A small and medium-sized reservoir scheduling optimization simulation method and system based on a hydrological and hydrodynamic coupling model

Abstract

The application discloses a kind of based on hydrological hydrodynamic coupling model's small and medium-sized reservoir scheduling optimization method, obtains the basic information of reservoir basin and carries out data processing;Set boundary condition, adopt SCS runoff generation model to carry out runoff generation calculation to reservoir basin grid;Based on two-dimensional N-S equation, model is constructed, two-dimensional hydrodynamic calculation is realized;And according to actual data, using different reservoir area calculation method, construct reservoir basin hydrological hydrodynamic coupling model;Carry out reservoir basin multi-source water resources allocation, for scheduling rule optimization boundary inflow condition and water demand upper limit;According to coupling model, in combination with the objective function of reservoir, constraint condition and water demand upper limit, scheduling rule is optimized, obtains optimal scheduling parameter and scheduling scheme.Optimal scheduling strategy of real-time and forecast period reservoir can be given, and the problem that real-time or forecast optimization scheduling simulation is difficult due to the lack of hydrological data in the basin where small and medium-sized reservoir is located is preferably overcome.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of reservoir optimal scheduling, and particularly relates to a small and medium-sized reservoir scheduling optimization simulation method and system based on a hydrology and hydrodynamic coupling model. BACKGROUND

[0002] Reservoir scheduling plays an important role in water resources management, aiming to balance the water supply, flood control, irrigation and ecological needs of the reservoir, and maximize its comprehensive benefits. In particular, small and medium-sized reservoirs play an indispensable role in ensuring regional water supply, flood control and disaster reduction, and supporting agricultural production and ecological protection. However, many small reservoirs lack long-term measured data, and the traditional scheduling method relying on conceptual hydrological models and empirical rules faces challenges in these areas. These methods usually rely on a large amount of historical data for parameter calibration, and are not effective for data-poor basins.

[0003] Hydrodynamic models gradually become an effective tool for reservoir scheduling in data-poor areas, as they can accurately describe the changes of water level, flow rate and flow volume in the reservoir basin. However, the use of hydrodynamic models alone still faces challenges in model construction, large amount of calculation and real-time application. Therefore, the coupling technology of hydrological and hydrodynamic models emerges as the times require. This coupled model not only makes full use of limited hydrological data, but also greatly improves the accuracy and real-time performance of scheduling simulation through accurate hydrodynamic calculation.

[0004] In particular, it is worth noting that the hydrology and hydrodynamic coupling model can realize real-time simulation and prediction of the basin based on grid rainfall data. Through this capability, the model can quickly respond to sudden rainfall events and dynamic changes in hydrological conditions, providing strong support for flood safety. In practical application, this means that the scheduling system can predict changes in water level and flow before the flood arrives, optimize scheduling strategies, and reduce flood risk, thereby effectively protecting people's lives and property.

[0005] In addition, the application of the coupled model in water resources management has greatly improved the efficiency of reservoir scheduling. By combining real-time rainfall data, the system can reasonably allocate water resources while ensuring flood control, ensuring the stability of agricultural irrigation and urban water supply, thereby achieving sustainable management of water resources on the basis of flood control and disaster reduction.

[0006] In summary, the hydrology and hydrodynamic coupling model has shown significant advantages in ensuring flood safety, optimizing water resources management, and flood control and disaster reduction. Developing an optimal scheduling simulation method and system based on this model not only helps to improve the accuracy of small and medium-sized reservoir scheduling, but also has important practical significance for ensuring the safe management of regional water resources and flood control and disaster reduction. SUMMARY

[0007] The application aims to provide a small and medium-sized reservoir scheduling optimization simulation method and system based on a hydrological and hydrodynamic coupling model, so as to solve the aforementioned problems in the prior art.

