Method for determining reservoir flood control capacity release mode in stages
By comprehensively considering factors such as the rainy season in the basin, excess flood volume, and inflow between sections, the timing of phased release of flood control capacity in reservoirs is determined, which solves the shortcomings of traditional reservoir flood control capacity release methods and achieves efficient utilization of flood resources and flood control safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-11
- Publication Date
- 2026-07-21
AI Technical Summary
Traditional reservoir flood control capacity release methods fail to fully consider the hydrological changes in the basin, resulting in low flood control risk and low efficiency in flood resource utilization, and are unable to adapt to the gradual decline of flood volume in the basin.
By comprehensively considering factors such as the timing of the rainy season in the basin, the historical water level time series of downstream flood control stations, the spatiotemporal distribution of excess flood volume, and the spatiotemporal distribution of inflow in the interval, the timing of phased release of flood control storage capacity is determined, and the gradual release method of flood control storage capacity is recommended through flood regulation calculations and risk mapping.
It has improved the efficiency of flood resource utilization, adapted to the characteristics of the gradual decline of flood volume in the basin, ensured flood control safety, enhanced the flexibility and scientific nature of dispatching, reduced water loss, and improved the utilization of hydropower resources.
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Figure CN122434028A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of reservoir scheduling technology, specifically relating to a method for determining the scheduling mode of gradually releasing flood control capacity in stages at the end of the flood season. Background Technology
[0002] The design phase of a reservoir stipulates that reservoirs with flood control functions must reserve flood control capacity for downstream flood-protected areas. This capacity, between the flood control limit level and the flood control high level, is specifically used during the flood season to ensure the flood safety of downstream flood-protected areas. However, reservoir design regulations often prioritize flood safety, controlling the operating water level near the flood control limit level throughout the flood season. Only after the flood season has passed can the reservoir gradually release the reserved flood control capacity for downstream flood protection.
[0003] However, the flood season in the basin is relatively long, generally lasting 2-4 months. The possibility of a major flood at the end of the flood season is extremely low. If reservoirs consistently reserve sufficient flood control capacity and maintain water levels near flood control limits, it will affect the subsequent water storage process. Especially in dry years, low post-flood water levels may impact the benefits of urban water supply, power generation, and ecological water use in the following water supply year. To fully utilize the comprehensive functions of reservoirs and meet downstream water demand, it is urgent to study the hydrological changes and characteristics of the basin at the end of the flood season from a holistic perspective. Under the premise of ensuring flood control safety, it is necessary to explore the possibility of gradually releasing flood control capacity in stages at the end of the flood season to increase reservoir fullness and ensure water supply security.
[0004] Traditional technologies do not comprehensively consider the timing of releasing flood control capacity from reservoirs. They only consider the single factor of the rainy season and cannot reflect the hydrological changes in the basin, nor can they judge the evolution of the flood control situation and flood control needs in the downstream area. Furthermore, traditional technologies release flood control capacity in a one-time manner, which cannot adapt to the gradual decline of flood volume in the basin, resulting in flood control risks and low efficiency in the utilization of flood resources. Summary of the Invention
[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for determining the phased release of flood control capacity at the end of the flood season. This method comprehensively considers factors such as the timing of the rainy season in the basin, historical water level time series at downstream flood control stations, the spatiotemporal distribution of excess flood volume, and the spatiotemporal distribution of inflow within the basin to determine the timing of flood control capacity release. By selecting a typical year to conduct flood regulation calculations and drawing a flood risk map, the recommended phased release method of flood control capacity is determined. This solves the technical problem that previous methods or technologies are difficult to adapt to the hydrological changes in the basin and the evolution of downstream flood control situations. It is of great significance for the resource utilization of floodwater at the end of the flood season, improving the reservoir's water storage guarantee rate, and ensuring downstream flood control and water security.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The method for determining the phased release of reservoir flood control capacity at the end of the flood season includes the following steps: Step 1: Collect and organize basic data, including: hydrological and meteorological data, information on downstream flood control protection targets, and reservoir scheduling parameters. Step 2: Determine the timing of releasing the reservoir's flood control capacity by considering multiple factors; Step 3: Determine the criteria for releasing flood control capacity of the reservoir based on the water level characteristics of the flood control station; Step 4: Flood risk analysis and risk mapping of reservoir flood control capacity release; Step 5: Based on the flood risk map, determine the recommended flood control reservoir capacity release and scheduling method.
[0007] Preferably, the hydrological and meteorological data in step 1 include watershed rainfall data, water level and flow processes at flood control stations, actual flood processes at the dam site in different typical years, and tributary inflow and outflow processes; Information on downstream flood protection targets includes flood control standards, flood control sections, and safe discharge capacity; Reservoir scheduling parameters include flood control limit water level, flood control high water level, water level-reservoir capacity curve, discharge flow-tailwater level curve, and discharge capacity curve.
