Multi-parameter prediction method for hydraulic debris flow in small watershed

Abstract

The application provides a small watershed hydraulic debris flow multi-parameter prediction method, and relates to the technical field of geological disaster prevention and control. In the small watershed hydraulic debris flow multi-parameter prediction method, a design rainfall process is determined according to design rainfall parameters and rainfall types, then hydrological analysis and debris flow process analysis are carried out according to the design rainfall process, and whether the debris flow occurs, the debris flow starting time and the debris flow flow process can be obtained as the debris flow prediction parameters, so that the prediction of the debris flow starting and process can be realized. In the application, the design rainfall parameters and land parameters of the target watershed can be used to output the debris flow process prediction including rich parameters (whether the debris flow occurs, the flow required for the debris flow starting and the corresponding time), so that the possible occurrence of the debris flow can be early warned before the rainfall event occurs. The timely prevention measures can be taken, and the personnel life safety and property safety can be protected.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the technical field of geological disaster prevention, and particularly relates to a small watershed water type debris flow multi-parameter prediction method. BACKGROUND

[0002] Debris flow is a common natural disaster, which brings serious threat to people's life and property safety. Due to the complex causes and high treatment cost, it is currently impossible to achieve comprehensive treatment. Debris flow prediction as a quick disaster reduction method has important significance for disaster prevention and reduction.

[0003] The method for debris flow prediction in the related art mainly includes: collecting rainfall conditions of debris flow events and rainfall conditions of non-debris flow events in history, the rainfall conditions including rainfall amount, rainfall intensity, rainfall duration and other meteorological data, performing statistical analysis, determining a threshold line of the rainfall condition, and combining rainfall monitoring to predict debris flow.

[0004] However, these methods depend on the data of debris flow events in history, so if the historical data is insufficient or inaccurate, the accuracy of the determined threshold line is affected, and then the prediction accuracy is affected. In addition, these methods depend on the relationship between historical rainfall conditions and debris flow occurrence, but the occurrence of debris flow is also affected by other factors such as terrain, soil type and underground water level. Therefore, the prediction result obtained by the above method has low reference significance. In addition, the prediction of peak flow and scale of debris flow is very important for debris flow disaster reduction, but the existing debris flow prediction only focuses on the time of debris flow occurrence, and cannot meet the actual needs of debris flow disaster reduction.

[0005] Therefore, there is an urgent need for a new debris flow prediction method. SUMMARY

[0006] The embodiment of the present application provides a small watershed water type debris flow multi-parameter prediction method to at least partially solve the problems in the related art.

[0007] The first aspect of the embodiment of the present application provides a small watershed water type debris flow multi-parameter prediction method, and the method comprises:

[0008] Obtaining design rainfall parameters and land parameters of a target watershed, the design rainfall parameters including maximum rainfall values of different rainfall return periods, and the land parameters including land use types and soil types;

[0009] Determining a design rainfall process according to the design rainfall parameters and rainfall types;

[0010] determining the surface runoff at each time corresponding to the design rainfall process according to the design rainfall process, land parameters and hydrological conditions;

[0011] determining the debris flow discharge at each time according to the surface runoff at each time;

[0012] determining whether the debris flow occurs, the starting time of the debris flow and the debris flow discharge process after the starting of the debris flow according to the debris flow discharge at each time;

[0013] outputting the debris flow prediction parameters, the debris flow prediction parameters including whether the debris flow occurs, the starting time of the debris flow and the debris flow discharge process parameter after the starting.

[0014] Optionally, the determining the surface runoff at each time corresponding to the design rainfall process according to the design rainfall process, land parameters and hydrological conditions comprises:

[0015] determining the surface runoff at each time corresponding to the design rainfall process according to the following formula:

[0016] P t =(P-I a ) 2 / (P-I a +S);

[0017] I a =0.2S;

[0018] S=25400 / CN-254;

[0019] wherein P t represents the surface runoff corresponding to the time t, P represents the cumulative rainfall depth at the time t, the cumulative rainfall depth being determined according to the rainfall intensity at each time, I a represents the initial rainfall loss, S represents the maximum water storage of the target watershed soil, and CN represents the dimensionless parameter of the surface runoff forming capacity of the target watershed, representing the runoff curve value of the hydrological conditions, land use type and soil type of the target watershed.

