A rationality verification method for estimating reservoir inflow flood based on dam site flood

Abstract

The present invention discloses a method for checking the rationality of inflow floods deduced from dam-site floods, comprising the steps of obtaining a series of data on the maximum flood peak flows and flood volumes in previous years before and after the construction of a reservoir to be analyzed; establishing a correlation between the flood peak flow and flood volume at the dam-site flood and a correlation between the flood peak flow and flood volume at the inflow flood; obtaining a multiple ratio coefficient between the flood peak flows of the inflow floods in the second to nth years after the construction of the reservoir and the flood peak flows of the dam-site floods before the construction of the reservoir; accumulating and averaging the coefficients; and providing a rationality analysis opinion on the deduced inflow flood data. The inflow flood can be used to review whether an existing flood control design is rational. The present invention can perform a rationality test on the inflow flood deduced from the dam-site flood, thereby avoiding erroneous conclusions when reviewing the flood control design due to unreasonable deduced inflow floods.

Description

Technical Field

[0001] The invention belongs to the calculation of design flood for water conservancy and hydropower engineering, and relates to a rationality inspection method for deducing reservoir flood based on dam site flood. Background Art

[0002] When designing a reservoir, it is necessary to determine an area for dam construction, namely the dam site area. Floods in the dam site area must be considered when building a dam. The floods in the dam site area are defined as dam site floods. The dam site floods are floods at the pre-built dam before the reservoir is built.

[0003] After a reservoir is built, floods resulting from inflows from the reservoir area and direct rainfall on the reservoir surface are called reservoir inflow floods. Natural river channels and adjacent slopes within the reservoir area are submerged, altering runoff generation and confluence conditions within the reservoir area. Confluence patterns within the pre-reservoir construction river channels change to simultaneous inflows from main and tributary rivers and reservoir areas along the reservoir perimeter.

[0004] If the difference between the inflow flood and the dam site flood is small, the dam site flood can be used as the basis for flood control design; if the difference between the two is large, the inflow flood must be used as the basis for flood control design, otherwise the flood control design will be unsafe.

[0005] Most of my country's existing reservoirs use the design flood at the dam site section before construction, known as the dam site flood, as the basis for flood control design. Inflowing floods are not considered during flood control design. However, after the reservoir is built, the propagation speed of floodwaters from the surrounding areas accelerates. With the exception of reservoirs in steep mountainous canyon areas, where the storage capacity of the reservoir channel remains relatively unchanged, inflowing floods in other reservoirs, such as those located on plains, exhibit earlier peaks and more concentrated peaks relative to the dam site floods. This is detrimental to reservoir operation and the safety of downstream areas. Therefore, inflowing floods are often used in flood control design, for example, to verify the flood control capacity of existing dams and calculate the flood control capacity of downstream rivers.

[0006] Currently, the main methods for calculating inflow floods include flow superposition, flow inversion, and water balance. In engineering design, different calculation methods are often selected based on data conditions. Patent CN106592504A proposes a method for calculating the inflow flood volume of a hydropower station based on short-term precipitation forecasts, as an optimization of conventional methods. However, the above calculation method does not fully utilize the dam site flood data before reservoir construction. Patent CN104727264B proposes a dam site flood restoration method based on Copula functions, which aims to use the inflow flood to reversely infer the dam site flood, thereby generating a longer series of consistent dam site flood data.

[0007] Most reservoirs in my country were built in the 1960s and 1970s. Post-construction data series often include longer inflows than pre-construction data. Using dam-site flood data to estimate inflows is both convenient for reservoir management and beneficial for safe operation. In reservoir management, especially in flood control operations at large reservoirs, increasing emphasis is being placed on estimating inflows based on pre-construction dam-site flood data.

[0008] In engineering, the correlation method is generally used. First, it is assumed that the long-term flood volume before and after the reservoir is built remains unchanged. The correlation between the peak flow before and after the reservoir is built and the long-term flood volume is established respectively. The ratio coefficient of the peak flow before and after the reservoir is built is derived, and then the dam site flood is deduced to obtain the reservoir inflow flood. The above method has a relatively clear mechanism, but the above work is greatly affected by the data conditions and personal subjective experience. The ratio coefficients obtained by different series lengths and operators are often different, which directly affects the rationality of the subsequent deduction of the reservoir inflow flood. The different series lengths refer to the selection of reservoir inflow flood data of different time lengths such as five years, ten years, or twenty years as the basis for calculation, and the calculated ratio coefficients will be different. Therefore, how to test the rationality of the reservoir inflow flood deduced from the dam site flood is a problem that needs to be solved urgently. Summary of the Invention

[0009] Aiming at the problems that the existing method of calculating reservoir inflow flood from dam site flood is highly random and there is a lack of a method to verify the rationality of the results of calculating reservoir inflow flood from dam site flood, the present invention proposes a method to verify whether the calculated reservoir inflow flood data is reasonable by calculating the cumulative average through an increasing multiple ratio series.