[0008] Preferably, step 2 specifically includes: Step 2.1, Statistical analysis of the rainy season in the basin: Statistically analyze the start time, end time, duration, and cumulative rainfall of the rainy season in the basin, and analyze the evolution trend of the rainy season in the basin over time; Step 2.2, Time-history distribution analysis of excess flood volume: Based on the long-term flow data of flood control stations, calculate and analyze the excess flood volume, and draw a distribution map of the excess flood volume of control stations over time to analyze the variation law of excess flood volume over time; Step 2.3, Analysis of downstream flood control station water level data: Based on long-term water level data, analysis is conducted to calculate the average water level of the flood control stations, analyze the trend of water level changes over time, and summarize the laws governing flood evolution. The calculation method for the average water level of the flood control stations is as follows: ; In the formula, For flood control station in the long series i Year j Daily water level; N The number of years in a long series; For the first j The daily average water level over many years; Step 2.4, Interval Inflow Time History Distribution Analysis: Based on long-series interval inflow data, calculate the average interval inflow, analyze the trend of interval inflow over time, and summarize the evolution law of interval inflow. The calculation method for the average interval inflow is as follows: ; In the formula, For the first in the long series i Year j Inflow value between the dam site of the reservoir and the flood control station; For the first j Daily interval inflow average; N The number of years in a long series; Step 2.5: Based on the rainy season, excess flood volume, water levels at downstream flood control stations, and the evolution of inflow patterns within the interval, determine the timing for releasing flood control storage capacity. .
[0009] Preferably, in step 2.2, the method for calculating and analyzing excess flood volume is as follows: Step 2.2.1, calculate the composite flow rate at the flood control station: ; In the formula, For the first in the long series i Year j Daily reservoir dam site flow rate For the first in the long series i Year j Inflow between the dam site of the Rishui Reservoir and the flood control station; For the series of flood control station chiefs i Year j Daily synthetic flow rate; Step 2.2.2, calculate the excess flood volume: ; In the formula, This is the safe discharge capacity corresponding to the downstream flood control station. For the first i Year j The daily excess flood volume; For the series of flood control station chiefs i Year j Daily synthetic flow rate; Step 2.2.3, Calculate the average and maximum values of excess flood volume: Based on the excess flood volume for each day of each year in the long series, calculate the average and maximum values of the excess flood volume. The calculation method is as follows: ; In the formula, For the first j The multi-year average of daily excess flood volume; The first in a long series of flood control stations j The maximum daily excess flood volume For the first i Year j The daily excess flood volume; N The number of years in a long series; Step 2.2.4, draw the excess flood volume distribution map: with the date as the horizontal axis and the excess flood volume as the vertical axis, plot the average excess flood volume and the maximum excess flood volume on the same graph to obtain the distribution map of the excess flood volume over time.
[0010] Preferably, step 3 specifically includes: Step 3.1: Statistically analyze the highest water level values of flood control stations for each year within a long series, identify patterns, and explore the release timing determined in Step 2. Water level indicators that do not require flood control scheduling in subsequent periods This indicator meets the following conditions: ; In the formula, N The number of years in a long series; The first in the long series i Years Previous water level value; This refers to the definite water level identification index; For the i-th year in a long series Subsequent water level values; This refers to the warning water level at the flood control station; specifically, this condition means that for any year in a long series of years, the timing of release... The previous highest water level was lower than the discrimination index. When to release Subsequent water levels were all below the warning level of the flood control station, meaning there was no need for flood control. Step 3.2, Select the release timing During the previous period, the water level at the flood control station did not exceed the water level judgment index. The maximum inflow rate within the corresponding interval is used as the indicator for judging the inflow rate within the interval. This indicator meets the following conditions: ; In the formula, That is, the inflow rate discrimination index for a defined interval; This refers to the definite water level identification index; For the i-th year in a long series Subsequent water level values; Preferably, step 4 specifically includes: Step 4.1, Selection of Typical Floods: Typical major floods that may pose a flood control risk downstream are selected as calculation samples to comprehensively describe the flood control needs of the middle and lower reaches; the flood series corresponding to the selected typical major floods are shown below: ; In the formula, Flood s This represents the selected typical major flood series; This represents the flow rate on the last day of the flood series; S is the typical quantity of the selected major flood. Step 4.2, Calculation scheme formulation: at a certain time interval, at the release timing Afterwards, draft At different time points, at a certain water level interval, the reservoir's flood control limit water level... Above the flood control high water level The following is proposed The calculation scheme is formed by combining different starting water levels of various reservoirs. Step 4.3, Flood Regulation Calculation: With the downstream river section requiring flood protection not exceeding the guaranteed water level as the scheduling objective, the reservoir discharge flow is controlled to not exceed the safe discharge. For a certain scheme, the proposed starting water level is used as the initial scheduling state. Flood regulation calculations are performed for the flood series following this time point in each typical major flood, and the maximum flood regulation water level of the reservoir is calculated. Step 4.4, Flood Risk Mapping: Based on the calculation results of the highest flood control water level of reservoirs at different time points, different starting water levels, and different typical major flood series, draw a flood risk map.
[0011] Preferably, the calculation scheme in step 4.2 is as follows: The time point is At that time, the starting water level was , ... ; The time point is At that time, the starting water level was , ... ; ... The time point is At that time, the starting water level was , ... .
