Simulation method and application of basin unit hydrograph based on flood peak delay time and shape factor

Abstract

To provide a simulation method and application of a basin unit hydrograph based on a flood peak delay time and a shape factor.SOLUTION: An instantaneous unit hydrograph of a basin is calculated by adopting a formula of an instantaneous unit hydrograph based on a flood peak delay time and a shape factor. The formula of the instantaneous unit hydrograph based on the flood peak delay time and the shape factor has following characteristics irrespective of values of parameters Tp, C3. A time axis and a surrounding area are equal to 1. A form of a function first increases and then decreases. This is a uni-modal function. Within a range of T≥0, all the values of the function are 0 or more. Due to the properties, the function can be naturally compliant with some basic definitions of the unit hydrograph. Many difficulties in conventional estimation of a unit hydrograph can be avoided. A parameter can be quickly calibrated. The efficiency in calibration and calculation of the unit hydrograph can be enhanced. The parameters Tp, C3 have clear physical significance compared with the Nash instantaneous unit hydrograph, which facilitates parameter calibration and application and spread of the proposed method.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to the technical field of numerical calculation of water conservancy engineering, and in particular to a simulation method and application of a drainage basin unit map based on flood peak delay time and shape coefficient. [Background technology]

[0002] The discharge process at the basin outlet is an important object of attention in flood forecasting and also an important input parameter in the calculation of high-precision river hydraulic models. The use of basin unit diagrams for short-term flood forecasting is currently a commonly used technical means. The definition of basin unit diagram can be expressed as follows: For any concrete basin, the surface runoff hydrograph at the basin outlet station formed by unit net rainfall uniformly distributed within a unit period is called a unit diagram. The basin unit diagram is a conceptual black-box model, and its application complies with the principles of multiple proportions and superposition. Flood Peak Delay Time: The delay time from the center of excess rainfall to the peak discharge (or hydrograph specifically). Shape coefficient: A coefficient that determines the shape of the instantaneous unit hydrograph.

[0003] However, it is difficult to estimate a watershed unit diagram in the traditional sense, and many constraints are often set based on the definition of the unit diagram (e.g., the unit diagram first increases and then decreases, the area enclosed by the unit diagram and the time axis is equal to the precipitation of the watershed, the values ​​on the unit diagram are all equal to or greater than zero, etc.), and are solved using optimization algorithms such as analytical methods, trial-and-error methods, least-squares methods, and linear methods. Nevertheless, some of the estimated unit diagrams still have a zigzag shape, which does not comply with general natural laws. Another method is to apply the formula of the Nash instantaneous unit diagram, but the essence of the Nash instantaneous unit diagram is to consider the watershed as n linear reservoirs with the same adjustment and storage effects in series. Although this was mathematically successful, it was very outlandish from the point of view of physical concepts, and also resulted in the fact that the parameters of the Nash instantaneous unit diagram (i.e., n and K) do not have an intuitive physical explanation. Summary of the Invention

[0004] In view of this, the present invention aims to propose a simulation method and application of a drainage basin unit chart based on flood peak delay time and shape coefficient. This drainage basin unit chart model is simple and practical, and the parameters of the model have clear physical meanings, thus overcoming the difficulties of estimating traditional drainage basin unit charts and the difficulties that the physical meanings of the parameters of the Nash instantaneous unit chart are unclear, and providing a solution to drainage basin flood forecasting.

[0005] In order to achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0006] A method for simulating a watershed unit diagram based on flood peak delay time and shape coefficient, comprising: a formula for an instantaneous unit diagram based on flood peak delay time and shape coefficient; adopting the formula for the instantaneous unit diagram based on flood peak delay time and shape coefficient to calculate the instantaneous unit diagram of a watershed; the formula for the instantaneous unit diagram based on flood peak delay time and shape coefficient is as follows: JPEG2025024669000002.jpg25170, where Q(t) is the instantaneous unit diagram of the basin, Q is the calculated surface runoff, and T p , C3 is the parameter of the instantaneous unit diagram, T p is the flood peak delay time, C3 is the shape coefficient, exp() represents the exponential function, and Gamma() represents the gamma function.

