Method for calculating sediment volume of river-channel type reservoir and evaluating morphological parameters of river reach and river channel of reservoir area

Abstract

The invention relates to the technical field of navigation channel engineering planning, in particular to a river channel type reservoir siltation amount calculation and reservoir area river reach river channel morphological parameter evaluation method. The method includes the following steps that river reach erosion and deposition amount prediction is conducted, firstly, data collection and time interval division are conducted, key parameters are calculated, then an erosion and deposition amount empirical model is constructed, and model parameter calibration and verification are conducted; and then evaluating morphological parameters of the low-water river channel of the river reach, firstly collecting section morphological data, then calculating scale parameters of the river reach, then modeling a relationship between the morphological parameters and erosion and deposition, and finally verifying and optimizing the model. According to the method, an empirical model is constructed based on actually measured data, and a dynamically associated erosion and deposition amount prediction formula is established by integrating influence of multiple factors such as incoming water and incoming sand conditions, reservoir regulation and early-stage accumulated deposition amount, so that a river channel erosion and deposition rule can be accurately reflected; and the method is directly used for reservoir scheduling optimization and channel maintenance decision making, and has a clear engineering practical value.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waterway engineering planning, in particular to a method for calculating the siltation amount of a river-type reservoir and evaluating the river channel form parameters of a reservoir area. BACKGROUND

[0002] In the planning and design of waterway engineering, it is often necessary to calculate the siltation amount of the river channel in the reservoir area and the river channel form parameters. Research shows that the river channel erosion and deposition change and the river channel adjustment are mainly related to the water and sediment conditions, the downstream erosion datum plane and the river channel perimeter conditions. Among them, the water and sediment conditions mainly include the water and sediment amount, the change process and the sediment composition; the downstream erosion datum plane includes the water surface of the control outlet section or the corresponding water surface of the resistant rock layer limiting the development of the river flow in the longitudinal direction; and the river channel perimeter conditions are mainly related to the geological and geomorphological conditions of the river section, including the river channel form, the riverbed composition and the previous siltation amount. When the above factors change, the riverbed will change in erosion and deposition, the river channel form will also be adjusted, which will inevitably lead to changes in the waterway conditions. However, there is no mature method for calculating the siltation amount of a river-type reservoir and evaluating the river channel form parameters of a reservoir area.

[0003] Based on this, the present application provides a method for calculating the siltation amount of a river-type reservoir and evaluating the river channel form parameters of a reservoir area to solve the above technical problems. SUMMARY

[0004] The present application aims to provide a method for calculating the siltation amount of a river-type reservoir and evaluating the river channel form parameters of a reservoir area to solve the problems in the background art.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0006] The first aspect of the present application is:

[0007] A method for calculating the siltation amount of a river-type reservoir and evaluating the river channel form parameters of a reservoir area is provided, comprising the following steps:

[0008] S1. Perform river section erosion and deposition prediction, first perform data collection and time period division and calculate key parameters, then build an erosion and deposition amount empirical model and perform model parameter calibration and verification;

[0009] S2. Then evaluate the low water river channel form parameters of the river section, first collect cross section form data, then calculate the river section scale parameters, then model the relationship between the form parameters and the erosion and deposition, and finally perform model verification and optimization;

[0010] S3. Based on the flow of steps S1 and S2, the actual application is carried out, first, the actual calculation area is selected for data integration and input, then the calculation and verification of the scouring and silting amount are carried out, and the results are applied after the prediction of the low-water channel shape.