[0020] Optionally, the determining the debris flow discharge at each time according to the surface runoff at each time comprises:

[0021] determining the debris flow discharge at each time according to the following formula:

[0022] Q d =(1+λ)Q w D u ;

[0023] wherein Qd represents the debris flow discharge, Qw represents the flood discharge, and Qw=P t, Du represents the channel blockage coefficient, and λ represents the flow correction coefficient.

[0024] Optionally, the determination of whether a debris flow occurs, a starting time of the debris flow, and a debris flow flow process after the starting of the debris flow according to the debris flow flow at each time comprises:

[0025] The following formula is used to determine the critical starting flow of the debris flow:

[0026] wherein Q C represents the critical starting flow of the debris flow, D m is the particle size of the solid matter in the target watershed, and θ is the bed slope of the target watershed.

[0027] In the case that the debris flow flow at the first time is greater than the critical starting flow of the debris flow in the design rainfall process, it is determined that the debris flow will occur under the design rainfall condition, the first time is taken as the starting time of the debris flow, the debris flow flow at each time after the occurrence of the debris flow is obtained, and the debris flow flow process after the starting of the debris flow is determined.

[0028] Optionally, the rainfall types include a strong-weak type, a weak-strong type, and a mid-front type, and the design rainfall process is determined according to the design rainfall parameters and the rainfall type, comprising:

[0029] The maximum rainfall values in different time periods are homogenized according to the rainfall type, to obtain a first design rainfall process corresponding to the strong-weak type, a second design rainfall process corresponding to the weak-strong type, and a third design rainfall process corresponding to the mid-front type.

[0030] The surface runoff at each time corresponding to the design rainfall process is determined according to the design rainfall process, the land parameters, and the hydrological calculation, comprising:

[0031] The surface runoff at each time corresponding to the three design rainfall processes respectively is determined according to the first design rainfall process, the second design rainfall process, and the third design rainfall process, in combination with the land parameters and the hydrological calculation.

[0032] Optionally, the determination of whether a debris flow occurs, a starting time of the debris flow, and a debris flow flow process after the starting of the debris flow is taken as a debris flow prediction parameter, and a debris flow prediction is output, comprising:

[0033] A flood hydrograph is obtained according to the surface runoff at each time.

[0034] A debris flow hydrograph is obtained according to the debris flow flow at each time.

[0035] The flood hydrograph and the debris flow hydrograph are superimposed according to time to obtain a flood-debris flow hydrograph.

[0036] outputting whether the debris flow occurs, a starting time of the debris flow, and the flood-debris flow hydrograph.

[0037] The second aspect of the embodiment of the present application provides a small watershed hydraulic debris flow multi-parameter prediction device, which comprises:

[0038] a parameter acquisition module, configured to acquire design rainfall parameters and land parameters of a target watershed, wherein the design rainfall parameters comprise maximum rainfall values of different rainfall return periods, and the land parameters comprise land use types and soil types;

[0039] a rainfall process determination module, configured to determine a design rainfall process according to the design rainfall parameters and a rainfall type;

[0040] a surface runoff determination module, configured to calculate surface runoff at each time corresponding to the design rainfall process according to the design rainfall process, the land parameters and hydrological conditions;

[0041] a debris flow flow determination module, configured to determine debris flow flow at each time according to the surface runoff at each time;

[0042] a debris flow process determination module, configured to determine whether a debris flow occurs, a starting time of the debris flow and a debris flow flow process after the starting of the debris flow according to the debris flow flow at each time;

[0043] a prediction module, configured to output debris flow prediction parameters, wherein the debris flow prediction parameters comprise whether the debris flow occurs, the starting time of the debris flow and the debris flow flow process parameter after the starting.

[0044] Optionally, the surface runoff determination module is configured to:

[0045] determine the surface runoff at each time corresponding to the design rainfall process according to the following formula:

[0046] P t =(P-I a ) 2 / (P-I a +S);

[0047] I a =0.2S;

[0048] S=25400 / CN-254;

[0049] wherein P t represents the surface runoff corresponding to t time, P is a cumulative rainfall depth at t time, the cumulative rainfall depth is determined according to the rainfall intensity at each time, I arepresents the initial rainfall loss, S represents the maximum water storage capacity of the target watershed soil, CN represents a dimensionless parameter of the surface runoff forming capacity of the target watershed, and represents the runoff curve number of the target watershed hydrological conditions, land use type, and soil type.