[0008] In order to achieve the above-mentioned purpose, the technical solution adopted by the application is as follows:

[0009] A small and medium-sized reservoir scheduling optimization method based on a hydrological and hydrodynamic coupling model,

[0010] S1, basic data acquisition and data processing:

[0011] Basic data of the reservoir basin are acquired; the basic data of the reservoir basin are used to divide the calculation grid, and the rainfall data in the basic data and the Manning coefficient and CN2 value obtained by using the basic data are distributed to the calculation grid to generate a rainfall grid, a Manning coefficient grid and a CN2 grid respectively, so as to realize data processing;

[0012] S2, coupling of SCS-CN method and two-dimensional hydrodynamic model:

[0013] Boundary conditions are set for the reservoir basin, and the SCS runoff generation model is used to calculate the runoff of the reservoir basin grid; when the reservoir basin has underwater topography, a two-dimensional hydrodynamic model is constructed based on the simplified analysis of three-dimensional N-S equation to realize two-dimensional hydrodynamic calculation; when the runoff of the reservoir basin grid is greater than a preset threshold, it is taken as a source term of the two-dimensional hydrodynamic model, and meanwhile, the zero-dimensional reservoir area calculation and the discharge calculation are combined to construct a hydrological and hydrodynamic coupling model of the reservoir basin, so as to realize the coupling calculation of the hydrological and hydrodynamic model of the reservoir basin;

[0014] S3, multi-source water resource allocation of the reservoir basin:

[0015] Starting from the water balance relationship in the partition of the reservoir basin, the water sources outside the river channel are allocated among different water users to set the upper limit of the boundary inflow condition and water demand for the optimization of the scheduling rule;

[0016] S4, real-time and forecast scheduling rule optimization of the reservoir:

[0017] According to the hydrological and hydrodynamic coupling model of the reservoir basin, the scheduling rule is optimized by using the NSGA-II algorithm in combination with the objective function, constraint condition and upper limit of water demand of the reservoir, and the optimal scheduling parameter and scheduling scheme are obtained by using the analytic hierarchy process.

[0018] Preferably, the boundary conditions set for the reservoir basin are specifically,

[0019] The grid rainfall is set as the global boundary of the reservoir basin, and the reservoir discharge building is set as the downstream boundary of the reservoir basin; if there is other inflow in the reservoir basin, the boundary conditions are increased according to the actual situation.

[0020] Preferably, the runoff calculation is performed by using the SCS runoff model, and the SCS runoff model is established based on the water balance principle, and the runoff calculation formula is derived according to the principle and basic assumption of the SCS runoff model.

[0021] The water balance principle is expressed as,

[0022] P = I a +F+R (1)

[0023] The basic assumptions include that the ratio of the generated surface runoff depth to the rainfall amount minus the initial loss amount is equal to the ratio of the actual infiltration amount to the maximum soil storage capacity, and the rainfall initial loss amount is proportional to the maximum soil storage capacity; and the formula is expressed as,

[0024]

[0025] I a =λS (3)

[0026] The initial loss coefficient λ is 0.2, and the runoff calculation formula is obtained by combining (1), (2) and (3),

[0027]

[0028] wherein, P is the rainfall amount; I a is the initial loss amount; F is the actual infiltration amount; R is the runoff depth; and S is the maximum soil storage capacity.

[0029] Preferably, the two-dimensional water dynamic model is constructed based on the simplified analysis of the three-dimensional N-S equation, and the two-dimensional water dynamic model is constructed based on the simplified analysis of the three-dimensional N-S equation.

[0030] The three-dimensional N-S equation is integrated along the water depth direction to convert into a two-dimensional problem, so as to be simplified and analyzed, and then the two-dimensional water dynamic model is obtained; the two-dimensional water dynamic model includes a continuity equation and a momentum equation,

[0031] The continuity equation is,

[0032]

[0033] H(x,y,t)=z(x,y)+h(x,y,t) (6)

[0034] wherein, t is the time; x and y are the plane positions of the reference coordinate system; V is the velocity vector; q is the external contribution or flux term; H is the water level altitude; z is the river bed elevation; and h is the water level;

[0035] The momentum equation is,

[0036]

[0037] wherein, is the Hamiltonian operator; V is the velocity vector, V = (u, v) T For dry cells, the bottom friction term dominates in the equation, taking the limit form V = 0; v t is the horizontal eddy viscosity; c f is the friction coefficient; f c is the Coriolis force factor; k is the unit vector perpendicular to the plane of rotation; g is the gravitational acceleration.

[0038] Preferably, the zero-dimensional reservoir area calculation is specifically that, when there is no underwater terrain in the reservoir basin, a zero-dimensional water conservation model is constructed, and the upstream two-dimensional hydrodynamic model is input as a flow boundary;

[0039] At this time, for the reservoir area,

[0040]

[0041] wherein, V t , V t+1 is the water storage at the beginning and end of the t period of the reservoir; is the average inflow to the reservoir in the t period; is the average outflow from the reservoir in the t period; f (*) is the reservoir storage curve; Δt is the time interval from the t period to the t+1 period; Z t is the storage of the reservoir in the t period.