[0010] To achieve the above objectives, the technical solution of the present invention is:

[0011] A method for verifying the rationality of inferring reservoir flood based on dam site flood, comprising the following steps:

[0012] Step 1: Obtain the maximum flood peak flow and flood volume series data before and after the construction of the reservoir to be analyzed;

[0013] Step 2: Establish relevant relationships;

[0014] The correlation between the peak discharge and flood volume of the dam site is established as follows:

[0015] Q 坝 =a W 坝 (1)

[0016] Where:

[0017] Q 坝 is the peak flood discharge at the dam site;

[0018] W 坝 is the flood volume at the dam site;

[0019] a is the correlation coefficient between the peak discharge and flood volume of the dam site flood;

[0020] The correlation between the peak flow rate of flood entering the reservoir and the flood volume is established as follows:

[0021] Q 库i =a i W 库i , i=2,3,...,n (2)

[0022] Where:

[0023] Q 库i is the peak flow of the flood entering the reservoir in year i;

[0024] W 库i is the flood volume entering the reservoir in year i;

[0025] a i is the correlation coefficient between peak flow and flood volume established based on the flood data entering the reservoir in year i;

[0026] n is the total length of the reservoir inflow flood series, that is, the reservoir inflow flood data for n years were collected.

[0027] Step 3: Calculate the ratio coefficient b i ;

[0028] Based on the reasonable assumption that the flood volume at the dam site and the flood volume entering the reservoir do not change before and after the project, it is assumed that the flood volume at the dam site of the same flood before and after the reservoir construction is W 坝 and the flood volume W 库i Equal; in the W 坝 =W 库i On this basis, combining formula (1) with formula (2), we get:

[0029]

[0030] make

[0031] Then Q 库i =b i Q 坝 , i=2,3,...,n (5)

[0032] b i is the correlation coefficient a between peak flow and flood volume established based on the flood data entering the reservoir in year i after the reservoir is built i The multiple coefficient of the correlation coefficient a between the peak discharge and flood volume of the dam site flood before the reservoir was built;

[0033] The rest of the symbols have the same meaning as above;

[0034] A total of n-1 b are obtained i value.

[0035] Step 4: Cumulative average of coefficients;

[0036] Take the cumulative average of the n-1 multiple ratio coefficients obtained in step 3 and calculate the cumulative average

[0037]

[0038] n is the number of years of selected flood data entering the reservoir; the other symbols have the same meanings as above;

[0039] A total of n-2 cumulative averages are obtained

[0040] Step 5: Analyze the rationality of the results;

[0041] Analyze the rationality of calculating the inflow flood from the dam site flood using formula (5) through correlation in step 3;

[0042] Observe n-2 cumulative averages whether it tends to be stable;

[0043] if The value tends to be stable and Value and b i If the relative error is within the pre-set range, then the calculation of the inflow flood from the dam site flood using formula (5) in step 3 is reasonable;

[0044] if If the value does not stabilize, then b in step 3 i The parameter selection is unreasonable, that is, the parameter b at this time i It is unreasonable to use the correlation relationship in step 3 to calculate the inflow flood from the dam site flood using formula (5).

[0045] Furthermore, in step 3, the ratio coefficient b i The calculation method is as follows: Based on the selected peak flow and flood volume data of the dam site floods over the years, the value of a is calculated according to the univariate linear regression related parameter formula; the maximum peak flow and flood volume data points of the dam site floods over the years are plotted in the coordinate system, with the vertical axis being the peak flow of the dam site flood Q 坝 The horizontal axis is the flood volume W at the dam site. 坝 , the intercept is controlled to be 0, and the slope of the regression line obtained according to the univariate linear regression relationship is the a value;

[0046] Select the flood data of previous years and draw the coordinate system of the peak flow and volume of the flood entering the reservoir. Select the peak flow and volume of the flood entering the reservoir for two years, three years, and up to n years and draw them in the coordinate system. That is, draw the data of two points, three points, and up to n points in the coordinate system. Control the intercept to 0, and obtain the regression line slope of two points (i.e., the peak flow and volume of the flood entering the reservoir in two years) according to the univariate linear regression relationship; the regression line slope of three points (i.e., the peak flow and volume of the flood entering the reservoir in three years); and the regression line slope of n points. The slope of each regression line is an a i Value, a total of n-1 a i value;

[0047] Get the value of a and n-1 a i After the value is calculated, according to formula (4), n-1 b i value.