[0050] Optionally, the debris flow flow rate determination module is configured to:

[0051] The debris flow flow rate at each time point is determined according to the following formula:

[0052] Q d =(1+λ)Q w D u ;

[0053] wherein Qd represents the debris flow flow rate, Qw represents the flood flow rate, Qw=P t , Du represents the channel clogging coefficient, and λ represents the flow correction coefficient.

[0054] Optionally, the debris flow process determination module is configured to:

[0055] The debris flow critical starting flow rate is determined according to the following formula:

[0056]

[0057] wherein Q C represents the debris flow critical starting flow rate, D m is the particle size of the solid matter in the target watershed, and θ is the gully bed slope of the target watershed.

[0058] In the case where the debris flow flow rate at the first time point is greater than the debris flow starting critical flow rate in the design rainfall process, it is determined that the debris flow will occur under the design rainfall condition, the first time point is taken as the debris flow starting time point, the debris flow flow rate at each time point after the debris flow occurs is obtained, and the debris flow flow rate process after the debris flow starts is determined.

[0059] Optionally, the rainfall types include a strong-weak type, a weak-strong type, and a mid-front type, and the rainfall process determination module is configured to: perform homogenization processing on the maximum rainfall values of different time periods according to the rainfall type, to obtain a first design rainfall process corresponding to the strong-weak type, a second design rainfall process corresponding to the weak-strong type, and a third design rainfall process corresponding to the mid-front type.

[0060] The surface runoff determination module is configured to: according to the first design rainfall process, the second design rainfall process, and the third design rainfall process, respectively, in combination with the land parameter and the hydrological calculation, determine the surface runoff at each time point corresponding to each of the three design rainfall processes.

[0061] Optionally, the prediction module is configured to:

[0062] obtaining a flood hydrograph according to the surface runoff at the respective time;

[0063] obtaining a debris flow hydrograph according to the debris flow flow at the respective time;

[0064] superimposing the flood hydrograph and the debris flow hydrograph according to time to obtain a flood-debris flow hydrograph;

[0065] outputting whether the debris flow occurs, a starting time of the debris flow and the flood-debris flow hydrograph.

[0066] The third aspect of the embodiment of the present application provides an electronic device, which comprises a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor realizes the small watershed hydrological debris flow multi-parameter prediction method according to the first aspect of the present application when executed.

[0067] The fourth aspect of the embodiment of the present application provides a computer readable storage medium, which stores a computer program, and the program realizes the small watershed hydrological debris flow multi-parameter prediction method according to the first aspect of the present application when executed by a processor.

[0068] The fifth aspect of the embodiment of the present application provides a computer program product, which comprises computer programs / instructions, and the computer programs / instructions realize the steps in the small watershed hydrological debris flow multi-parameter prediction method according to the first aspect of the present application when executed by a processor.

[0069] In the small watershed hydrological debris flow multi-parameter prediction method provided by the embodiment of the present application, the design rainfall process is determined according to the design rainfall parameter and the rainfall type, and then the hydrological analysis and the debris flow process analysis are performed according to the design rainfall process, so that whether the debris flow occurs, the starting time of the debris flow and the debris flow flow process can be determined, and the parameters are used as the debris flow prediction parameters.

[0070] In the embodiment of the present application, the design rainfall parameter and the land parameter of the target watershed can be used to output the debris flow process prediction including rich parameters (whether the debris flow occurs, the flow required for starting the debris flow and the corresponding time and the debris flow flow process), so that the possible occurrence of the debris flow can be warned in advance before the rainfall event occurs. This is helpful for taking timely prevention measures to protect the safety of personnel and property.

[0071] In the embodiment of the present application, the design rainfall parameter of the target watershed can be used to realize the risk assessment of the debris flow of the target watershed, and determine the risk degree of the debris flow of the target watershed. Then, corresponding planning and disaster prevention measures can be made, such as reasonable planning of buildings, roads, water conservancy facilities, etc., to reduce the risk of debris flow disasters. And based on the debris flow forecast, the rescue and disaster prevention resources can be reasonably allocated before the occurrence of debris flow disasters. Specifically, when the actual rainfall reaches the design rainfall parameter, the rescue team, equipment and materials can be mobilized in advance to deal with possible debris flow disasters, and the rescue efficiency and emergency response capability can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0072] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments of the present application will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0073] Figure 1 A step flow chart of the small watershed hydrological debris flow multi-parameter prediction method provided by the embodiment of the present application is shown;

