A cross-section terrain-based riverbed elevation spatio-temporal evolution trend prediction method

Abstract

The application provides a cross-section terrain-based riverbed elevation spatio-temporal evolution trend prediction method, which comprises the following steps: obtaining a plurality of first riverbed elevation parameters, first distance parameters and second distance parameters of a plurality of cross-sections in a target river section; each cross-section comprises at least one preset observation point; determining a second riverbed elevation parameter of each cross-section under a target water level parameter according to the first riverbed elevation parameter, the second distance parameter and the first distance parameter; the target water level parameter is a water level parameter of a characteristic water level of the cross-section; determining a target model of the target river section based on the second riverbed elevation parameter; and predicting the cross-section according to the target model to obtain a target riverbed elevation parameter of the cross-section, which can integrate discrete observation data into a unified index representing the overall state of the cross-section, provide a standard input for a prediction model, and thus improve the prediction accuracy of the average riverbed elevation state.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of river management, in particular to a riverbed elevation spatiotemporal evolution trend prediction method based on cross-section topography. BACKGROUND

[0002] In related technologies, the deepest point (for example, the thalweg point) of each cross-section is extracted by software such as Flytime, and is connected to form a thalweg longitudinal profile line, or the thalweg longitudinal profile line is drawn by identifying and connecting the deep groove elevation points of each cross-section based on long-time sequence of measured large cross-section data. However, the above technical method mainly focuses on the static description and analysis of single or limited times of measurement data, and it is difficult to capture and predict the dynamic trend of spatiotemporal changes, and it is impossible to quantitatively calculate the riverbed elevation state in the river section. SUMMARY

[0003] The present application provides a riverbed elevation spatiotemporal evolution trend prediction method based on cross-section topography, which aims to efficiently, quickly and simply determine the average riverbed elevation state in the river section.

[0004] The present application provides a riverbed elevation spatiotemporal evolution trend prediction method based on cross-section topography, comprising:

[0005] Obtaining a first riverbed elevation parameter, a first distance parameter and a second distance parameter of a plurality of cross-sections in a target river section; each of the cross-sections comprises at least one preset observation point; the first riverbed elevation parameter is a riverbed elevation parameter corresponding to each of the preset observation points, the first distance parameter is a distance parameter between the cross-section and a preset dam site, and the second distance parameter is a distance parameter between the cross-section and each of the preset observation points;

[0006] Determining a second riverbed elevation parameter of each of the cross-sections under a target water level parameter according to the first riverbed elevation parameter, the second distance parameter and the first distance parameter; the target water level parameter is a water level parameter of a characteristic water level of the cross-section;

[0007] Determining a target model of the target river section based on the second riverbed elevation parameter;

[0008] Predicting the cross-section according to the target model to obtain a target riverbed elevation parameter of the cross-section.

[0009] In the embodiments of the present application, the first riverbed elevation parameter, the first distance parameter and the second distance parameter of the cross-section are obtained to determine the second riverbed elevation parameter under the characteristic water level, and then the target model is constructed and predicted, which can integrate the discrete observation data into a unified index representing the overall state of the cross-section, provide a standard input for the prediction model, and thus improve the prediction accuracy of the average riverbed elevation state. BRIEF DESCRIPTION OF DRAWINGS

[0010] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments will be briefly introduced. Obviously, the drawings in the following description only represent some of the embodiments of the present application, and all other drawings obtained by those skilled in the art without creative effort based on these drawings also belong to the protection scope of the present application.

[0011] Figure 1 A flowchart of a cross-section terrain-based riverbed elevation spatiotemporal evolution trend prediction method provided by an embodiment of the present application;

[0012] Figure 2 Another flowchart of a cross-section terrain-based riverbed elevation spatiotemporal evolution trend prediction method provided by an embodiment of the present application;

[0013] Figure 3 A schematic diagram of a calculation result of riverbed average elevation along the river course under different characteristic water levels of Jingjiang River section provided by an embodiment of the present application;

[0014] Figure 4 A schematic diagram of a calculation result of riverbed average elevation time variation process under different characteristic water levels of Jing26 cross-section provided by an embodiment of the present application;

[0015] Figure 5 A schematic diagram of a simulation result of riverbed average elevation along the river course of dry river channel of Jingjiang River section provided by an embodiment of the present application;

[0016] Figure 6 A schematic diagram of a simulation result of riverbed average elevation time variation process of dry river channel of Jing26 cross-section provided by an embodiment of the present application;

[0017] Figure 7 A structural schematic diagram of a cross-section terrain-based riverbed elevation spatiotemporal evolution trend prediction device provided by an embodiment of the present application;

[0018] Figure 8 A hardware structural schematic diagram of an electronic device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments only represent some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort also belong to the protection scope of the present application.

[0020] Riverbed elevation is the core basic parameter of river system management and protection, and its along-stream distribution law and time evolution process deeply affect the river stability, water flow dynamic characteristics, flood evolution, channel conditions and ecological environment. Therefore, accurately mastering the spatio-temporal dynamic change law of riverbed elevation is of great importance for scientific cognition of river evolution, optimization of water-related engineering design, improvement of flood control and disaster reduction capacity and maintenance of river and lake health.

[0021] However, the related art method mainly focuses on the static description and analysis of single or limited measurement data, which is difficult to effectively represent the continuous along-stream distribution law of riverbed average elevation (rather than single-point thalweg / deep trough) in space, lacks dynamic modeling ability for long-term continuous time series evolution process of riverbed elevation, and therefore is difficult to capture and predict the dynamic trend of its spatio-temporal change, and cannot quantitatively calculate the riverbed average elevation state at any position and any time in the study reach.

[0022] Under this background, based on long-time series of measured large-section data and characteristic water level data, the thalweg at different characteristic water levels is taken as the target channel, the riverbed average elevation of the target channel at different characteristic water levels is calculated by statistical calculation, the riverbed average elevation values of different measurement times and different sections in the study reach are obtained, and a spatio-temporal two-dimensional matrix of riverbed elevation values is formed; on this basis, a spatial decay model describing the continuous distribution of riverbed average elevation along the stream and a time evolution equation reflecting the time evolution law thereof are constructed, and the parameters in the above model are determined through a simulation (for example, MATLAB) program; based on the established spatial distribution model and time evolution equation, the simulation and prediction of the average riverbed elevation at any position and any time in the study reach can be realized, so as to efficiently, quickly and simply identify the spatio-temporal evolution law and future trend of the riverbed elevation of alluvial rivers.