[0011] Preferably, the implementation step of step S1 is:

[0012] S11. Data collection and time period division:

[0013] S111. Collecting the measured data of the river section, including daily average sediment concentration, daily average flow, water level before the dam, river section gradient and cumulative silting amount in the previous period;

[0014] S112. Dividing the calculation time period, and counting the total number of days, average flow, average sediment concentration and average gradient of each time period;

[0015] S12. Key parameter calculation:

[0016] S121. Time period average sediment coefficient: calculated by summing the product of daily average sediment concentration and daily average flow, and then dividing by the total number of days in the time period, used to represent the upstream water and sediment conditions;

[0017] S122. Flow sediment carrying capacity: combined with flow and gradient, determine the power relationship between sediment carrying capacity and flow, reflect the carrying capacity of water flow to sediment;

[0018] S123. Critical scouring and silting parameters: determine the critical value of the river bed scouring and silting balance state according to the historical data, used to judge the current time period river bed is in scouring, silting or balance state;

[0019] S13. Construction of empirical model of scouring and silting amount:

[0020] S131. Establishing the scouring and silting amount calculation formula by integrating the sediment coefficient, flow sediment carrying capacity, water level before the dam and the cumulative silting amount in the previous period;

[0021] S132. Introducing the "scouring and silting influence comprehensive parameter", integrating the combined influence of water and sediment conditions, reservoir operation and previous silting amount on river bed scouring and silting;

[0022] S14. Model parameter calibration and verification:

[0023] S141. Using historical time period data to calibrate the coefficients in the model, to ensure that the calculated value is consistent with the measured value;

[0024] S142. Using independent time period data to verify the accuracy of the model, comparing the calculated value and the measured value of the annual silting amount and the cumulative silting amount, and evaluating the reliability of the model.

[0025] Preferably, the river section gradient in the step S111 is calculated by the difference between the upstream and downstream water level stations, and the calculation period is divided into years or flood season / non-flood season in the step S112.

[0026] Preferably, the power relationship between the sediment carrying capacity and the flow rate in the step S122 is the product of the flow rate 2.5 power and the gradient.

[0027] Preferably, the reservoir scheduling in the step S132 is embodied by the water level in front of the dam.

[0028] Preferably, the model coefficients in the step S141 are the critical scouring and silting parameters and the exponential term.

[0029] Preferably, the implementation steps of the step S2 are as follows:

[0030] S21. Cross section morphology data collection: fixed observation cross sections are arranged in the river section, and the channel morphology parameters at low water level are measured, including river width, cross section area, average water depth and width-depth ratio;

[0031] S22. Calculation of river section scale parameters: the average morphology parameters of the river section scale are calculated by using the section spacing weighted average method combined with logarithmic conversion geometric average;

[0032] S23. Modeling of morphology parameters and scouring and silting relationship:

[0033] S231. An empirical relationship model is established between the morphology parameters of the river section scale and the comprehensive parameters of scouring and silting influence, and the adjustment law of the silting process on the river channel morphology is analyzed;

[0034] S232. The constant term and the exponential term in the model are determined, reflecting the joint influence of the previous silting amount, sediment inflow and water level in front of the dam on the morphology parameters;

[0035] S24. Model verification and optimization: the fitting accuracy of the model on the water depth, area and width-depth ratio is verified using the calibration period data, the reasons for the low prediction accuracy of the river width are analyzed, the model is optimized or high-frequency cross section measurement data is supplemented to improve the prediction ability.

[0036] Preferably, the width-depth ratio in the step S21 is the ratio of the square root of the river width to the water depth, the average morphology parameters in the step S22 are the average river width, the average water depth, the average cross section area and the average width-depth ratio, the morphology parameters in the step S231 are the average water depth and the cross section area, the exponential term in the step S232 is the sensitivity of the silting amount to the river width and the water depth, and the reasons for the low prediction accuracy of the river width in the step S24 include silting distribution limitation or measurement error.

[0037] Preferably, the implementation steps of the step S3 are as follows:

[0038] S31. Data integration and input: The data of Zhongxian Station and Shibaozhai Water Level Station are used to determine the slope of the river section, the measured flow, sediment concentration and water level data before the dam are combined, the historical data of the cumulative deposition amount in the early stage are input, and a time period division table is established;

[0039] S32. Deposition and erosion amount calculation and verification are performed;

[0040] S33. The river channel shape parameters in the low water period are predicted, and the results show that the average water depth, cross-sectional area, width-depth ratio and deposition process are significantly related, and the river width prediction needs to be combined with the deposition elevation distribution for optimization;

[0041] S34. According to the prediction results, the waterway navigation conditions are evaluated, the optimization suggestions for reservoir scheduling are proposed, the measured data are regularly updated, and the model parameters are dynamically corrected to adapt to long-term riverbed evolution.