[0048] Furthermore, the The value tends to be stable and Value and b i If the relative error is within the preset range, then b in formula (5) i Take a stable The value is the flood entering the reservoir calculated from the flood at the dam site.

[0049] The beneficial effects of the present invention are:

[0050] 1. The inflow flood can be used to review whether the existing flood control design is reasonable. The present invention can perform a rationality test on the inflow flood calculated from the dam site flood, thereby avoiding erroneous conclusions when reviewing the flood control design due to unreasonable calculated inflow flood.

[0051] 2. To verify whether a reservoir dam meets flood control requirements based on inflow flood data, it is necessary to consider the inflow flood data of many consecutive years as a whole and combine it with parameters such as the dam height to evaluate whether the dam meets flood control requirements. If the dam is built a short time ago, such as five or eight years, only using the inflow flood data of five or eight years to evaluate whether the dam meets flood control requirements may lead to incorrect conclusions due to the short data series for evaluation. In this case, a reasonable multiplication coefficient b can be determined according to the method of the present invention. i After the value is calculated, based on the dam site flood before the reservoir was built, it is calculated what the corresponding reservoir inflow flood would be in a certain year if the dam was built in the year before the reservoir was built, thereby calculating the reservoir inflow flood data of more years, and then forming a longer series of reservoir inflow flood data; a longer series of reservoir inflow data for evaluation is conducive to improving the accuracy of the evaluation results.

[0052] 3. The present invention calculates the inflowing flood using a stable cumulative average value, and the calculation result is more accurate and scientific. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a flow chart of the technical solution of the present invention.

[0054] Figure 2 For the embodiment of the present invention, the data points of the dam site flood peak flow and flood volume for 8 years from 1952 to 1959 are gathered in a coordinate system.

[0055] Figure 3 This is a relationship diagram between the peak flow and flood volume of the flood entering the reservoir established at three points from 1960 to 1962 in an embodiment of the present invention.

[0056] Figure 4 This is a relationship diagram between the peak flow and flood volume of floods entering the reservoir established at eight points from 1960 to 1967 in an embodiment of the present invention.

[0057] Figure 5 This is a relationship diagram between the peak flow and flood volume of floods entering the reservoir established at 16 points from 1960 to 1975 in an embodiment of the present invention.

[0058] Figure 6 This is a relationship diagram between the peak flow and flood volume of floods entering the reservoir established at 36 points from 1960 to 1995 in an embodiment of the present invention.

[0059] Figure 7 This is a distribution diagram of the annual multiple ratio coefficients and their cumulative average values calculated in an embodiment of the present invention. DETAILED DESCRIPTION

[0060] In order to make the purpose, technical solutions and advantages of the invention clearer, the present invention is further described below with reference to the accompanying drawings.

[0061] The present invention establishes a correlation between the dam site flood and the reservoir flood in an increasing series, that is, according to the data of each year, calculates the multiple ratio coefficient, and performs cumulative averaging on the multiple ratio coefficient to identify the cumulative average value of the multiple ratio coefficient that tends to be stable. According to the relationship between the multiple ratio coefficient used in the calculation and the above-mentioned cumulative average value that tends to be stable, the rationality of the result of deducing the reservoir flood from the dam site flood is analyzed.

[0062] The present invention proposes a method for verifying the rationality of inferring reservoir flood based on dam site flood. The specific technical solution includes five steps: obtaining flood data, establishing correlation, calculating multiple ratio coefficients, accumulating and averaging coefficients, and analyzing the rationality of the results, as shown below.

[0063] Step 1: Obtain flood information

[0064] Obtain the maximum flood peak flow and flood volume series of the years before and after the construction of the reservoir to be analyzed. Among them, the flood before the reservoir is the dam site flood, which is often the measured value or calculated according to relevant hydrological methods; the flood after the reservoir is built is the reservoir inflow flood, which is often obtained through the flow superposition method, flow inversion method, water balance method, etc. The corresponding data are historical storage data and are accurate.

[0065] The maximum flood peak flow in all years is a series of data formed by selecting the maximum flood peak flow data of each year for many consecutive years.

[0066] The maximum flood volume series in all years refers to the series of data formed by the largest flood volume data values in each year for many consecutive years in historical data.

[0067] Peak flow, as used in this context, refers to the period during which runoff from various locations in a watershed, such as during heavy rain or snowmelt, converges into the riverbed in descending order of proximity. This is when river flow begins to increase, and the water level rises accordingly. As runoff from upstream flows downstream, the flow continues to increase. When the majority of the high-intensity runoff from the basin converges, the river flow reaches its maximum. This peak flow is measured in cubic meters per second.

[0068] The flood volume in the present invention refers to the total amount of flood, that is, the volume of flood passing through a certain section of the river during a flood process or within a given period of time, referred to as flood volume.