[0023] The embodiment provides a riverbed elevation spatio-temporal evolution trend prediction method based on section topography, as shown in Figure 1 The method comprises the following steps:

[0024] Step 101: acquiring a first riverbed elevation parameter, a first distance parameter and a second distance parameter of a plurality of sections in a target reach; each section comprises at least one preset observation point; the first riverbed elevation parameter is a riverbed elevation parameter corresponding to each preset observation point, the first distance parameter is a distance parameter between the section and a preset dam site, and the second distance parameter is a distance parameter between the section and each preset observation point.

[0025] In the embodiment, the target river section can be a river section that needs to be predicted. The section can be a survey section arranged along the river transversely, which is used to reflect the terrain features of the river transversely, for example, the section can be a large section. The preset observation point can be a measurement point for obtaining the distance parameter at the position. The distance parameter can be distance information related to the section and / or the observation point position, for example, the distance parameter can be large section data; the first river bed elevation parameter can be the measured river bed elevation value Y at the preset observation point; the first distance parameter can be the horizontal distance L between the section and the preset dam site; and the second distance parameter can be the horizontal distance between the section and each preset observation point, that is, the distance X from the starting point of the section to each observation point.

[0026] In the embodiment, the process of obtaining the first river bed elevation parameter, the first distance parameter and the second distance parameter of the plurality of sections in the target river section can include: obtaining the first river bed elevation parameter, the first distance parameter and the second distance parameter of a plurality of measurements of the target river section in at least one preset time sequence, wherein each measurement can be a measurement of at least one preset observation point corresponding to at least one section at a preset time.

[0027] As an example, the measured large section terrain observation data can be collected and sorted, the measured large section data of the target river section for a long time sequence T years (T≥10) can be collected, each measurement contains mm sections, the maximum number of observation points of each section is dd, and the observation time of each measurement is yy, and a three-dimensional data set is constructed: {X (i, j, k), Y (i, j, k), L (i)} (i=1, 2,...,mm; j=1, 2,..., dd; k=1, 2, …, yy), wherein X is the distance of the observation point from the starting point of the measured large section, that is, the starting point distance; Y is the measured river bed elevation of the observation point; and L is the distance of the measured large section from the dam site, that is, the distance from the dam mileage. The measured large section terrain observation data is standardized and stored, the same measurement data is stored in a table (Excel) file named according to the measurement time t (format: YYYYMMDD) according to the format of the starting point distance X and the elevation Y, and the dam mileage L of different sections of the measurement is stored in different sheets (sheets) of the above Excel file; the data of different measurements is stored in different Excel files.

[0028] Step 102: determining the second river bed elevation parameter of each section under the target water level parameter according to the first river bed elevation parameter, the second distance parameter and the first distance parameter; the target water level parameter is the water level parameter of the characteristic water level of the section.

[0029] In the embodiment, the target water level parameter can be the water level value Z corresponding to the characteristic water level of the section typicalwherein the characteristic water level can be a low water level, a bankfull water level, a flood water level, etc. The second riverbed elevation parameter can be an average elevation value that can represent the overall riverbed state of the cross section under the target water level parameter.

[0030] In some embodiments, determining the second riverbed elevation parameter of each cross section under the target water level parameter according to the first riverbed elevation parameter, the second distance parameter and the first distance parameter comprises:

[0031] determining the target water level parameter of each cross section based on the first distance parameter;

[0032] determining the target cross section interval of the cross section according to the target water level parameter, the second distance parameter and the first riverbed elevation parameter;

[0033] determining the second riverbed elevation parameter based on the target cross section interval.

[0034] In the present embodiment, the target cross section interval can be the effective channel range within the cross section under the target water level parameter. In the embodiments of the present application, by determining the target water level parameter based on the first distance parameter, determining the target cross section interval according to the target water level parameter and the first riverbed elevation parameter, and then determining the second riverbed elevation parameter, the effective channel range under the characteristic water level can be accurately defined, and the second riverbed elevation parameter can truly reflect the overall state of the channel, thereby improving the technical problem of inaccurate index caused by ambiguous channel range definition in the related art.

[0035] In some embodiments, determining the target water level parameter of each cross section based on the first distance parameter comprises:

[0036] obtaining a preset distance parameter and a preset water level parameter corresponding to a preset position in the target river reach; the preset distance parameter is a distance parameter between the preset position and the preset dam site; the preset water level parameter is a water level parameter of a characteristic water level of the preset position;

[0037] determining the target water level parameter of each cross section based on the preset distance parameter, the preset water level parameter and the first distance parameter.

[0038] In the present embodiment, the preset position can be a typical position or a reference position in the target river reach where a long-term water level observation device is provided, for example, a position where a hydrological station or a water level station is located. The preset distance parameter can be a horizontal distance between the preset position and the preset dam site. The preset water level parameter can be a water level value of a characteristic water level corresponding to the preset position. For example, the preset water level parameter can include a low water level value, denoted as Z low , a bankfull water level value, denoted as Z bankfull , and a flood water level value, denoted as Z flood , which can be obtained by collecting and organizing typical positions (such as hydrological stations and water level stations) in the target river reach.

[0039] In the embodiment, the preset position can include a first position and a second position; the first position can be an upstream position; the second position can be a downstream position; the preset distance parameter can include a first preset distance parameter corresponding to the first position and a second preset distance parameter corresponding to the second position; the preset water level parameter can include a first preset water level parameter and a second preset water level parameter; and the first distance parameter can be a horizontal distance L(i) between the i th cross section and the preset dam site.

[0040] In the embodiment, based on the preset distance parameter, the preset water level parameter and the first distance parameter, the process of determining the target water level parameter of each cross section can include: subtracting the first preset distance parameter from the first distance parameter of the i th cross section to obtain a first distance difference value between the i th cross section and the upstream reference position; and dividing the distance difference value by a second distance difference value between the downstream reference position and the upstream reference position to obtain a relative distance proportion of the cross section between the upstream reference position and the downstream reference position, which reflects the spatial position relationship of the cross section relative to the upstream reference position; multiplying the relative distance proportion obtained above by a dry water level difference value between the upstream reference position and the downstream reference position to obtain a dry water level change amount of the i th cross section relative to the upstream reference position, which is based on the assumption of constant water surface slope and ensures that the water level change and the distance change are in linear correspondence; and adding the first preset water level parameter of the upstream reference position to the dry water level change amount calculated above to obtain the dry water level target water level parameter of the i th cross section.