[0042] Preferably, the discharge calculation is specifically that, the flow of the hydraulic structure is determined by the hydrological conditions of the upstream and downstream and the opening and closing conditions of the weir gate, according to the outflow situation, the corresponding hydraulic formula is selected for flow calculation;

[0043] When the gate is closed, the gate flow Q = 0;

[0044] When the gate is opened, the gate flow is calculated according to the wide-top weir formula,

[0045] When , it is free outflow, and the gate flow calculation formula is,

[0046]

[0047] When , it is submerged outflow, and the gate flow calculation formula is,

[0048]

[0049] wherein, m is the free outflow coefficient; is the submerged outflow coefficient; B is the total width of the gate opening; Z u is the water level upstream of the gate; Z d is the water level downstream of the gate; H swherein h is the water depth downstream of the sluice; and g is the acceleration due to gravity.

[0050] Preferably, in the coupling calculation process of the hydrological and hydrodynamic model, the hydrological and hydrodynamic coupling model adopts a method combining finite difference and finite volume to discretely solve the two-dimensional hydrodynamic model; for the case that the regular grid boundary and the dual grid boundary are orthogonal, the finite difference method is used for numerical discretization, and for the case that the non-dual grid boundary is orthogonal, the finite volume method is used for numerical discretization.

[0051] Preferably, the step S4 specifically comprises the following contents,

[0052] S41, according to the reservoir regulation rule, the simulation calculation of reservoir regulation is carried out, the boundary condition is adjusted, the step S2 is re-executed, the new discharge is obtained, and each target function value is obtained;

[0053] S42, the NSGA-II algorithm is used, the scheduling parameters are optimized and adjusted according to the target function value, and the newly generated scheduling parameters are obtained;

[0054] S43, the steps S41-S42 are repeated until the scheduling parameter set and the scheduling scheme set meeting the preset condition are obtained;

[0055] S44, the optimal scheduling parameter and scheduling scheme are selected from the scheduling parameter set and the scheduling scheme set by using the analytic hierarchy process.

[0056] Preferably, the step S1 specifically comprises the following contents,

[0057] S11, obtaining basic data: obtaining the terrain data, real-time or forecast rainfall data, land use data, soil data, existing regulation rules and discharge building parameters of the reservoir basin;

[0058] S12, data processing: (a) terrain data processing: converting the original terrain data into terrain DEM after processing and correction; (b) dividing the calculation grid: combining the terrain DEM and the river position, using the grid tool to divide the calculation grid; (c) generating the rainfall grid: distributing the rainfall data to the calculation grid through the GIS tool; (d) generating the Manning coefficient grid: calculating the Manning coefficient distribution according to the land use data, and distributing the Manning coefficient to the calculation grid through the GIS tool; (e) generating the CN2 grid: calculating the CN2 distribution according to the land use data and the soil data, and distributing the CN2 value to the calculation grid through the GIS tool.

[0059] The purpose of the present application is also to provide a small and medium-sized reservoir scheduling optimization system based on a hydrological and hydrodynamic coupling model, which can realize the above-mentioned method, and the system comprises,

[0060] Basic data acquisition and data processing module: acquire basic data of the reservoir basin; divide the calculation grid based on the basic data of the reservoir basin, and distribute the rainfall data in the basic data and the Manning coefficient and CN2 value obtained by the basic data to the calculation grid to generate a rainfall grid, a Manning coefficient grid and a CN2 grid respectively, so as to realize data processing;

[0061] SCS-CN method and two-dimensional water dynamic model coupling module: set boundary conditions for the reservoir basin, and use the SCS runoff model to calculate the runoff of each grid in the reservoir basin; when there is underwater topography in the reservoir basin, a two-dimensional water dynamic model is constructed based on the simplified analysis of three-dimensional N-S equation to realize two-dimensional water dynamic calculation; when the runoff of the grid in the reservoir basin is greater than a preset threshold, the grid is regarded as a source term of the two-dimensional water dynamic model, and meanwhile, the zero-dimensional reservoir area calculation and discharge calculation are combined to construct a hydrological and water dynamic coupling model of the reservoir basin, so as to realize the coupling calculation of the hydrological and water dynamic model of the reservoir basin;

