A method for determining reservoir water supply based on reservoir capacity

Abstract

The present invention discloses a method for determining the water supply of a reservoir based on its beneficial storage capacity, comprising the following steps: determining the runoff process of a representative low-flow year based on a monthly inflow runoff data series of the reservoir over the years; performing a full annual regulation calculation on the runoff process of the representative low-flow year to obtain the required full annual regulation storage capacity V 完 and the corresponding water supply; compare the reservoir's beneficial storage capacity V 兴 With the required full annual regulation storage capacity V 完 The relationship between the size of the reservoir and the annual regulation reservoir is used to determine whether the reservoir is an annual regulation reservoir or a multi-year regulation reservoir; the required beneficial storage capacity for each hypothetical water supply and water consumption scheme for the annual regulation reservoir and the multi-year regulation reservoir is determined; the water supply of each water supply and water consumption scheme and the required beneficial storage capacity V are plotted. 兴 (i) The maximum water supply capacity of the corresponding reservoir is determined based on the relationship curve according to the actual beneficial storage capacity of the reservoir. The present invention can provide a reference for analyzing the water supply capacity of existing reservoirs when the upper limit of water demand is not clear.

Description

Technical Field

[0001] The present invention relates to the field of water supply in water conservancy projects, and in particular to a method for determining the water supply volume of a reservoir according to the beneficial storage capacity of the reservoir. Background Art

[0002] The random nature of natural runoff processes dictates that high-quality development of human life and production requires the use of reservoirs to store water for various uses, as well as to detain floodwaters to mitigate flood threats. Most reservoirs in my country were constructed between the 1950s and 1970s. Some reservoirs primarily serve irrigation and power generation (e.g., the Liuxi River Reservoir, Huanglongdai Reservoir, and Jiuwantan Reservoir, all located in the Liuxi River basin in Guangzhou). However, with urbanization, economic and social development, and improved living standards, irrigation water demand has decreased, while water supply demand has continued to grow. To fully utilize these reservoirs' water storage and utility functions and address the increasingly prominent contradiction between water supply and demand, these reservoirs must be fully tapped. Therefore, it is necessary to explore a method for determining reservoir water supply based on their utility capacity.

[0003] A common and easy method is to calculate the required beneficial storage capacity for a given design guarantee rate, given the reservoir's water supply and use. This is because the reservoir's regulation performance, whether annual or multi-year, can be determined based on the water inflow at the design guarantee rate and the reservoir's water supply and use. If the reservoir's regulation performance is annual, the calendar method is used to calculate the beneficial storage capacity based on the water supply and use; if it is multi-year regulation, the probability method is used.

[0004] If a reservoir's beneficial storage capacity is known, deriving its water supply and use under a given design guarantee rate becomes complex and difficult. Because the reservoir's water supply and use are unknown, the first question to be answered is how to determine the reservoir's regulating performance. Once the reservoir's regulating performance is determined, since the water supply and use are unknown, how to apply temporal or probabilistic methods to analyze and calculate the reservoir's water supply and use becomes another challenge. Summary of the Invention

[0005] The present invention aims to propose a method for determining the water supply capacity of a reservoir based on the analysis of the reservoir's beneficial storage capacity, with the goal of fully utilizing the reservoir's beneficial storage capacity to increase water supply.

[0006] To achieve the purpose of the present invention, the present invention provides a method for determining the water supply of a reservoir based on the beneficial storage capacity of the reservoir, comprising the following steps:

[0007] Determine the runoff process of the representative dry year based on the monthly inflow runoff data series of the reservoir over the years;

[0008] Perform full annual regulation calculation on the runoff process of the representative low-water year to obtain the required full annual regulation reservoir capacity V 完and the corresponding water supply;

[0009] Comparison of reservoir beneficial storage capacity V 兴 With the required full annual regulation storage capacity V 完 The size relationship between the reservoir and the annual regulation reservoir is used to determine whether the reservoir is an annual regulation reservoir or a multi-year regulation reservoir;

[0010] Determine the beneficial storage capacity required for each hypothetical water supply and water supply scenario for the annual regulating reservoir and the multi-year regulating reservoir respectively;

[0011] Draw the water supply and required beneficial storage capacity V for each water supply and water consumption scheme 兴 (i) The maximum water supply capacity of the corresponding reservoir is determined based on the relationship curve according to the actual beneficial storage capacity of the reservoir.