[0041] As an example, based on the assumption of constant water surface slope, the water level values of the characteristic water levels (including the dry water level, the bankfull water level and the flood water level) of all the measured large cross sections can be obtained by linear interpolation calculation, for example, the calculation formula of the dry water level value of the large cross section is: wherein, and are the water level values of the dry water levels of the upstream reference position and the downstream reference position respectively, is the water level value of the dry water level of the i th cross section, and are the distances from the dam of the reference positions respectively, and L(i) is the horizontal distance between the i th cross section and the preset dam site. bankfull (i), Z flood (i) are calculated in the same way, forming a data set of the water level values of each cross section at the characteristic water levels Water Level = {L(i), Z low (i), Z bankfull (i), Z flood (i)}.

[0042] ​​​​In the embodiments of the present application, by acquiring the preset distance parameter and the preset water level parameter of the preset section, and combining the first distance parameter of the to-be-solved section to determine the target water level parameter, the characteristic water level of each section of the whole river section can be efficiently calculated based on limited reference data, the water level distribution is ensured to conform to the actual hydrological law of the river section, and thus the technical problems of low determination efficiency or poor accuracy of the characteristic water level in the related art are improved.

[0043] In some embodiments, the target section interval of the section is determined according to the target water level parameter, the second distance parameter and the first riverbed elevation parameter, including:

[0044] At least one third riverbed elevation parameter is determined in the plurality of first riverbed elevation parameters based on the target water level parameter;

[0045] A first observation point corresponding to each third riverbed elevation parameter is determined;

[0046] The plurality of first observation points and the second distance parameter corresponding to the first observation points are subjected to connected domain analysis processing to obtain a plurality of section intervals of the section;

[0047] A second observation point of the section is determined in the at least one preset observation point based on the at least one first riverbed elevation parameter and the at least one second distance parameter;

[0048] The target section interval of the section is determined based on the second observation point and the plurality of section intervals.

[0049] In the embodiments, the third riverbed elevation parameter can be an elevation value smaller than the target water level parameter in the first riverbed elevation parameter, that is, the elevation of the observation point below the characteristic water level. The first observation point can be an observation point corresponding to the third riverbed elevation parameter in the at least one preset observation point. The section interval can be a region formed by a plurality of continuously distributed first observation points. The second observation point can be the deepest point or the lowest point (thalweg) on the section, that is, the observation point corresponding to the point with the smallest value in the first riverbed elevation parameter or the third riverbed elevation parameter. The target section interval can be a section interval containing the second observation point, that is, the main channel range below the characteristic water level.

[0050] In the embodiments, the process of determining at least one third riverbed elevation parameter in the plurality of first riverbed elevation parameters based on the target water level parameter can include: comparing the value of each first riverbed elevation parameter with the value of the target water level parameter, and if the value of the first riverbed elevation parameter is smaller than or equal to the value of the target water level parameter, determining the first riverbed elevation parameter as the third riverbed elevation parameter. The process of determining the first observation point corresponding to each third riverbed elevation parameter can include: determining the observation point corresponding to the third riverbed elevation parameter as the first observation point. As an example, the measured large-section riverbed elevation smaller than the characteristic water level Z typical (dry water level Z low, the flat water level Z bankfull and the flood water level Z flood ), that is, all node positions NodeSet satisfying Y(i, j) < Z typical .

[0051] In the embodiment, the process of obtaining a plurality of cross-section intervals of the cross-section by performing connected component analysis on the plurality of first observation points and the second distance parameters corresponding to the first observation points can include: performing connected component analysis on NodeSet, and dividing the area where the cross-section riverbed elevation is less than the characteristic water level Z typical into different sub-intervals {Sub_k}. The process of determining the target cross-section interval of the cross-section based on the second observation point and the plurality of cross-section intervals can include: determining the sub-interval where the thalweg point is located as the river channel range under the characteristic water level, and recording the left and right nodes of the river channel range as node left , node right , and recording the left and right node starting points as X left , X right .

[0052] In the embodiments of the present application, by screening the third riverbed elevation parameter and the first observation point, the cross-section interval is obtained through connected component analysis, and the target cross-section interval is determined in combination with the second observation point, which can accurately define the main river channel range under the characteristic water level, and ensure that the subsequent analysis focuses on the effective river channel area, thereby improving the technical problem of inaccurate river channel range identification in the related art.

[0053] In some embodiments, based on the plurality of first riverbed elevation parameters and the plurality of second distance parameters, the second observation point of the cross-section is determined in at least one preset observation point, including:

[0054] determining a target riverbed elevation parameter of the cross-section from the plurality of first riverbed elevation parameters;

[0055] determining a target distance parameter corresponding to the target riverbed elevation parameter from the plurality of second distance parameters;

[0056] determining the observation point corresponding to the target riverbed elevation parameter and / or the target distance parameter as the second observation point.

[0057] In the embodiment, the target riverbed elevation parameter can be an elevation value (water level value) of the lowest point of the current section; and the target distance parameter can be a starting point distance corresponding to the lowest point elevation value of the current section. The process of determining the target riverbed elevation parameter from the plurality of first riverbed elevation parameters can include determining a value of the smallest first riverbed elevation parameter in at least one first riverbed elevation parameter of each section to obtain the target riverbed elevation parameter. The process of determining the target distance parameter corresponding to the target riverbed elevation parameter from the plurality of second distance parameters can include determining the target distance parameter corresponding to the target riverbed elevation parameter from the plurality of second distance parameters according to an index value of the target riverbed elevation parameter, where the index value can be a section node serial number.

[0058] As an example, the following MATLAB statements can be executed on the i-th section starting point distance X(i, :) and the elevation array Y(i, :), [Z min , idx] = min(Y(i,:)),X thaw = X(i, idx(1)),to obtain the lowest point elevation Z min of the section and the corresponding starting point distance X thaw ; and then, the observation point corresponding to the lowest point elevation Z min and / or the starting point distance X thaw is determined as the second observation point.

