A two-dimensional evaluation method for reservoir sedimentation risk

Abstract

The application discloses a reservoir sedimentation risk two-dimensional evaluation method, comprising the following steps: determining reservoir sedimentation risk evaluation indexes; evaluating reservoir sedimentation present situation; evaluating reservoir sedimentation future development trend; constructing a reservoir sedimentation risk two-dimensional evaluation graph, evaluating reservoir sedimentation risk zoning; analyzing reservoir sedimentation risk regional characteristics; determining reservoir sedimentation risk control measures and engineering quantity schemes. The application comprehensively considers factors such as reservoir sedimentation amount, incoming water and sediment conditions, sediment particle size distribution and slope, quantitatively evaluates reservoir sedimentation risk from two aspects of reservoir sedimentation present situation and future development trend, accurately identifies reservoir groups with the most urgent needs of sedimentation control and reservoir capacity recovery, and gives reservoir sedimentation risk control schemes, which are important bases for reservoir sedimentation control and function recovery.

Description

TECHNICAL FIELD

[0001] The present application relates to a reservoir sedimentation risk assessment method, in particular to a two-dimensional reservoir sedimentation risk assessment method. BACKGROUND

[0002] Reservoir sedimentation is a common problem in reservoirs at home and abroad, especially in China. The average annual sedimentation rate of reservoirs in China is 2.3%, which is 2-3 times the world average. This not only greatly affects the play of reservoir flood control and beneficial effects, but also seriously threatens the normal operation of water conservancy hubs and the ecological health of downstream rivers and lakes.

[0003] Sediment control and function recovery methods such as reducing sediment in the upper reaches of the reservoir, water power sedimentation, and sedimentation of sediment loss reservoir capacity have become the main way to control and restore the function of reservoir sedimentation, avoiding the adverse effects of project land occupation, resettlement, and environment caused by building new reservoirs, and saving huge investment in building new projects with the same function. However, which reservoirs need sediment control, how to determine the best sediment control opportunity, how to choose the appropriate sediment control method, and how to clearly define the appropriate sediment control and reservoir capacity recovery engineering quantity, sediment risk assessment of reservoir sedimentation is needed.

[0004] At present, the risk of reservoir sedimentation under natural conditions is mostly expressed by the size of the reservoir sedimentation amount or the annual sedimentation rate under the influence of single factors such as inflow, sediment, and reservoir operation mode. However, the reservoir sedimentation amount or the annual sedimentation rate under the influence of single factors cannot reflect the sedimentation risk under different natural conditions of different reservoirs, so it cannot effectively guide the prevention and control of reservoir sedimentation. SUMMARY

[0005] The purpose of the present application is to provide a two-dimensional reservoir sedimentation risk assessment method for quantifying the risk of reservoir sedimentation, accurately identifying the most urgent reservoir group for sediment control and reservoir capacity recovery, and providing the best solution to reduce the risk of reservoir sedimentation as an important basis for reservoir sedimentation control and reservoir capacity recovery.

[0006] Technical scheme: The two-dimensional reservoir sedimentation risk assessment method of the present application comprises the following steps:

[0007] (1) According to the reservoir sedimentation amount, inflow and sediment conditions, reservoir sedimentation morphology and sediment particle size distribution, determine the reservoir sedimentation risk evaluation index, including: the design capacity V0 of the sedimentation balance reservoir and the evaluation reservoir, the annual present capacity V of the evaluation reservoir, the average annual flood period sediment inflow rate Q sin , the average annual flood period inflow Q in , the reservoir bed slope J, and the average annual flood period median particle size D 50 of the reservoir sediment;

[0008] (2) According to the reservoir siltation survey data, the reservoir siltation degree R in the evaluation year is calculated, and the present situation of reservoir sedimentation is evaluated;

[0009] (3) According to the reservoir siltation balance parameter fitting reservoir siltation balance line, the reservoir siltation balance coefficient K is calculated, and the future development trend of reservoir sedimentation is evaluated;

[0010] (4) Constructing a two-dimensional evaluation map of reservoir sedimentation risk, carrying out the risk zoning evaluation of reservoir sedimentation, and determining the risk grade of reservoir sedimentation;

[0011] (5) The siltation indexes of all reservoirs in the evaluation area are counted, the risk grade distribution of reservoir sedimentation is calculated, the regional characteristics of reservoir sedimentation risk in the evaluation area are analyzed, and the siltation risk control reservoir is determined;

[0012] (6) The preliminary control scheme of reservoir sedimentation risk is drafted, the position of reservoir in the two-dimensional evaluation map after the implementation of each scheme is calculated, each scheme is compared, and the risk control measures and engineering quantity scheme of reservoir sedimentation are determined.

[0013] Further, in the case that the river bed slope J of the reservoir in step (1) lacks measured data, the multi-year average flood season dam front water depth H and the multi-year average flood season backwater length L are calculated according to the reservoir scheduling data, and the calculation formula is:

[0014] J = H / L.

[0015] Further, step (2) is specifically:

[0016] According to the design reservoir capacity V0 and the present situation reservoir capacity V in step (1), the reservoir siltation degree R in the evaluation year is calculated;

[0017]

[0018] When R≥R0, the present situation of reservoir sedimentation is serious; when R

[0019] Further, step (3) includes the following steps:

[0020] (31) The multi-year average flood season sediment inflow rate Q sin , the multi-year average flood season inflow Q in , the river bed slope J of the reservoir, the multi-year average flood season median particle size D 50 of the inflow sediment and other evaluation indexes selected in step (1) are substituted into the river channel siltation balance formula QJ~GD 50 , and the reservoir siltation balance relationship is obtained:

[0021] Q sinD 50 ~Q in J

[0022] (32)According to the reservoir data in step (1), the annual average flood season sediment yield rate Q sin , the annual average flood season inflow Q in , the reservoir bed slope J, and the annual average flood season sediment median particle size D 50 are screened out, and the reservoir erosion and deposition balance line is fitted;