[0012] Furthermore, the method for determining the runoff process of the representative dry year based on the monthly reservoir runoff data series over the years is as follows:

[0013] Conduct frequency analysis on the reservoir runoff data series in the year of inflow (hydrological year) to determine the theoretical frequency curve type;

[0014] According to the determined theoretical frequency curve type, the design dry year runoff of the frequency corresponding to the design water supply guarantee rate is obtained;

[0015] The actual representative year is determined by combining the monthly inflow runoff data series of the reservoir over the years and the designed dry year runoff. The runoff process of the designed dry year is allocated using the same multiple ratio method based on the runoff process of the actual representative year.

[0016] Furthermore, if V 兴 ≤V 完 , then the reservoir is an annual regulation reservoir, if V 兴 >V 完 , the reservoir is a multi-year regulating reservoir.

[0017] Furthermore, if the reservoir is an annual regulation reservoir, then assume that several water supply and water consumption plans are less than the water supply and water consumption of full annual regulation. For each water supply and water consumption plan, the long series method is used to calculate the beneficial regulation to obtain the required beneficial storage capacity V 兴 (i) When runoff data series are lacking, the representative year method can be used to determine the required beneficial storage capacity V 兴 (i).

[0018] Furthermore, when using the long series method for water conservation and regulation calculation, the water conservation and regulation calculation is first performed for each year's runoff process to obtain the required regulation storage capacity. Then, the required regulation storage capacity over the years is arranged in ascending order, and a frequency analysis is performed to obtain the regulation storage capacity corresponding to the design guarantee rate, which is the required water conservation and regulation capacity V under the corresponding water supply and water consumption plan. 兴 (i).

[0019] Furthermore, the design representative year method is used to determine the required beneficial storage capacity V 兴 (i) First, calculate the beneficial storage capacity V required for the water supply scheme by calculating the runoff process of the representative dry year. 兴 (i).

[0020] Furthermore, if the reservoir is a multi-year regulation reservoir, then assuming that several water supply and water consumption scenarios are greater than the water supply and water consumption scenario for full annual regulation, calculate the annual regulation storage capacity V required under each water supply and water consumption scenario. 年 (i) and interannual regulation reservoir capacity V 多 (i) V 年 (i) and V 多 (i) Add them together to get the required storage capacity V 兴 (i).

[0021] Furthermore, the annual regulation storage capacity V 年 (i) is determined as follows: Under each water supply and water consumption scenario, several years with water inflow close to the set water supply and water consumption and with longer and drier dry seasons are found from the reservoir runoff series data. The water inflow processes of these representative years are scaled to be equal to the set water supply and water consumption by the same multiple of the water inflow. Annual regulation calculations are performed for each representative year. The maximum value of the required regulation storage capacity is the annual regulation storage capacity V required for the water supply and water consumption scenario. 年 (i).

[0022] Furthermore, the interannual regulation storage capacity is determined as follows:

[0023]

[0024] Where β is the multi-year storage capacity coefficient, It is the average inflow into the reservoir over many years.

[0025] The multi-year storage capacity coefficient β is determined as follows:

[0026] The intermediate parameter m is calculated based on the coefficient of variation Cv and skewness Cs of the inflow runoff series.

[0027] m=Cs / Cv

[0028] According to the preset water consumption W 用 Calculate the adjustment coefficient α

[0029]

[0030] When m=2, according to the water supply guarantee rate P, α, Cv, check the Pleshkov line diagram ( Figure 2 Pleshkov line diagram with 95% assurance rate) to obtain β;

[0031] When m≠2, α and Cv must be converted:

[0032] α0=(m-2) / m

[0033] α′=(α-α0) / (1-α0)

[0034] Cv′=Cv / (1-α0)

[0035] β′ is obtained by plotting the Pleshkov line based on the converted α′, Cv′, and the water guarantee rate P. Substituting β′ into the following formula yields the multi-year adjustment coefficient β.

[0036] β=β′×(1-α0)

[0037] Furthermore, if the priority water consumption of some water users downstream of the reservoir is known, the priority water consumption will be listed separately as a fixed water consumption in the benefit regulation calculation, and this part of water will be deducted from the runoff water. The regulated flow will then be calculated as the water supply after deducting the fixed water consumption.

[0038] Compared with the prior art, the method of determining the water supply of a reservoir based on the beneficial storage capacity of the reservoir proposed in the present invention has at least the following beneficial effects:

[0039] (1) According to the different beneficial regulation capacities of reservoirs, the corresponding beneficial regulation calculation method is adjusted, and the statistical characteristics of the inflow runoff of different reservoirs are taken into consideration. By performing beneficial regulation calculations on multiple water supply and use schemes, a complete set of methods for analyzing and calculating the water supply capacity of reservoirs under various working conditions can be formed.