[0059] In the embodiments of the present application, by determining the target riverbed elevation parameter from the first riverbed elevation parameters and the corresponding second observation point, the deepest point on the section can be accurately positioned, which provides a core basis for subsequent definition of the main river channel range, thereby improving the technical problem of low or inaccurate recognition efficiency of the thalweg point in the related art.

[0060] In some embodiments, the second riverbed elevation parameter is determined based on the target section interval, including:

[0061] determining an area parameter and a width parameter of the target section interval;

[0062] determining a depth parameter of the target section interval based on the area parameter and the width parameter;

[0063] determining the second riverbed elevation parameter according to the depth parameter and the target water level parameter.

[0064] In this embodiment, the area parameter can be the cross-sectional area of the target section interval, i.e., the water area of the target section interval at the characteristic water level, for example, the area parameter can be the river channel cross-sectional area. The width parameter can be the lateral length of the target section interval, i.e., the horizontal distance between the left and right boundaries of the interval, for example, the width parameter can be the river channel width. The depth parameter can be the average water depth of the target section interval, i.e., the ratio of the area parameter to the width parameter, for example, the depth parameter can be the river channel water depth. The second riverbed elevation parameter can be the average riverbed elevation obtained by subtracting the depth parameter from the target water level parameter, for example, the second riverbed elevation parameter can be the average riverbed elevation below the characteristic water level.

[0065] In this embodiment, the process of determining the area parameter of the target section interval can include: using the adjacent observation point trapezoidal area summation method to calculate the river channel cross-sectional area A between [X left , X right ] at the characteristic water level. The process of determining the width parameter of the target section interval can include: taking the difference between the left and right node starting points as the river channel width, denoted as W=X right -X left . The process of determining the depth parameter of the target section interval based on the area parameter and the width parameter can include: the river channel water depth H=A / W. The process of determining the second riverbed elevation parameter according to the depth parameter and the target water level parameter can include: the average riverbed elevation E=Z typical -H below the characteristic water level. In some embodiments, the for loop statement in MATLAB can be used to calculate the average riverbed elevation below the characteristic water level for different sections of the same measurement.

[0066] In the embodiments of the present application, by determining the area parameter and the width parameter of the target section interval, calculating the depth parameter and obtaining the second riverbed elevation parameter, the complex section terrain can be converted into a unified average elevation index, accurately reflecting the overall riverbed state of the river channel, thereby improving the technical problem in the related art that it is difficult to use a single index to represent the overall riverbed characteristics of the section.

[0067] Step 103: determining the target model of the target river reach based on the second riverbed elevation parameter.

[0068] In this embodiment, the target model can be a mathematical model for predicting the riverbed elevation.

[0069] In some embodiments, the target model includes a first target model for representing the spatial decay of the section; determining the target model of the target river reach based on the second riverbed elevation parameter includes:

[0070] constructing a first initial model for representing the spatial decay of the section based on the first distance parameter and the second riverbed elevation parameter;

[0071] fitting the first distance parameter, the second riverbed elevation parameter and the first initial model to obtain a first parameter of the first initial model;

[0072] determining the first target model according to the first parameter and the first initial model.

[0073] In this embodiment, the first initial model can be a mathematical model for describing the change of the second riverbed elevation parameter with the first distance parameter, for example, a spatial decay model. The first parameter can be an undetermined parameter in the first initial model, which is determined by fitting. For example, the first parameter can be at least one of a decay coefficient and an undetermined parameter. The first target model can be the first initial model after substituting the first parameter, which is used to represent the decay law of the cross section with space.

[0074] In this embodiment, the first initial model is constructed based on the first distance parameter and the second riverbed elevation parameter to describe the functional relationship between the two; the first distance parameter, the second riverbed elevation parameter and the first initial model are fitted to obtain the first parameter; and the first target model is obtained by substituting the first parameter into the first initial model, so as to quantify the decay characteristics of the cross section with space.

[0075] As an example, a spatial decay model of the riverbed elevation can be constructed as follows: wherein, and is the riverbed elevation and slope at the starting point (x = 0), and L is the distance from the dam; is the decay coefficient. The undetermined parameters include , and , the independent variable is L, and the dependent variable is . The MATLAB nonlinear fitting function is used, the along-the-course calculation formula of the target river section average riverbed elevation is given, then the for loop statement is used to calculate the average riverbed elevation below the different measurement river channel characteristic water level, and the along-the-course calculation formula of the target river section average riverbed elevation is given.

[0076] In the embodiments of the present application, by constructing the first initial model, fitting the first parameter and determining the first target model, the decay law of the riverbed elevation with space can be accurately described, a reliable model is provided for the riverbed elevation prediction of the cross section at different positions, and thus the technical problem that the spatial distribution characteristics of the riverbed elevation are difficult to be quantified in the related art is solved.

[0077] In some embodiments, the target model includes a second target model for representing the evolution of the cross section with time; the target model of the target river section is determined based on the second riverbed elevation parameter, including:

[0078] at least one time parameter for measuring the cross section is obtained, and the second riverbed elevation parameter corresponding to each time parameter is obtained;

[0079] A second initial model for characterizing the evolution of the cross-section over time is constructed based on the second riverbed elevation parameters and time parameters.

[0080] The time parameters, the second riverbed elevation parameters, and the second initial model are fitted to obtain the second parameters of the second initial model.

[0081] The second target model is determined based on the second parameter and the second initial model.

[0082] In this embodiment, the time parameter can be the moment or period of measurement of the cross-section, such as the year and month of measurement. The second initial model can be a mathematical model describing the change of the second riverbed elevation parameter with time, such as a time evolution equation. The second parameter can be an undetermined parameter in the second initial model, determined through fitting; for example, the second parameter can be an empirical coefficient. The second target model can be the second initial model after substituting the second parameter, used to characterize the evolution law of the cross-section over time.

[0083] Specifically, multiple time parameters and corresponding second riverbed elevation parameters are obtained to form a time series; a second initial model is constructed based on these parameters to describe the functional relationship between the two; the time parameters, the second riverbed elevation parameters, and the second initial model are fitted to obtain the second parameters; the second parameters are substituted into the second initial model to obtain the second target model, so as to quantify the evolution characteristics of the cross section over time.