[0074] Figure 2 A general schematic diagram of the target watershed in the exemplary embodiment provided by the embodiment of the present application is shown;

[0075] Figure 3 A rainfall process schematic diagram of three rainfall types in the exemplary embodiment provided by the embodiment of the present application is shown;

[0076] Figure 4 A surface runoff process schematic diagram corresponding to the three rainfall types in the exemplary embodiment provided by the embodiment of the present application is shown;

[0077] Figure 5 A flood-debris flow hydrograph schematic diagram in the prediction result in the exemplary embodiment provided by the embodiment of the present application is shown;

[0078] Figure 6 A structural block diagram of the small watershed hydrological debris flow multi-parameter prediction device provided by the embodiment of the present application is shown. DETAILED DESCRIPTION

[0079] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0080] In the embodiment of the present application, a small watershed hydrological debris flow multi-parameter prediction method is provided, as shown in Figure 1 Figure 1 ​The flowchart illustrates the steps of the multi-parameter prediction method for hydraulic debris flows in small watersheds provided by an embodiment of the present invention; specifically, the method includes the following steps:

[0081] S101, Obtain the design rainfall parameters and land parameters of the target watershed. The design rainfall parameters include the maximum rainfall value for different rainfall return periods, and the land parameters include the land use type and soil type.

[0082] S102, Determine the design rainfall process based on the design rainfall parameters and rainfall type;

[0083] S103, calculate and determine the surface runoff at each moment corresponding to the design rainfall process based on the design rainfall process, land parameters and hydrological conditions;

[0084] S104, Determine the debris flow rate at each time point based on the surface runoff at each time point;

[0085] S105, determine whether a debris flow has occurred, the start time of the debris flow, and the debris flow flow process after the debris flow starts based on the debris flow flow rate at each time.

[0086] S106, Output debris flow forecast parameters, which include: whether a debris flow will occur, the start time of the debris flow, and the flow rate parameters after the start of the debris flow.

[0087] In this embodiment of the invention, the target watershed to be analyzed and studied can first be determined based on the actual debris flow forecasting requirements. Further, based on the local meteorological and hydrological conditions of the target watershed, the design rainfall parameters for the watershed are determined. These design rainfall parameters are calculated from a large amount of historical data to obtain the maximum rainfall values ​​for 10-, 20-, 50-year, and even 100-year return periods at different time periods. For example, the design rainfall parameters for a certain watershed with a 20-year return period are: 58.5 mm in 1 hour, 139.3 mm in 6 hours, and 264 mm in 24 hours. Specifically, these parameters can be determined by consulting local hydrological manuals.

[0088] In this embodiment of the invention, relevant hydrological calculation methods can be used to determine the surface runoff at each moment corresponding to the design rainfall process based on the design rainfall process and the land parameters of the target watershed. For example, the full-storage runoff model, the infiltration-excess runoff model, the mixed runoff model, the unit hydrograph method, and the SCS runoff calculation method can be used. The specific hydrological calculation method can be selected according to actual needs.

[0089] In an optional implementation, the SCS (Soil Conservation Service) runoff calculation method is used to calculate the rainfall-flood process. The SCS runoff calculation method is a method for calculating runoff generated by rainfall. This method can simulate the runoff process based on factors such as soil water storage capacity and rainfall intensity, using a series of parameters and formulas. Specifically, step S103 includes:

[0090] The surface runoff for each time period corresponding to the designed rainfall event is determined using the following formula:

[0091] P t =(PI) a ) 2 / (PI a +S) (1)

[0092] I a =0.2S (2)

[0093] S=25400 / CN-254 (3)

[0094] Among them, P t Let P be the surface runoff at time t (unit: mm), and let P be the cumulative rainfall depth at time t (unit: mm), which is determined based on the rainfall intensity at each time (unit: mm / h); a The initial rainfall loss is represented by S (mm), the maximum water storage capacity of the soil in the target watershed is represented by S (mm), and CN is a dimensionless parameter representing the surface runoff capacity of the target watershed. The values ​​of the runoff curves characterize the hydrological conditions, land use type, and soil type of the target watershed.

[0095] Specifically, the rainfall intensity at any given moment can reflect the rainfall intensity per minute, hour, or any other time interval. Multiplying the rainfall intensity of each time interval by the length of that time interval yields the rainfall amount within that time interval. For each moment, adding the rainfall amount within its corresponding time interval to the cumulative rainfall amount before that moment yields the cumulative rainfall depth at that moment. By iterating through each moment, the cumulative rainfall depth at each moment can be obtained, and thus the corresponding surface runoff can be calculated.