[0012] Preferably, in step 4.3, the flood control calculation method is as follows: Step 4.3.1, Initial reservoir capacity in the previous period and reservoir water level For the initial period, this refers to the initial water level and its corresponding reservoir capacity. Step 4.3.2: Determine the reservoir discharge flow rate for the current time period. The specific formula is as follows: ; In the formula, This represents the average inbound flow rate for the current period. This represents the average inflow rate over the current time period. To ensure safe discharge at flood control stations; This represents the current outflow from the reservoir. Step 4.3.3 Calculate the reservoir capacity at the end of the current period based on the water balance equation. The specific formula is as follows: ; In the formula, This represents the initial reservoir capacity for the current period. This represents the reservoir capacity at the end of the current period. The duration of the time period; This represents the average inbound flow rate for the current period. This represents the current outflow from the reservoir. Step 4.3.4 Determine the reservoir water level at the end of the current period based on the reservoir water level-capacity curve. The specific formula is as follows: ; In the formula, This represents the reservoir water level at the end of the current period. f This is a reservoir water level and storage capacity curve; This represents the reservoir capacity at the end of the current period. Step 4.3.5, repeating steps 4.3.1 to 4.3.4, starting from the first calculation period, sequentially calculate the average outflow, reservoir capacity at the end of each period, and reservoir water level for all calculation periods under typical conditions of this major flood, when the reservoir starts regulating from a certain water level. Step 4.3.6: Repeat steps 4.3.1 to 4.3.5 to carry out flood control calculations for different time points, different starting water levels, and different typical flood series, until the flood control calculations for all calculation schemes are completed, and obtain the highest flood control water level of the reservoir under each condition.
[0013] Preferably, in step 4.4, the method for drawing the flood risk map is as follows: Step 4.4.1: At a given time point, under a specific initial water level regulation, the highest flood regulation water level of each typical major flood is taken as the outermost value and used as the maximum highest flood regulation water level starting from that water level at that time point, as follows: ; In the formula, Indicates the first m Under the condition of adjusting the water level...S The maximum value of the highest flood control water level in a typical major flood; Indicates the reservoir as the first m Under the condition that the water level is adjusted at the starting level, the highest water level calculated for the flood control of the s-th typical major flood; Step 4.4.2, Flood Risk Assessment, the specific assessment method is as follows: ; In the formula, This refers to flood control risks; Indicates the first m Under the condition of adjusting the water level... S The maximum value of the highest flood control water level in a typical major flood; This represents the flood control high water level corresponding to the flood control storage capacity reserved for flood control in the middle and lower reaches of the river. When the highest water level calculated for flood control in different typical major flood series is greater than the flood control high water level under a certain initial water level regulation, it indicates that there is a flood control risk; otherwise, the flood control risk is 0. Step 4.4.3, Flood Risk Map Drawing: For a specific time point, draw a flood risk map with the starting water level as the horizontal axis and flood risk as the vertical axis; Step 4.4.4: Create flood risk maps for different time points to form a flood risk map.
[0014] Preferably, in step 5, the specific steps for determining the recommended flood control storage capacity release method based on the flood control risk map are as follows: Step 5.1: Based on the flood risk map, determine the highest starting water level value for flood control at any given time point when the flood risk is 0, as follows: ; In the formula, This indicates the highest starting water level when the flood control risk is 0 at time point T; This represents the i-th water level at time point T. Step 5.2, reverse-engineer the flood control reservoir release corresponding to the highest starting water level at a certain time point when the flood control risk is 0: ; In the formula, f This is a reservoir water level and storage capacity curve; Indicates time node Flood control capacity that can be released under certain circumstances; The water level is set as a flood control limit for the reservoir. This indicates the highest starting water level when the flood control risk is 0 at time point T; Step 5.3: The sequence of flood control storage capacity release at different time points is the recommended flood control storage capacity release method, as detailed below: ; The above formula indicates that at the time node Release flood control capacity At the time point Release flood control capacity , ……
[0015] The present invention has the following beneficial effects: 1. The method for determining the phased release of flood control storage capacity at the end of the flood season provided by the present invention determines the timing of flood control storage capacity release by comprehensively considering factors such as the timing of the rainy season in the basin, the trend of water receding in the middle and lower reaches, the time history distribution of excess flood volume, and the time history distribution of inflow in the interval. Compared with a single factor, it can better reflect the hydrological change pattern of the basin, thus meeting the changing trend of downstream flood control scheduling needs.
[0016] 2. This invention establishes multiple time points, selects typical years to carry out flood regulation calculations and draws flood control risk maps to determine the recommended gradual release method of flood control storage capacity. Compared with the traditional technology that releases flood control storage capacity in a one-time manner, it is more adaptable to the characteristics of the gradual decline of flood volume in the basin, and greatly improves the efficiency of flood resource utilization while ensuring no risk of flooding.
[0017] 3. The method proposed in this invention can accurately determine the timing of flood control capacity release by considering multiple factors, adapting to the evolution of flood control situation and flood control needs in the downstream basin. At the same time, it uses a method of calculating the flood control risk at different starting water levels at multiple time nodes to inversely deduce the amount of flood control capacity that can be released at each time node, realizing the phased release of flood control capacity. Under the premise of ensuring flood control safety, it greatly improves the flexibility of scheduling and is of great significance for the resource utilization of floodwater at the end of the flood season. This method is more in line with the actual scheduling of reservoirs, and is committed to solving the problems existing in actual scheduling, and can provide support for scheduling decisions. Attached Figure Description
[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments of the present invention will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 This is a flowchart illustrating a method for determining the phased release of flood control capacity at the end of the flood season, as per the present invention.
[0020] Figure 2 This is a time-history distribution map of excess flood volume in region B in an embodiment of the present invention.
[0021] Figure 3This is a time history distribution diagram of the average water level at the CLJ flood control station in an embodiment of the present invention.
[0022] Figure 4 This is a time history distribution diagram of the mean inflow over a long series interval in an embodiment of the present invention.