[0042] Preferably, the optimization suggestion for reservoir scheduling in step S34 is to adjust the water level before the dam to control the deposition rate.

[0043] Compared with the prior art, the present application has the following beneficial effects:

[0044] The present application constructs an empirical model based on measured data, integrates the inflow and sediment conditions, reservoir scheduling and the cumulative deposition amount in the early stage and the like, establishes a dynamic correlation deposition and erosion amount prediction formula, can accurately reflect the river channel deposition and erosion law, at the same time, the cross-section spacing weighted average method is used to evaluate the low water channel shape parameters at the river section scale, the adjustment mechanism of the deposition process on the key parameters such as water depth and cross-sectional area is revealed, the prediction precision is high, the model is calibrated by historical data and verified by independent time periods, the reliability is strong, and directly serves the optimization of reservoir scheduling and the decision of waterway maintenance, has clear engineering practical value, in addition, the present application also provides a quantitative basis for long-term riverbed evolution management through parameter sensitivity analysis. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 It is a relationship diagram of the deposition amount and the sediment coefficient of Huanghuacheng in the present application;

[0046] Figure 2 It is a correlation diagram of the flow and sediment transport rate of Huanghuacheng river section in the present application;

[0047] Figure 3 It is a correlation diagram of the deposition amount and the flow sediment transport capacity of Huanghuacheng river section in the present application;

[0048] Figure 4 It is a correlation diagram of the deposition amount and the early deposition amount of Huanghuacheng river section in the present application;

[0049] Figure 5 It is a comparison diagram of the measured annual deposition amount, cumulative deposition amount and the calculated annual deposition amount, cumulative deposition amount of Huanghuacheng river section in the present application;

[0050] Figure 6 Figure 1 is a variation process diagram of a scale dry river channel form parameter of a Huanghua city river section according to the present application. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work are within the protection scope of the present application.

[0052] Please refer to Figures 1 to 6 The present application provides a method for calculating the siltation amount of a river-type reservoir and evaluating the river channel form parameters of a reservoir area, which specifically includes the following steps:

[0053] S1. Predicting the river section erosion and deposition amount, first collecting data and dividing time periods and calculating key parameters, then constructing an erosion and deposition amount empirical model and performing model parameter calibration and verification;

[0054] It should be noted that the implementation steps of step S1 are as follows:

[0055] S11. Data collection and time period division:

[0056] S111. Collecting river section measured data, including daily average sediment concentration, daily average flow, dam front water level, river section gradient and previous cumulative deposition amount;

[0057] S112. Dividing the calculation time period, and counting the total number of days, average flow, average sediment concentration and average gradient of each time period;

[0058] S12. Key parameter calculation:

[0059] S121. Time period average sediment coefficient: calculated by summing the product of daily average sediment concentration and daily average flow, and then dividing by the total number of days in the time period, used to represent the upstream water and sediment conditions;

[0060] S122. Flow sediment carrying capacity: combined with flow and gradient, determine the power relationship between sediment carrying capacity and flow, reflecting the sediment carrying capacity of the flow;

[0061] S123. Critical erosion and deposition parameter: determine the critical value of the riverbed erosion and deposition balance state according to historical data, used to judge whether the current time period riverbed is in erosion, deposition or balance state;

[0062] S13. Erosion and deposition amount empirical model construction:

[0063] S131. Synthesize the sediment transport coefficient, sediment transport capacity, water level before the dam, and the cumulative sedimentation amount in the previous period to establish the formula for calculating the erosion and deposition amount;

[0064] S132. Introduce the "erosion and deposition impact comprehensive parameter" to integrate the combined effects of water and sediment conditions, reservoir operation, and the previous sedimentation amount on riverbed erosion and deposition;

[0065] S14. Model parameter calibration and verification:

[0066] S141. Calibrate the coefficients in the model using historical period data to ensure that the calculated values match the measured values;