[0040] (2) The method proposed in the present invention is to draw the water supply under the design water supply guarantee rate, the required beneficial storage capacity V 兴 The relationship curve (i) can more clearly present the relationship between water supply guarantee rate, water supply and water consumption, and beneficial storage capacity.

[0041] (3) The present invention can provide a reference for analyzing the water supply capacity of existing reservoirs when the upper limit of water demand is not clear. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a flow chart of a method for determining the water supply of a reservoir based on the beneficial storage capacity of the reservoir, provided by an embodiment of the present invention.

[0043] Figure 2 This is a diagram of the Pleshkov line corresponding to the 95% assurance rate.

[0044] Figure 3 The monthly water supply in the embodiment of the present invention is 6.4 million m 3 Frequency curve of reservoir capacity adjustment required by the scheme.

[0045] Figure 4 The monthly water supply and required beneficial storage capacity V for the Guangzhou A reservoir at 97% of the design water supply guarantee rate in the embodiment of the present invention are 兴 (i) The relationship curve diagram.

[0046] Figure 5 The monthly water supply volume and required beneficial storage capacity V for the Guangzhou B reservoir at 97% of the design water supply guarantee rate according to the embodiment of the present invention are 兴 (i) The relationship curve diagram. DETAILED DESCRIPTION

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0048] See also Figure 1 The present invention provides a method for determining the water supply of a reservoir according to the reservoir's beneficial storage capacity. The method is based on relevant basic data, such as the actual beneficial storage capacity of the reservoir, the monthly inflow data series of the reservoir over the years, and the relevant data on the evaporation and leakage losses of the reservoir. It takes into account the differences and characteristics of different regulating performances of reservoirs, and adopts corresponding analysis and calculation methods according to the different regulating performances of reservoirs, and clearly gives specific analysis and calculation steps.

[0049] Example 1

[0050] The present invention provides a method for determining the water supply of a reservoir based on the beneficial storage capacity of the reservoir, comprising the following steps:

[0051] Step 1: Determine the runoff process of the representative dry year based on the monthly inflow runoff data series of the reservoir over the years.

[0052] In this step, the runoff process for the representative low-flow year is determined based on the reservoir inflow data series, including the following sub-steps:

[0053] Step 1.1: First, perform frequency analysis on the reservoir's annual runoff data series (hydrological year) to determine the appropriate theoretical frequency curve type, such as P-III type, and match it;

[0054] In frequency analysis, a goodness of fit analysis is performed to optimize the probability distribution pattern and determine the appropriate theoretical frequency curve type. Its indicators include the root mean square error (RMSE) and the coefficient of certainty (R-square).

[0055] ①RMSE (root mean square error)

[0056] This parameter is also called the fitting standard deviation. The closer its value is to 0, the better the fitting effect.

[0057]

[0058] where y i Indicates the measured value, represents the model prediction value, and n is the sample size.

[0059] ②R-square (coefficient of certainty)

[0060] This parameter indicates the goodness of fit of the curve model, R 2 The closer it is to 1, the better the fitting effect. When the actual value is exactly equal to the predicted value, R 2 =1, indicating a perfect fit.

[0061]

[0062] Among them, y i Indicates the measured value, represents the model prediction value, Represents the mean of the measured values.

[0063] Step 1.2: Based on the determined theoretical frequency curve type, obtain the design dry year runoff at the frequency corresponding to the design water supply guarantee rate;

[0064] Step 1.3: From the monthly inflow runoff data series of the reservoir over the years, select a less favorable year with an inflow close to the runoff volume of the designed dry year and a longer dry period as the actual representative year. Based on the runoff process of the actual representative year, use the same multiple ratio method to allocate the runoff process of the designed dry year.

[0065] Step 2: Perform full annual regulation calculation on the runoff process of the representative low-water year to obtain the required full annual regulation reservoir capacity V 完 and the corresponding water supply.

[0066] The total annual runoff in the representative year of the design dry season is deducted from the total fixed water consumption and evaporation and leakage losses (in Example 2, the annual ecological water consumption, annual evaporation and leakage losses, and the annual irrigation water consumption with a 90% guaranteed rate, etc.) and then divided by 12 to obtain the monthly regulated flow Q 调 , which is the corresponding water supply.