[0062] Reservoir basin multi-water source water resource allocation module: starting from the water balance relationship in the reservoir basin partition, the water source outside the river is allocated among different water users to optimize the boundary inflow condition and the upper limit of water demand for the dispatching rule;

[0063] Real-time and forecast dispatching rule optimization module of reservoir: according to the hydrological and water dynamic coupling model of the reservoir basin, combining the objective function, constraint condition and upper limit of water demand of the reservoir, the NSGA-II algorithm is used to optimize the dispatching rule, and the optimal dispatching parameter and dispatching scheme are obtained by combining the analytic hierarchy process.

[0064] The beneficial effects of the present application are: 1. The present application fully considers the problem of lack of hydrological data in the reservoir basin, and through the coupling of the SCS-CN method and the two-dimensional water dynamic model, only a small amount of input data such as rainfall grid and CN2 grid can be used to construct a reservoir basin simulation and prediction model, and the real-time and forecast dispatching rule optimization of the reservoir is realized. 2. The present application provides a new method and technical framework for reservoir dispatching and water resource allocation of data-deficient reservoirs, which can support simulation and prediction, dispatching decision-making of data-deficient reservoirs, and ensure the flood control safety and water resource safety of the reservoir basin. BRIEF DESCRIPTION OF DRAWINGS

[0065] Figure 1 is a flow chart of the method in the embodiment of the present application;

[0066] Figure 2 is a technical route map of the method in the embodiment of the present application;

[0067] Figure 3 is a reservoir water supply dispatching diagram in the embodiment of the present application;

[0068] Figure 4 is a flow chart of the NSGA-II algorithm in the embodiment of the present application. DETAILED DESCRIPTION

[0069] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings. It should be understood that the specific embodiments described herein are merely intended to explain the present application and not to limit the present application.

[0070] As shown in Figure 1 and Figure 2 In this embodiment, a small and medium-sized reservoir scheduling optimization simulation method based on a hydrological and hydrodynamic coupling model is provided. The method couples a hydrological model, a hydrodynamic model and a reservoir optimization scheduling algorithm, and then gives a real-time and forecast period optimal scheduling strategy of the reservoir, which can overcome the problem of real-time or forecast optimization scheduling simulation difficulty caused by lack of hydrological data in the small and medium-sized reservoir basin. The method mainly includes the following parts,

[0071] I. Basic data acquisition and data processing

[0072] The basic data of the reservoir basin is obtained; the calculation grid is divided based on the basic data of the reservoir basin, and the rainfall data in the basic data and the Manning coefficient and CN2 value obtained by the basic data are distributed to the calculation grid to generate rainfall grid, Manning coefficient grid and CN2 grid respectively, realizing data processing. Specifically, it includes the following contents:

[0073] 1.1. Obtain basic data: obtain the topographic data, real-time or forecast rainfall data, land use data, soil data, existing scheduling rules and discharge structure parameters of the reservoir basin.

[0074] 1.2. Data processing:

[0075] (a) Topographic data processing: convert the original topographic data to topographic DEM after processing and correction.

[0076] (b) Divide the calculation grid: use the grid tool to divide the calculation grid in combination with the topographic DEM and river position data.

[0077] (c) Generate rainfall grid: distribute the rainfall data to the calculation grid by using GIS tool to generate rainfall grid.

[0078] (d) Generate Manning coefficient grid: calculate the Manning coefficient distribution according to the land use data, and distribute the Manning coefficient to the calculation grid by using GIS tool to generate the Manning coefficient grid.

[0079] (e) Generate CN2 grid: calculate the CN2 distribution according to the land use data and soil data, and distribute the CN2 value to the calculation grid by using GIS tool to generate CN2 grid.

[0080] The data processing processes of (a)-(e) above are all performed in the same projection coordinate system.