[0084] As an example, the average riverbed elevation of different measurements at the same cross-section i is extracted to form an elevation time series E(i) = [E(t1), E(t2), ..., E(tT)]. The time evolution equation of the riverbed elevation is then constructed: ,in: and They are respectively t Time and t =0, the riverbed elevation at the initial moment; a , b , k These are empirical coefficients. The independent variable is... t The dependent variable is The method employs a MATLAB nonlinear fitting function, providing a time evolution equation for the average riverbed elevation of the target cross-section. Then, using a for loop, it calculates the average riverbed elevation below the characteristic water level of different cross-sections and provides a time evolution equation for the average riverbed elevation.

[0085] In the embodiments of the present application, by constructing the second initial model, fitting the second parameters and determining the second target model, the evolution law of the riverbed elevation over time can be accurately described, a reliable model can be provided for the riverbed elevation prediction of the section at different time, and thus the technical problem that the time variation characteristics of the riverbed elevation are difficult to be quantified in the related art is improved.

[0086] Step 104: predicting the section according to the target model to obtain the target riverbed elevation parameter of the section.

[0087] In the embodiments, the target riverbed elevation parameter can be the riverbed elevation value at any position and / or at any time predicted by the target model.

[0088] In some embodiments, predicting the section according to the target model to obtain the target riverbed elevation parameter of the section includes:

[0089] According to the first distance parameter and the first target model, the target riverbed elevation parameter of the section is predicted.

[0090] In the embodiments, the first distance parameter can be the distance from the dam (the longitudinal starting point distance) of the section. Specifically, the distance from the dam of the section is obtained; the distance from the dam is input into the first target model, and the corresponding target riverbed elevation parameter is calculated by the model to realize the riverbed elevation prediction in the spatial dimension. For example, based on the spatial decay model of the average riverbed elevation, the average riverbed elevation at any position can be obtained.

[0091] In the embodiments of the present application, by obtaining the first distance parameter and combining the first target model for prediction, the riverbed elevation at the actual observation point can be quickly obtained based on the spatial decay law, the convenience and accuracy of the prediction are improved, and thus the technical problem that the spatial dimension riverbed elevation prediction efficiency is low in the related art is improved.

[0092] In some embodiments, predicting the section according to the target model to obtain the target riverbed elevation parameter of the section includes:

[0093] The target time parameter of the section is obtained; the target time parameter is any time parameter related to the section;

[0094] According to the target time parameter and the second target model, the target riverbed elevation parameter of the section is predicted.

[0095] In this embodiment, the target time parameter can be a time point or a time period that needs to be predicted. Specifically, the target time parameter that needs to be predicted is obtained; the target time parameter is input into the second target model, and a corresponding target riverbed elevation parameter is calculated by the model to realize the prediction of the riverbed elevation in the time dimension. For example, based on the time evolution equation of the average riverbed elevation, the average riverbed elevation of the same section at any time can be obtained. In some embodiments, based on the spatial decay model and the time evolution equation, the average riverbed elevation at any position and at any time can be obtained, and thus the evolution trend can be predicted.

[0096] In the embodiments of the present application, by obtaining the actual time parameter and combining the second target model for prediction, the riverbed elevation at any time can be quickly obtained based on the time evolution law, the reliability of long-term prediction is improved, and thus the technical problem of low prediction accuracy of the riverbed elevation in the time dimension in the related art is solved.

[0097] Based on the measured large-section data and the characteristic water level data of a long time sequence, the present application takes the river channel where the thalweg is located under different characteristic water levels as a target river channel, calculates the average riverbed elevation of the target river channel under different characteristic water levels by statistical calculation, obtains the average riverbed elevation values of different sections and different measurement times of the study reach, and forms a two-dimensional matrix of the riverbed elevation values in space and time. On this basis, a spatial decay model (calculation formula) describing the continuous distribution of the average riverbed elevation along the river and a time evolution equation reflecting the time evolution law thereof are constructed, and the parameters in the above model are determined through the MATLAB program. Based on the established spatial distribution model and the time evolution equation, the average riverbed elevation at any position and at any time in the study reach can be simulated and predicted, so that the spatiotemporal evolution law and future trend of the riverbed elevation of the alluvial river can be efficiently, quickly and simply determined, which is of great significance for predicting the river evolution characteristics, formulating appropriate river (navigation) regulation schemes and flood prediction, etc.

[0098] Hereinafter, a method for predicting the spatiotemporal evolution trend of the riverbed elevation based on the section topography provided by the embodiments of the present application is described.

[0099] The present application aims to provide a method for predicting the spatiotemporal evolution trend of the riverbed elevation based on the section topography, which can efficiently, quickly and simply realize the automatic calculation of the riverbed elevation of the alluvial river and the simulation and prediction of the spatiotemporal evolution law. As shown in Figure 2 The method comprises the following steps:

[0100] The measured large-section river channel range is identified, specifically including: collecting the low water level, the bankfull water level, the flood water level and the dam distance data; arraying the section serial number i, the observation point number j and the observation time k; standardizing the measured large-section topography array Excel and the measured large-section typical water level data set Excel, which can be determined by standardizing the measured large-section long sequence observation data and the measured large-section typical water level data set.

[0101] Collect the measured cross-section data of the target river section for a long time series T years (T≥10), each measurement containing mm cross-sections, the maximum number of observation points for each cross-section being dd, and the observation time for each measurement being yy, where i=1, 2,..., mm; j=1, 2,..., dd; k=1, 2,..., yy. Store the data of the same measurement in the format of starting distance X and elevation Y in an Excel file named by the measurement time t (format: YYYYMMDD). Table 1 is the standardized data set of different cross-sections of the same measurement, as shown in Table 1. At the same time, store the distance from the dam L of different cross-sections in different sheets of the above Excel file. Store the data of different measurements in different Excel files.

[0102] Table 1

[0103]

[0104] Collect and organize the typical location (such as hydrological station, water level station) of the target river section dry water level value Z low , bankfull water level value Z bankfull , flood water level value Z flood Based on the assumption of constant water surface slope, calculate the values of all measured cross-section characteristic water levels (including dry water level, bankfull water level, and flood water level) by linear interpolation, forming a data set containing cross-section name, distance from dam L, dry water level value Z low , bankfull water level value Z bankfull , and flood water level value Z flood Table 2 is the measured cross-section characteristic parameter data set, as shown in Table 2:

[0105] Table 2

[0106]

[0107] Measured cross-section river channel range identification, specifically including: obtaining the elevation and location of the thalweg point and obtaining the cross-section nodes under the characteristic water level, determining the river channel range below a certain water level, and using MATLAB connected domain analysis to obtain the river channel range where the thalweg point is located. The river channel range below the characteristic water level can be automatically identified.