[0067] Starting from the last month of the design dry year, D(1) and difference (1) correspond to the last month, D(2) and difference (2) correspond to the second to last month, and so on, calculating in reverse chronological order:

[0068] Difference (i) = Design runoff volume per month in dry year - (fixed water consumption for that month + evaporation and leakage loss + Q 调 )

[0069] Calculate D(i):

[0070] D(1)=min(difference(1),0); (min means the minimum value between difference(1) and 0)

[0071] D(2)=min(D(1)+difference(2),0);

[0072] D(3)=min(D(2)+difference(3),0);

[0073] …

[0074] D(12)=min(D(11)+difference(12),0)

[0075] The absolute value of the minimum value in D(i) |min(D(i))| is the full annual regulation storage capacity V 完 When D(i) is negative, in order to ensure that the water demand in the last i months is met, the water storage at the end of the 12th-i month must be at least |(D(i))|. When D(i) is non-negative, no water storage is required at the end of the 12th-i month, and the corresponding water demand can be met by adjusting the runoff water in the next month.

[0076] Step 3: Compare the reservoir's beneficial storage capacity V 兴 With the required full annual regulation storage capacity V 完 The size relationship is used to determine whether the reservoir is an annual regulation reservoir or a multi-year regulation reservoir.

[0077] In this step, if V 兴 ≤V 完 , then the reservoir is an annual regulation reservoir, if V 兴 >V 完 , the reservoir has a certain multi-year regulation capacity and is a multi-year regulation reservoir.

[0078] Step 4: For different regulation performances, use the corresponding analysis and calculation methods to analyze and calculate the required beneficial storage capacity for each hypothetical water supply and use scheme.

[0079] (1) If the reservoir is an annual regulation reservoir (V 兴 ≤V 完 ), then assume that several water supply and water consumption plans are less than the water supply and water consumption plan for complete annual regulation in step 2. For each water supply and water consumption plan, use the long series method to calculate the required beneficial storage capacity V 兴 (i) When runoff data series are lacking, the design representative year method may also be used.

[0080] Preferably, the required beneficial storage capacity is calculated for each water supply and consumption scenario. When the long series method is used, the beneficial regulation calculation is performed for each annual runoff process to determine the required regulating storage capacity. The required regulating storage capacity over the years is then arranged in ascending order, and a frequency analysis is performed to determine the regulating storage capacity corresponding to the design guarantee rate, which is the beneficial storage capacity V required under the water supply and consumption scenario. 兴 (i) If the design representative year method is used, it is only necessary to calculate the beneficial regulation of the runoff process in the design low-water representative year. The calculated regulation storage capacity is the beneficial storage capacity V required under the water supply plan. 兴 (i).

[0081] (2) If the reservoir has multi-year regulation capacity (V 兴 >V 完 ), then assume that several water supply and water consumption are greater than the scheme of fully regulating water supply and water consumption in step 2, and calculate the required annual regulating reservoir capacity V under each water supply and water consumption scheme. 年 (i) and interannual regulation reservoir capacity V 多 (i) and thus obtain the required beneficial storage capacity V 兴 (i).

[0082] Preferably, if the reservoir has multi-year regulation capacity (V 兴 >V 完 ), then assume that several water supply and water use plans have water supply and water use that is greater than the full annual regulation water supply and water use in step (2). Under each water supply and water use plan, find several years from the reservoir runoff series data where the water inflow is close to the set water supply and water use and the dry season is longer and drier. Scale the water flow processes in these representative years to be equal to the set water supply and water use by the same multiple of the water inflow. Perform annual regulation calculations for each representative year, and find the largest value of the required regulation reservoir capacity, which is the annual regulation reservoir capacity V required for each water supply and water use plan. 年 (i).

[0083] Preferably, the inter-annual regulation storage capacity V 多 The acquisition steps of (i) include:

[0084]

[0085] Where β is the multi-year storage capacity coefficient, It is the average inflow into the reservoir over many years.

[0086] Among them, the multi-year storage capacity coefficient β is determined as follows:

[0087] The intermediate parameter m is calculated based on the coefficient of variation Cv and the coefficient of skewness Cs of the inflow runoff series:

[0088] m=Cs / Cv

[0089] According to the preset water consumption W, the adjustment coefficient α is calculated:

[0090]

[0091] When m=2, according to the water supply guarantee rate P, α, Cv, check the Pleshkov line diagram ( Figure 2 Pleshkov line diagram with 95% assurance rate) to obtain β;

[0092] When m≠2, α and Cv must be converted:

[0093] α0=(m-2) / m

[0094] a′=(a-a0) / (1-α0)

[0095] Cv′=Cv / (1-α0)

[0096] Based on the water supply guarantee rate P and the converted α′ and Cv′, the Chapleshkov line diagram yields β′. Substituting β′ into the following formula yields the multi-year adjustment coefficient β.