[0023] Figure 5 This is a diagram showing the relationship between the water level of the long series CLJ stations and the inflow between them in an embodiment of the present invention.
[0024] Figures 6-8 This is a flood risk map at different time points in an embodiment of the present invention; Detailed Implementation To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.
[0025] like Figure 1 As shown, this invention provides a method for determining the phased release of flood control capacity at the end of the flood season, comprising: Step 1: Collect and organize basic data. This includes: hydrological and meteorological data, information on downstream flood control protection targets, reservoir scheduling parameters, etc. Specifically, this includes basin rainfall data, water level and flow processes at flood control stations, actual flood processes at the dam site in different typical years, and tributary inflow and outflow processes; downstream flood protection information includes flood control sections and safe discharge. Reservoir operation parameters include flood control limit water level, flood control high water level, water level-reservoir capacity curve, discharge-tailwater level curve, and discharge capacity curve. It also includes design floods, typical flood processes, and inter-dam flood data at different frequencies.
[0026] Step 2: Determine the timing of releasing the reservoir's flood control capacity by considering multiple factors.
[0027] Step 2.1, Statistical Analysis of the Rainy Season in the Watershed. This mainly involves statistically analyzing parameters such as the start and end times of the rainy season, its duration, and cumulative rainfall, and analyzing the evolution trend of the rainy season over time. Step 2.2, Time-history distribution analysis of excess flood volume. Based on the long-term flow data of flood control stations, the excess flood volume is calculated and analyzed, and a distribution map of the excess flood volume of control stations over time is plotted to analyze the variation law of excess flood volume over time.
[0028] Step 2.3, Analysis of Water Level Data from Downstream Flood Control Stations. Based on long-term water level data, analysis is conducted to calculate the average water level at the flood control stations, analyze the trend of water level changes over time, and summarize the patterns of flood evolution. The calculation method for the average water level at the flood control stations is as follows: ; In the formula, For flood control station in the long series i Year j Daily water level; N The number of years in a long series; For the first j The daily average water level over many years; Step 2.4, Interval Inflow Time-History Distribution Analysis. Based on long-series interval inflow data, calculate the average interval inflow, analyze the trend of interval inflow over time, and summarize the evolution law of interval inflow. The calculation method for the average interval inflow is as follows: ; In the formula, For the first in the long series i Year j Inflow value between the dam site of the reservoir and the flood control station; For the first j Daily interval inflow average; N The number of years in a long series; Step 2.5: Based on the rainy season, excess flood volume, water levels at downstream flood control stations, and the evolution of inflow patterns within the interval, determine the timing for releasing flood control storage capacity. .
[0029] Furthermore, in step 2.2, the calculation and analysis method for excess flood volume is as follows: Step 2.2.1, calculate the composite flow rate at the flood control station: ; In the formula, For the first in the long series i Year j Daily reservoir dam site flow rate For the first in the long series i Year j Inflow between the dam site of the Rishui Reservoir and the flood control station; For the series of flood control station chiefs i Year j Daily synthetic flow rate; Step 2.2.2, calculate the excess flood volume: ; In the formula, This is the safe discharge capacity corresponding to the downstream flood control station. For the firsti Year j The daily excess flood volume; For the series of flood control station chiefs i Year j Daily synthetic flow rate; Step 2.2.3: Calculate the average and maximum excess flood volume. Based on the calculated excess flood volume for each day of each year in the long series, calculate the average and maximum excess flood volume. The calculation method is as follows: ; In the formula, For the first j The multi-year average of daily excess flood volume; The first in a long series of flood control stations j The maximum daily excess flood volume For the first i Year j The daily excess flood volume; N The number of years in a long series; Step 2.2.4: Draw the excess flood volume distribution map. With date as the horizontal axis and excess flood volume as the vertical axis, plot the average excess flood volume and the maximum excess flood volume on the same graph to obtain the distribution map of excess flood volume over time.
[0030] Step 3: Determine the criteria for releasing flood control capacity of the reservoir based on the water level characteristics of the flood control control station.
[0031] Step 3.1: Statistically analyze the highest water level values of flood control stations for each year within a long series, identify patterns, and explore the release timing determined in Step 2. Water level indicators that do not require flood control scheduling in subsequent periods This indicator meets the following conditions: ; In the formula, N The number of years in a long series; The first in the long series i Years Previous water level value; This refers to the definite water level identification index; For the i-th year in a long series Subsequent water level values; The warning water level for flood control stations; this condition means: for any year in a long series of years, when the release timing... The previous highest water level was lower than the discrimination index. When to release Subsequent water levels were all below the warning level of the flood control station, meaning there was no need for flood control.
[0032] Step 3.2, Select the release timing During the previous period, the water level at the flood control station did not exceed the water level judgment index. The maximum inflow rate within the corresponding interval is used as the indicator for judging the inflow rate within the interval. This indicator meets the following conditions: ; In the formula, That is, the inflow rate discrimination index for a defined interval; This refers to the definite water level identification index; For the i-th year in a long series Subsequent water level values; Step 4: Risk analysis and risk mapping of reservoir flood control capacity release.