[0069] The reservoir selected in the embodiment of the present invention was built in 1960. There are eight years of dam site flood data from 1952 to 1959 and sixty-two years of reservoir inflow flood data from 1960 to 2021. The relevant data are historical archived data and can be used for flood analysis of the selected reservoir.

[0070] Step 2: Establish relevant relationships

[0071] There is a correlation between flood volume and peak flow.

[0072] The correlation between the peak discharge and flood volume of the dam site is established as follows:

[0073] Q 坝 =a W 坝 (1)

[0074] Where:

[0075] Q 坝 is the peak flood discharge at the dam site;

[0076] W 坝 is the flood volume at the dam site;

[0077] a is the correlation coefficient between the peak discharge and flood volume of the dam site flood.

[0078] In the embodiment of the present invention, since there are eight years of dam site flood peak flow data and dam site flood volume data from 1952 to 1959, the value a can be calculated according to the univariate linear regression related parameter formula, and the flood peak flow and flood volume are both the maximum values of each of the eight years; Figure 2 As shown in the figure, the data points of the annual maximum dam site flood peak flow and flood volume for eight years from 1952 to 1959 are gathered in the coordinate system, with the vertical axis being the dam site flood peak flow Q 坝 The horizontal axis is the flood volume W at the dam site. 坝 ,, the intercept is controlled to be 0; the slope of the regression line obtained according to the univariate linear regression relationship is 0.0967, that is, a=0.0967 in the embodiment of the present invention. According to the historical data collected in the embodiment of the present invention, Q is obtained in this embodiment. 坝 and W 坝 The following relationship:

[0079] Q 坝 =0.0967W 坝

[0080] The correlation between the peak flow rate of flood entering the reservoir and the flood volume is established as follows:

[0081] Q 库i =a i W 库i , i=2,3,...,n (2)

[0082] Where:

[0083] Q 库i is the peak flow of the flood entering the reservoir in year i;

[0084] W 库i is the flood volume entering the reservoir in year i;

[0085] a i is the correlation coefficient between peak flow and flood volume established based on the flood data entering the reservoir in year i;

[0086] n is the total length of the reservoir inflow flood series, that is, the reservoir inflow flood data for n years were collected.

[0087] Correlation coefficient a i The calculation method is:

[0088] Among them, after the database is built, n-1 groups of relationships are established according to the series of years from 2 years to n years. For example, in the embodiment of the present invention, a total of 62 years of reservoir inflow flood data from 1960 to 2021 are collected, and the peak flow and flood volume data points of the two years of 1960 and 1961 are gathered in the coordinate system, with the vertical axis being the peak flow of the reservoir inflow flood Q. 库i The horizontal axis is the flood volume W entering the reservoir. 库i, the intercept is controlled to be 0; the slope of the regression line can be obtained according to the univariate linear regression relationship.

[0089] like Figure 3 As shown in the embodiment of the present invention, the peak flow and flood volume data points of the three years from 1960 to 1963 are gathered in the coordinate system, and the vertical axis is the peak flow of the flood entering the reservoir Q 库i The horizontal axis is the flood volume W entering the reservoir. 库i , the intercept is controlled to be 0; according to the univariate linear regression relationship, the slope of the regression line can be obtained to be 0.0992.

[0090] like Figure 4 As shown in the embodiment of the present invention, the peak flow and flood volume data points of the eight years from 1960 to 1967 are gathered in the coordinate system, and the vertical axis is the peak flow of the flood entering the reservoir Q 库i The horizontal axis is the flood volume W entering the reservoir. 库i , the intercept is controlled to be 0; according to the univariate linear regression relationship, the slope of the regression line can be obtained to be 0.1295.

[0091] like Figure 5 As shown in the embodiment of the present invention, the peak flow and flood volume data points of the flood entering the reservoir for 16 years from 1960 to 1975 are gathered in the coordinate system, and the vertical axis is the peak flow of the flood entering the reservoir Q 库i The horizontal axis is the flood volume W entering the reservoir. 库i , the intercept is controlled to be 0; according to the univariate linear regression relationship, the slope of the regression line can be obtained to be 0.119.

[0092] like Figure 6 As shown in the embodiment of the present invention, the peak flow and flood volume data points of the flood entering the reservoir for 36 years from 1960 to 1995 are gathered in the coordinate system, and the vertical axis is the peak flow of the flood entering the reservoir Q 库i The horizontal axis is the flood volume W entering the reservoir. 库i , the intercept is controlled to be 0; according to the univariate linear regression relationship, the slope of the regression line can be obtained to be 0.1253.