[0096] In this embodiment of the invention, the CN value can be determined by consulting relevant CN value tables based on land use type and soil type. The CN value tables are derived from measured data and empirical summaries, providing CN values ​​corresponding to different land use types and soil types.

[0097] In this embodiment of the invention, by using the SCS runoff calculation method, the runoff at each moment can be calculated based on the designed rainfall process. Specifically, runoff represents the portion of rainfall that is converted into surface runoff, which is related to flood flow and debris flow, among others. It can be used to assess the runoff characteristics of a target watershed, predict the timing and scale of floods, and understand the potential risks of natural disasters such as debris flows.

[0098] In one optional implementation, step S104 includes:

[0099] The debris flow rate at each moment is determined using the following formula:

[0100] Q d = (1+λ) Q w D u (4)

[0101] Where Qd represents debris flow discharge, Qw represents flood discharge, and Qw = P t Du represents the channel blockage coefficient, and λ represents the flow correction coefficient.

[0102] In this embodiment of the invention, the channel blockage coefficient can be obtained by referring to a table, and the flow correction coefficient is usually a constant, which can be obtained by consulting the local hydrological manual.

[0103] In this embodiment of the invention, the debris flow rate at time t can be determined based on the surface runoff at time t.

[0104] In one optional implementation, step S105 includes:

[0105] S1051, the critical initiation flow rate for debris flow is determined using the following formula: Among them, Q C D represents the critical initiation flow rate of debris flow. m θ is the particle size of solid matter in the target watershed, and θ is the gradient of the ditch bed in the target watershed;

[0106] S1052, during the designed rainfall process, if the debris flow rate at a first moment is greater than the critical starting flow rate of the debris flow, it is determined that a debris flow will occur under the designed rainfall conditions. The first moment is taken as the starting moment of the debris flow, and the debris flow rate at each moment after the debris flow occurs is obtained to determine the debris flow rate process after the debris flow starts.

[0107] In this embodiment of the invention, the particle size of solid matter in the target watershed and the gradient of the gully bed can both be obtained by consulting local hydrological manuals or relevant publicly available literature, or determined by the following methods: For particle size, sediment samples can be collected at different locations and depths within the target watershed, and the sediment samples can be sieved using a series of sieves with different apertures. The mass of sediment passing through each sieve is recorded to determine the particle size distribution. For more precise particle size measurement, a microscope can be used to observe and measure particle size. For the gradient of the gully bed, multiple points can be selected along the gully bed using topographic maps, GPS devices, or rangefinders, and the elevation of each point can be measured. Then, the elevation difference and horizontal distance between the points can be calculated to obtain the gradient. Alternatively, large-scale topographic information can be obtained through drone photography or satellite image analysis, and then the average gradient of the gully bed can be calculated.

[0108] In this embodiment of the invention, after obtaining the debris flow initiation flow rate, it can be determined whether there is a debris flow flow rate at a certain moment that is greater than the debris flow initiation flow rate among the debris flow flow rates determined in step S104. If it is greater, it indicates that a debris flow disaster will occur.

[0109] In this embodiment of the invention, the finer the granularity of dividing each time point in step S102, the more accurate the debris flow disaster occurrence time point can be obtained in step S105. For example, if each minute is considered as a time period in step S102, and the start time of each minute is taken as each time point, then the debris flow disaster occurrence time point can be obtained with accuracy down to the minute. In practical applications, the granularity of dividing each time point in step S102 can be determined according to actual needs to obtain the debris flow disaster occurrence time point with the required accuracy.

[0110] In one optional implementation, the rainfall type includes: strong-then-weak, weak-then-strong, and mid-front type. Step S102 includes: flattening the maximum rainfall value for different time periods according to the rainfall type to obtain the first design rainfall process corresponding to the strong-then-weak type, the second design rainfall process corresponding to the weak-then-strong type, and the third design rainfall process corresponding to the mid-front type.

[0111] In this embodiment, step S103 includes: determining the surface runoff at each time corresponding to the first, second, and third design rainfall processes by combining land parameters and hydrological calculations.

[0112] In this embodiment of the invention, the rainfall is flattened based on the maximum rainfall value in different time periods (e.g., 1h, 6h, 24h) and three different rainfall types to obtain the designed rainfall process for different rainfall types.