[0007] It further includes the following steps: S1: Collect hydrological data for the basin. S2: Using the formula for the instantaneous unit diagram based on the flood peak delay time and shape coefficient, S3: Convert the instantaneous unit diagram based on the flood peak delay time and shape coefficient into a period unit diagram; S4: Parameter T of the time unit map according to the historical data of the basin p , calibrate C3, S5: Use the estimated unit period map to perform short-term flood forecasts.

[0008] Furthermore, in step S1, hydrological data of the basin required for unit map flood forecasting is collected, and the hydrological data of the basin includes a basin area F, a time series of historical floods, a net rainfall series, and an observed surface runoff series.

[0009] Furthermore, in step S3, converting the instantaneous unit chart based on the flood peak delay time and the shape coefficient into a period unit chart includes the following steps S31 to S33: In S31, the integral of the instantaneous unit diagram with respect to time t is calculated, JPEG2025024669000003.jpg25168 where S(t) is the integral function of the instantaneous unit diagram of the basin with respect to time, Q(τ) is the instantaneous unit diagram of the basin, and τ is the time variable of the integral. JPEG2025024669000004.jpg29148 is obtained, where S(t) is the integral function of the instantaneous unit diagram of the basin with respect to time, C3 is the shape coefficient, and T p is the flood peak delay time, and the two-parameter gamma function is the upper incomplete gamma function, In S32, the period unit diagram is calculated by subtracting two S curves. JPEG2025024669000005.jpg18152 is obtained, where U(Δt,t) is the period unit diagram, Δt is the time interval, S(t) is the integral function with respect to time of the instantaneous unit diagram of the basin, and S(Δt,t) is the S curve with a delay of Δt on the time axis. JPEG2025024669000006.jpg18152 is obtained, In the formula, U(Δt,t) is the time unit diagram, Gamma() represents the gamma function, and T p , C3 is the parameter of the instantaneous unit diagram, T p is the flood peak delay time, C3 is the shape coefficient, Δt is the time interval, max() is the function to find the maximum value, In S33, in particular, the catchment area is F, and the unit is km 2 , for a unit diagram with time interval Δt, unit h, and net rainfall of 10 mm, JPEG2025024669000007.jpg18146In the formula, q(Δt,t) is the unit map corresponding to 10 mm net rainfall, F is the catchment area, Δt is the time interval, and U(Δt,t) is the period unit map.

[0010] In step S4, the parameter T of the time unit map is calculated based on the historical data of the basin. p , Calibrating C3 includes the following calibration process: Divide the net rainfall for each period by 10 mm and multiply it by the period unit diagram for 10 mm net rainfall to obtain the runoff process corresponding to the net rainfall for this period. The runoff processes generated by the net rainfall in each period are sequenced forward and backward on the time axis, and the flood simulation results are obtained by superimposing each runoff process on the time axis, and the formula is as follows: JPEG2025024669000008.jpg17138 Here, Q c,i is the historical flood simulation result for the i-th period, and r jis the net rainfall in the jth period, i is the period number of the simulation, j is the period number of the unit chart calculation, and 1 ≤ j ≤ i, q(Δt,t) is the unit chart corresponding to 10 mm net rain, and Δt is the time interval.

[0011] Furthermore, in step S4, the parameter calibration adopts the principle that the historical flood simulation error is minimized to calibrate the parameter T p and C3 is determined, and a parameter calibration algorithm is used in the parameter calibration process, and the parameter calibration algorithm is a traverse method or a trial and error method or an SCE-UA method.

[0012] Furthermore, in step S5, performing short-term flood forecasting using the estimated period unit chart includes the following contents.

[0013] When making a short-term flood forecast using the estimated period unit diagram, the net rainfall for each period is divided by 10 mm and multiplied by the period unit diagram for a net rainfall of 10 mm to obtain the runoff process corresponding to the net rainfall for this period. The runoff processes generated by the net rainfall in each period are sequenced forward and backward on the time axis, and the flood forecast results are obtained by superimposing each runoff process on the time axis, and the formula is as follows: JPEG2025024669000009.jpg17145Here, Q c,i is the flood forecast result for the i-th period number, and r j is the net rainfall for the jth period, i is the forecast period number, j is the period number for unit chart calculation, and 1≦j≦i, q(Δt,t) is the unit chart corresponding to 10 mm net rain, and Δt is the time interval.

[0014] Further, an electronic device is provided, comprising a processor and a memory communicatively connected to the processor for storing instructions executable by the processor, the processor being used to execute the above short-term flood forecasting method.