[0033] Step 4.1, Selection of Typical Floods: Typical major floods that may pose a flood control risk downstream are selected as calculation samples to comprehensively describe the flood control needs of the middle and lower reaches; the flood series corresponding to the selected typical major floods are shown below: ; In the formula, Flood s This represents the selected typical major flood series; This represents the flow rate on the last day of the flood series; S is the typical quantity of the selected major flood. Step 4.2, Calculation scheme formulation. At a certain time interval, at the release timing... Afterwards, draft At different time points, at a certain water level interval, the reservoir's flood control limit water level... Above the flood control high water level The following is proposed The calculation scheme is formed by combining different starting water levels of various reservoirs, as detailed below: Table 1 Calculation Scheme
[0034] Step 4.3, Flood Regulation Calculation: With the downstream river section requiring flood protection not exceeding the guaranteed water level as the scheduling objective, the reservoir discharge flow is controlled to not exceed the safe discharge. For a certain scheme, the proposed starting water level is used as the initial scheduling state. Flood regulation calculations are performed for the flood series following this time point in each typical major flood, and the maximum flood regulation water level of the reservoir is calculated. Step 4.4, Flood Risk Mapping: Based on the calculation results of the highest flood control water level of reservoirs at different time points, different starting water levels, and different typical major flood series, draw a flood risk map.
[0035] In step 4.3, the flood control calculation method is as follows: Step 4.3.1, Initial reservoir capacity in the previous period and reservoir water level For the initial period, this refers to the initial water level and its corresponding reservoir capacity. Step 4.3.2: Determine the reservoir discharge flow rate for the current time period. The specific formula is as follows: ; In the formula, This represents the average inbound flow rate for the current period. This represents the average inflow rate over the current time period. To ensure safe discharge at flood control stations; This represents the current outflow from the reservoir. Step 4.3.3 Calculate the reservoir capacity at the end of the current period based on the water balance equation. The specific formula is as follows: ; In the formula, This represents the initial reservoir capacity for the current period. This represents the reservoir capacity at the end of the current period. The duration of the time period; This represents the average inbound flow rate for the current period. This represents the current outflow from the reservoir. Step 4.3.4 Determine the reservoir water level at the end of the current period based on the reservoir water level-capacity curve. The specific formula is as follows: ; In the formula, This represents the reservoir water level at the end of the current period. f This is a reservoir water level and storage capacity curve; This represents the reservoir capacity at the end of the current period. Step 4.3.5, repeating steps 4.3.1 to 4.3.4, starting from the first calculation period, sequentially calculate the average outflow, reservoir capacity at the end of each period, and reservoir water level for all calculation periods under typical conditions of this major flood, when the reservoir starts regulating from a certain water level. Step 4.3.6: For different time points, different starting water levels, and different typical flood series, repeat steps 4.3.1 to 4.3.5 to carry out flood regulation calculations until all calculation schemes are completed and the highest flood regulation water level of the reservoir is obtained under each condition.
[0036] In step 4.4, the method for drawing the flood risk map is as follows: Step 4.4.1: At a given time point, under a specific initial water level regulation, the highest flood regulation water level of each typical major flood is taken as the outermost value and used as the maximum highest flood regulation water level starting from that water level at that time point, as follows: ; In the formula, Indicates the first m Under the condition of adjusting the water level... S The maximum value of the highest flood control water level in a typical major flood; Indicates the reservoir as the first m Under the condition that the water level is adjusted at the starting level, the highest water level calculated for the flood control of the s-th typical major flood; Step 4.4.2, Flood Risk Assessment, the specific assessment method is as follows: ; In the formula, This refers to flood control risks; Indicates the first m Under the condition of adjusting the water level... S The maximum value of the highest flood control water level in a typical major flood; This represents the flood control high water level corresponding to the flood control storage capacity reserved for flood control in the middle and lower reaches of the river. When the highest water level calculated for flood control in different typical major flood series is greater than the flood control high water level under a certain initial water level regulation, it indicates that there is a flood control risk; otherwise, the flood control risk is 0. Step 4.4.3, Flood Risk Map Drawing: For a specific time point, draw a flood risk map with the starting water level as the horizontal axis and flood risk as the vertical axis; Step 4.4.4: Create flood risk maps for different time points to form a flood risk map.
[0037] Step 5: Based on the flood risk map, determine the recommended flood control reservoir capacity release and scheduling method.
[0038] Step 5.1: Based on the flood risk map, determine the highest starting water level value for flood control at any given time point when the flood risk is 0, as follows: ; In the formula, Indicates time node The highest starting water level when the flood control risk is 0. This represents the i-th water level at time point T. Step 5.2, reverse-engineer the flood control reservoir release corresponding to the highest starting water level at a certain time point when the flood control risk is 0: ; In the formula, f This is a reservoir water level and storage capacity curve; Indicates time node Flood control capacity that can be released under certain circumstances; The water level is set as a flood control limit for the reservoir. This indicates the highest starting water level when the flood control risk is 0 at time point T; Step 5.3: The sequence of flood control storage capacity release at different time points is the recommended flood control storage capacity release method, as detailed below: ; The above formula indicates that at the time node Release flood control capacity At the time point Release flood control capacity , ……
[0039] Example 1 Reservoir A is a large reservoir on the main stream of the Yangtze River with comprehensive utilization needs. Region B is located downstream of Reservoir A. Reservoir A also has the task of flood control for Region B. When floods occur, the reserved flood control capacity needs to be used to impound floodwaters and ensure the flood control safety of Region B. To this end, Reservoir A has reserved a flood control capacity of 7.69 billion cubic meters for Region B. 3 The corresponding flood control high water level is 158m. For area B, the hydrological station that directly indicates whether there is a flood control need is the water level at station CLJ. The warning water level at this station is 32.5m, the guaranteed water level is 34.4m, and the safe discharge is 60,000 m³. 3 / s.