[0113] In this embodiment of the invention, the design rainfall parameters can be analyzed for different rainfall types to obtain debris flow forecasts under various rainfall types. By taking rainfall type as one of the parameters to be considered in debris flow forecasting, a more realistic debris flow forecast can be obtained.

[0114] In this embodiment of the invention, when a debris flow disaster is determined to occur, the flood process during the period when no debris flow occurs can be combined with the debris flow process during the period when debris flow occurs to obtain the flow rate process of the debris flow, thereby predicting the time and scale of the debris flow.

[0115] In one optional implementation, step S106 includes:

[0116] S1061, Flood process curves are obtained based on the surface runoff at each time point;

[0117] S1062, Obtain the debris flow process line based on the debris flow rate at each time point;

[0118] S1063, the flood process line and the debris flow process line are superimposed according to the time to obtain the flood-debris flow process line;

[0119] S1064 outputs whether a debris flow has occurred, the start time of the debris flow, and the flood-debris flow process curve.

[0120] In this embodiment of the invention, flood hydrographs and debris flow hydrographs are obtained separately, and then superimposed to obtain a flood-debris flow hydrograph, which is then displayed as a debris flow forecast, enabling relevant personnel to analyze debris flow disasters more intuitively and conveniently.

[0121] For ease of understanding, an exemplary embodiment of the present invention is also provided:

[0122] Specifically, the target watershed is located in the Ergou area along the Dujiangyan-Wenchuan Highway, such as... Figure 2 As shown, this is a schematic diagram of the target watershed in an exemplary embodiment of the present invention. Ergou is located in the central-eastern part of Wenchuan County, Sichuan Province. It is a first-level tributary on the right bank of the upper reaches of the Minjiang River, with a watershed area of ​​approximately 39.4 km². The main gully is about 14 km long, and its mouth is about 6 km from Yingxiu Town, the epicenter of the Wenchuan earthquake. It is a typical high mountain canyon landform, with an elevation of 930 m at the mouth and the highest point in the watershed at 4140 m, a drop of 3210 m. The longitudinal gradient of the gully is 147‰. Ergou belongs to the subtropical humid monsoon climate zone on the edge of the Sichuan Basin. Summers are hot and rainy, with an annual rainfall of approximately 1000-1200 mm. Secondary disasters such as flash floods, landslides, mudslides, and collapses occur frequently.

[0123] In this embodiment of the invention, according to the Sichuan Provincial Hydrological Manual, the design rainfall values ​​for a 20-year return period for the basin are determined to be: 58.5 mm in 1 hour, 139.3 mm in 6 hours, and 264 mm in 24 hours.

[0124] In this embodiment of the invention, three rainfall types are set (strong-then-weak, weak-then-strong, and mid-front type, such as...). Figure 3 As shown in the figure, it illustrates the rainfall process of three rainfall types, and the design rainfall process for different rainfall types is obtained.

[0125] In this embodiment of the invention, based on the above three designed rainfall processes, the rainfall-flood process is calculated using the SCS runoff calculation formulas (1), (2), and (3), thereby realizing the calculation of the surface runoff process (e.g., Figure 4 As shown, it illustrates the surface runoff process corresponding to the three rainfall types in an embodiment of the present invention.

[0126] In this embodiment of the invention, formula (4) is further used to calculate the debris flow process, and formula (5) is used to determine the debris flow conditions for a debris flow disaster. The calculated schematic diagram and forecast results of a 20-year flood-debris flow process are shown below. Figure 5 As shown.

[0127] In this embodiment of the invention, a forecasting method based on flood flow calculation and debris flow flow calculation is realized through hydrological calculation and debris flow formation process analysis. It can simultaneously forecast comprehensive parameters such as whether debris flow will occur, the time period of occurrence, and the flow process, thus enriching the debris flow forecasting parameters.

[0128] Furthermore, in this embodiment of the invention, by introducing design rainfall parameters and combining design rainfall parameters with rainfall type, the design rainfall process is obtained. At the same time, by combining hydrological calculation methods, the determination of whether debris flow occurs and the calculation of the flow process line are realized.

[0129] As can be seen, in this embodiment of the invention, the forecasting method based on a series of debris flow formation processes, including rainfall, surface runoff, and debris flow, breaks through the traditional statistical method that uses rainfall as an indicator, and provides a completely new approach to debris flow forecasting.