[0093] In the process of drawing the coordinate system of the flood peak flow and flood volume entering the reservoir, data of different years are selected each time to be drawn in the coordinate system, such as selecting data of two, three, four, sixteen, thirty-six, sixty-two or other years. That is, the number of points drawn in the coordinate system is different, and the slope of the regression line obtained according to the data of different years is different. For example, Figures 3 to 6 As shown in the embodiment of the present invention, the flood data in 1960 is used as the first year's data, and the slopes of the fitting lines obtained by selecting data for three consecutive years, eight consecutive years, sixteen consecutive years, and thirty-six consecutive years are different.

[0094] In the embodiment of the present invention, the inflow flood data from 1960 to 2021 are selected to draw a coordinate system for the inflow flood peak flow and flood volume. The inflow flood data of 1960 is taken as the data of the first year, and the inflow flood peak flow and flood volume of two consecutive years, three consecutive years, and four consecutive years are selected in sequence, and accumulated year by year until the inflow flood peak flow and flood volume of sixty-two consecutive years are selected to draw the coordinate system, that is, the data of two points, three points, four points, and up to sixty-two points are drawn in the coordinate system, and the intercept is controlled to 0 through linear fitting; the slope of the regression line formed by the two points, i.e., the peak flow and flood volume of the inflow flood in two years; the slope of the regression line formed by the three points, i.e., the peak flow and flood volume of the inflow flood in three years, and the slope of the regression line formed by the four points until the slope of the regression line formed by the sixty-two points are obtained, and a total of sixty-one a i Value, the sixty-one a i The value range is 0.0992 to 0.1295. Based on the historical data collected by the embodiment of the present invention, the following formula is obtained:

[0095] Q 库i =(0.0992~0.1295)W 库i

[0096] Regarding the selection of data from different years, data on floods entering the reservoir from several consecutive years should be selected.

[0097] Step 3: Calculate the multiplier coefficient

[0098] In engineering design, it is often assumed that the flood volume at the dam site and the flood volume entering the reservoir will not change before and after the project. That is, based on the reasonable assumption that the flood volume at the dam site and the flood volume entering the reservoir will not change before and after the project, it is assumed that the flood volume at the dam site of the same flood before and after the reservoir construction will be W 坝 and the flood volume W 库i Equal; in the W 坝 =W 库i On this basis, formula (1) combined with formula (2) yields

[0099]

[0100] The multiple ratio coefficient series b of the reservoir flood and dam site flood from the 2nd to nth year can be further obtained i . b i It is the ratio coefficient of the peak flow of floods entering the reservoir from the 2nd to the nth year after the reservoir is built to the peak flow of floods at the dam site before the reservoir is built.

[0101] make

[0102] Then Q 库i =b i Q 坝 , i=2,3,...,n(5)

[0103] n is the total length of the reservoir inflow flood series, that is, the reservoir inflow flood data of n years are collected; in the embodiment of the present invention, a total of 62 years of reservoir inflow flood data are selected.

[0104] The calculation method of correlation coefficient a is: based on the selected peak flow and flood volume data of dam site floods in previous years, the largest peak flow and flood volume data points of each year in the dam site floods in previous years are plotted in the coordinate system, with the vertical axis being the peak flow of dam site flood Q 坝 The horizontal axis is the flood volume W at the dam site. 坝 , the intercept is controlled to 0, and the slope of the regression line obtained according to the univariate linear regression relationship is the a value.

[0105] Correlation coefficient a i The calculation method is as follows: select the flood data of previous years, draw the coordinate system of the flood peak flow and flood volume of the flood entering the reservoir, select the flood peak flow and flood volume of two consecutive years, three consecutive years, four consecutive years, and up to n consecutive years to draw the coordinate system, that is, draw two points, three points, and four points in the coordinate system and gradually accumulate the data until n points, and control the intercept to be 0; according to the univariate linear regression relationship, obtain the slope of the regression line formed by two points, i.e. the flood peak flow and flood volume of the flood entering the reservoir in two years; the slope of the regression line formed by three points, i.e. the flood peak flow and flood volume of the flood entering the reservoir in three years, and the slope of the regression line formed by four points until n points form the slope of the fitting line, and the slope of the regression line formed by each regression line is a i Value, a total of n-1 a i The coordinate system for drawing the flood peak flow and flood volume of the reservoir for two, three, four and n years is selected in sequence, which means taking the starting year of the selected data year as the first year, and selecting two consecutive years, three consecutive years, four consecutive years, and accumulating year by year until the coordinate system for drawing the flood peak flow and flood volume of the reservoir for n consecutive years is selected; the a value and n-1 a values are obtained. i After the value is calculated, according to formula (4), n-1 b i value.

[0106] Based on the historical data collected by the embodiment of the present invention and according to formula (4), the embodiment of the present invention can obtain the multiple ratio relationship between the peak flow of the flood entering the reservoir from 2 to 62 years and the peak flow of the flood at the dam site from 1952 to 1959.