[0023] Q sin D 50 =K0Q in J

[0024] Wherein, K0 is the threshold value of the reservoir erosion and deposition balance coefficient;

[0025] (33)According to the annual average flood season sediment yield rate Q sin , the annual average flood season inflow Q in , the reservoir bed slope J, and the annual average flood season sediment median particle size D 50 indicators obtained in step (1), the reservoir erosion and deposition balance coefficient K is calculated, and the reservoir deposition development trend evaluation point is drawn, with Q in J as the horizontal coordinate and Q sin D 50 as the vertical coordinate;

[0026]

[0027] Wherein, when the reservoir erosion and deposition balance coefficient K = K0, the reservoir reaches the erosion and deposition balance state; when K>K0, the reservoir tends to continue to deposit, and the deposition risk is high; when K

[0028] Further, step (4) comprises the following steps:

[0029] (41)Considering the reservoir sediment deposition status evaluation and the reservoir sediment deposition future development trend evaluation, the reservoir sediment deposition risk two-dimensional evaluation diagram is constructed, with the reservoir erosion and deposition balance coefficient K as the horizontal coordinate and the reservoir deposition degree R as the vertical coordinate;

[0030] In the reservoir sediment deposition risk two-dimensional evaluation diagram, the erosion and deposition balance coefficient threshold K0 and the reservoir deposition degree threshold R0 divide the reservoir into four categories: Ⅰ high risk reservoir, Ⅱ present deposition risk high, future deposition development risk low reservoir, Ⅲ low risk reservoir, and Ⅳ present deposition risk low, future deposition development risk high reservoir;

[0031] (42) According to the results of the current situation evaluation of reservoir sedimentation in step (2) and the results of the future development trend evaluation of reservoir sedimentation in step (3), the reservoir sedimentation risk evaluation points are plotted in the reservoir sedimentation risk evaluation map;

[0032] (43) According to the positions of the reservoir sedimentation risk evaluation points obtained in step (42), the sedimentation risk zoning of the reservoir is determined.

[0033] Further, step (5) includes the following steps:

[0034] (51) For all reservoirs in the evaluation area, the sedimentation risk evaluation indexes Q sin , Q in , J, D 50 , H, L of each reservoir, and the sedimentation degree R and the scouring and silting balance coefficient K of each reservoir are calculated;

[0035] (52) According to the sedimentation degree R and the scouring and silting balance coefficient K of each reservoir, the sedimentation risk evaluation points of all reservoirs in the evaluation area are plotted in the two-dimensional evaluation map of reservoir sedimentation risk;

[0036] (53) According to the positions of the sedimentation risk evaluation points of all reservoirs in step (52), the distribution of each reservoir in the evaluation area in the I area, the II area, the III area, and the IV area is determined, and the regional characteristics of the reservoir sedimentation risk are analyzed;

[0037] (54) According to the regional characteristics of the reservoir sedimentation risk in step (53), the reservoirs in the I area are determined as the engineering objects that urgently need to be controlled and functionally recovered.

[0038] Further, step (6) includes the following steps:

[0039] (61) For the sedimentation risk control reservoirs determined in step (5), a plurality of sedimentation risk control and functional recovery schemes are preliminarily proposed;

[0040] (62) The sedimentation risk evaluation indexes Q sin , Q in , J, D 50 , H, L, and the sedimentation degree R and the scouring and silting balance coefficient K of the sedimentation risk control reservoirs after the implementation of each sedimentation risk control and functional recovery scheme are calculated;

[0041] (63) According to the sedimentation degree R and the scouring and silting balance coefficient K calculated in step (62), the sedimentation risk evaluation points of the reservoirs after the implementation of different schemes are plotted in the two-dimensional evaluation map of reservoir sedimentation risk;

[0042] (64) According to the position of the sediment deposition risk evaluation point of the reservoir after the implementation of the different schemes in step (63), the effects of the different reservoir sediment deposition risk control and function recovery schemes are judged;

[0043] (65) According to the implementation effects of the schemes in step (64) and the budget of the reservoir management unit for implementing the reservoir sediment deposition risk control and function recovery scheme, the reservoir sediment deposition risk control measure and engineering quantity scheme are selected.

[0044] The reservoir sediment deposition risk two-dimensional evaluation system comprises:

[0045] An evaluation index determination module is configured to determine reservoir sediment deposition risk evaluation indexes according to reservoir deposition amount, incoming water and sediment conditions, reservoir deposition morphology and sediment particle size distribution, including: design reservoir capacity V0 of a scouring and silting balanced reservoir and a non-scouring and silting balanced reservoir, current reservoir capacity V of an evaluation year, incoming sediment rate Q sin of a reservoir in a flood season in an average year, incoming flow rate Q in of a reservoir in a flood season in an average year, reservoir river bed gradient J and median particle size D 50 of incoming sediment of a reservoir in a flood season in an average year.

[0046] An evaluation module is configured to calculate reservoir deposition degree R of an evaluation year according to reservoir deposition investigation data, evaluate the current status of reservoir sediment deposition, fit a reservoir scouring and silting balance line according to parameters of a scouring and silting balanced reservoir, calculate a reservoir scouring and silting balance coefficient K and evaluate the future development trend of reservoir sediment deposition.

[0047] An evaluation graph drawing module is configured to construct a reservoir sediment deposition risk two-dimensional evaluation graph with the reservoir scouring and silting balance coefficient K as the horizontal coordinate and the reservoir deposition degree R as the vertical coordinate, and determine the reservoir sediment deposition risk grade according to the evaluation graph.

[0048] A regional feature analysis module is configured to determine the sediment deposition risk grade of all reservoirs in the evaluation region and determine the deposition risk control reservoir.