[0130] Based on the same inventive concept, embodiments of the present invention also provide a multi-parameter forecasting device for hydraulic debris flows in small watersheds, such as... Figure 6 The diagram shows a structural block diagram of a multi-parameter forecasting device for hydraulic debris flows in small watersheds provided in an embodiment of the present invention. Specifically, the device includes:

[0131] The parameter acquisition module 601 is used to acquire the design rainfall parameters and land parameters of the target watershed. The design rainfall parameters include the maximum rainfall value for different rainfall return periods, and the land parameters include the land use type and soil type.

[0132] The rainfall process determination module 602 is used to determine the design rainfall process based on the design rainfall parameters and rainfall type;

[0133] The surface runoff determination module 603 is used to calculate and determine the surface runoff at each moment corresponding to the design rainfall process based on the design rainfall process, land parameters and hydrological conditions;

[0134] The debris flow rate determination module 604 is used to determine the debris flow rate at each time based on the surface runoff at each time.

[0135] The debris flow process determination module 605 is used to determine whether a debris flow has occurred, the start time of the debris flow, and the debris flow process after the start of the debris flow based on the debris flow flow rate at each time.

[0136] The forecast module 606 is used to output debris flow forecast parameters, which include: whether a debris flow will occur, the start time of the debris flow, and the flow rate parameters after the start of the debris flow.

[0137] Based on the same inventive concept, embodiments of the present invention also provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the steps in the multi-parameter forecasting method for hydraulic debris flows in small watersheds as described in any of the above embodiments.

[0138] Based on the same inventive concept, embodiments of the present invention also provide a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps in the multi-parameter forecasting method for hydraulic debris flows in small watersheds described in any of the above embodiments.

[0139] Based on the same inventive concept, embodiments of the present invention provide a computer program product, including a computer program / instruction, which, when executed by a processor, implements the steps in the multi-parameter forecasting method for small watershed hydraulic debris flows described in any of the above embodiments.

[0140] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0141] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present invention.

[0142] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0143] The above provides a detailed description of a multi-parameter forecasting method for hydraulic debris flows in small watersheds provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A multi-parameter prediction method for hydraulic debris flows in small watersheds, characterized in that, The method includes: The design rainfall parameters and land parameters of the target watershed are obtained. The design rainfall parameters include the maximum rainfall value for different rainfall return periods. The land parameters include land use type and soil type. The design rainfall parameters are calculated from a large amount of historical data to obtain the maximum rainfall values ​​of 10-year, 20-year, 50-year, and 100-year return rainstorms in the target watershed at different time periods. The design rainfall process is determined based on the design rainfall parameters and rainfall type. The surface runoff at each moment corresponding to the designed rainfall process is calculated based on the designed rainfall process, land parameters, and hydrological conditions. The debris flow rate at each time point is determined based on the surface runoff at each time point. Determine whether a debris flow has occurred, the initiation time of the debris flow, and the debris flow rate process after the debris flow has started, based on the debris flow rate at each moment. Output debris flow forecast parameters, which include: whether a debris flow will occur, the debris flow initiation time, and debris flow flow process parameters after initiation; The rainfall types include: initially heavy then weak, initially weak then heavy, and mid-front type. Based on the design rainfall parameters and rainfall types, the design rainfall process is determined, including: The maximum rainfall values ​​for different time periods were flattened according to the rainfall type to obtain the first design rainfall process corresponding to the first strong-then-weak type, the second design rainfall process corresponding to the first weak-then-strong type, and the third design rainfall process corresponding to the mid-front type. The surface runoff at each moment corresponding to the design rainfall process is determined based on the design rainfall process, land parameters, and hydrological calculations, including: Based on the first, second, and third design rainfall processes, the surface runoff at each time point corresponding to each of the three design rainfall processes is determined by combining land parameters and hydrological calculations. Output debris flow forecast parameters, including debris flow forecast parameters under different rainfall types.

2. The multi-parameter forecasting method for hydraulic debris flows in small watersheds according to claim 1, characterized in that, The surface runoff at each moment corresponding to the design rainfall process is determined based on the design rainfall process, land parameters, and hydrological calculations, including: The surface runoff for each time period corresponding to the designed rainfall event is determined using the following formula: P t =（ P - I a ） 2 / （ P - I a +S）； I a =0.2 S ； S =25400 / CN -254； in, P t Let be the surface runoff at time t. P It is the cumulative rainfall depth at time t, and the cumulative rainfall depth is determined based on the rainfall intensity at each time. I a Indicates initial rainfall loss, S This indicates the maximum water storage capacity of the soil in the target watershed. CN A dimensionless parameter representing the surface runoff capacity of a target watershed, representing the runoff curve values ​​that characterize the hydrological conditions, land use type, and soil type of the target watershed.