[0097] β=β′×(1-a0)

[0098] V 年 (i)+V 多 (i) is the beneficial storage capacity V required for multi-year regulation of the reservoir under the corresponding water supply and water consumption plan 兴 (i).

[0099] i represents the i-th water supply plan, V 多 (i) is the inter-annual regulation storage capacity required under the i-th water supply and consumption scheme, V 多 The general formula for calculating the inter-annual regulation storage capacity provided by the present invention is: when calculating the i-th water supply and consumption scheme, substitute W (i) of the water supply and consumption scheme into the calculation V 多 The general formula is used to calculate the corresponding required interannual regulation storage capacity.

[0100] Preferably, if the priority water consumption of some water users downstream of the reservoir is known, the priority water consumption will be listed separately as a fixed water consumption in the benefit regulation calculation in steps 3 and 4, and this part of the water will be subtracted from the runoff water, and the regulated flow will be calculated as the water supply after deducting the fixed water consumption.

[0101] Step 5: Draw the water supply and required beneficial storage capacity V for each water supply and water consumption scheme 兴 (i) and then find the corresponding reservoir design water supply capacity on the relationship curve based on the actual beneficial storage capacity of the reservoir.

[0102] In this step, determine the required storage capacity V for each water supply and water consumption plan. 兴 (i) After that, plot the annual regulating reservoir water supply and the required beneficial storage capacity V 兴(i) The relationship curve should be based on the required beneficial storage capacity V for each water supply scenario. 兴 (i) is the ordinate, and the regulated flow rate of each water supply and water consumption scheme is the abscissa. The data corresponding to each water supply and water consumption scheme are plotted. Then, a suitable linear fitting curve is selected based on the data. The curve is the relationship between water supply and required beneficial storage capacity V. 兴 (i) After drawing the relationship curve between the annual regulating reservoir water supply and the required beneficial storage capacity, according to the actual beneficial storage capacity V 兴 , the corresponding regulated flow on the relationship curve is the designed water supply capacity of the reservoir.

[0103] In order to make the method of determining the water supply of a reservoir based on the beneficial storage capacity of the reservoir proposed in the present invention easier to understand, the water supply analysis and calculation of Guangzhou Reservoir A and Reservoir B are now taken as examples for further explanation.

[0104] Example 2

[0105] The method provided in Example 1 is verified through specific examples.

[0106] Take Guangzhou A Reservoir as an example: the dead water level of the reservoir is 180 meters and the dead storage capacity is 1.98 million m 3 The normal water level is 216 meters, and the corresponding storage capacity is 26.86 million m 3 ; Xingli reservoir capacity 24.88 million m 3 In the early stages of operation, Reservoir A addressed irrigation water issues in the nearby C Irrigation District by replenishing water to the canal, combining this with water storage and diversion at the barrage. Today, due to various factors, such as urban development and land occupation for road construction, the amount of irrigated land in Irrigation District C has decreased. Reservoir A no longer replenishes water to Irrigation District C and now only provides urban and rural water. According to the "Hydraulic Calculation Specifications for Water Conservancy Projects" (SL104-2015), and taking into account the needs of urban development, a 97% guaranteed urban and rural water supply rate for Reservoir A was selected.

[0107] (1) Based on the monthly average inflow data of Reservoir A from 1980 to 2021, the runoff series for 41 years from April 1980 to March 2021 was calculated according to the hydrological year.

[0108] The average annual runoff over the years is calculated to be 169.8091 million m 3 , coefficient of variation Cv = 0.33, skewness coefficient CS = 1. The design runoff volume with a frequency of 97% is 90,097,500 m 3 By comparing the runoff processes of measured years with similar water volume (see Table 1-1), 1990, which had a longer dry season and smaller flow, was selected as the representative year. The runoff process of the design representative year was obtained by scaling its runoff process at the same ratio.

[0109] (2) Perform full annual regulation calculation for the design dry year with a frequency of 97% and obtain the corresponding V 完 34.0915 million m 3 , regulating flow is 7.28 million m 3 / moon.

[0110] (3) A reservoir's beneficial storage capacity V 兴 24.88 million m 3 , V 兴 <V 完 , Reservoir A is an annual regulating reservoir.