[0108] Take Jing 3 cross-section of a certain year as an example to illustrate the identification process of the river channel range below the characteristic water level. Use the min statement in MATLAB to determine the lowest point elevation of the cross-section, i.e. the thalweg point elevation Z_min=20m, and the cross-section node number idx=18, which corresponds to the starting distance X thaw =1220. Take the bankfull water level Z bankfull as an example, use the find statement in MATLAB to extract the cross-section river bed elevation less than the bankfull water level Zbankfull =41.65m, all the node positions NodeSet of the region are [3, 26], including the cross-section node 18 where the knickpoint is located, then the region is determined as the range of the flat-bed channel, the left and right nodes of the range are recorded as node left =3, node right =26, and the difference between the left and right node starting points is recorded as X left =100, X right =1365.

[0109] The average riverbed elevation under the measured large cross-section characteristic water level is calculated, specifically including: the trapezoidal area summation method is used to calculate the cross-section area A of the river channel under the characteristic water level, the river channel width W, and then the river channel water depth H and the average riverbed elevation E below the characteristic water level are calculated; the for statement of MATLAB is used to calculate the average riverbed elevation below the characteristic water level of different cross-sections in the same measurement, which can be calculated by the average riverbed elevation under the measured large cross-section characteristic water level.

[0110] The flat-bed water level Z bankfull =41.65m is calculated by the trapezoidal area summation method of adjacent observation points; the flat-bed channel cross-section area A in the region with the node range [3, 26] below the node 41.65m; the difference between the left and right node starting points is recorded as W=X right - X left =1277.65, the river channel water depth H=A / W=10.48, the flat-bed water level Z bankfull =41.65m, and the average riverbed elevation E below the flat-bed water level Z typical =41.65m is H=41.65-10.48=31.16.

[0111] Then, the for loop statement in MATLAB is used to calculate the flat-bed water level Z bankfull below the average riverbed elevation of different cross-sections in the same measurement. Similarly, the average riverbed elevation below the low water level Z low and the average riverbed elevation below the flood water level Z flood of different cross-sections in the same measurement can be obtained. The average riverbed elevation below the low water level Z low , the average riverbed elevation below the flat-bed water level Z bankfull , and the average riverbed elevation below the flood water level Z flood of each measured large cross-section in the Jingjiang River section in a year are calculated. Figure 3

[0112] ​The along-stream calculation formula of the average riverbed elevation of different survey times is determined, specifically including: constructing a spatial decay model of the riverbed elevation; using a MATLAB nonlinear fitting function (for example, lsqcurvefit) to give the along-stream calculation formula of the average riverbed elevation of the target river section; using a for statement of MATLAB to calculate the average riverbed elevation below the characteristic water level of different survey times, and giving the along-stream calculation formula of the average riverbed elevation of the target river section, which can be determined by the along-stream calculation formula of the average riverbed elevation of different survey times.

[0113] Based on the calculation results of the average riverbed elevation below the characteristic water level of different sections of the same survey time, a spatial decay model of the riverbed elevation is constructed: Taking the average riverbed elevation below the annual low water level as an example, a MATLAB nonlinear fitting function lsqcurvefit is used, a model equation is defined as model = @(params, x) params(1) + (params(2) / params(3)).*(1 - exp(-params(3).*x)); and based on the given initial values of the model parameters params0 = [30, -1 / 10000, 0.00001], the upper limit of the parameters ub = [34, -1 / 1000000, 0.0001] and the lower limit of the parameters lb = [26, -1 / 10000, 0.000001], the along-stream calculation formula of the average riverbed elevation of the target river section is fitted. .

[0114] The riverbed elevation time evolution equation of each section or river section is determined, specifically including: constructing a riverbed elevation time evolution equation of each section or river section; using a MATLAB nonlinear fitting function lsqcurvefit to give the average riverbed elevation time evolution equation of the target section or river section, which can be constructed by the riverbed elevation time evolution equation.

[0115] Taking the average riverbed elevation of different survey times of each section as an example, the elevation time sequence is formed, and the calculation results of the average riverbed elevation time variation process of different characteristic water levels of Jing 26 section are shown in Figure 4 .

[0116] The time evolution equation of the riverbed elevation is constructed: The nonlinear fitting function lsqcurvefit of MATLAB is used, the model equation is defined as model = @(params, t) params(1).* (params(2) +params(3).* exp(-params(4).* t)), the initial value of the model parameter is params0= [26.95, 0.86, 0.13, 0.10], the upper limit of the parameter is ub = [28, inf, inf, inf], and the lower limit of the parameter is lb = [26, -inf, -inf, 1e-6], and the target section average riverbed elevation time evolution equation is fitted: .

[0117] The evolution trend of the average riverbed elevation below the characteristic water level is predicted. Through the spatial decay model based on the average riverbed elevation, the average riverbed elevation at any position can be obtained; through the spatial decay model based on the average riverbed elevation of different survey times, the time series of the average riverbed elevation at any position can be obtained. On this basis, through the time evolution equation of the average riverbed elevation, the average riverbed elevation at any position and at any time can be obtained, so that the evolution trend is predicted. For example, the simulation result of the average riverbed elevation of the dry channel of the Jingjiang River section in a year is shown in Figure 5 . The simulation result of the time variation process of the average riverbed elevation of the Jing26 section dry channel is shown in Figure 6 .

[0118] As shown in Figure 7 , the embodiment of the application provides a riverbed elevation space-time evolution trend prediction device based on section topography, and the device 700 comprises:

[0119] The acquisition module 701 is configured to acquire a first riverbed elevation parameter, a first distance parameter and a second distance parameter of a plurality of sections in a target river section; each section comprises at least one preset observation point; the first riverbed elevation parameter is a riverbed elevation parameter corresponding to each preset observation point, the first distance parameter is a distance parameter between the section and a preset dam site, and the second distance parameter is a distance parameter between the section and each preset observation point;

[0120] The first determination module 702 is configured to determine a second riverbed elevation parameter of each section under a target water level parameter according to the first riverbed elevation parameter, the second distance parameter and the first distance parameter; the target water level parameter is a water level parameter of a characteristic water level of the section;

[0121] The second determination module 703 is configured to determine a target model of the target river section based on the second riverbed elevation parameter;

[0122] The prediction module 704 is configured to predict the section according to the target model, and obtain a target riverbed elevation parameter of the section.