[0081] II. Coupling of SCS-CN method and two-dimensional hydrodynamic model

[0082] Boundary conditions are set for the reservoir basin, and the SCS runoff generation model is used to calculate the runoff generation of the reservoir basin grid; when the reservoir basin has underwater topography, a two-dimensional hydrodynamic model is constructed based on the simplified analysis of the three-dimensional N-S equation to realize two-dimensional hydrodynamic calculation; when the runoff of the reservoir basin grid is greater than the preset threshold, it is regarded as the source term of the two-dimensional hydrodynamic model, and at the same time, the zero-dimensional reservoir area calculation and discharge calculation are combined to construct a hydrological and hydrodynamic coupling model of the reservoir basin, realizing the coupling calculation of the hydrological and hydrodynamic model of the reservoir basin. Specifically, the following contents are included:

[0083] 2.1, Boundary conditions: set the grid rainfall as the global boundary of the reservoir basin, and set the reservoir discharge building as the downstream boundary of the reservoir basin; if there are other inflows in the reservoir basin, additional boundary conditions are added according to the actual situation.

[0084] 2.2, Runoff calculation: the SCS runoff generation model is used for runoff calculation. The SCS runoff generation model has only one model parameter, i.e., the runoff curve number (Curve Number, CN), which is determined by the underlying surface conditions and the soil moisture level of the previous period. The establishment of the SCS runoff generation model is based on the water balance principle,

[0085] The water balance principle can be expressed as,

[0086] P = I a +F+R (1)

[0087] The SCS runoff generation model includes two basic assumptions: (1) the ratio of the generated surface runoff depth to the rainfall minus the initial loss is equal to the ratio of the actual infiltration to the maximum soil storage capacity; (2) the initial loss of rainfall is proportional to the maximum soil storage capacity, i.e.,

[0088]

[0089] I a =λS (3)

[0090] The initial loss coefficient λ is generally taken as 0.2. By combining (1), (2), and (3), the runoff calculation formula is obtained as,

[0091]

[0092] wherein, P is the rainfall, mm; I aWhere, I is the initial loss, mm; F is the actual infiltration, mm; R is the runoff depth, mm; S is the maximum soil water storage capacity, mm. S is related to soil type, land use type, and soil initial moisture content, which can be expressed by the dimensionless coefficient CN, and the calculation formula is The value range of CN is generally 30-100, which is determined by experience according to land use type and soil grouping.

[0093] 2.3, Two-dimensional water dynamic calculation: The derivation of the two-dimensional water dynamic model (two-dimensional shallow water equation) is based on the three-dimensional Navier-Stokes (N-S) equation. Since it is relatively complex to directly solve the three-dimensional N-S equation, for shallow water problems, it can be assumed that the water surface fluctuation value is small compared to the water depth, and the N-S equation is integrated along the water depth direction, thereby transforming into a two-dimensional problem and simplifying the analysis. The simplified equation is the two-dimensional shallow water equation, which consists of two parts: the continuity equation and the momentum equation.

[0094] The continuity equation is,

[0095]

[0096] H(x,y,t)=z(x,y)+h(x,y,t) (6)

[0097] Where, the variable t is time; x, y are the plane positions of the reference coordinate system; V is the velocity vector; q is the external contribution or flux term (source / sink term); H is the water level altitude; z is the river bed elevation; h is the water level;

[0098] The momentum equation is,

[0099]

[0100] Where, is the Hamiltonian operator; V is the velocity vector, V=(u,v) T For dry cells, the bottom friction term dominates in the equation, taking the limit form V=0; v t is the horizontal eddy viscosity; c f is the friction coefficient; f c is the Coriolis force; k is the unit vector perpendicular to the rotation plane; g is the acceleration of gravity.

[0101] 2.4, Zero-dimensional reservoir area calculation: When the reservoir has underwater topography, a two-dimensional water dynamic model is directly constructed using the relevant steps described above. When the reservoir basin has no underwater topography, a zero-dimensional water conservation model is constructed, and the upstream two-dimensional water dynamic model is input as a flow boundary;

[0102] At this time, for the reservoir area,

[0103]

[0104] where, V t , V t+1 is the water storage at the beginning and end of the reservoir t period; is the average inflow of the reservoir t period, which is obtained by the two-dimensional hydrodynamic model and rainfall runoff module, unit m 3 / s; is the average outflow of the reservoir t period, unit m 3 / s; f(*) is the reservoir storage curve; Δt is the time interval from t period to t+1 period; Z t is the reservoir storage of the reservoir t period.