[0107] In the specific embodiment of the present invention, a=0.0967; according to the historical dam site flood data and reservoir inflow flood data selected in the embodiment of the present invention, sixty-one a can be obtained in step 2 i Value, according to the sixty-one a i Combining the formula (4) we can get sixty-one b i Value; obtained multiple coefficient series b iThe range is 1.02 to 1.34, and the multiple ratio coefficient series refers to the series values formed by the multiple ratio coefficients of each year.

[0108] Step 4: Cumulative average of coefficients

[0109] Take the cumulative average of the n-1 multiple ratio coefficients obtained in step 3 and calculate the cumulative average A total of n-2 cumulative averages can be obtained

[0110]

[0111] In the embodiment of the present invention, a total of 62 years of flood data are selected, and the maximum value of n is 62. In step 3 of the embodiment of the present invention, at most 61 b can be obtained. i Value, according to sixty-one b i The cumulative average value of sixty can be obtained The embodiment of the present invention calculates The range is between 1.03 and 1.21.

[0112] Step 5: Analyze the rationality of the results

[0113] Finally, the rationality of calculating the inflow flood from the dam site flood using the correlation relationship and formula (5) in step 3 is analyzed.

[0114] Observe n-2 cumulative averages whether it tends to be stable;

[0115] if The value tends to be stable and Value and b i If the relative error is within the pre-set range, then the calculation of the inflow flood from the dam site flood using formula (5) in step 3 is reasonable;

[0116] if If the value does not stabilize, then b in step 3 i The parameter selection is unreasonable, that is, the parameter b at this time i It is unreasonable to use the correlation relationship in step 3 to calculate the inflow flood from the dam site flood using formula (5).

[0117] The purpose of calculating the inflow flood is to verify whether the existing flood control design is reasonable. If the calculated inflow flood data is unreasonable, it will lead to incorrect review conclusions. Therefore, it is necessary to verify whether the calculated inflow flood data is reasonable.

[0118] Analyze the n-2 cumulative Value change trend, see Whether the value tends to be stable; with the year as the horizontal axis, the bi and Draw the coordinate system for the vertical axis and set b i and Draw a picture and observe Observe the change pattern over time Whether the value tends to be stable.

[0119] In the embodiment selected by the present invention, Figure 7 As shown, with the year as the horizontal axis, the b of the corresponding year i and Draw the coordinate system for the vertical axis and put sixty-one b i Worth sixty The dots are drawn into a picture, Figure 7 Display when hour, tends to be stable, and When it becomes stable, i Almost no error.

[0120] Regarding the calculation of the inflow flood from the dam site flood, the formula (5) Q 库i =b i Q 坝 Calculate the flood inflow, the present invention introduces the cumulative average value If the calculation The value tends to be stable, and The stable value and b i If the relative error is stable within the set range, it is reasonable to use the correlation relationship in step 3 to calculate the reservoir flood from the dam site flood using formula (5). The set range can be 1%, and the set range can also be adjusted based on experience according to the actual data series.

[0121] if If the value does not tend to be stable, the data series is still unstable, which will lead to the flood inflow calculated at the dam site being too large or too small. If the value has not stabilized yet, it is considered that the correlation formula (5)b in step 3 i The parameter selection is unreasonable, that is, the parameter b at this time i It is unreasonable to use the correlation relationship in step 3 to calculate the reservoir inflow flood from the dam site flood using formula (5). The reservoir inflow flood series derived from the correlation relationship, that is, the reservoir inflow flood for each year, is not reasonable; the reservoir inflow flood data of the correlation series should be used with caution.

[0122] If the calculated inflow flood is too large, the review of whether the reservoir dam meets the flood control requirements may lead to the conclusion that the reservoir dam cannot meet the flood control requirements, and because the calculated inflow flood is too large, the project investment may increase in the process of reconstructing the dam facilities or raising the dam; if the calculated inflow flood is too small, the review of whether the reservoir dam meets the flood control requirements may lead to the wrong conclusion that the reservoir dam can meet the flood control requirements, which will cause serious flood consequences when a flood occurs; therefore, whether the calculation of the inflow flood is reasonable will have a significant impact on the flood control review conclusion, so it is necessary to test whether the calculation of the inflow flood is reasonable. Only when the test shows that the calculated inflow flood is reasonable can the calculated inflow flood be used for flood control review.

[0123] The present invention also proposes a new ratio coefficient b i The value method is, if the cumulative average tends to be stable, then the multiple ratio coefficient b in formula (5) i Take a stable value, that is, to tend to be stable The value is used as the ratio coefficient of the flood peak flow at the dam site and the flood peak flow into the reservoir.