[0049] A control measure and engineering quantity scheme determination module is configured to preliminarily determine a reservoir sediment deposition risk control scheme, calculate the position of the deposition risk control reservoir in the two-dimensional evaluation graph after the implementation of each scheme, compare each scheme and determine the reservoir sediment deposition risk control measure and engineering quantity scheme.

[0050] The device comprises a memory and a processor.

[0051] The memory is configured to store a computer program capable of running on the processor.

[0052] The processor is configured to execute the steps of the above-described reservoir sediment deposition risk two-dimensional evaluation method when the computer program is running.

[0053] The application also provides a storage medium, wherein the storage medium stores a computer program, and the computer program is executed by at least one processor to implement the steps of the two-dimensional reservoir sedimentation risk evaluation method.

[0054] Beneficial effects: compared with the prior art, the method can obtain the following beneficial effects: first, by comprehensively considering the reservoir sedimentation status, inflow and sediment conditions, sediment particle size distribution, slope and other multi-factor influences, the reservoir sedimentation risk is quantified, and a complete and scientific reservoir sedimentation risk evaluation method is formed; second, by analyzing the regional characteristics of the reservoir sedimentation risk, the reservoir with the most serious sedimentation risk is accurately identified, the engineering investment is guided, the effective reservoir capacity is restored and maintained, and the maximum economic, social and ecological environmental benefits are generated; third, the scientific formulation of the reservoir sedimentation control and reservoir capacity recovery scheme is guided, the investment of the dredging project itself is saved to the maximum extent, and direct economic benefits are generated. BRIEF DESCRIPTION OF DRAWINGS

[0055] Figure 1 is a flowchart of the method of the application;

[0056] Figure 2 is a two-dimensional reservoir sedimentation risk evaluation diagram;

[0057] Figure 3 is a reservoir sedimentation risk evaluation result of Longyangxia Reservoir;

[0058] Figure 4 is a reservoir sedimentation risk evaluation result of the reservoir group in the Yellow River Basin;

[0059] Figure 5 is the sedimentation risk control effect of Sanmenxia Reservoir after implementation of different schemes. DETAILED DESCRIPTION

[0060] The application will be described in detail below in combination with the drawings and specific embodiments.

[0061] At the present stage, it is urgent to expand the natural factors affecting the reservoir sedimentation risk from a single factor to multiple factors, and to build a two-dimensional reservoir sedimentation risk evaluation method considering multiple influencing factors from the aspects of the sedimentation status and future sedimentation trend prediction. Before the reservoir sedimentation risk evaluation, the concept of reservoir sedimentation risk is first proposed: the sedimentation risk of the reservoir in the natural state is the possibility of the increase of the sedimentation amount of the reservoir in a long period of time. The reservoir sedimentation risk is related to factors such as the natural conditions of the basin and the conditions of the reservoir itself, the risk influencing factor identification method of risk investigation is adopted, and the influences of four risk factors, i.e., reservoir capacity, inflow and sediment conditions, sediment particle size distribution and reservoir sedimentation shape on the reservoir sedimentation risk are mainly considered.

[0062] As Figure 1 shown, the reservoir sedimentation risk two-dimensional evaluation method of the application mainly includes the following steps:

[0063] (1) determining the reservoir sedimentation risk evaluation index;

[0064] The reservoir sedimentation risk evaluation index is determined from four aspects of reservoir sedimentation amount, inflow and sediment conditions, reservoir sedimentation morphology, and sediment particle size distribution: ① reservoir sedimentation amount. Reservoir sedimentation invades the reservoir regulation capacity, reduces the regulation capacity of the reservoir, so the reservoir capacity is the most commonly used index to describe the reservoir sedimentation. The larger the reservoir sedimentation amount, the smaller the reservoir capacity, the weaker the reservoir sedimentation capacity, and the higher the reservoir sedimentation risk. ② Inflow and sediment conditions. The more the inflow of the reservoir, the greater the average flow velocity of the reservoir section under the condition that the section shape of the reservoir area does not change, the stronger the sediment carrying capacity of the water flow, and the lower the reservoir sedimentation risk. The larger the inflow of the reservoir, the heavier the burden of the water flow on sediment transport, and the reservoir sedimentation risk is higher when the water flow does not have corresponding sediment transport capacity. ③ Reservoir sedimentation morphology. The smaller the reservoir slope, the longer the backwater distance of the reservoir, and the lower the sediment discharge efficiency of the reservoir, and the higher the sedimentation risk of the reservoir. ④ Sediment particle size distribution. Sediment particle size distribution is also an important factor for determining the sediment carrying capacity of the water flow. Under the condition that other conditions remain unchanged, the larger the sediment particle size, the greater the sediment particle settling velocity, the less the sediment that can be transported under the same water flow condition, and the higher the sedimentation risk.

[0065] The design reservoir capacity V0 (billion m 3 ) is used to represent the reservoir sedimentation amount, the evaluation year present reservoir capacity V (billion m 3 ) is used to represent the reservoir sedimentation amount, the multi-year average flood period inflow sediment transport rate Q sin (t / s) is used to represent the reservoir inflow and sediment conditions, the multi-year average flood period inflow flow rate Q in (m 3 / s) is used to represent the reservoir inflow and sediment conditions, the reservoir bed slope J is used to represent the reservoir sedimentation morphology, and the multi-year average flood period inflow sediment median particle size D 50 (mm) is used to represent the reservoir sediment particle size distribution. Among them, the design reservoir capacity V0 is obtained by consulting the reservoir design parameters, the evaluation year present reservoir capacity V and the reservoir bed slope J are obtained by reservoir topographic survey, and the calculation formula of the rest of the indexes is:

[0066]

[0067]

[0068]

[0069] Among them, the reservoir data is n years, Q sin (i) is the average inflow sediment transport rate of the flood period of the i-th year, Qin (i) is the average inflow discharge of the i-th year flood season, D 50 (i) is the median grain size of the i-th year flood season, data from the hydrological yearbook.