[0015] Further, a server includes at least one processor and a memory communicatively connected to the processor, wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the processor, causing the at least one processor to execute the above-mentioned short-term flood forecasting method.

[0016] Furthermore, there is provided a computer-readable storage medium storing a computer program, which, when executed by a processor, realizes the above-mentioned short-term flood forecasting method.

[0017] Compared with the prior art, the simulation method and application of drainage basin unit map based on flood peak delay time and shape coefficient described in the present invention has the following advantages: (1) The present invention describes a method and application of simulating a drainage basin unit map based on flood peak delay time and shape coefficient. The formula of instantaneous unit map based on flood peak delay time and shape coefficient proposed by the present invention has the following characteristics regardless of the values ​​of parameters Tp and C3: The area enclosed by the time axis is equal to 1. The form of the function first increases and then decreases. It is a unimodal function. In the range of t≧0, the values ​​of the function are all greater than or equal to 0. Due to the above properties, the function can naturally comply with some basic definitions of unit maps. It avoids many difficulties in the estimation of traditional unit maps, allows the parameters to be calibrated quickly, and improves the calibration and calculation efficiency of this unit map method.

[0018] (2) This invention describes a method and application of simulating a drainage basin unit map based on flood peak delay time and shape coefficient. The function peak value of this method is t=T p appears in, i.e., T p represents the flood peak delay time in the basin intuitively. In practical applications, the parameter T p It is possible to determine the approximate range.

[0019] (3) This invention describes a simulation method and application of the drainage basin unit diagram based on the flood peak delay time and shape coefficient. Compared with the Nash instantaneous unit diagram, the time when the function peak value appears is determined by the parameter T p is determined only by T p After is determined, the shape of the function is determined by the parameter C3. Since the physical meaning is clear, the parameter calibration and application of the proposed method are easy. [Brief description of the drawings]

[0020] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention, and the exemplary embodiments of the present invention and the description thereof are used to explain the present invention and are not intended to constitute an undue limitation of the present invention. [Figure 1] FIG. 13 is a schematic diagram of a function graph of an equation of an instantaneous unit diagram based on flood peak delay time and shape factor according to an embodiment of the present invention. [Diagram 2] FIG. 13 is a schematic diagram of the relationship between parameter Tp and function result of the proposed instantaneous unit diagram when parameter C3 is determined according to an embodiment of the present invention. [Diagram 3] FIG. 13 is a schematic diagram of the relationship between parameter C3 and function result of the proposed instantaneous unit diagram when parameter Tp is determined according to an embodiment of the present invention. [Figure 4] FIG. 2 is a schematic diagram of a curve of a period unit diagram obtained by subtracting two S curves according to an embodiment of the present invention. [Diagram 5] FIG. 13 is a schematic diagram of contour lines of the evaluation index NSE in the parameter calibration process according to an embodiment of the present invention. [Figure 6] FIG. 13 is a schematic diagram of an optimal result after parameter calibration according to an embodiment of the present invention. [Figure 7] FIG. 13 is a schematic diagram of a period unit diagram obtained by calibration according to an embodiment of the present invention. [Figure 8] FIG. 2 is a schematic diagram of short-term flood forecasting using an estimated time unit diagram according to an embodiment of the present invention. [Figure 9]1 is a process diagram of a short-term flood forecasting method according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Furthermore, where no contradiction exists, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0022] In the present description, the orientation or positional relationship indicated by terms such as "center", "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., is merely for convenience and simplification of the description of the present invention based on the orientation or positional relationship shown in the drawings, and is not intended to limit the present invention, as it does not indicate or suggest that the proposed device or component necessarily has a specific orientation and is constructed and operated in a specific orientation. In addition, technical terms such as "first", "second", etc. are used for descriptive purposes only and cannot be understood as indicating or suggesting a relative importance or implying the number of technical features shown. Thus, features defined by "first" and "second" may include one or more of the features, either explicitly or implicitly. In the present description, unless otherwise specified, "plurality" means two or more.

[0023] In the description of the present invention, unless otherwise clearly specified and limited, the terms "attached", "coupled" and "connected" should be understood in a broad sense. For example, it may be a fixed connection, a removable connection, or an integral connection. It may be a mechanical connection or an electrical connection. It may be a direct connection, an indirect connection via an intermediate medium, or an internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in the present invention can be understood according to the specific situation.