[0111] (4) Under the water supply guarantee rate of 97%, the monthly water supply must be less than the regulated flow of 7.28 million m3 in (2). 3 / month, assuming the monthly water supply is 6.3 million m 3 , 6.4 million m 3 , 6.5 million m 3 , 6.6 million m 3 , 6.7 million m 3 , 6.8 million m 3 , 6.9 million m 3 Seven schemes were used. The regulation storage capacity sequence required for each water supply scheme was obtained by annual regulation calculation in each hydrological year, and frequency analysis was performed (the monthly water supply was 6.4 million m3). 3 The frequency curve of storage capacity adjustment required for the scheme is shown in Figure 3 Determine the regulating storage capacity with the frequency corresponding to the design water supply guarantee rate of 97%, that is, the regulating storage capacity that can just meet the design water supply guarantee rate as the beneficial storage capacity V required for this plan. 兴 (i) (See Table 1-2).

[0112] (5) Draw the water supply and required beneficial storage capacity V for each scheme 兴 (i) The relationship curve (see Figure 4 ), find the relationship curve with the actual beneficial storage capacity V of reservoir A 兴 The horizontal coordinate of the corresponding point is the designed water supply capacity of the reservoir: the water supply capacity of 97% of the designed water supply guarantee rate is 6.75 million m 3 / moon.

[0113] Table 1-1 Comparison of runoff processes in representative years

[0114] years Dry season months <![CDATA[Total water volume in dry season (10,000 m 3 )]]> <![CDATA[Annual runoff (10,000 m 3 )]]> 1985 6 2448 11008.99 1990 7 2301 11280.45 2009 6 3277 10475.57 2011 7 4045 9207.788

[0115] Table 1-2 Required beneficial storage capacity units for each water supply plan under 97% guarantee rate (10,000 m 3 )

[0116] Monthly water supply 630 640 650 660 670 680 690 <![CDATA[V 兴 (i)]]> 2295.7 2332.04 2367.97 2413.36 2463.86 2519.06 2577.16

[0117] Example 3

[0118] The method provided in Example 1 is verified by another specific example.

[0119] Take Guangzhou B Reservoir as an example: the dead water level of the reservoir is 139.91 meters, and the dead storage capacity is 12.4 million m 3 The normal water level is 173.4 meters, and the corresponding storage capacity is 82.89 million m 3 ; Xingli reservoir capacity 70.49 million m 3 The irrigation water guarantee rate is 90%, and the corresponding annual irrigation water demand is 10.87 million m 3 (In years with a frequency exceeding 90%, the irrigation water consumption still takes this value), and the annual ecological water demand is 10.4 million m 3 According to the "Water Conservancy Calculation Specification for Water Conservancy Projects" (SL104-2015) and urban development needs, 97% is selected as the urban and rural water supply guarantee rate of Reservoir A. Using the method of determining the water supply volume of a reservoir based on its beneficial storage capacity described in the present invention, the water supply capacity of Reservoir B after deducting the 90% guaranteed rate of irrigation water and ecological water supply is calculated, that is, steps 1 to 5 of the present invention are implemented step by step:

[0120] (1) Based on the daily average inflow data of Reservoir B from 1977 to 2022, the runoff series for 45 years from April 1977 to March 2022 was calculated according to the hydrological year.

[0121] The average annual runoff over the years is calculated to be 103.7626 million m 3 , coefficient of variation Cv = 0.3, skewness coefficient CS = 0.3. The design runoff volume of 97% frequency is 49.2853 million m 3 By comparing the runoff processes of measured years with similar water volume, 1990, which had a longer dry season and smaller flow, was selected as the representative year. The runoff process of the design representative year was obtained by scaling its runoff process at the same ratio.

[0122] (2) Perform full annual regulation calculation for the design dry year with a frequency of 97% (see Table 2-1) and obtain the corresponding V 完 19.221 million m 3 The adjustment coefficient α is 0.48, corresponding to an annual water supply of 49.806 million m 3 .

[0123] (3) B reservoir's beneficial storage capacity V 兴 70.49 million m 3 , V 兴 >V 完 , Reservoir B is a multi-year regulating reservoir.

