certain year other than the current year, represents a certain water level, represents the difference between the flow corresponding to the same water level under different water level-flow relationship lines, represents the threshold of the flow difference, represents the comprehensive water level-flow relationship line, represents the control flow corresponding to the same water level under the comprehensive line.

4. The method of claim 1, wherein the method further comprises: In S3, the meteorological and hydrological forecast level analysis specifically includes: Rainfall forecast level: accuracy of the precipitation process in a certain period and the precipitation forecast accuracy of different forecast periods Evaluation is carried out, if and , the rainfall forecast in the forecast period is more available;​ Hydrological forecast level: the hydrological forecast in the same period as the rainfall forecast is evaluated for different forecast periods ( ). If , the hydrological forecast in the forecast period is more reliable. based on the analysis results of the rainfall prediction level and the hydrological prediction level, as the prediction period of the reservoir flood control level float calculation; wherein: represents the accuracy of the precipitation process for a certain period, represents the forecast period the accuracy of the precipitation forecast, represents the forecast period the accuracy of the hydrological forecast, represents the forecast period the flow value of the forecast, represents the forecast period the flow value of the live.

5. The method of claim 1, wherein: The method for dynamic control of reservoir water level during the flood season involves collecting and organizing reservoir characteristic parameters and water level-capacity curves. The analysis of influencing factors on the dynamic control of reservoir flood control water level is conducted using discharge capacity curves and reservoir flood control scheduling methods. The reservoir characteristic parameters include normal storage water level, flood control high water level, dead water level and their corresponding reservoir capacity and full discharge.

6. The reservoir flood operation water level dynamic control method according to claim 5, characterized in that: In S4, the inflow process of the interval calculated using the flow difference is calculated using the following formula: In the formula, denotes the interval flow, denotes the flow of the downstream flood control section, denotes the flow of the upstream flood control section.

7. The reservoir flood operation water level dynamic control method according to claim 5, characterized in that: In S4, the calculation of the water inflow process in the interval using the area ratio method is performed by the following formula: In the formula: represents the catchment area represented by the downstream flood control section, represents the catchment area represented by the reservoir dam site; Consider the reservoir distance flood control section interval of maximum inflow , calculate the maximum reservoir discharge , combined with the reservoir full discharge , determine the reservoir pre-discharge flow range: when , the reservoir pre-discharge flow ; Otherwise the reservoir is discharged as much as possible ; In the formulae: denotes the maximum value in the interval flow series, denotes the pre-discharge flow of the reservoir, denotes the maximum discharge flow of the reservoir.

8. The method for dynamic control of reservoir operating water level during flood season according to claim 5, characterized in that: In S5, if the inflow process of the reservoir is stable during the forecast period, the degree of rise in the reservoir's operating water level is determined by using a reverse calculation approach, specifically including: Assuming the reservoir water level is above the flood control level m, the reservoir water level is , and the corresponding reservoir capacity difference is ; If the prediction period is , , the reservoir needs to increase discharge on the basis of the inflow in the prediction period; If , it indicates that the reservoir floats up to ; In the formulae: represents the flood control water level of the reservoir, represents the degree of floating above the flood control water level of the reservoir, represents the floating water level of the reservoir, represents the reservoir capacity corresponding to the flood control water level, represents the reservoir capacity corresponding to the floating water level, represents the difference between the reservoir capacity corresponding to the floating water level and the reservoir capacity corresponding to the flood control water level, represents the flow that needs to be additionally discharged on the basis of the existing inflow flow if the floating water level is to be discharged to the flood control water level within the foreseeable period .

9. The method for dynamic control of the operating water level of a reservoir during the flood season according to claim 5, characterized in that: In S5, if the inflow to the reservoir shows an upward trend during the forecast period, the specific calculation of the reservoir's potential water level rise during the continuous rise includes: Assuming the forecast period is ( ), the pre-discharge flow is preset level;​ If the pre-discharge flow is , the current reservoir inflow and the maximum reservoir inflow at the end of the forecast period are set as , and optionally the current reservoir inflow and the maximum reservoir inflow at the end of the forecast period and , and the floating calculation is carried out, provided that , and . water that can be released in the foreseeable period based on the reservoir water level-storage capacity curve the floating water level is calculated, ; Traverse all Combinations, calculate the floating water level of each combination on the reservoir, from the safety point of view, the highest water level allowed to float on the reservoir under each Combination is ; wherein: represents the number of discharge options set directly by the pre-discharge flow rate and the maximum discharge flow rate, represents the jth current reservoir inflow flow rate set when the pre-discharge flow rate is represents the jth current reservoir inflow flow rate set when the pre-discharge flow rate is represents the kth future end-of-period maximum inflow flow rate set when the pre-discharge flow rate is represents the kth future end-of-period maximum inflow flow rate set when the pre-discharge flow rate is represents the amount of pre-dischargeable water within the prediction period, represents the floatable water level.

10. The method of claim 5, wherein the method further comprises: In S5, from the perspective of actual reservoir inflow, the verification of whether the reservoir can release water to the flood control limit level under different forecast periods and different pre-discharge flows specifically includes: Based on the actual hourly inflow process of reservoirs for many years, set several maximum reservoir inflow values , according to different prediction periods ( ), from the maximum reservoir inflow value to the reservoir inflow at the beginning of the prediction period , get several actual inflow processes ; Adopting different pre-discharge flow , calculate the pre-discharge water volume in the forecast period, and calculate the floating water level based on the reservoir water level-storage curve; Traverse all Combination, calculate the actual water scene under each combination of reservoir floating water level , From the safety point of view, the highest water level allowed by the reservoir to float under each Combination is ; In the formulae: represents a certain maximum inflow value, represents the forecast period is calculated by counting back from the maximum inflow value to the inflow at the beginning of the forecast period, represents the amount of water that can be released during the forecast period, represents the floatable water level.

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