[0124] To stabilize The value is calculated according to the formula Q 库i =b i Q 坝 The inflowing flood peak flow is calculated based on the dam-site flood peak flow before reservoir construction. That is, the dam-site flood peak flow in a certain year before reservoir construction is used to estimate the inflowing flood peak flow that would have corresponded to the dam-site flood peak flow in that year if the reservoir had been built. The dam-site flood peak flows in each year before reservoir construction are used to estimate the inflowing flood peak flow that would have corresponded to the dam-site flood peak flow in each year if the reservoir had been built. After obtaining the inflowing flood peak flow data for multiple consecutive years, combined with parameters such as the height and width of the reservoir dam, the inflowing flood peak flow data can be used to verify whether the existing dam meets flood control requirements. If the verification based on the calculated inflowing flood peak flow data indicates that the existing dam cannot meet flood control requirements, the existing dam should be rebuilt. The calculated inflowing flood data also provides a basis for flood control design during the reconstruction of flood control facilities. If the verification based on the calculated inflowing flood peak flow data indicates that the existing dam can meet flood control requirements, the dam can continue to be used.

[0125] For example, the reservoir selected in the embodiment of the present invention is designed for flood control based on the dam site flood before the reservoir was built. In this embodiment, the selected reservoir was built in 1960, and there are eight years of dam site flood data from 1952 to 1959. Formula Q 库i =bi Q 坝 b in i Take a stable The value is calculated based on the peak flow of the dam site flood in 1952. If the reservoir dam was built in 1952, what would the corresponding peak flow of the flood entering the reservoir in 1952 be? i Take a stable Under the condition of the value of b, it can also be calculated that if the reservoir dam was built in 1953, the corresponding flood peak flow in 1953 should be what; i Take a stable In the case of value, according to the formula Q 库i =b i Q 坝 We can calculate in sequence that if a reservoir dam had been built in any of the years between 1952 and 1959, what the peak flow of the flood entering the reservoir in that year would have been, and then we can obtain the flood data entering the reservoir for eight years.

[0126] If a reservoir was built in any year between 1952 and 1959, then formula Q 库i =b i Q 坝 b in i Take a stable The flood inflow data of the year when the reservoir was built and the years after the reservoir was built can be obtained by using the value. Since the reservoir selected in this embodiment is designed for flood control based on the dam site flood, the flood inflow situation is not considered in the flood control design. If the flood control design is not considered for flood control, there is a problem of unsafe flood control design. In this case, When the value tends to be stable, the formula Q 库i =b i Q 坝 b in i Take a stable The flood inflow data from 1952 to 1959 were calculated based on the values. Combined with the height, width and other parameters of the reservoir dam, the flood inflow data from 1952 to 2021 were used to verify whether the current flood control capacity of the reservoir dam selected in this embodiment meets the standards and whether it needs to be further raised.

[0127] In the embodiment of the present invention, Figure 7 As shown, with the year as the horizontal axis, the b of the corresponding year i and Draw the coordinate system for the vertical axis and put sixty-one b i Worth sixty The dots are drawn into a picture, Figure 7 Display when hour, tends to be stable, and When it becomes stable,i There is almost no error, then b i It is appropriate to take 1.21, that is, Q 库i =1.21Q 坝 , on the contrary, as b i If 1.34 or 1.02 is used, the data series is still unstable, which may cause the reservoir inflow flood calculated at the dam site to be too large or too small. If the calculated reservoir inflow flood is used to verify whether the reservoir dam selected in this embodiment meets the flood control requirements, an incorrect conclusion may be drawn. In addition, since the calculated reservoir inflow flood result is too large, the process of reconstructing the dam facilities or raising the dam may lead to adverse consequences such as increased project investment and incorrect flood control review conclusions.

[0128] To verify whether a reservoir dam meets flood control requirements based on inflow floods, it is necessary to take the inflow flood data of many consecutive years as a whole and combine it with parameters such as the height and width of the dam to evaluate whether the dam meets flood control requirements; if the dam is built a short time ago, for example, five or eight years, only using the inflow flood data of five or eight years to evaluate whether the dam meets flood control requirements may lead to erroneous conclusions due to the short data series for evaluation; in this case, according to the method of the present invention, based on the dam site flood before the reservoir was built, it can be inferred what the inflow flood would have been in a certain year before the reservoir was built if the dam had been built in the said year, thereby inferring the inflow flood data of more years, and then forming a longer series of inflow flood data; the longer series of inflow data for evaluation is conducive to improving the accuracy of the evaluation results.