[0070] In the case of lack of measured data of reservoir river bed slope J, according to the reservoir operation data, the average annual flood season dam water depth H (m) and the average annual flood season backwater length L (m) are calculated, and the reservoir river bed slope is calculated, and the calculation formula is:

[0071] J = H / L

[0072] (2) Reservoir sedimentation status assessment;

[0073] (21) According to the design reservoir capacity V0 (billion m 3 ) obtained in step (1), the evaluation year reservoir capacity V (billion m 3 ) is calculated, and the evaluation year reservoir sedimentation degree R is calculated.

[0074]

[0075] The greater the R value calculated, the more serious the reservoir sedimentation; on the contrary, the smaller the R value, the less serious the reservoir sedimentation.

[0076] (22) According to the evaluation year reservoir sedimentation degree R value calculated in step (21), the reservoir sedimentation status is divided into two evaluation results of serious and not serious, and the evaluation year reservoir sedimentation degree threshold is R0. When R≥R0, the reservoir sedimentation status is relatively serious; when R

[0077] (3) Reservoir sedimentation future development trend assessment;

[0078] (31) The river channel scouring and filling balance formula QJ~GD 50 is introduced into reservoir sedimentation evolution, wherein Q is the river channel flow (m 3 / s), J is the river channel slope, G is the river channel sediment transport rate (t / s), and D 50The median particle size (mm) of sediment entering the river channel. For reservoirs, the scour-deposition balance state means that, over a period of time, the amount of sediment entering and leaving the reservoir is almost equal, with no significant increase in sedimentation. By analogy, a reservoir scour-deposition balance formula can be constructed. Based on the multi-year average flood season sediment transport rate Q selected in step (1) sin (t / s), average inflow during the flood season Q in (m 3 / s), Reservoir-riverbed gradient J, and median particle size of sediment entering the reservoir during the multi-year average flood season D. 50 Substituting evaluation indicators such as (mm) into the river channel scour and deposition balance formula QJ~GD 50 The reservoir scour-deposition balance equation is obtained as follows:

[0079] Q sin D 50 ~Q in J

[0080] (32) Based on the reservoir data in step (1), the average annual sediment transport rate Q during the flood season of the scour-deposition balance period of reservoirs such as Wanjiazhai, Qingtongxia, and Naodehai is selected. sin (t / s), average inflow during the flood season Q in (m 3 / s), Reservoir-riverbed gradient J, and median particle size of sediment entering the reservoir during the multi-year average flood season D. 50 (mm), fitting the reservoir scouring and sedimentation equilibrium line;

[0081] Q sin D 50 =K0Q in J

[0082] Where K0 is the threshold value of the reservoir scour-deposition balance coefficient;

[0083] (33) Based on the multi-year average flood season sediment transport rate Q obtained in step (1), sin (t / s), average inflow during the flood season Q in (m 3 / s), Reservoir-riverbed gradient J, and median particle size of sediment entering the reservoir during the multi-year average flood season D. 50 (mm) index, in Q in J is the x-axis, Q sin D 50 Using the vertical axis as the ordinate, calculate the reservoir scouring and sedimentation balance coefficient K, and plot the assessment points for the future development trend of reservoir sedimentation.

[0084]

[0085] Wherein, when the reservoir scouring and silting balance coefficient K = K0, the reservoir reaches the scouring and silting balance state; when K > K0, the reservoir tends to continue to silt, and the siltation risk is high; when K < K0, the reservoir is still developing towards the scouring and silting balance state, and the siltation risk is low.

[0086] (4) Constructing a two-dimensional evaluation map of reservoir sediment siltation risk;

[0087] (41) Considering the reservoir sediment siltation present situation evaluation and the reservoir sediment siltation future development trend evaluation comprehensively, taking the reservoir scouring and silting balance coefficient K as the horizontal coordinate and the reservoir sediment siltation degree R as the vertical coordinate, a two-dimensional evaluation map of reservoir sediment siltation risk is constructed. Figure 2 ) In the two-dimensional evaluation map of reservoir sediment siltation risk, the reservoir scouring and silting balance coefficient threshold K0 and the reservoir sediment siltation degree threshold R0 divide the reservoir into four risk levels: I high risk reservoir, II present siltation risk high and future siltation development risk low reservoir, III low risk reservoir, and IV present siltation risk low and future siltation development risk high reservoir, as shown in the following figure. Figure 2 The area where the reservoir scouring and silting balance coefficient K is greater than the threshold K0 and the reservoir sediment siltation degree R is greater than the threshold R0 is divided into I high risk reservoir, the area where the reservoir scouring and silting balance coefficient K is less than the threshold K0 and the reservoir sediment siltation degree R is greater than the threshold R0 is divided into II present siltation risk high and future siltation development risk low reservoir, the area where the reservoir scouring and silting balance coefficient K is less than the threshold K0 and the reservoir sediment siltation degree R is less than the threshold R0 is divided into III low risk reservoir, and the area where the reservoir scouring and silting balance coefficient K is greater than the threshold K0 and the reservoir sediment siltation degree R is less than the threshold R0 is divided into IV present siltation risk low and future siltation development risk high reservoir.

[0088] (42) According to the reservoir sediment siltation present situation evaluation result of step (2) and the reservoir sediment siltation future development trend evaluation result of step (3), the reservoir sediment siltation risk evaluation point is plotted in the two-dimensional evaluation map of reservoir sediment siltation risk.

[0089] (43) According to the position of the reservoir siltation risk evaluation point obtained in step (42), the sediment siltation risk level to which the reservoir belongs is determined.

[0090] (5) Regional characteristic analysis of reservoir sediment siltation risk;

[0091] (51) Different reservoirs have different operating stages, and the evaluation indexes of reservoir sediment siltation risk are also different. According to the method of step (1), the evaluation indexes of reservoir sediment siltation risk of each reservoir in the evaluation region are counted, including Q sin , Q in , J, D 50 , H, and L.