[0124] (4) Under the condition of 97% water supply guarantee rate, the adjustment coefficient must be greater than the adjustment coefficient of 0.48 given in (2) (i.e. the total water supply volume is greater than 49.806 million m3). 3 ), after a preliminary calculation narrowing the range, we assumed seven water supply and consumption scenarios with adjustment coefficients a of 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, and 0.69, and used 1990, 2003, and 2007 as representative years to calculate runoff regulation and obtain the corresponding annual reservoir capacities, as shown in Table 2-1. By comparing the required regulation reservoir capacities of each representative year, we found that the required regulation reservoir capacity in 1990 was the largest, so the required regulation reservoir capacity in 1990 was selected as V. 年 (i) Based on the known design water supply guarantee rate, the coefficient of variation Cv, the coefficient of skewness Cs, and the adjustment coefficient a of the inflow runoff series, the multi-year storage capacity coefficient β is calculated by the Pleshkov multi-year adjustment line diagram, and then the multi-year adjustment storage capacity V is calculated. 多 (i). V 年 (i) With V 多 (i) Add them together to get the required storage capacity V 兴 (i), see Table 2-2.

[0125] (5) Draw the water consumption and required beneficial storage capacity V for each scheme 兴 (i) The relationship curve (see Figure 5 ), and then the actual beneficial storage capacity of the reservoir V 兴 Find the corresponding point on the relationship curve, and its horizontal coordinate is the designed water supply capacity of the reservoir: Under a 97% guarantee rate, the water supply capacity of reservoir B is 3.685 million m 3 / moon.

[0126] Table 2-1 Calculation of full annual regulation for the design dry year with a frequency of 97% Unit: (10,000 m 3 )

[0127] Time Monthly runoff The sum of fixed water consumption and evaporation and leakage losses Q-tune Difference (i) D(i) April 1077.28 139.70 210.17 727.41 0 May 744.8 211.96 210.17 322.66 -727.41 June 928.4 291.15 210.17 427.08 -1050.07 July 736.44 117.75 210.17 408.58 -1477.15 August 436.13 189.56 210.17 36.4 -1885.73 September 356.2 317.56 210.17 -171.53 -1922.13 October 153.65 315.50 210.17 -372.02 -1750.6 November 137.96 139.05 210.17 -211.26 -1378.58 December 56.24 197.78 210.17 -351.71 -1167.32 January 51.76 212.63 210.17 -371.04 -815.61 February 131.4 124.01 210.17 -202.78 -444.57 March 118.27 149.89 210.17 -241.79 -241.79 total 4928.53 2406.55 2521.98

[0128] Table 2-2 Annual storage capacity required in different representative years under various water supply and consumption plans with a 97% guarantee rate (unit: 10,000 m 3 )

[0129] Adjustment coefficient α 0.69 0.68 0.67 0.66 0.65 0.64 0.63 1990 2766.31 2727.05 2687.78 2648.52 2609.26 2570.00 2530.73 2003 1811.70 1786.27 1760.84 1735.41 1709.99 1684.56 1659.13 2007 1944.85 1917.50 1890.14 1862.78 1835.42 1808.07 1780.71

[0130] Note: The required annual storage capacity in 1990 was the largest, so 1990 was chosen as the representative year.

[0131] Table 2-3 Required beneficial storage capacity units under various water supply and consumption plans with a 97% guaranteed rate (10,000 m 3 )

[0132] Adjustment coefficient α 0.69 0.68 0.67 0.66 0.65 0.64 0.63 Total water supply 7159.44 7055.68 6951.92 6848.16 6744.4 6640.64 6536.88 Monthly water supply 391 383 374 366 357 349 341 Year V (i) 2766.31 2727.05 2687.78 2648.52 2609.26 2570.00 2530.73 V more (i) 5125.70 4839.19 4565.10 4302.89 4052.04 3812.07 3582.50 VXing(i) 7892.01 7566.23 7252.88 6951.41 6661.30 6382.07 6113.24

[0133] In summary, for example, reservoir A, which considers annual regulation, and reservoir B, which considers multi-year regulation, the method of the present invention can be used to determine the relationship between the beneficial storage capacity of the reservoir and the water supply under a certain guarantee rate, regardless of whether the downstream water demand is clear, and obtain the water supply corresponding to the actual beneficial storage capacity of the reservoir.