[0129] Finally, it should be noted that the contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field. The above description is only the preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A method for verifying the rationality of inferring reservoir flood based on dam site flood, characterized by: It includes the following steps: Step 1: Obtain the maximum flood peak flow and flood volume series data before and after the construction of the reservoir to be analyzed; Step 2: Establish relevant relationships; The correlation between the peak discharge and flood volume of the dam site is established as follows: Q 坝 =a W 坝 (1) Where: Q 坝 is the peak flood discharge at the dam site; W 坝 is the flood volume at the dam site; a is the correlation coefficient between the peak discharge and flood volume of the dam site flood; The correlation between the peak flow rate of flood entering the reservoir and the flood volume is established as follows: Q 库i =a i W 库i ,i=2,3,...,n (2) Where: Q 库i is the peak flow of the flood entering the reservoir in year i; W 库i is the flood volume entering the reservoir in year i; a i is the correlation coefficient between peak flow and flood volume established based on the flood data entering the reservoir in year i; n is the total length of the reservoir inflow flood series, that is, the reservoir inflow flood data were collected for n years in total; Step 3: Calculate the ratio coefficient b i ; Based on the reasonable assumption that the flood volume at the dam site and the flood volume entering the reservoir do not change before and after the project, it is assumed that the flood volume at the dam site of the same flood before and after the reservoir construction is W 坝 and the flood volume W 库i Equal; in the W 坝 =W 库i On this basis, combining formula (1) with formula (2), we get: make Then Q 库i =b i Q 坝 , i=2,3,...,n (5) Where: Q 库i is the peak flow of the flood entering the reservoir in year i; W 库i is the flood volume entering the reservoir in year i; a is the correlation coefficient between the peak discharge and flood volume of the dam site flood; a i is the correlation coefficient between peak flow and flood volume established based on the flood data entering the reservoir in year i; n is the total length of the reservoir inflow flood series, that is, the reservoir inflow flood data were collected for n years in total; b i is the correlation coefficient a between peak flow and flood volume established based on the flood data entering the reservoir in year i after the reservoir is built i The multiple coefficient of the correlation coefficient a between the peak discharge and flood volume of the dam site flood before the reservoir was built; A total of n-1 b are obtained i value; Step 4: Cumulative average of coefficients; Take the cumulative average of the n-1 multiple ratio coefficients obtained in step 3 and calculate the cumulative average value bi; n is the number of years of selected flood data entering the reservoir; b i is the correlation coefficient a between peak flow and flood volume established based on the flood data entering the reservoir in year i after the reservoir is built i The multiple coefficient of the correlation coefficient a between the peak discharge and flood volume of the dam site flood before the reservoir was built; A total of n-2 cumulative averages are obtained Step 5: Analyze the rationality of the results; Analyze the rationality of calculating the inflow flood from the dam site flood using formula (5) through correlation in step 3; Observe n-2 cumulative averages Is it stabilizing? if The value tends to be stable and Value and b i If the relative error is within the pre-set range, then the calculation of the inflow flood from the dam site flood using formula (5) in step 3 is reasonable; if If the value does not stabilize, then b in step 3 i The parameter selection is unreasonable, that is, the parameter b at this time i It is unreasonable to use the correlation relationship in step 3 to calculate the inflow flood from the dam site flood using formula (5).

2. The method for verifying the rationality of inferring reservoir flood based on dam site flood according to claim 1, characterized in that: In step 3, the calculation method of the proportional coefficient a is as follows: based on the selected peak flow and flood volume data of the dam site floods in previous years, the maximum peak flow and flood volume data points of each year in the dam site floods in previous years are plotted in the coordinate system, with the vertical axis being the peak flow of the dam site flood Q 坝 The horizontal axis is the flood volume W at the dam site. 坝 , the intercept is controlled to 0, and the slope of the regression line obtained according to the univariate linear regression relationship is the a value.

3. The method for verifying the rationality of inferring reservoir flood based on dam site flood according to claim 1, characterized in that: In step 3, the formula parameter a i The calculation method is to select the flood data of previous years, draw the coordinate system of the flood peak flow and flood volume of the flood entering the reservoir, and select the flood peak flow and flood volume of two years, three years, four years, and up to n years to draw the coordinate system, that is, draw the data of two points, three points, four points, and up to n points in the coordinate system, control the intercept to be 0, and obtain the regression line slope of the flood peak flow and flood volume of the two points, i.e., the two years; the regression line slope of the three points, i.e., the three years; the regression line slope of the n points; the slope of each regression line is a i Value, a total of n-1 a i value; Get the value of a and n-1 a i After the value is calculated, according to formula (4), n-1 b i value.

4. The method for verifying the rationality of inferring reservoir flood based on dam site flood according to claim 1, characterized in that: described The value tends to be stable and Value and b i The relative error is within the preset range, and b in formula (5) i Take a stable The value is the flood entering the reservoir calculated from the flood at the dam site.

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