[0092] (52) Calculate the deposition degree R of all reservoirs in the evaluation area according to step (21);

[0093] (53) Calculate the scour-deposition balance coefficient K of all reservoirs in the evaluation area according to step (33);

[0094] (54) According to the calculation results of step (52) and step (53), draw the sediment deposition risk assessment points of all reservoirs in the evaluation area in the reservoir sediment deposition risk assessment map;

[0095] (55) According to the positions of the sediment deposition risk assessment points of all reservoirs in step (54), determine the distribution of each reservoir in the I area, the II area, the III area, and the IV area, and analyze the regional characteristics of the reservoir sediment deposition risk;

[0096] (56) According to the analysis results in (55), determine the reservoirs in the I area as the engineering objects that need to be controlled and functionally recovered for sediment deposition risk.

[0097] (6) Reservoir sediment deposition risk control measures and engineering quantity scheme determination;

[0098] (61) For the sediment deposition risk control and functional recovery engineering objects determined in (56), preliminarily draft several sediment deposition risk control and functional recovery schemes for each object;

[0099] (62) According to the method of step (1), calculate the Q sin , Q in , J, D 50 , H, L of each reservoir in the I area after the implementation of different sediment deposition risk control and functional recovery schemes in (61);

[0100] (63) According to step (21), calculate the deposition degree R of the reservoirs in the I area after the implementation of different sediment deposition risk control and functional recovery schemes in (61);

[0101] (64) According to step (33), calculate the scour-deposition balance coefficient K of the reservoirs in the I area after the implementation of different sediment deposition risk control and functional recovery schemes in (61);

[0102] (65) According to the calculation results of step (63) and step (64), draw the sediment deposition risk assessment points of each reservoir in the I area after the implementation of different schemes in the reservoir sediment deposition risk two-dimensional assessment map;

[0103] (66) According to the positions of the sediment deposition risk assessment points of the reservoirs after the implementation of different schemes in (65), judge the effects of the sediment deposition risk control and functional recovery schemes of different reservoirs, and the sediment deposition risk assessment points in the III area have the best effect;

[0104] (67) According to the implementation effect of each scheme in (66), the budget of the reservoir sedimentation risk control and function recovery scheme implemented by the reservoir management unit is selected to select the reservoir sedimentation risk control measure and the engineering quantity scheme.

[0105] The reservoir sedimentation risk two-dimensional evaluation system of the application comprises:

[0106] The evaluation index determination module is used to determine the reservoir sedimentation risk evaluation index according to the reservoir sedimentation amount, the incoming water and sediment condition, the reservoir sedimentation form and the sediment particle size distribution, and comprises: the design reservoir capacity V0 of the scouring and silting balanced reservoir and the non-scouring and silting balanced reservoir, the evaluation year present reservoir capacity V, the multi-year average flood season incoming reservoir sediment rate Q s , the multi-year average flood season incoming flow Q in , the reservoir riverbed gradient J and the multi-year average flood season incoming sediment median particle size D 50 .

[0107] The evaluation module is used to calculate the evaluation year reservoir sedimentation degree R according to the reservoir sedimentation investigation data, evaluate the present situation of the reservoir sedimentation, fit the reservoir scouring and silting balance line according to the scouring and silting balanced reservoir parameters, calculate the reservoir scouring and silting balance coefficient K, and evaluate the future development trend of the reservoir sedimentation;

[0108] The evaluation graph drawing module is used to construct the reservoir sedimentation risk two-dimensional evaluation graph with the reservoir scouring and silting balance coefficient K as the horizontal coordinate and the reservoir sedimentation degree R as the vertical coordinate, and determine the reservoir sedimentation risk grade according to the evaluation graph;

[0109] The regional feature analysis module is used to determine the sedimentation risk grade of all the reservoirs in the evaluation region and determine the sedimentation risk control reservoir.

[0110] The control measure and engineering quantity scheme determination module is used to preliminarily draft the reservoir sedimentation risk control scheme, calculate the position of the sedimentation risk control reservoir in the two-dimensional evaluation graph after the implementation of each scheme, compare each scheme, and determine the reservoir sedimentation risk control measure and engineering quantity scheme.

[0111] The device of the application comprises a memory and a processor, wherein:

[0112] The memory is used to store a computer program capable of running on the processor;

[0113] The processor is used to execute the steps of the above-mentioned reservoir sedimentation risk two-dimensional evaluation method when running the computer program, and achieve the consistent technical effects of the above-mentioned method.

[0114] The storage medium of the present application, the storage medium has a computer program, the computer program is executed by at least one processor to realize the steps of the two-dimensional evaluation method of the reservoir sedimentation risk, and achieve the technical effect consistent with the above method.

[0115] Embodiments:

[0116] Taking Longyangxia Reservoir as an example to evaluate the two-dimensional reservoir sedimentation risk, the following steps are mainly included:

[0117] (1) Determine the evaluation index of Longyangxia Reservoir sedimentation risk;

[0118] Through consulting the reservoir design parameter data, reservoir topographic survey data and hydrological yearbook data, it is known that the design storage capacity V0 is 247.0 billion m 3 , the current storage capacity V is 242.9 billion m 3 , the evaluation index statistical period is 2006-2017, the average annual flood period sediment inflow rate Q sin is 0.5936 t / s, the average annual flood period inflow Q in is 933 m 3 / s, the average annual flood period water depth before the dam is 115.68 m, the average annual flood period backwater length is 98 km, then the reservoir bed slope J is 0.00118, and the average annual flood period inflow sediment median particle size D 50 is 0.02 mm.