[0067] S142. Verify the model accuracy using independent period data, compare the calculated and measured values of annual sedimentation and cumulative sedimentation, and evaluate the model reliability;

[0068] It should be noted that the river section slope in step S111 is calculated by the difference between the upstream and downstream water level stations, and the calculation period in step S112 is divided into years or flood / non-flood periods;

[0069] It should be noted that the power relationship between sediment transport capacity and flow in step S122 is the product of flow to the power of 2.5 and slope;

[0070] It should be noted that the reservoir operation in step S132 is reflected by the water level before the dam;

[0071] It should be noted that the model coefficients in step S141 are the critical erosion and deposition parameters and the exponential term;

[0072] S2. Then evaluate the river section low water channel morphology parameters, first collect cross-section morphology data, then calculate the river section scale parameters, then model the relationship between morphology parameters and erosion and deposition, and finally verify and optimize the model;

[0073] It should be noted that the implementation steps of step S2 are:

[0074] S21. Cross-section morphology data collection: Set up fixed observation cross-sections in the river section, measure the low water channel morphology parameters, including river width, cross-section area, average water depth, and width-depth ratio;

[0075] S22. Calculation of river section scale parameters: Use the cross-section spacing weighted average method combined with logarithmic conversion of geometric mean to calculate the average morphology parameters of the river section scale;

[0076] S23. Modeling of the relationship between morphology parameters and erosion and deposition:

[0077] S231. Establish an empirical relationship model between the morphology parameters of the river section scale and the erosion and deposition impact comprehensive parameter to analyze the adjustment rules of the sedimentation process on the river channel morphology;

[0078] S232. Determine the constant term and the exponential term in the model, reflecting the joint influence of the previous deposition amount, sediment amount and water level before the dam on the morphological parameters;

[0079] S24. Model verification and optimization: use the calibration period data to verify the fitting accuracy of the model for water depth, area, width-depth ratio, analyze the reasons for the low prediction accuracy of river width, optimize the model or supplement high-frequency cross-section measurement data to improve the prediction ability;

[0080] It should be noted that the width-depth ratio in step S21 is the ratio of the square root of the river width to the water depth, the average morphological parameters in step S22 are the average river width, the average water depth, the average cross-sectional area and the average width-depth ratio, the morphological parameters in step S231 are the average water depth and the cross-sectional area, the exponential term in step S232 is the sensitivity of the deposition amount to the river width and the water depth, and the reasons for the low prediction accuracy of the river width in step S24 include deposition distribution limitation or measurement error.

[0081] S3. Based on the processes of steps S1 and S2, first select the actual calculation area for data integration and input, then perform the calculation and verification of the erosion and deposition amount, and then perform the result application after the prediction of the low-water channel morphology;

[0082] It should be noted that the implementation steps of step S3 are as follows:

[0083] S31. Data integration and input: use the data of Zhongxian Station and Shibaozhai water level station to determine the gradient of the river section, combine the measured flow, sediment concentration and water level data before the dam, input the historical data of the previous cumulative deposition amount, and establish a time period division table;

[0084] S32. Perform the calculation and verification of the erosion and deposition amount;

[0085] S33. Predict the channel morphological parameters in the low-water period, and the results show that the average water depth, cross-sectional area, width-depth ratio are significantly related to the deposition process, and the river width prediction needs to be optimized in combination with the deposition elevation distribution;

[0086] S34. Evaluate the navigation conditions of the waterway according to the prediction results, propose optimization suggestions for the reservoir operation, regularly update the measured data, and dynamically correct the model parameters to adapt to the long-term riverbed evolution;

[0087] It should be noted that the optimization suggestions for the reservoir operation in step S34 are to adjust the water level before the dam to control the deposition rate.