[0134] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for determining the water supply of a reservoir based on the beneficial storage capacity of the reservoir, characterized in that: The following steps are involved: Determine the runoff process of the representative dry year based on the monthly inflow runoff data series of the reservoir over the years; Perform full annual regulation calculation on the runoff process of the representative low-water year to obtain the required full annual regulation storage capacity and the corresponding water supply; Comparison of reservoir storage capacity With the required full annual regulation storage capacity The size relationship between the two can determine whether the reservoir is an annual regulation reservoir or a multi-year regulation reservoir; Determine the beneficial storage capacity required for each hypothetical water supply and water supply scenario for the annual regulating reservoir and the multi-year regulating reservoir respectively; Draw the water supply and required beneficial storage capacity V for each water supply and water consumption scheme 兴 (i) a relationship curve, and determining the corresponding maximum water supply capacity of the reservoir based on the actual beneficial storage capacity of the reservoir; The method for determining the runoff process of the design low-flow representative year based on the monthly reservoir runoff data series over the years is: Conduct frequency analysis on the reservoir's annual runoff data series to determine the theoretical frequency curve type; According to the determined theoretical frequency curve type, the design dry year runoff of the frequency corresponding to the design water supply guarantee rate is obtained; Determine the actual representative year by combining the monthly inflow runoff data series of the reservoir over the years and the designed dry year runoff, and allocate the runoff process of the designed dry year using the same multiple ratio method based on the runoff process of the actual representative year; If the reservoir is an annual regulation reservoir, then assume that several water supply and water volume plans are less than the water supply and water volume of the complete annual regulation. For each water supply and water volume plan, use the long series method to calculate the beneficial regulation and obtain the required beneficial storage capacity V 兴 (i) When runoff data series are lacking, the representative year method can be used to determine the required beneficial storage capacity V 兴 (i); If the reservoir is a multi-year regulation reservoir, then assume that several water supply and water demand scenarios are greater than the water supply and water demand for full annual regulation, and calculate the required annual regulation storage capacity V under each water supply and water demand scenario. 年 (i) and interannual regulation reservoir capacity V 多 (i) V 年 (i) and V 多 (i) Add them together to get the required storage capacity V 兴 (i).

2. The method for determining the water supply of a reservoir according to the beneficial storage capacity of the reservoir according to claim 1, characterized in that: If V 兴 V 完 , then the reservoir is an annual regulation reservoir, if V 兴 >V 完 , the reservoir is a multi-year regulating reservoir.

3. The method for determining the water supply of a reservoir according to the beneficial storage capacity of the reservoir according to claim 1, characterized in that: When using the long series method for water conservation and regulation calculation, first perform water conservation and regulation calculation for each year's runoff process to obtain the required regulation storage capacity. Then, arrange the required regulation storage capacity in previous years in ascending order, perform frequency analysis, and calculate the regulation storage capacity corresponding to the design guarantee rate, which is the required water conservation and regulation capacity V under the corresponding water supply and water consumption plan. 兴 (i).

4. The method for determining the water supply of a reservoir according to the beneficial storage capacity of the reservoir according to claim 1, characterized in that: Use the design representative year method to determine the required beneficial storage capacity V 兴 (i) First, calculate the beneficial storage capacity V required for the runoff process in the representative dry year. The obtained regulation storage capacity is the beneficial storage capacity V required under the corresponding water supply and consumption plan. 兴 (i).

5. The method for determining the water supply of a reservoir according to the beneficial storage capacity of the reservoir according to claim 1, characterized in that: The annual regulation storage capacity V 年 (i) is determined as follows: Under each water supply and water consumption scenario, several years with water inflow close to the set water supply and water consumption and with longer and drier dry seasons are found from the reservoir runoff series data. The water inflow processes of these representative years are scaled to be equal to the set water supply and water consumption by the same multiple of the water inflow. Annual regulation calculations are performed for each representative year. The maximum value of the required regulation storage capacity is the annual regulation storage capacity V required for the water supply and water consumption scenario. 年 (i).

6. The method for determining the water supply of a reservoir according to the beneficial storage capacity of the reservoir according to claim 1, characterized in that: The interannual regulation storage capacity is determined as follows: V 多 = Where, is the multi-year storage capacity coefficient, is the average inflow of the reservoir over many years; Multi-year storage capacity coefficient The determination method is: The intermediate parameter m is calculated based on the coefficient of variation Cv and the coefficient of skewness Cs of the inflow runoff series: =Cs / Cv According to preset water consumption Calculate the adjustment coefficient : = When m=2, according to the water supply guarantee rate P, , Cv Chapleshkov line diagram to obtain ; When m 2 o'clock, yes , Cv for conversion: According to the converted 、 The water supply guarantee rate P is obtained by the Pleshkov line diagram ,Will Substitute into the formula , and obtain the multi-year adjustment coefficient .

7. A method for determining the water supply of a reservoir based on the beneficial storage capacity of the reservoir according to any one of claims 1 to 6, characterized in that: If the priority water consumption of some water users downstream of the reservoir is known, the priority water consumption will be listed separately as a fixed water consumption in the benefit regulation calculation, and the fixed water consumption will be subtracted from the runoff water. The regulation flow will then be calculated as the water supply after deducting the fixed water consumption.

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