[0119] (2) Evaluation of the current situation of reservoir sedimentation;

[0120] According to the design storage capacity V0 (billion m 3 ) obtained in step (1) and the current storage capacity V (billion m 3 ) of the evaluation year, the reservoir sedimentation degree R of the evaluation year is calculated as R=(247.0-242.9) / 247.0=1.66%; According to the International Commission on Large Dams No. 147 Announcement "Sedimentation and Sustainable Use of Reservoirs and River Systems", Longyangxia Reservoir is a power generation reservoir, R0=80%, then R

[0121] (3) Evaluation of the future development trend of reservoir sedimentation;

[0122] The average annual flood period sediment inflow rate Q sin (t / s), the average annual flood period inflow Q in (m 3 / s), Reservoir-riverbed gradient J, and median particle size of sediment entering the reservoir during the multi-year average flood season D. 50 By fitting parameters such as (mm), the reservoir scouring and sedimentation balance relationship was obtained:

[0123] Q sin D 50 =0.0291Q in J

[0124] According to step (1), the average annual sediment transport rate Q during the flood season of Longyangxia Reservoir sin (t / s), average inflow during the flood season Q in (m 3 / s), Reservoir-riverbed gradient J, and median particle size of sediment entering the reservoir during the multi-year average flood season D. 50 (mm) index, in Q in J = 1.101 is the x-axis, Q sin D 50 Using 0.012 as the ordinate, calculate the reservoir scour-deposition balance coefficient K = Q. sin D 50 / Q in J = 0.0109, the reservoir scour-deposition balance coefficient K < 0.0291, indicating that the reservoir is developing towards a state of scour-deposition balance and the risk of siltation is low.

[0125] (4) Construct a two-dimensional assessment map of reservoir siltation risk;

[0126] Taking into account both the current status assessment and the future development trend assessment of reservoir sedimentation, a two-dimensional assessment map of reservoir sedimentation risk is constructed, using the reservoir scour-deposition balance coefficient K as the abscissa and the reservoir sedimentation degree R as the ordinate. In this two-dimensional assessment map, the reservoir scour-deposition balance coefficient threshold K0 and the reservoir sedimentation degree threshold R0 classify reservoirs into four risk levels: I. High-risk reservoirs; II. Reservoirs with high current sedimentation risk and low future sedimentation development risk; III. Low-risk reservoirs; IV. Reservoirs with low current sedimentation risk and high future sedimentation development risk. Figure 3 As shown, reservoirs with a scour-deposition balance coefficient K greater than its threshold K0 and a sedimentation degree R greater than its threshold R0 are classified as: I. High-risk reservoirs; II. Reservoirs with a high current sedimentation risk and low future sedimentation development risk; III. Low-risk reservoirs; and IV. Reservoirs with a low current sedimentation risk and high future sedimentation development risk.

[0127] According to the results of the reservoir sedimentation present situation evaluation in step (2) and the results of the reservoir sedimentation future development trend evaluation in step (3), the reservoir sedimentation risk evaluation point of Longyangxia Reservoir is plotted in the reservoir sedimentation risk two-dimensional evaluation graph, and the sedimentation risk grade of the evaluation reservoir is determined, such as Figure 3 .

[0128] (5) Analysis of regional characteristics of reservoir sedimentation risk in the Yellow River Basin;

[0129] Taking the reservoir group in the Yellow River Basin as an example, the regional characteristics of reservoir sedimentation risk are analyzed (Table 1). Different reservoirs have different operation stages, and the evaluation indexes of reservoir sedimentation risk are also different. According to the method in step (1), the evaluation indexes of reservoir sedimentation risk of each reservoir in the Yellow River Basin are counted, including Q sin , Q in , J, D 50 , H, L, the sedimentation degree R and the scouring and silting balance coefficient K of all reservoirs are calculated.

[0130] Table 1 Information table of reservoirs for sedimentation risk evaluation in the Yellow River Basin

[0131]

[0132] According to the calculation results of the sedimentation degree R and the scouring and silting balance coefficient K, the sedimentation risk evaluation points of all reservoirs are plotted in the reservoir sedimentation risk evaluation graph, the distribution of each reservoir in the I area, the II area, the III area and the IV area is determined, the regional characteristics of reservoir sedimentation risk are analyzed, and the Sanmenxia Reservoir and the Tianqiao Reservoir in the I area are determined as the engineering objects which need to be controlled and functionally recovered, see Figure 4 .

[0133] (6) Determination of reservoir sedimentation risk control measures and engineering quantity scheme;

[0134] Taking the Sanmenxia Reservoir as an example, three sedimentation risk control and functional recovery schemes (Table 2) are preliminarily proposed for the engineering objects determined in (5), the Q sin , Q in , J, D 50 , H, L of the Sanmenxia Reservoir after the implementation of different sedimentation risk control and functional recovery schemes are calculated; the sedimentation degree R and the scouring and silting balance coefficient K of the reservoir after the implementation of different sedimentation risk control and functional recovery schemes are calculated, the sedimentation risk evaluation points of the Sanmenxia Reservoir after the implementation of different schemes are plotted in the reservoir sedimentation risk two-dimensional evaluation graph, see Figure 5 . Figure 5It is shown that the Sanmenxia Reservoir is located in the III area after the implementation of the third scheme, and thus the third scheme has the best effect of sediment deposition risk control and function recovery, that is, the engineering scheme combining mechanical dredging and tree and grass planting.

[0135] Table 2 Sanmenxia Reservoir sediment deposition risk control and function recovery scheme

[0136]

[0137] The reservoir sediment deposition risk two-dimensional evaluation method of the application comprehensively considers factors such as reservoir deposition amount, incoming water and sediment conditions, sediment particle size distribution, and slope, quantitatively evaluates reservoir sediment deposition risk from two aspects of reservoir deposition present situation and future development trend, accurately identifies the reservoir group with the most urgent need of deposition control and reservoir capacity recovery, and gives a reservoir sediment deposition risk control scheme, which serves as an important basis for reservoir deposition control and function recovery.