[0088] In actual application, the method for calculating the deposition amount of a river channel type reservoir and evaluating the channel morphological parameters of a reservoir area according to the present application comprises the following steps:

[0089] River section erosion and deposition amount prediction:

[0090] The method is based on the measured data, through the establishment of river channel erosion and sedimentation volume and water and sediment conditions of the empirical relationship;

[0091] First, considering the sediment coefficient is often widely used to reflect the river reach erosion and sedimentation volume of water and sediment conditions, the time period average sediment coefficient is expressed as formula (1):

[0092]

[0093] In the formula: N is the total number of days; S i The daily average sediment concentration, kg / m3; Q i The daily average flow, m3 / s;

[0094] For river type reservoir river reach, its erosion and sedimentation volume change not only by the upstream water and sediment, but also by the downstream reservoir scheduling;

[0095] Reservoir scheduling can be used to reflect the change of dam water level;

[0096] When the same reservoir inflow, the higher the dam water level, the smaller the reservoir section slope, the smaller the flow sediment carrying capacity, the greater the reservoir sedimentation;

[0097] Learn from the concept of flow sediment carrying capacity, flow sediment carrying capacity is generally proportional to the m times of flow and slope J, where the index m can be determined by the relationship between sediment transport rate and flow, so formula (1) can be further written as formula (2):

[0098]

[0099] The actual water and sediment parameters reflecting the change of river reach erosion and sedimentation;

[0100] When W i =0, the river bed is in a state of no erosion and no sedimentation, assuming

[0101] When the river bed is in a state of erosion, When the river bed is in a state of erosion, Then formula (4) can be written as formula (3):

[0102]

[0103] In the formula: m is the index; A is the critical erosion and sedimentation parameter; the rest of the symbols are the same as before;

[0104] The previous period of river reach erosion and sedimentation will have a certain influence on the erosion and sedimentation of the next period of sediment;

[0105] The current period of cumulative sedimentation When the river bed reaches the deposition balance, the river bed no longer accumulates, at this time W i = 0, written as a general formula as formula (4):

[0106]

[0107] In the formula: B is the total amount of deposition at the time of deposition balance; n is the index; the rest of the symbols are the same as before;

[0108] Synthesize formula (3), formula (4), the annual deposition amount W j The calculation formula can be summarized as formula (5):

[0109]

[0110] In the formula: k is a coefficient, and the rest of the symbols are the same as before;

[0111] Among them, is the comprehensive parameter of reservoir deposition and erosion, which comprehensively reflects the influence of water and sediment conditions, previous deposition and reservoir operation mode on river erosion and deposition;

[0112] Evaluation of low water channel parameters of the river section:

[0113] For river-type reservoir sections, there are significant differences between the channel shape parameters of different sections, and the channel shape of a specific section cannot represent the shape characteristics of the entire low water channel of the river section;

[0114] In order to analyze the evolution law of the entire low water channel of the river section, the method of river section average is used to calculate the low water channel shape parameters of the river section scale;

[0115] The method of combining logarithmic conversion and section distance weighted average is used to calculate the channel shape parameters of the river section scale;

[0116] Assume that the length of the study river section is L, and a number of fixed sections are set, the channel shape parameter G i (including river width (B i ), cross-section average area (A i ), water depth (H i ), width-depth ratio (η i )), which can be expressed as formula (6):

[0117]

[0118] In the formula: x j represents the distance of the jth section from the dam, m; N is the number of sections in the calculation river section;

[0119] The adjustment of the channel shape is essentially the result of the river erosion and deposition process;

[0120] The deposition process of the reservoir reach is related to the upstream incoming water and sediment, reservoir operation and the previous accumulated deposition. Therefore, the relationship between the morphological parameters of the low-water channel and the comprehensive parameters of the reservoir impact is established, and formula (7) is obtained:

[0121]

[0122] In the formula, G i is the channel morphological parameter of the river reach in the i-th year, C is a constant term, and the remaining symbols are the same as before.

[0123] Step 3: Specific implementation:

[0124] The Huanghuacheng reach in the Three Gorges reservoir area is selected as an example to implement the method;

[0125] Deposition calculation:

[0126] Table 1 is the deposition of the Huanghuacheng reach after the impoundment of the Three Gorges reservoir;

[0127] Table 2 is the parameter calibration results of formula (10);

[0128] Figure 1 is the annual deposition of the Huanghuacheng reach and the average sediment coefficient of the corresponding period. As shown in the figure, the annual deposition and the sediment coefficient are proportional, and the correlation coefficient is 0.72. The fitting formula is shown in formula (8):

[0129]

[0130] In the formula, W i is the annual deposition of the river reach, 104 m3, and the remaining symbols are the same as before.