[0040] According to step 1), long-term rainy season data for region B, long-term water level data for station CLJ, long-term inflow data between reservoir A and station CLJ, as well as flood discharge capacity curves and water level-storage capacity curves for reservoir A have been collected.
[0041] Based on step 2), the statistical analysis parameters for the rainy season in region B are shown in Table 1. The table shows that the rainy season basically ended in early August. The time-history distribution map of excess flood volume in region B is shown below. Figure 2 As shown in the figure, the excess flood volume in region B began to decrease significantly starting in early August. The time-history distribution map of the average water level at station CLJ is shown below. Figure 3 As shown in the figure, the floodwaters in area B began to recede in late July, and the water level at the flood control station CLJ began to drop significantly. The inflow time history distribution map between Reservoir A and station CLJ is shown below. Figure 4 As shown in the figure, the inflow in the section reached its maximum in early July, and then began to recede. By early August, the flood season for the inflow in the section was basically over.
[0042] In summary, the timing for releasing the flood control capacity of Reservoir A as determined in step 2) can be early August, that is, starting from August 1st, the flood control capacity reserved by Reservoir A for flood control in area B can be gradually released.
[0043] Table 1. Statistical characteristics of the rainy season in Region B
[0044] Based on step 3), an analysis of the highest water level values at the CLJ flood control station revealed that when the highest water level before the release date (August 1st) was below 31.0m, the water levels after August 1st were all below the warning level of 32.5m at the CLJ station, indicating no flood control demand in area B. Further analysis of the inflow characteristics in the region when the CLJ station water level was below 31m after August 1st is detailed below [link to analysis]. Figure 5 Statistics show that when the water level at CLJ station is below 31m, the inflow during the same period is also 15,000m. 3 The percentage is below / s and above 99%.
[0045] Based on the above analysis, the criteria for releasing reservoir flood control capacity determined in step 3) are: before August 1st, the highest water level at CLJ station should not exceed 31m, and after August 1st, the inflow between stations should not exceed 15000m. 3 At a rate of / s, Reservoir A can gradually release flood control capacity reserved for flood control in region B.
[0046] The typical flood years selected in step 4) are 1896, 1945, 1958, 1966, 1974, and 1993. Considering different starting water levels at Reservoir A (150.0m, 152.0m, 154.0m, 155.0m, 157.0m, and 158m), with time points of August 21st, September 1st, and September 11th respectively, the flood control risk maps for different time points are shown in the flood control calculations. Figures 6-8 .
[0047] Based on step 5), the final recommended method for releasing the flood control capacity reserved by Reservoir A for flood control in region B is as follows: a maximum release of 3.78 billion m³ is possible in early to mid-August. 3 The maximum release of funds could reach 5.65 billion m³ in late August. 3 The maximum release of funds in early September could reach 7.69 billion m³. 3 .
[0048] This invention provides a method for determining the phased release of flood control capacity in reservoirs at the end of the flood season, solving the scheduling problem of wasted flood resources caused by "empty reservoirs waiting" during the flood season. It improves the accuracy of judgment by comprehensively considering key factors such as rainy season characteristics, the temporal distribution of excess flood volume, the evolution of water levels at flood control stations, and the temporal distribution of inflows between regions. This method accurately captures the evolutionary patterns of floods, breaking through the limitations of traditional single-factor analysis and enabling scientific determination of the timing of reservoir flood control capacity release. This greatly improves the consistency between flood control decisions and actual flood trends, providing solid and reliable decision support for scheduling. Furthermore, it enhances the scientific nature of scheduling decisions by deeply analyzing long-term hydrological big data from flood control stations to accurately identify water level characteristic indicators closely related to downstream flood risks and determine accordingly. The system establishes indicators for judging the release of flood control storage capacity, resolving the fundamental problem of the lack of standards for flood control storage capacity release and providing a scientific basis for scheduling. It also enhances the operability of scheduling by selecting representative flood years for flood control calculations, quantifying flood risk assessments and drawing risk maps. Based on the risk analysis results, it determines the flood control risk characteristic values of different starting water levels at different time points, and constructs a dynamic scheduling method for the gradual release of flood control storage capacity. This provides a scientific basis for reservoir flood control scheduling, ensuring that the scheduling method is both quantifiable and operable, effectively protecting downstream areas from flood threats.
[0049] In addition, the method of the present invention, by accurately judging the timing of the release of flood control storage capacity, gradually releases the flood control storage capacity, reduces water wastage losses, and improves power generation efficiency; at the same time, the rise in water level caused by the release of flood control storage capacity significantly improves the power output of the reservoir power station units during the flood season and improves the efficiency of water resource utilization.
[0050] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.
[0051] It should be understood that any parts not described in detail in this specification belong to the prior art.
[0052] It should be understood that the above description of the preferred embodiments is quite detailed, but it should not be considered as a limitation on the scope of protection of this invention. Those skilled in the art, under the guidance of this invention, can make substitutions or modifications without departing from the scope of protection of the claims of this invention, and all such substitutions or modifications fall within the scope of protection of this invention. The scope of protection of this invention should be determined by the appended claims.