[0105] 2.5, discharge calculation: the flow pattern near the hydraulic structure is very complex, it is difficult to simulate with one-dimensional model, only can be simplified, generally considered that the flow of hydraulic structure is determined by the upstream and downstream hydrological conditions and the opening and closing of the gate. According to the outflow situation, the corresponding hydraulic formula is selected for flow calculation.

[0106] When the gate is closed, the gate flow Q = 0;

[0107] When the gate is opened, the gate flow is calculated according to the wide top weir formula,

[0108] When , it is free outflow, and the gate flow calculation formula is,

[0109]

[0110] wherein, formula (7) can be linearized as follows,

[0111]

[0112] When , it is submerged outflow, and the gate flow calculation formula is,

[0113]

[0114] wherein, m is the free outflow coefficient, generally taken between 0.325-0.385; is the submerged outflow coefficient, generally taken as a number less than 1; B is the total width of the gate opening; Z u is the water level above the gate; Z d is the water level below the gate; H s is the water depth below the gate.

[0115] 2.6, hydrological and hydrodynamic model coupling calculation

[0116] A runoff threshold is set. When the runoff of the reservoir basin grid obtained in the runoff calculation is greater than the threshold, it is used as the source term in the two-dimensional hydrodynamic model. Combined with the 2.4 zero-dimensional reservoir area calculation and 2.5 discharge calculation, the reservoir front water level and reservoir storage capacity are calculated.

[0117] During the coupled calculation of the hydrological and hydrodynamic model, the hydrological and hydrodynamic coupling model uses a combination of finite difference and finite volume methods to discretize the two-dimensional hydrodynamic model. For the case where the conventional grid boundary and the dual grid boundary are orthogonal, that is, the case of local orthogonality, the finite difference method is used for numerical discretization. In general, the local orthogonality condition is difficult to meet, so the finite volume method is used for numerical discretization.

[0118] III. Allocation of Water Resources from Multiple Sources in Reservoir Basins

[0119] The basin's water resources system primarily consists of multiple sources, including natural water from rivers, groundwater, recycled water, and externally transferred water, supplying a wide range of water users, including domestic, industrial, agricultural, and ecological services. Multi-source water resource allocation in reservoir basins, based on the water balance within reservoir basin zones, allocates groundwater, recycled water, and other external sources among different water users, optimizing boundary inflow conditions and water demand limits for scheduling rules.

[0120] 4. Optimization of reservoir real-time and forecast dispatching rules

[0121] According to the reservoir basin hydrological and hydrodynamic coupling model, combined with the reservoir's objective function, constraints and water demand upper limit, the NSGA-II algorithm is used to optimize the scheduling rules, and the hierarchical analysis method is combined to obtain the optimal scheduling parameters and scheduling scheme.

[0122] The decision variable is the reservoir operation diagram for the simulation period or forecast period, which is solved by the simulation-optimization method. The reservoir operation diagram divides the reservoir into different operation intervals through the operation limit line, such as Figure 3 The diagram shows a predefined form of a reservoir water supply scheduling diagram with three water supply tasks: ecological, domestic, and agricultural. Its scheduling restriction lines divide the reservoir capacity into four scheduling areas: A, B, C, and D, which are the water supply restriction area, ecological water supply guarantee area, domestic water supply guarantee area, and agricultural water supply guarantee area, respectively. When using the scheduling diagram, water supply decisions are made for water users based on the location of the initial water level in the water supply scheduling area during the simulation or forecast period. This section specifically includes the following contents:

[0123] 4.1. Carry out reservoir operation simulation calculations according to reservoir operation rules, adjust the parameters of the discharge structure, that is, adjust the boundary conditions in 2.1, and then re-execute step S2 to obtain the new discharge flow to obtain the values ​​of each objective function.

[0124] 4.2, optimization unit: the optimization algorithm is NSGA-II algorithm, according to the feedback of each objective function value, the scheduling parameters are optimized and adjusted, and the newly generated scheduling parameters are obtained.