[0024] The invention will now be described in detail with reference to the accompanying drawings and examples.

[0025] As shown in Figures 1 to 9, a simulation method for a basin unit map based on flood peak delay time and shape coefficient includes an equation for an instantaneous unit map based on flood peak delay time and shape coefficient, and adopts the equation for the instantaneous unit map based on flood peak delay time and shape coefficient to calculate the instantaneous unit map of the basin, and the equation for the instantaneous unit map based on flood peak delay time and shape coefficient is as follows: JPEG2025024669000010.jpg24170 where Q(t) is the instantaneous unit diagram of the basin, Q is the calculated surface runoff, and T p , C3 is the parameter of the instantaneous unit diagram, T p is the flood peak delay time, C3 is the shape coefficient, exp() represents the exponential function, and Gamma() represents the gamma function.

[0026] As shown in FIG. 9, in a preferred embodiment of the present invention, a short-term flood forecasting method is proposed that includes the following steps S1 to S5, using a simulation method for a drainage basin unit map based on the above-mentioned flood peak delay time and shape coefficient. S1: Collect hydrological data for the basin. Hydrological data for the basin required for unit map flood forecasting is collected, and the hydrological data for the basin includes the basin area F, a time series of historical floods, a net rainfall series, and a measured surface runoff series.

[0027] S2: Use the formula for instantaneous unit diagram based on flood peak delay time and shape factor. Assume that the instantaneous unit diagram of the drainage basin can be expressed as: JPEG2025024669000011.jpg24170In the formula, Q(t) is the instantaneous unit diagram of the watershed, Q is the surface runoff to be calculated, and T p , C3 is the parameter of the instantaneous unit diagram, T p is the flood peak delay time, C3 is the shape coefficient, exp() represents the exponential function, and Gamma() represents the gamma function.

[0028] S3: Convert the instantaneous unit diagram based on the flood peak delay time and shape coefficient into a period unit diagram. Calculate the integral of the instantaneous unit diagram with respect to time t, JPEG2025024669000012.jpg21153Here, S(t) is the integral function with respect to time of the instantaneous unit diagram of the watershed (also called the S-curve), Q(τ) is the instantaneous unit diagram of the watershed, and τ is the time variable of the integral. JPEG2025024669000013.jpg26162 Obtained, where S(t) is the integral function with respect to time of the instantaneous unit diagram of the watershed (also called the S-curve), C3 is the shape coefficient, and T p is the flood peak delay time, and the two-parameter gamma function is the upper incomplete gamma function.

[0029] By subtracting the two S-curves, we obtain the period-unit diagram, JPEG2025024669000014.jpg19149Here, U(Δt,t) is the period unit diagram, Δt is the time interval, S(t) is the integral function with respect to time of the instantaneous unit diagram of the basin, and S(Δt,t) is the S curve with a delay of Δt on the time axis. JPEG2025024669000015.jpg29170 Obtained, In the formula, U(Δt,t) is the time unit diagram, Gamma() represents the gamma function, and T p , C3 is the parameter of the instantaneous unit diagram, T p is the flood peak delay time, C3 is the shape coefficient, Δt is the time interval, and max() is a function to find the maximum value.

[0030] In particular, if the catchment area is F (km 2 ), time interval Δt (h), and net rain10 (mm) for the unit diagram: JPEG2025024669000016.jpg17132In the formula, q(Δt,t) is the unit figure corresponding to 10 mm net rain, F is the catchment area, Δt is the time interval, and U(Δt,t) is the period unit figure.

[0031] S4: According to the historical data of the basin, the parameters of the period unit diagram (T p , C3) is calibrated. According to the actual needs of the basin flood forecast, the unit period length Δt of the period unit diagram is determined, and the parameter T p Given C3, the period unit diagram proposed by this invention can be used to carry out historical flood simulation. The specific process is as follows: Divide the net rainfall of each period by 10mm, multiply by the period unit diagram with 10mm net rainfall to obtain the runoff process corresponding to the net rainfall of this period, sequence the runoff processes generated by each net rainfall forward and backward on the time axis, and superimpose each runoff process on the time axis to obtain the flood forecast result. The formula is: JPEG2025024669000017.jpg14170Here, Q c,i is the historical flood simulation result for the i-th period, and r j is the net rainfall in the jth period, i is the period number of the simulation, j is the period number of the unit chart calculation, and 1 ≤ j ≤ i, q(Δt,t) is the unit chart corresponding to 10 mm net rain, and Δt is the time interval.