3. The multi-parameter forecasting method for hydraulic debris flows in small watersheds according to claim 2, characterized in that, The debris flow rate at each time point is determined based on the surface runoff at each time point, including: The debris flow rate at each moment is determined using the following formula: Q d = (1+ λ ) Q w D u ； in, Qd Indicates debris flow rate Qw Indicates flood flow rate, Qw=P t Du Indicates the channel blockage coefficient , λ This represents the flow correction factor.

4. The multi-parameter forecasting method for hydraulic debris flows in small watersheds according to claim 3, characterized in that, Determining whether a debris flow has occurred, the initiation time of the debris flow, and the debris flow rate process after the initiation of the debris flow based on the debris flow flow rate at each moment includes: The critical initiation flow rate for debris flow is determined using the following formula: ； in, Q C This indicates the critical initiation flow rate for debris flows. D m It refers to the particle size of solid matter in the target watershed. θ It refers to the gradient of the gully bed in the target watershed; If, during the designed rainfall process, the debris flow rate at a first moment is greater than the critical debris flow initiation flow, it is determined that a debris flow will occur under the designed rainfall conditions. The first moment is taken as the debris flow initiation moment, and the debris flow rate at each moment after the debris flow occurs is obtained to determine the debris flow rate process after the debris flow initiation.

5. The multi-parameter forecasting method for hydraulic debris flows in small watersheds according to claim 1, characterized in that, The occurrence of debris flow, the initiation time, and the flow rate after initiation are determined as debris flow prediction parameters, and the debris flow prediction is output, including: The flood process curve is obtained based on the surface runoff at each of the aforementioned times; The debris flow process curve is obtained based on the debris flow rate at each time point. By superimposing the flood process line and the debris flow process line at different times, a flood-debris flow process line is obtained. Output whether a debris flow has occurred, the start time of the debris flow, and the flood-debris flow process curve.

6. A multi-parameter forecasting device for hydraulic debris flows in small watersheds, characterized in that, The device includes: The parameter acquisition module is used to acquire the design rainfall parameters and land parameters of the target watershed. The design rainfall parameters include the maximum rainfall value for different rainfall return periods. The land parameters include the land use type and soil type. The design rainfall parameters are calculated from a large amount of historical data to obtain the maximum rainfall values ​​of 10-year, 20-year, 50-year, and 100-year return rainstorms in the target watershed at different time periods. The rainfall process determination module is used to determine the design rainfall process based on the design rainfall parameters and rainfall type. The surface runoff determination module is used to calculate and determine the surface runoff at each moment corresponding to the design rainfall process based on the design rainfall process, land parameters and hydrological conditions; The debris flow rate determination module is used to determine the debris flow rate at each time point based on the surface runoff at each time point. The debris flow process determination module is used to determine whether a debris flow has occurred, the start time of the debris flow, and the debris flow process after the debris flow starts, based on the debris flow flow rate at each time. The forecast module is used to output debris flow forecast parameters, which include: whether a debris flow will occur, the start time of the debris flow, and the flow rate parameters after the start of the debris flow. The rainfall types include: strong-then-weak, weak-then-strong, and mid-front. The rainfall process determination module is used to: flatten the maximum rainfall values ​​for different time periods according to the rainfall type to obtain the first design rainfall process corresponding to the strong-then-weak type, the second design rainfall process corresponding to the weak-then-strong type, and the third design rainfall process corresponding to the mid-front type. The surface runoff determination module is used to: determine the surface runoff at each time corresponding to the first, second, and third design rainfall processes, respectively, based on land parameters and hydrological calculations. The forecasting module is used to output debris flow forecast parameters under different rainfall types.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the multi-parameter prediction method for hydraulic debris flows in small watersheds as described in any one of claims 1-5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the multi-parameter prediction method for hydraulic debris flows in small watersheds as described in any one of claims 1-5.

9. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instruction is executed by the processor, it implements the steps in the multi-parameter prediction method for hydraulic debris flows in small watersheds as described in any of claims 1-5.

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