[0123] In some embodiments, the first determining module 702 is further configured to determine a target water level parameter of each section based on the first distance parameter; determine a target section interval of the section according to the target water level parameter, the second distance parameter and the first riverbed elevation parameter; and determine the second riverbed elevation parameter based on the target section interval.

[0124] In some embodiments, the first determining module 702 is further configured to obtain a preset distance parameter and a preset water level parameter corresponding to a preset position in the target river section; the preset distance parameter is a distance parameter between the preset position and a preset dam site; the preset water level parameter is a water level parameter of a characteristic water level of the preset position; and determine the target water level parameter of each section based on the preset distance parameter, the preset water level parameter and the first distance parameter.

[0125] In some embodiments, the first determining module 702 is further configured to determine at least one third riverbed elevation parameter in the plurality of first riverbed elevation parameters based on the target water level parameter; determine a first observation point corresponding to each third riverbed elevation parameter; perform connected domain analysis processing on the plurality of first observation points and second distance parameters corresponding to the first observation points to obtain a plurality of section intervals of the section; determine a second observation point of the section in at least one preset observation point based on the plurality of first riverbed elevation parameters and the plurality of second distance parameters; and determine a target section interval of the section based on the second observation point and the plurality of section intervals.

[0126] In some embodiments, the first determining module 702 is further configured to determine a target riverbed elevation parameter of the section in the plurality of first riverbed elevation parameters; determine a target distance parameter corresponding to the target riverbed elevation parameter in the plurality of second distance parameters; and determine an observation point corresponding to the target riverbed elevation parameter and / or the target distance parameter as the second observation point.

[0127] In some embodiments, the first determining module 702 is further configured to determine an area parameter and a width parameter of the target section interval; determine a depth parameter of the target section interval based on the area parameter and the width parameter; and determine the second riverbed elevation parameter according to the depth parameter and the target water level parameter.

[0128] In some embodiments, the target model includes a first target model for characterizing the decay of the section with space; and the second determining module 703 is further configured to construct a first initial model for characterizing the decay of the section with space based on the first distance parameter and the second riverbed elevation parameter; perform fitting processing on the first distance parameter, the second riverbed elevation parameter and the first initial model to obtain a first parameter of the first initial model; and determine the first target model according to the first parameter and the first initial model.

[0129] In some embodiments, the prediction module 704 is further configured to predict the target riverbed elevation parameter of the cross section according to the first distance parameter and the first target model.

[0130] In some embodiments, the target model comprises a second target model for representing evolution of the cross section over time; the second determination module 703 is further configured to acquire at least one time parameter of the measurement of the cross section, and a second riverbed elevation parameter corresponding to each time parameter; construct a second initial model for representing evolution of the cross section over time based on the second riverbed elevation parameter and the time parameter; perform fitting processing on the time parameter, the second riverbed elevation parameter and the second initial model to obtain a second parameter of the second initial model; and determine the second target model according to the second parameter and the second initial model.

[0131] In some embodiments, the prediction module 704 is further configured to acquire a target time parameter of the cross section; the target time parameter is any time parameter related to the cross section; and predict the target riverbed elevation parameter of the cross section according to the target time parameter and the second target model.

[0132] To implement the method of the embodiments of the present application, as shown in Figure 8 The embodiments of the present application also provide an electronic device 80, which can include a memory 801 configured to store a computer program, and a processor 802 configured to execute the computer program to implement the method of any of the above. The processor 802 can implement the steps in any of the methods described above, and thus will not be repeated here.

[0133] It should be noted that the electronic device provided by the above embodiments and the method embodiments belong to the same concept, and the specific implementation process is described in the method embodiments, which will not be repeated here.

[0134] Of course, in actual application, as shown in Figure 8 The electronic device 80 can further include at least one network interface 803. The various components in the electronic device are coupled together by a bus system 804. It can be understood that the bus system 804 is used to realize the connection and communication between the components. In addition to the data bus, the bus system 804 also includes a power bus, a control bus and a status signal bus. However, for the sake of clarity, only the data bus is shown in Figure 8The various buses are labeled as bus system 804. The number of processors 802 can be at least one. The network interface 803 is used for wired or wireless communication between the electronic device and other devices. The memory 801 in the embodiments of the present application is used to store various types of data to support the operation of the electronic device. The above-mentioned method disclosed in the embodiments of the present application can be applied to the processor 802 or implemented by the processor 802. The processor 802 can be an integrated circuit chip having a processing capability. In the implementation process, each step of the above-mentioned method can be completed by the integrated logic circuit of hardware in the processor 802 or the instruction in the form of software. The above-mentioned processor 802 can be a general-purpose processor, a digital signal processor (DSP), or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, etc. The processor 802 can implement or execute the methods, steps and logic block diagrams disclosed in the embodiments of the present application. The general-purpose processor can be a microprocessor or any conventional processor, etc. In combination with the steps of the method disclosed in the embodiments of the present application, it can be directly embodied as a combination of hardware and software modules in a single-chip microcomputer for execution. The software module can be located in the storage medium, which is located in the memory 801, and the processor 802 reads the information in the memory 801, and combines the hardware to complete the steps of the above-mentioned method. In the exemplary embodiments, the electronic device 80 can be implemented by one or more application-specific integrated circuits (ASICs), DSPs, programmable logic devices (PLDs), complex programmable logic devices (CPLDs), field programmable gate arrays (FPGAs), general-purpose processors, controllers, microcontrollers (MCUs), microprocessors (Microprocessors), or other electronic elements, for executing the above-mentioned method.

[0135] Specifically, the embodiments of the present application provide a computer readable storage medium having a computer program stored thereon, for example, the memory 801 storing the computer program, and the above-mentioned computer program can be executed by the processor 802 to complete the above-mentioned method steps. The computer readable storage medium can be FRAM, ROM, PROM, EPROM, EEPROM, Flash Memory, magnetic surface memory, optical disc, or CD-ROM, etc.

[0136] In addition, each of the functional units in each embodiment of the present application can be integrated into one processing unit, or each unit can be separately implemented as a single unit, or two or more units can be integrated into one unit; the integrated unit can be implemented in the form of hardware or in the form of hardware plus software function unit.