Claims
1. A method for determining the phased release of flood control capacity at the end of the flood season, characterized in that, Includes the following steps: Step 1: Collect and organize basic data, including: hydrological and meteorological data, information on downstream flood control protection targets, and reservoir scheduling parameters. Step 2: Determine the timing of releasing the reservoir's flood control capacity by considering multiple factors; Step 3: Determine the criteria for releasing flood control capacity of the reservoir based on the water level characteristics of the flood control station; Step 4: Flood risk analysis and risk mapping of reservoir flood control capacity release; Step 5: Based on the flood risk map, determine the recommended flood control reservoir capacity release and scheduling method.
2. The method for determining the phased release of flood control storage capacity at the end of the flood season according to claim 1, characterized in that, The hydrological and meteorological data in step 1 include watershed rainfall data, water level and flow processes at flood control stations, actual flood processes at the dam site in different typical years, and tributary inflow and outflow processes; Information on downstream flood protection targets includes flood control standards, flood control sections, and safe discharge capacity; Reservoir scheduling parameters include flood control limit water level, flood control high water level, water level-reservoir capacity curve, discharge flow-tailwater level curve, and discharge capacity curve.
3. The method for determining the phased release of flood control storage capacity at the end of the flood season according to claim 1, characterized in that, Step 2 specifically includes: Step 2.1, Statistical analysis of the rainy season in the basin: Statistically analyze the start time, end time, duration, and cumulative rainfall of the rainy season in the basin, and analyze the evolution trend of the rainy season in the basin over time; Step 2.2, Time-history distribution analysis of excess flood volume: Based on the long-term flow data of flood control stations, calculate and analyze the excess flood volume, and draw a distribution map of the excess flood volume of control stations over time to analyze the variation law of excess flood volume over time; Step 2.3, Analysis of downstream flood control station water level data: Based on long-term water level data, analysis is conducted to calculate the average water level of the flood control stations, analyze the trend of water level changes over time, and summarize the laws governing flood evolution. The calculation method for the average water level of the flood control stations is as follows: ； In the formula, For flood control station in the long series i Year j Daily water level; N The number of years in a long series; For the first j The daily average water level over many years; Step 2.4, Interval Inflow Time History Distribution Analysis: Based on long-series interval inflow data, calculate the average interval inflow, analyze the trend of interval inflow over time, and summarize the evolution law of interval inflow. The calculation method for the average interval inflow is as follows: ； In the formula, For the first in the long series i Year j Inflow value between the dam site of the reservoir and the flood control station; For the first j Daily interval inflow average; N The number of years in a long series; Step 2.5: Based on the rainy season, excess flood volume, water levels at downstream flood control stations, and the evolution of inflow patterns within the interval, determine the timing for releasing flood control storage capacity. .
4. The method for determining the phased release of flood control storage capacity at the end of the flood season according to claim 3, characterized in that, In step 2.2, the calculation and analysis method for excess flood volume is as follows: Step 2.2.1, calculate the composite flow rate at the flood control station: ； In the formula, For the first in the long series i Year j Daily reservoir dam site flow rate For the first in the long series i Year j Inflow between the dam site of the Rishui Reservoir and the flood control station; For the series of flood control station chiefs i Year j Daily synthetic flow rate; Step 2.2.2, calculate the excess flood volume: ； In the formula, This is the safe discharge capacity corresponding to the downstream flood control station. For the first i Year j The daily excess flood volume; For the series of flood control station chiefs i Year j Daily synthetic flow rate; Step 2.2.3, Calculate the average and maximum values of excess flood volume: Based on the excess flood volume for each day of each year in the long series, calculate the average and maximum values of the excess flood volume. The calculation method is as follows: ； In the formula, For the first j The multi-year average of daily excess flood volume; The first in a long series of flood control stations j The maximum daily excess flood volume For the first i Year j The daily excess flood volume; N The number of years in a long series; Step 2.2.4, draw the excess flood volume distribution map: with the date as the horizontal axis and the excess flood volume as the vertical axis, plot the average excess flood volume and the maximum excess flood volume on the same graph to obtain the distribution map of the excess flood volume over time.
5. The method for determining the phased release of flood control storage capacity at the end of the flood season according to claim 3, characterized in that, Step 3 specifically includes: Step 3.1: Statistically analyze the highest water level values of flood control stations for each year within a long series, identify patterns, and explore the release timing determined in Step 2. Water level indicators that do not require flood control scheduling in subsequent periods This indicator meets the following conditions: ； In the formula, N The number of years in a long series; The first in the long series i Years Previous water level value; This refers to the definite water level identification index; For the i-th year in a long series Subsequent water level values; This refers to the warning water level at the flood control station; specifically, this condition means that for any year in a long series of years, the timing of release... The previous highest water level was lower than the discrimination index. When to release Subsequent water levels were all below the warning level of the flood control station, meaning there was no need for flood control. Step 3.2, Select the release timing During the previous period, the water level at the flood control station did not exceed the water level judgment index. The maximum inflow rate within the corresponding interval is used as the indicator for judging the inflow rate within the interval. This indicator meets the following conditions: ； In the formula, That is, the inflow rate discrimination index for a defined interval; This refers to the definite water level identification index; For the i-th year in a long series The subsequent water level value.