[0125] 4.3, repeat steps 4.1-4.2 until the satisfactory scheduling parameter set and scheduling scheme set are obtained. As shown in Figure 4 The NSGA-II includes three key operators: non-dominated sorting, crowding distance calculation and elite reservation. Among them, the non-dominated sorting compares the dominance relationship between each individual and other individuals in the population, judges whether it dominates all other individuals, and calculates the Pareto solution set; the crowding distance calculation calculates the sum of the distance difference of each individual and its two adjacent individuals in each sub-objective function. When the individual belongs to different levels of Pareto solution set, the individual with smaller level serial number is preferred, and if the individual belongs to the same level of Pareto solution set, the individual with larger crowding distance is preferred. The elite reservation keeps the good individuals in the parent generation directly into the offspring to prevent the loss of Pareto optimal solution. Repeat the non-dominated sorting and crowding distance calculation until the satisfactory scheduling parameter set and scheduling scheme set are obtained.

[0126] 4.4, using the analytic hierarchy process (AHP) to select the optimal scheduling parameter and scheduling scheme from the scheduling parameter set and scheduling scheme set. The AHP aims to select the optimal scheduling scheme, there are n candidate schemes and m evaluation criteria (average guarantee rate, water abandonment and opening degree modification times, etc.). Construct a judgment matrix, solve the characteristic vector to obtain the weight of each criterion. According to the expert opinion, score the performance of each scheme under each criterion. Finally, multiply the score of each scheme by its corresponding criterion weight, and add up to get the total score of each scheme. The scheme with the highest score is the optimal choice.

[0127] In this embodiment, a small and medium-sized reservoir scheduling optimization system based on a hydrological and hydrodynamic coupling model is also provided. The system can implement the method described above, and the system comprises,

[0128] (1) Basic data acquisition and data processing module: acquire the basic data of the reservoir basin; divide the calculation grid based on the basic data of the reservoir basin, and distribute the rainfall data in the basic data and the Manning coefficient and CN2 value obtained by the basic data to the calculation grid to generate rainfall grid, Manning coefficient grid and CN2 grid respectively, and realize data processing.

[0129] (2) SCS-CN method and two-dimensional hydrodynamic model coupling module: set the boundary conditions for the reservoir basin, use the SCS runoff model to calculate the runoff of each grid in the reservoir basin; when the reservoir basin has underwater topography, a two-dimensional hydrodynamic model is constructed based on the simplified analysis of three-dimensional N-S equation to realize two-dimensional hydrodynamic calculation; when the runoff of the grid in the reservoir basin is greater than the preset threshold, it is regarded as the source term of the two-dimensional hydrodynamic model, and meanwhile, the zero-dimensional reservoir area calculation and discharge calculation are combined to construct a hydrological and hydrodynamic coupling model of the reservoir basin, so as to realize the coupling calculation of the hydrological and hydrodynamic model of the reservoir basin.

[0130] (3) Reservoir basin multi-water source water resource allocation module: starting from the water balance relationship in the reservoir basin partition, the water source outside the river is allocated among different water users to provide the upper limit of the boundary inflow condition and water demand for the optimization of the scheduling rule.

[0131] (4) Real-time and forecast scheduling rule optimization module of reservoir: according to the hydrological and hydrodynamic coupling model of the reservoir basin, combining the objective function, constraint condition and upper limit of water demand of the reservoir, the NSGA-II algorithm is used to optimize the scheduling rule, and the analytic hierarchy process is used to obtain the optimal scheduling parameter and scheduling scheme.

[0132] By using the above technical solutions disclosed in the present application, the following beneficial effects are obtained:

[0133] The present application provides a small and medium-sized reservoir scheduling optimization simulation method and system based on a hydrological and hydrodynamic coupling model, which fully considers the problem of lack of hydrological data in the reservoir basin, and through the coupling of the SCS-CN method and the two-dimensional hydrodynamic model, only a small amount of input data such as rainfall grid and CN2 grid is needed to construct a reservoir basin simulation and prediction model, and realize real-time and forecast scheduling rule optimization of the reservoir. The present application provides a new method and technical framework for reservoir scheduling and water resource allocation of data-deficient reservoirs, which can support simulation and prediction, scheduling decision-making of data-deficient reservoirs, and ensure the flood control safety and water resource safety of the reservoir basin.

[0134] The above is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled persons in the technical field, some improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should be regarded as the protection scope of the present application.