[0032] The parameter calibration of this method adopts the principle of minimizing the historical flood simulation error, and the parameter T p and C3 is determined. The specific process of the parameters can use any mature parameter calibration algorithm. Recommended algorithms include the traverse method, the trial and error method, the SCE-UA method, etc.

[0033] S5: Use the estimated unit period map to perform short-term flood forecasts. Determine the unit period length Δt of the corresponding period unit diagram, and calibrate to find the optimal parameter T p After obtaining C3, the estimated period unit diagram can be used to make short-term flood forecasts. During forecast calculation, the net rainfall in each period is divided by 10 mm, and multiplied by the period unit diagram with a net rainfall of 10 mm to obtain the runoff process corresponding to the net rainfall in this period. The runoff processes generated by the net rainfall in each period are ordered forward and backward on the time axis, and each runoff process is superimposed on the time axis to obtain the flood forecast results. The formula is JPEG2025024669000018.jpg18152 Here, Q c,i is the historical flood forecast result for the i-th period, and r j is the net rainfall for the jth period, i is the forecast period number, j is the period number for unit chart calculation, and 1≦j≦i, q(Δt,t) is the unit chart corresponding to 10 mm net rain, and Δt is the time interval.

[0034] The formula derivation process: The derivation process of S3 is as follows: When converting the instantaneous unit chart into a period unit chart, we adopt the S curve and follow the definition of the S curve: JPEG2025024669000019.jpg16131S-curve expression: JPEG2025024669000020.jpg20170 is obtained, The expression after integration is JPEG2025024669000021.jpg26145, where the two-parameter gamma function is the upper incomplete gamma function.

[0035] By subtracting the two S-curves, we obtain the period-unit diagram, JPEG2025024669000022.jpg39170 is obtained, In the formula, max() is a function that finds the maximum value.

[0036] The catchment area is F (km 2 ), time interval Δt (h), and net rain10 (mm) for the unit diagram: JPEG2025024669000023.jpg19142About the incomplete gamma function, In Mathematica, Gamma() represents the upper incomplete gamma function, and in Matlab, gammainc(z,a) represents the normalized lower incomplete gamma function. The incomplete gamma function in this specification is consistent with the gamma function in the mathematical software Mathematica, so readers who try this method in the mathematical software Matlab should be aware of this difference.

[0037] The advantages of the present invention are as follows: (1) The formula of the instantaneous unit diagram based on the flood peak delay time and shape coefficient proposed by the present invention is based on the parameter T p Regardless of the value of C3, it has the following characteristics: The area enclosed by the time axis is equal to 1. The function shape first increases and then decreases. It is a unimodal function. Within the range of t≧0, the values ​​of the function are all greater than or equal to 0. Due to the above properties, the function can naturally conform to some basic definitions of the unit diagram. This avoids many of the difficulties in traditional unit diagram estimation and allows parameters to be calibrated quickly, improving the calibration and calculation efficiency of this unit diagram method.

[0038] (2) The function peaks at t=T p appears in, i.e., T p represents the flood peak delay time of the basin intuitively. In practical applications, the parameter T p It is possible to determine the approximate range.

[0039] (3) Compared with the Nash instantaneous unit diagram, the time when the function peak value appears is the parameter T p is determined only by T p After is determined, the shape of the function is determined by the parameter C3. Since the physical meaning is clear, the parameter calibration and application of the proposed method are easy.

[0040] Example 1 1) Collect hydrological data for the basin. Take the calculation example on page 71 of the "Hydrological Forecast (4th Edition)" by China Water Conservancy and Hydropower Press, which collects historical flood data for the basin managed by the Nanhe Kaifeng Valley Station, including the basin area, time, period net rainfall, and measured surface runoff. The basin area is 5239.02 km2. 2and other sources are shown in the table below.

[0041] JPEG2025024669000024.jpg204170

[0042] 2) Using the formula for instantaneous unit diagram based on flood peak delay time and shape factor. The process of the embodiment is completely consistent with the description of S2, so it will not be repeated here. To intuitively display the formula proposed by the present invention, Fig. 1 shows a function graph of the formula of the instantaneous unit diagram based on the flood peak delay time and the shape factor. Fig. 2 shows the function graph of the parameter T of the proposed instantaneous unit diagram when the parameter C3 is determined. p Figure 3 shows the relationship between the parameter T p Once established, the relationship between the parameter C3 of the proposed instantaneous unit diagram and the function result is shown.