6. The method for determining the phased release of flood control capacity at the end of the flood season according to claim 3, characterized in that, Step 4 specifically includes: Step 4.1, Selection of Typical Floods: Typical major floods that may pose a flood control risk downstream are selected as calculation samples to comprehensively describe the flood control needs of the middle and lower reaches; the flood series corresponding to the selected typical major floods are shown below: ； In the formula, Flood s This represents the selected typical major flood series; This represents the flow rate on the last day of the flood series; S is the typical quantity of the selected major flood. Step 4.2, Calculation scheme formulation: at a certain time interval, at the release time Afterwards, draft At different time points, at a certain water level interval, the reservoir's flood control limit water level... Above the flood control high water level The following is proposed The calculation scheme is formed by combining different starting water levels of various reservoirs. Step 4.3, Flood Regulation Calculation: With the downstream river section requiring flood protection not exceeding the guaranteed water level as the scheduling objective, the reservoir discharge flow is controlled to not exceed the safe discharge. For a certain scheme, the proposed starting water level is used as the initial scheduling state. Flood regulation calculations are performed for the flood series following this time point in each typical major flood, and the maximum flood regulation water level of the reservoir is calculated. Step 4.4, Flood Risk Mapping: Based on the calculation results of the highest flood control water level of reservoirs at different time points, different starting water levels, and different typical major flood series, draw a flood risk map.
7. The method for determining the phased release of flood control capacity at the end of the flood season according to claim 6, characterized in that, The calculation scheme in step 4.2 is as follows: The time point is At that time, the starting water level was , ... ; The time point is At that time, the starting water level was , ... ; …… The time point is At that time, the starting water level was , ... .
8. The method for determining the phased release of flood control storage capacity at the end of the flood season according to claim 6, characterized in that, In step 4.3, the flood control calculation method is as follows: Step 4.3.1, Initial reservoir capacity in the previous period and reservoir water level For the initial period, this refers to the initial water level and its corresponding reservoir capacity. Step 4.3.2: Determine the reservoir discharge flow rate for the current time period. The specific formula is as follows: ； In the formula, This represents the average inbound flow rate for the current period. This represents the average inflow rate over the current time period. To ensure safe discharge at flood control stations; This represents the current outflow from the reservoir. Step 4.3.3 Calculate the reservoir capacity at the end of the current period based on the water balance equation. The specific formula is as follows: ； In the formula, This represents the initial reservoir capacity for the current period. This represents the reservoir capacity at the end of the current period. The duration of the time period; This represents the average inbound flow rate for the current period. This represents the current outflow from the reservoir. Step 4.3.4 Determine the reservoir water level at the end of the current period based on the reservoir water level-capacity curve. The specific formula is as follows: ； In the formula, This represents the reservoir water level at the end of the current period. f This is a reservoir water level and storage capacity curve; This represents the reservoir capacity at the end of the current period. Step 4.3.5, repeating steps 4.3.1 to 4.3.4, starting from the first calculation period, sequentially calculate the average outflow, reservoir capacity at the end of each period, and reservoir water level for all calculation periods under typical conditions of this major flood, when the reservoir starts regulating from a certain water level. Step 4.3.6: Repeat steps 4.3.1 to 4.3.5 to carry out flood control calculations for different time points, different starting water levels, and different typical flood series, until the flood control calculations for all calculation schemes are completed, and obtain the highest flood control water level of the reservoir under each condition.
9. The method for determining the phased release of flood control capacity at the end of the flood season according to claim 6, characterized in that, In step 4.4, the method for drawing the flood risk map is as follows: Step 4.4.1: At a given time point, under a specific initial water level regulation, the highest flood regulation water level of each typical major flood is taken as the outermost value and used as the maximum highest flood regulation water level starting from that water level at that time point, as follows: ； In the formula, Indicates the first m Under the condition of adjusting the water level... S The maximum value of the highest flood control water level in a typical major flood; Indicates the reservoir as the first m Under the condition that the water level is adjusted at the starting level, the highest water level calculated for the flood control of the s-th typical major flood; Step 4.4.2, Flood Risk Assessment, the specific assessment method is as follows: ； In the formula, This refers to flood control risks; Indicates the first m Under the condition of adjusting the water level... S The maximum value of the highest flood control water level in a typical major flood; This represents the flood control high water level corresponding to the flood control storage capacity reserved for flood control in the middle and lower reaches of the river. When the highest water level calculated for flood control in different typical major flood series is greater than the flood control high water level under a certain initial water level regulation, it indicates that there is a flood control risk; otherwise, the flood control risk is 0. Step 4.4.3, Flood Risk Map Drawing: For a specific time point, draw a flood risk map with the starting water level as the horizontal axis and flood risk as the vertical axis; Step 4.4.4: Create flood risk maps for different time points to form a flood risk map.
10. The method for determining the phased release of flood control capacity at the end of the flood season according to claim 6, characterized in that, In step 5, based on the flood risk map, the specific steps for determining the recommended flood control storage capacity release method are as follows: Step 5.1: Based on the flood risk map, determine the highest starting water level value for flood control at any given time point when the flood risk is 0, as follows: ； In the formula, This indicates the highest starting water level when the flood control risk is 0 at time point T; This represents the i-th water level at time point T. Step 5.2, reverse-engineer the flood control reservoir release corresponding to the highest starting water level at a certain time point when the flood control risk is 0: ； In the formula, f This is a reservoir water level and storage capacity curve; Indicates time node Flood control capacity that can be released under certain circumstances; The water level is set as a flood control limit for the reservoir. This indicates the highest starting water level when the flood control risk is 0 at time point T; Step 5.3: The sequence of flood control storage capacity release at different time points is the recommended flood control storage capacity release method, as detailed below: ； The above formula indicates that at the time node Release flood control capacity At the time point Release flood control capacity , ……