[0131] To calculate the sediment carrying capacity of the flow m and the hydraulic gradient J need to be determined, where m can be determined by the relationship between the sediment carrying rate and the flow, and Figure 2 Therefore, m in the Huanghuacheng reach is about 2.5;

[0132] The gradient is determined according to the difference between the upstream and downstream water level stations (the upstream and downstream water level stations of the Huanghuacheng reach are Zhongxian and Shibaozhai water level stations);

[0133] According to Figure 3 It can be seen that the deposition of the Huanghuacheng reach is negatively correlated with the sediment carrying capacity of the flow, that is, as the water level before the dam decreases, the annual deposition of the Huanghuacheng reach decreases, which is consistent with the general law of river bed erosion and deposition in the reservoir reach.

[0134] Table 1 is the deposition of the Huanghuacheng reach after the impoundment of the Three Gorges reservoir;

[0135]

[0136] Table 2 Parameter calibration results in formula (10)

[0137]

[0138] According to the data in Table 1 from 2003 to 2016, the parameters of formula (5) are calibrated to obtain the siltation calculation formula (formula 8) of Huanghuacheng river section after the impoundment of Three Gorges Reservoir;

[0139] Figure 5 (a) is the comparison result of the calculated value and the measured value of the annual siltation of Huanghuacheng river section. It can be seen that the calculated value is in good agreement with the measured value, and the correlation coefficient R2 is 0.81. The measured data from 2017 to 2018 is used to verify formula (8), and the calculated value is consistent with the measured value in trend, and the two are relatively close;

[0140] Figure 5 (b) is the comparison result of the calculated value and the measured value of the cumulative siltation of Huanghuacheng river section, and the correlation coefficient R2 of the two is 0.99;

[0141] It shows that formula (8) can basically meet the calculation requirements of the siltation of Huanghuacheng river section after the impoundment of Three Gorges Reservoir;

[0142]

[0143] Low water channel parameter calculation and prediction:

[0144] The cross-section area (S i ), average water depth (H i ), river width (B i ) and width-depth ratio and other parameters under a certain water level are important indicators to describe the cross-section shape;

[0145] According to the Three Gorges Reservoir operation scheme, the water level before the dam drops to the flood control limit water level 145m around June 10 every year, which is the period of the lowest water level in Huanghuacheng river section all year round, and is the most unfavorable time for navigation;

[0146] Considering that Zhongxian station is located at the upper end of the river section and has a smaller slope in low water period, the water level of Huanghuacheng river section can be represented by Zhongxian station;

[0147] According to statistics, the multi-year average water level of Zhongxian station on June 10 from 2003 to 2018 is about 144.43m;

[0148] According to formula (6), the calculation results of low water channel shape parameters of Huanghuacheng river section from 2003 to 2018 are calculated; Figure 6

[0149] ​The parameters of formula (10) were calibrated using data from 2003 to 2016, and the rationality of the calibrated parameter values ​​was tested using the measured data from 2017 and 2018. The calibration results of the parameters are shown in Table 2, and the comparison between the calculated and measured values ​​of each parameter is shown in Figure 6 ;

[0150] As shown in Table 2, n in the empirical formula is greater than 0, α is less than 0, and β is greater than 0, indicating that the river width, water depth, cross-sectional area, and width-to-depth ratio of the low-water channel in the Huanghuacheng River section decrease with the increase of the previous sedimentation and upstream sediment volume, and increase with the increase of the water level in front of the dam, which is consistent with the general law of riverbed evolution.