[0043] 3) Convert the instantaneous unit diagram based on the flood peak delay time and shape coefficient into a period unit diagram. The process of the embodiment is completely consistent with the description of S3, so it will not be repeated here. To intuitively display the method proposed by the present invention, FIG. 4 shows the subtraction of two S-curves to obtain a curve diagram of a period unit chart.

[0044] 4) Calibrate the parameters of the period unit map according to historical data of the basin. In this embodiment, the unit period length Δt = 6h for unit map flood forecast is determined based on the collected data. The parameter T p We perform parameter optimization for C and C3 and evaluate the performance of the simulation process using the Nash-Sutcliffe efficiency coefficient (NSE). pFor the optimization interval and optimization step size of the C3 parameter, we traverse all possible parameter combinations and calculate the NSE value (NSE≦1) of the simulation result for each parameter combination. The closer the NSE value is to 1, the closer the simulation result is to the observation. The parameter combination with the largest NSE is adopted as the optimal parameter. In this embodiment, the parameter T p The optimization interval is 1h≦T p ≦24h, the optimization step size is 1h, the optimization interval for parameter C3 is 0.1≦C3≦5, and the optimization step size is 0.2. Traverse calculations were performed for all parameter combinations in the above interval, and the NSE contour map obtained is shown in Figure 5. The maximum NSE=0.94 is the optimal parameter: T p = 9, C3 = 1.1, and for the optimal parameters, the historical data simulation results are shown in Figure 6.

[0045] 5) Using the estimated unit period map, short-term flood forecasts are made. The optimal parameters obtained by calibration are used to determine the period unit map. In this example, the drainage area F = 5239.02 km 2 ,The time interval is Δt = 6h, and the commonly accepted net rain 10mm unit diagram is adopted to obtain the unit diagram as shown in Figure 7.

[0046] Assuming that rainfall occurs in the basin in the future, the net rainfall over a period is as shown in the table below.

[0047] JPEG2025024669000025.jpg179170

[0048] The short-term flood forecast was carried out using the period unit diagram, and the results obtained are shown in Figure 8.

[0049] The above is only a preferred embodiment of the present invention, and the present invention is not limited thereto. As long as it falls within the spirit and principle of the present invention, all modifications, equivalent replacements, improvements, etc., made should be included within the protection scope of the present invention.

Claims

1. A method for simulating a watershed unit diagram based on flood peak delay time and shape coefficient, comprising: a formula for an instantaneous unit diagram based on flood peak delay time and shape coefficient; adopting the formula for the instantaneous unit diagram based on flood peak delay time and shape coefficient to calculate the instantaneous unit diagram of a watershed; the formula for the instantaneous unit diagram based on flood peak delay time and shape coefficient is as follows: and where Q(t) is the instantaneous unit diagram of the basin, Q is the calculated surface runoff, and T ｐ , C ３ is the parameter of the instantaneous unit diagram, and T ｐ is the flood peak delay time, C ３ is a shape factor, exp() represents the exponential function, and Gamma() represents the gamma function. A method comprising:

2. A short-term flood forecasting method applying the simulation method of a drainage basin unit chart based on a flood peak delay time and a shape coefficient according to claim 1, comprising the following steps S1 to S5: S1: Collect hydrological data for the basin. S2: Using the formula for the instantaneous unit diagram based on the flood peak delay time and shape factor, S3: Convert the instantaneous unit chart based on the flood peak delay time and shape coefficient into a period unit chart; S4: According to the historical data of the basin, the parameter T of the period unit map ｐ , C ３ Calibrate and S5: A short-term flood forecasting method, comprising: performing short-term flood forecasting using the estimated period unit diagram.

3. 3. The short-term flood forecasting method according to claim 2, wherein in step S1, hydrological data of a basin required for unit map flood forecasting is collected, and the hydrological data of the basin includes a basin area F, a time series of historical floods, a net precipitation series, and an observed surface runoff series.