[0137] Those skilled in the art can understand that all or part of the steps of the above-mentioned method embodiments can be completed by program instruction related hardware, and the foregoing program can be stored in a computer readable storage medium, and the program executes the steps of the above-mentioned method embodiments when executed; and the foregoing storage medium includes mobile storage equipment, read-only memory (ROM), random access memory (RAM), magnetic disc or optical disc and various storage program codes.

[0138] Alternatively, the integrated unit of the present application, if implemented in the form of a software function module and sold or used as an independent product, can also be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the embodiments of the present application can be embodied in the form of a software product, which is stored in a storage medium and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the embodiments of the method of the present application. The foregoing storage medium includes mobile storage equipment, ROM, RAM, magnetic disc or optical disc and various storage program codes.

[0139] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the detailed description of other embodiments above, which will not be repeated here.

[0140] The embodiments of the present application are described in detail above, and the specific examples are applied to the principles and implementation modes of the present application. The above embodiment description is only used to help understand the method and core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed; in view of the above, the content of the specification should not be understood as the limitation of the present application.

Claims

1. A method for predicting the spatiotemporal evolution trend of riverbed elevation based on cross-sectional topography, characterized in that, include: Acquire the first riverbed elevation parameter, the first distance parameter, and the second distance parameter of multiple cross sections in the target river segment; each cross section includes at least one preset observation point; The first riverbed elevation parameter is the riverbed elevation parameter corresponding to each of the preset observation points; the first distance parameter is the distance parameter between the cross section and the preset dam site; and the second distance parameter is the distance parameter between the cross section and each of the preset observation points. The second riverbed elevation parameter of each cross section under the target water level parameter is determined based on the first riverbed elevation parameter, the second distance parameter, and the first distance parameter; the target water level parameter is the water level parameter of the characteristic water level of the cross section; the second riverbed elevation parameter is the average elevation value that can characterize the overall riverbed state of the cross section under the target water level parameter. The target model of the target river segment is determined based on the second riverbed elevation parameter; The target model is used to predict the cross section, and the target riverbed elevation parameters of the cross section are obtained.

2. The method according to claim 1, characterized in that, The step of determining the second riverbed elevation parameter of each cross-section under the target water level parameter based on the first riverbed elevation parameter, the second distance parameter, and the first distance parameter includes: The target water level parameters for each cross section are determined based on the first distance parameter. The target cross-sectional area of ​​the cross section is determined based on the target water level parameter, the second distance parameter, and the first riverbed elevation parameter. The second riverbed elevation parameters are determined based on the target cross-sectional area.

3. The method according to claim 2, characterized in that, Determining the target water level parameter for each cross-section based on the first distance parameter includes: Obtain preset distance parameters and preset water level parameters corresponding to preset locations in the target river section; the preset distance parameters are the distance parameters between the preset locations and the preset dam sites; the preset water level parameters are the water level parameters of the characteristic water level of the preset locations; Based on the preset distance parameter, the preset water level parameter, and the first distance parameter, the target water level parameter for each cross section is determined.

4. The method according to claim 2, characterized in that, Determining the target cross-sectional area of ​​the cross section based on the target water level parameter, the second distance parameter, and the first riverbed elevation parameter includes: Based on the target water level parameter, at least one third riverbed elevation parameter is determined from a plurality of first riverbed elevation parameters; Determine the first observation point corresponding to each of the third riverbed elevation parameters; Connectivity analysis is performed on multiple first observation points and the second distance parameters corresponding to the first observation points to obtain multiple cross-sectional intervals of the cross section; Based on multiple first riverbed elevation parameters and multiple second distance parameters, a second observation point of the cross section is determined among the at least one preset observation point; The target cross-sectional interval of the cross section is determined based on the second observation point and the multiple cross-sectional intervals.

5. The method according to claim 4, characterized in that, The step of determining a second observation point for the cross-section from at least one preset observation point based on multiple first riverbed elevation parameters and multiple second distance parameters includes: The target riverbed elevation parameter of the cross section is determined from a plurality of first riverbed elevation parameters; Determine the target distance parameter corresponding to the target riverbed elevation parameter from among multiple second distance parameters; The observation point corresponding to the target riverbed elevation parameter and / or the target distance parameter is determined as the second observation point.

6. The method according to claim 2, characterized in that, Determining the second riverbed elevation parameters based on the target cross-sectional area includes: Determine the area and width parameters of the target cross-sectional area; The depth parameter of the target cross-sectional area is determined based on the area parameter and the width parameter; The second riverbed elevation parameter is determined based on the depth parameter and the target water level parameter.

7. The method according to any one of claims 1-6, characterized in that, The target model includes a first target model for characterizing the spatial attenuation of the cross-section; the target model for determining the target river segment based on the second riverbed elevation parameter includes: A first initial model is constructed based on the first distance parameter and the second riverbed elevation parameter to characterize the spatial attenuation of the cross section. The first distance parameter, the second riverbed elevation parameter, and the first initial model are fitted to obtain the first parameter of the first initial model; The first target model is determined based on the first parameter and the first initial model.

8. The method according to claim 7, characterized in that, The step of predicting the cross-section based on the target model to obtain the target riverbed elevation parameters of the cross-section includes: Based on the first distance parameter and the first target model, the target riverbed elevation parameter of the cross section is obtained by prediction.

9. The method according to any one of claims 1-6, characterized in that, The target model includes a second target model for characterizing the evolution of the cross-section over time; the target model for determining the target river segment based on the second riverbed elevation parameter includes: Acquire at least one time parameter for measuring the cross section, and the second riverbed elevation parameter corresponding to each time parameter; A second initial model is constructed based on the second riverbed elevation parameter and the time parameter to characterize the evolution of the cross section over time. The time parameter, the second riverbed elevation parameter, and the second initial model are fitted to obtain the second parameter of the second initial model; The second target model is determined based on the second parameter and the second initial model.

10. The method according to claim 9, characterized in that, The step of predicting the cross-section based on the target model to obtain the target riverbed elevation parameters of the cross-section includes: Obtain the target time parameter of the cross section; the target time parameter is any time parameter related to the cross section; Based on the target time parameters and the second target model, the target riverbed elevation parameters of the cross section are obtained through prediction.

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