[0151] Judging from the accuracy of the formula fitting, the average water depth of the river section Average area Average aspect ratio The fitting effect is better, and the average river width B i The accuracy is poor, with an R2 of only 0.44. There are two main reasons for this: first, the sediment in the Huanghuacheng River section has been deposited in the river channel at an elevation of 142 m, and changes in water and sediment conditions over a short time scale will not cause a significant widening or narrowing of the river width; second, it is affected by the measurement accuracy;

[0152] But the H i 、A i ,η i With G i There is a good correlation between them, with the correlation coefficients R2 reaching 0.96, 0.97, and 0.94, respectively, indicating that the water depth, cross-sectional area, and width-to-depth ratio of the dry river channel in this river section can respond well to the sedimentation process in this river section;

[0153] The established empirical formula for low-water channel can be used to predict the changing trends of water depth, cross-sectional area and width-to-depth ratio of the low-water channel in this river section.

[0154] Throughout this specification, references to "one embodiment," "example," or "specific example" indicate that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0155] The preferred embodiments of the application disclosed above are only to facilitate the elucidation of the application. The preferred embodiments do not describe all the details of the application and limit the application to the specific embodiments described. Obviously, many modifications and variations can be made in light of the teachings above. The description is chosen and described in order to best explain the principles of the application and its practical application to thereby enable others skilled in the art to best utilize the application and get the best results from the application. The application is only limited by the scope of the appended claims and the full range of equivalents thereof.

Claims

1. A method for calculating the sedimentation volume of a river-type reservoir and evaluating the morphological parameters of a river channel in a reservoir area, characterized in that: The following steps are involved: S1. To predict the amount of erosion and sedimentation in a river section, first collect data, divide the time periods, and calculate key parameters. Then, construct an empirical model for erosion and sedimentation and calibrate and verify the model parameters. S2. Then, the morphological parameters of the low-water channel in the river section are evaluated. First, cross-sectional morphological data are collected, then the reach scale parameters are calculated, and then the relationship between morphological parameters and erosion and deposition is modeled. Finally, the model is verified and optimized. S3. Based on the process of step S1 and step S2, actual application is carried out. First, the actual calculation area is selected for data integration and input. Then, the erosion and siltation volume is calculated and verified. After the low-water river channel morphology is predicted, the results are applied.

2. A method for calculating sedimentation in a river channel reservoir and evaluating river channel morphological parameters in a river section of a reservoir according to claim 1, characterized in that: The implementation steps of step S1 are: S11. Data collection and time division: S111. Collect measured data on river sections, including daily average sediment concentration, daily average flow, water level in front of the dam, river section gradient, and previous accumulated sedimentation; S112. Divide the calculation period and calculate the total number of days, average flow, average sediment concentration and average gradient of each period; S12. Calculation of key parameters: S121. Average sediment inflow coefficient for a period: Calculated by multiplying the daily average sediment concentration by the daily average flow rate, then dividing the result by the total number of days in the period. This coefficient represents upstream water and sediment inflow conditions. S122. Sediment transport capacity of water flow: Combined with flow rate and gradient, determine the power relationship between sediment transport capacity and flow rate, reflecting the water flow's ability to transport sediment; S123. Critical scour and sedimentation parameter: Determines the critical value of the riverbed scour and sedimentation equilibrium state based on historical data, used to determine whether the riverbed is in a scour, sedimentation, or equilibrium state during the current period; S13. Construction of empirical model of erosion and deposition volume: S131. Establish a calculation formula for erosion and sedimentation based on the sediment inflow coefficient, sediment transport capacity of the water flow, water level in front of the dam, and previous accumulated sedimentation. S132. Introducing the "Comprehensive Parameter for Scour and Sedimentation Impacts" to integrate the combined effects of water and sediment conditions, reservoir operation, and previous sedimentation on riverbed scour and sedimentation; S14. Model parameter calibration and verification: S141. Use historical data to calibrate the coefficients in the model to ensure that the calculated values ​​are consistent with the measured values; S142. Use data from independent time periods to verify the accuracy of the model, compare the calculated values ​​of annual sedimentation and cumulative sedimentation with the measured values, and evaluate the reliability of the model.