4. In step S3, converting the instantaneous unit chart based on the flood peak delay time and the shape factor into a period unit chart includes the following steps S31 to S33: In S31, the integral of the instantaneous unit diagram with respect to time t is calculated; where S(t) is the integral function with respect to time of the instantaneous unit diagram of the basin, Q(τ) is the instantaneous unit diagram of the basin, and τ is the time variable of the integral. Obtained, where S(t) is the integral function of the instantaneous unit diagram of the watershed with respect to time, and C ３ is the shape factor, and T ｐ is the flood peak delay time, and the two-parameter gamma function is the upper incomplete gamma function, In S32, the two S curves are subtracted to obtain a period unit diagram. Obtained, where U(Δt,t) is the period unit diagram, Δt is the time interval, S(t) is the integral function with respect to time of the instantaneous unit diagram of the basin, and S(Δt,t) is the S curve with a delay of Δt on the time axis. Obtained, where U(Δt,t) is the time unit diagram, Gamma() represents the gamma function, and T ｐ , C ３ is the parameter of the instantaneous unit diagram, and T ｐ is the flood peak delay time, C ３ is a shape factor, Δt is a time interval, and max() is a function for finding the maximum value. In S33, in particular, the catchment area is F, and the unit is km ２ ,For a unit diagram with a time interval of Δt, units of h, and net rainfall of 10 mm, where q(Δt,t) is the unit map corresponding to 10 mm net rainfall, F is the catchment area, Δt is the time interval, and U(Δt,t) is the period unit map.

4. The method of claim 3, wherein the short-term flood forecasting method is

5. In step S4, the parameter T of the period unit map is calculated based on the historical data of the basin. ｐ , C ３ Calibrating the following calibration process: Divide the net rainfall for each period by 10 mm and multiply it by the period unit diagram for 10 mm net rainfall to obtain the runoff process corresponding to the net rainfall for this period; The runoff processes generated by the net rainfall in each period are sequenced forward and backward on the time axis, and the flood simulation results are obtained by superimposing each runoff process on the time axis, and the formula is as follows: Here, Q ｃ，ｉ is the historical flood simulation result for the i-th period, and r ｊ is the net rainfall in the jth period, i is the period number of the simulation, j is the period number of the unit chart calculation, and 1≦j≦i, q(Δt,t) is the unit chart corresponding to 10 mm net rain, and Δt is the time interval; 5. The method of claim 4, wherein the short-term flood forecasting method is

6. In step S4, the parameter calibration is carried out by adopting the principle that the historical flood simulation error is minimized to obtain the parameter T ｐ and C ３ Determine the parameter calibration process using a parameter calibration algorithm, the parameter calibration algorithm being a traverse method or a trial and error method or a SCE-UA method; 6. The method of claim 5, wherein the short-term flood forecasting method is

7. In step S5, performing short-term flood forecasting using the estimated period unit chart includes the following: When making a short-term flood forecast using the estimated period unit diagram, the net rainfall for each period is divided by 10 mm, and multiplied by the period unit diagram for a net rainfall of 10 mm to obtain the runoff process corresponding to the net rainfall for this period; The runoff processes generated by the net rainfall in each period are sequenced forward and backward on the time axis, and the flood forecast results are obtained by superimposing each runoff process on the time axis, and the formula is as follows: Here, Q ｃ，ｉ is the flood forecast result for the i-th period number, and r ｊ is the net rainfall for the jth period, i is the forecast period number, j is the unit chart calculation period number, and 1≦j≦i, q(Δt,t) is the unit chart corresponding to 10 mm net rain, and Δt is the time interval; 6. The method of claim 5, wherein the short-term flood forecasting method is

8. 1. An electronic device comprising: A method for forecasting short-term floods comprising: a processor; and a memory communicatively connected to the processor for storing instructions executable by the processor, the processor being adapted to execute the short-term flood forecasting method according to any one of claims 2 to 7 above.

1. An electronic device comprising:

9. A server, A method for forecasting floods comprising: at least one processor; and a memory communicatively connected to the processor, the memory storing instructions executable by the at least one processor, the instructions being executed by the processor to cause the at least one processor to execute the short-term flood forecasting method according to any one of claims 2 to 7. A server characterized by:

10. A computer-readable storage medium storing a computer program, the computer-readable storage medium being characterized in that, when the computer program is executed by a processor, the short-term flood forecasting method according to any one of claims 2 to 7 is realized.

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