Claims

1. A two-dimensional assessment method for reservoir siltation risk, characterized in that, Includes the following steps: (1) Based on the reservoir siltation volume, inflow and sediment conditions, siltation morphology, and sediment particle size distribution, determine the reservoir siltation risk assessment indicators, including the design capacity of the scour-siltation balance reservoir and the assessment reservoir. Evaluation of the current reservoir capacity Average sediment transport rate during the flood season over many years Average inflow during the flood season over many years Reservoir riverbed gradient The median particle size of sediment entering the reservoir during the flood season over many years ; Reservoir Riverbed Gradient In the absence of measured data, the average water depth in front of the dam during the flood season was calculated based on reservoir operation data. and the average backwater length during the flood season over many years The calculation formula is as follows: ； (2) Calculate the degree of reservoir siltation in the evaluation year based on the reservoir siltation survey data. An assessment of the current state of siltation in the reservoir was conducted. (3) Fit the reservoir scour-deposition balance line based on the scour-deposition balance reservoir parameters, and calculate the reservoir scour-deposition balance coefficient. An assessment of the future trend of reservoir siltation is conducted, including the following steps: (31) The multi-year average flood season sediment transport rate selected in step (1) Average inflow during the flood season over many years Reservoir riverbed gradient The median particle size of sediment entering the reservoir during the flood season over many years Substitute into the riverbed scour-deposition balance formula The reservoir scour-deposition balance equation is obtained as follows: ； (32) Based on the reservoir data in step (1), select the multi-year average sediment transport rate during the flood season for the scour-deposition balance reservoir. Average inflow during the flood season over many years Reservoir riverbed gradient The median particle size of sediment entering the reservoir during the flood season over many years Fit the reservoir scouring and sedimentation equilibrium line; ； in, The threshold value for the reservoir's scour-siltation balance coefficient; (33) Based on the multi-year average flood season sediment transport rate obtained in step (1) Average inflow during the flood season over many years Reservoir riverbed gradient The median particle size of sediment entering the reservoir during the flood season over many years Indicators, with The x-axis is... Using the vertical axis as the ordinate, calculate the reservoir scour-deposition balance coefficient. Map the assessment points for the development trend of reservoir siltation; ； Among them, the reservoir scour-siltation balance coefficient At that time, the reservoir reaches a state of equilibrium between scouring and sedimentation; when At that time, the reservoir tends to continuously accumulate sediment, posing a high risk of sedimentation; when At that time, the reservoir was still developing towards a state of equilibrium between scouring and sedimentation, and the risk of sedimentation was low. (4) Construct a two-dimensional assessment map of reservoir sedimentation risk, conduct zoning assessment of reservoir sedimentation risk, and determine the reservoir sedimentation risk level; including the following steps: (41) Taking into account both the current status assessment of reservoir sedimentation and the future development trend assessment of reservoir sedimentation, the reservoir scour-deposition balance coefficient is used. The horizontal axis represents the degree of reservoir siltation. Using the vertical axis as the ordinate, construct a two-dimensional assessment map of reservoir siltation risk; In the two-dimensional assessment diagram of reservoir sediment deposition risk, the threshold value of the scour-deposition balance coefficient is... and the threshold for reservoir siltation Reservoirs are classified into four categories: I. High-risk reservoirs; II. Reservoirs with high current siltation risk and low future siltation development risk; III. Low-risk reservoirs; IV. Reservoirs with low current siltation risk and high future siltation development risk. (42) Based on the assessment results of the current status of reservoir sedimentation in step (2) and the assessment results of the future development trend of reservoir sedimentation in step (3), draw the reservoir sedimentation risk assessment points on the reservoir sedimentation risk assessment map. (43) Based on the location of the reservoir siltation risk assessment point obtained in step (42), determine the siltation risk zone of the reservoir to be evaluated; (5) Statistically analyze all reservoir siltation indicators in the evaluation area, calculate the distribution of reservoir siltation risk levels, conduct regional characteristic analysis of reservoir siltation risk in the evaluation area, and determine the reservoirs for siltation risk control. (6) A preliminary plan for the risk control of reservoir sedimentation was drafted. The position of the reservoir on the two-dimensional assessment map after the implementation of each plan was calculated. The plans were compared and the risk control measures and engineering quantities for reservoir sedimentation were determined.

2. The two-dimensional assessment method for reservoir siltation risk according to claim 1, characterized in that, Step (2) specifically involves: Based on the design capacity obtained in step (1) Evaluation of the current reservoir capacity Calculate and evaluate the degree of reservoir siltation in the year ; ； when At that time, the reservoir's siltation was quite severe; when At that time, the siltation of the reservoir was not serious. This is the threshold for the degree of siltation in the reservoir.

3. The two-dimensional assessment method for reservoir siltation risk according to claim 1, characterized in that, Step (5) includes the following steps: (51) Calculate the sedimentation risk assessment index for each reservoir in the evaluation area. Q in J, D 50 H, L, and the degree of siltation R and the scour-siltation balance coefficient K of each reservoir; (52) Based on the siltation degree R and the scour-siltation balance coefficient K of each reservoir, draw the siltation risk assessment points of all reservoirs in the evaluation area on the two-dimensional assessment map of reservoir siltation risk. (53) Based on the location of the sedimentation risk assessment points of all reservoirs in step (52), determine the distribution of each reservoir in Zone I, Zone II, Zone III and Zone IV of the evaluation area, and analyze the regional characteristics of the sedimentation risk of the reservoirs. (54) Based on the regional characteristics of reservoir siltation risk in step (53), reservoirs in Zone I are identified as engineering objects that urgently need siltation risk control and functional restoration.