3. The method for calculating the sedimentation volume of a river channel reservoir and evaluating the morphological parameters of a river section in a reservoir area according to claim 1 is characterized in that: In step S111, the river section gradient is calculated by the difference between the upstream and downstream water level stations, and in step S112, the calculation period is divided into sections according to year or flood season / non-flood season.

4. The method for calculating the sedimentation volume of a river channel reservoir and evaluating the morphological parameters of a river section in a reservoir area according to claim 1 is characterized in that: The step S122 determines that the power relationship between the sediment transport capacity and the flow rate is the product of the 2.5th power of the flow rate and the gradient.

5. The method for calculating the sedimentation volume of a river channel reservoir and evaluating the morphological parameters of a river section in a reservoir area according to claim 1 is characterized in that: In step S132, the reservoir operation is reflected by the water level in front of the dam.

6. The method for calculating sedimentation of a river channel reservoir and evaluating morphological parameters of a river section in a reservoir area according to claim 1, characterized in that: The model coefficients in step S141 are critical scouring and silting parameters and exponential terms.

7. The method for calculating sedimentation of a river-type reservoir and evaluating morphological parameters of a river section in a reservoir area according to claim 1 is characterized in that: The implementation steps of step S2 are: S21. Cross-sectional morphology data collection: Fixed observation sections are set up within the river to measure river channel morphology parameters at low water levels, including river width, cross-sectional area, average water depth, and width-to-depth ratio. S22. Calculation of reach scale parameters: The average morphological parameters of the reach were calculated using the weighted average method of cross-section spacing combined with the logarithmic geometric mean. S23. Modeling the relationship between morphological parameters and erosion and deposition: S231. Establish an empirical relationship model between reach-scale morphological parameters and comprehensive parameters of scour and sedimentation, and analyze the regulation of river channel morphology by sedimentation. S232. Determine the constant and exponential terms in the model to reflect the combined effects of previous sedimentation, incoming sediment, and dam-front water level on morphological parameters; S24. Model verification and optimization: Use regular data to verify the model's fitting accuracy for water depth, area, and width-to-depth ratio. Analyze the reasons for the low accuracy of river width predictions. For low-precision river width parameters, optimize the model or supplement with high-frequency cross-sectional measurement data to improve prediction capabilities.

8. A method for calculating sedimentation in a river channel reservoir and evaluating river channel morphological parameters in a river section of a reservoir according to claim 7, characterized in that: The width-to-depth ratio in step S21 is the ratio of the square root of the river width to the water depth. The average morphological parameters in step S22 are the average river width, average water depth, average cross-sectional area, and average width-to-depth ratio. The morphological parameters in step S231 are the average water depth and cross-sectional area. The exponential term in step S232 is the sensitivity of the siltation amount to the river width and water depth. The reasons for the low accuracy of the river width prediction in step S24 include siltation distribution limitations or measurement errors.

9. The method for calculating sedimentation of a river channel reservoir and evaluating river channel morphological parameters of a river section in a reservoir area according to claim 1, characterized in that: The implementation steps of step S3 are: S31. Data Integration and Input: Data from the Zhongxian and Shibaozhai water level stations are used to determine the river gradient. This is combined with measured flow, sediment concentration, and dam-front water level data from the hydrological stations, along with historical data on accumulated sedimentation from previous periods, to create a time period division table. S32. Calculate and verify the erosion and deposition volume; S33. Prediction of river channel morphological parameters during low-water periods. Results show that average water depth, cross-sectional area, and width-to-depth ratio are significantly correlated with sedimentation processes. River width prediction requires optimization in conjunction with sedimentation elevation distribution. S34. Evaluate the navigation conditions of the waterway based on the prediction results, propose suggestions for optimizing reservoir operation, regularly update the measured data, and dynamically modify the model parameters to adapt to the long-term riverbed evolution.

10. A method for calculating sedimentation in a river channel reservoir and evaluating river channel morphological parameters in a river section of a reservoir according to claim 9, characterized in that: The reservoir operation optimization suggestion in step S34 is to adjust the water level in front of the dam to control the sedimentation rate.

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