4. The two-dimensional assessment method for reservoir siltation risk according to claim 1, characterized in that, Step (6) includes the following steps: (61) For the reservoirs identified in step (5) for siltation risk control, several siltation risk control and function restoration plans are initially proposed; (62) Calculate the sedimentation risk assessment index of the reservoir after implementing various sedimentation risk control and function restoration schemes. Q in J, D 50 H, L, as well as the degree of siltation R and the scouring-siltation balance coefficient K; (63) Based on the siltation degree R and scour-siltation balance coefficient K calculated in step (62), draw the siltation risk assessment points of the reservoir after the implementation of different schemes in the two-dimensional assessment map of reservoir siltation risk. (64) Based on the location of the reservoir siltation risk assessment point after the implementation of different schemes in step (63), determine the effectiveness of different reservoir siltation risk control and function restoration schemes; (65) Based on the implementation effect of each scheme in step (64), and in conjunction with the budget of the reservoir management unit for implementing the reservoir siltation risk control and function restoration scheme, select the reservoir siltation risk control measures and engineering quantity scheme.

5. A two-dimensional assessment system for reservoir siltation risk, characterized in that, include: The evaluation index determination module is used to determine the reservoir sedimentation risk assessment indicators based on the reservoir sedimentation volume, inflow and sediment conditions, sedimentation morphology, and sediment particle size distribution. These indicators include the design capacity of reservoirs with and without sedimentation balance. Evaluation of the current reservoir capacity Average sediment transport rate during the flood season over many years Average inflow during the flood season over many years Reservoir riverbed gradient The median particle size of sediment entering the reservoir during the flood season over many years Includes a reservoir riverbed gradient calculation unit, used for calculating the reservoir riverbed gradient. In the absence of measured data, the average water depth in front of the dam during the flood season was calculated based on reservoir operation data. and the average backwater length during the flood season over many years The calculation formula is as follows: ; The assessment module is used to calculate the degree of reservoir siltation in the evaluation year based on reservoir siltation survey data. An assessment of the current state of sediment deposition in the reservoir was conducted; based on the reservoir parameters for sediment-erosion balance, a sediment-erosion balance line was fitted, and the sediment-erosion balance coefficient of the reservoir was calculated. This assessment evaluates the future trend of reservoir sediment deposition, including a reservoir scour-deposition balance coefficient calculation unit, which comprises: The reservoir sedimentation balance calculation unit is used to calculate the selected multi-year average flood season sediment transport rate. Average inflow during the flood season over many years Reservoir riverbed gradient The median particle size of sediment entering the reservoir during the flood season over many years Substitute into the riverbed scour-deposition balance formula The reservoir scour-deposition balance equation is obtained as follows: ； The reservoir scour-deposition balance line fitting unit is used to screen out the multi-year average flood season sediment transport rate of scour-deposition balance reservoirs based on reservoir data. Average inflow during the flood season over many years Reservoir riverbed gradient The median particle size of sediment entering the reservoir during the flood season over many years Fit the reservoir scouring and sedimentation equilibrium line; ； in, The threshold value for the reservoir's scour-siltation balance coefficient; The reservoir sedimentation development trend assessment point mapping unit is used to calculate the average sediment transport rate during the flood season over many years. Average inflow during the flood season over many years Reservoir riverbed gradient The median particle size of sediment entering the reservoir during the flood season over many years Indicators, with The x-axis is... Using the vertical axis as the ordinate, calculate the reservoir scour-deposition balance coefficient. Map the assessment points for the development trend of reservoir siltation; ； Among them, the reservoir scour-siltation balance coefficient At that time, the reservoir reaches a state of equilibrium between scouring and sedimentation; when At that time, the reservoir tends to continuously accumulate sediment, posing a high risk of sedimentation; when At that time, the reservoir was still developing towards a state of equilibrium between scouring and sedimentation, and the risk of sedimentation was low. The assessment diagram drawing module is used to calculate the reservoir scour-siltation balance coefficient. The horizontal axis represents the degree of reservoir siltation. Using the vertical axis as the ordinate, a two-dimensional assessment map of reservoir sedimentation risk is constructed, and the reservoir sedimentation risk level is determined based on the assessment map; including: Taking into account both the current status assessment and the future development trend assessment of reservoir sedimentation, the reservoir scour-deposition balance coefficient is used. The horizontal axis represents the degree of reservoir siltation. Using the vertical axis as the ordinate, construct a two-dimensional assessment map of reservoir siltation risk; In the two-dimensional assessment diagram of reservoir sediment deposition risk, the threshold value of the scour-deposition balance coefficient is... and the threshold for reservoir siltation Reservoirs are classified into four categories: I. High-risk reservoirs; II. Reservoirs with high current siltation risk and low future siltation development risk; III. Low-risk reservoirs; IV. Reservoirs with low current siltation risk and high future siltation development risk. Based on the assessment results of the current status of reservoir sedimentation and the assessment results of the future development trend of reservoir sedimentation, reservoir sedimentation risk assessment points are drawn on the reservoir sedimentation risk assessment map. Based on the location of the reservoir siltation risk assessment points, the siltation risk zones of the assessed reservoirs are determined. The regional characteristic analysis module is used to determine the siltation risk level of all reservoirs in the evaluation area and to identify reservoirs subject to siltation risk control. The module for determining control measures and engineering quantities is used to initially formulate reservoir siltation risk control schemes, calculate the location of the reservoir under siltation risk control on the two-dimensional evaluation map after the implementation of each scheme, compare the schemes, and determine the reservoir siltation risk control measures and engineering quantities schemes.

6. A device, characterized in that, Includes memory and processor, wherein: Memory is used to store computer programs that can run on a processor; A processor, configured to, while running the computer program, perform the steps of the two-dimensional assessment method for reservoir siltation risk as described in any one of claims 1-4.

7. A storage medium, characterized in that, The storage medium stores a computer program, which, when executed by at least one processor, implements the steps of the two-dimensional assessment method for reservoir siltation risk as described in any one of claims 1-4.

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