Claims

1. A method for optimizing the operation of small and medium-sized reservoirs based on a hydrological and hydrodynamic coupling model, characterized by: S1. Basic information acquisition and data processing: Obtain basic data of the reservoir basin; divide the calculation grid based on the basic data of the reservoir basin, and distribute the rainfall data in the basic data and the Manning coefficient and CN2 values ​​obtained from the basic data to the calculation grid to generate the rainfall grid, Manning coefficient grid and CN2 grid respectively, thereby realizing data processing; S2, SCS-CN method coupled with two-dimensional hydrodynamic model: Boundary conditions are set for the reservoir basin, and the SCS runoff model is used to calculate the runoff of the reservoir basin grid. When the reservoir basin has underwater topography, a two-dimensional hydrodynamic model is constructed based on the simplified analysis of the three-dimensional NS equations to achieve two-dimensional hydrodynamic calculations. When the runoff of the reservoir basin grid is greater than the preset threshold, it is used as the source term of the two-dimensional hydrodynamic model. At the same time, combined with the zero-dimensional reservoir area calculation and discharge calculation, a reservoir basin hydrological and hydrodynamic coupling model is constructed to achieve coupled calculations of the reservoir basin hydrological and hydrodynamic models. The two-dimensional hydrodynamic model is constructed based on the simplified analysis of the three-dimensional NS equations. Assuming that the water surface fluctuation value is small compared with the water depth, the three-dimensional NS equation is integrated along the water depth direction to transform it into a two-dimensional problem, which can simplify the analysis and obtain a two-dimensional hydrodynamic model; the two-dimensional hydrodynamic model includes the continuity equation and the momentum equation. The continuity equation is, H(x,y,t)=z(x,y)+h(x,y,t) (6) Wherein, variable t is time; x, y are the positions in the reference coordinate system plane; V is the velocity vector; q is the external contribution or flux term; H is the water level altitude; z is the riverbed elevation; h is the water level; The momentum equation is, in, is the Hamiltonian operator; V is the velocity vector, V=(u,v) T For dry elements, the bottom friction term is dominant in the equation, and the limiting form V = 0; v t is the horizontal eddy viscosity; c f is the friction coefficient; f c is the Coriolis force factor; k is the unit vector perpendicular to the rotation plane; g is the acceleration due to gravity; Specifically, the zero-dimensional reservoir area calculation is as follows: when there is no underwater topography in the reservoir basin, a zero-dimensional water conservation model is constructed, and the upstream two-dimensional hydrodynamic model is used as the flow boundary input; At this time, for the reservoir area, Among them, V t , V t+1 is the water storage capacity of the reservoir at the beginning and end of period t; is the average inflow flow during period t; is the average outflow during period t; f(*) is the reservoir capacity curve; Δt is the time interval from period t to period t+1; Z t is the storage capacity of the reservoir during period t; S3. Allocation of water resources from multiple sources in reservoir basins: Based on the water balance relationship in the reservoir basin, the off-river water sources are allocated among different water users to optimize the boundary inflow conditions and water demand upper limit for the scheduling rules; S4. Optimization of reservoir real-time and forecast dispatching rules: According to the reservoir basin hydrological and hydrodynamic coupling model, combined with the reservoir's objective function, constraints and water demand upper limit, the NSGA-II algorithm is used to optimize the scheduling rules, and the hierarchical analysis method is combined to obtain the optimal scheduling parameters and scheduling scheme.

2. The method for optimizing the operation of small and medium-sized reservoirs based on the hydrological and hydrodynamic coupling model according to claim 1 is characterized in that: The boundary conditions for the reservoir basin are as follows: Set grid rainfall as the global boundary of the reservoir basin, and set the reservoir discharge structure as the downstream boundary of the reservoir basin; if there are other water inflow conditions in the reservoir basin, add boundary conditions based on actual conditions.

3. The method for optimizing the operation of small and medium-sized reservoirs based on the hydrological and hydrodynamic coupling model according to claim 1 is characterized in that: The SCS runoff model is used to calculate runoff. Specifically, the SCS runoff model is established based on the water balance principle, and the runoff calculation formula is derived based on the principles and basic assumptions of the SCS runoff model. The water balance principle is expressed as, P=I a +F+R (1) The basic assumptions include that the ratio of the generated surface runoff depth to the rainfall minus the initial loss is equal to the ratio of the actual infiltration volume to the maximum soil storage capacity, and the initial loss of rainfall is proportional to the maximum soil storage capacity; the formula is expressed as follows: I a =λS (3) The initial loss coefficient λ is set to 0.

2. Combining (1), (2), and (3), the flow calculation formula is: Where P is the rainfall; I a is the initial loss; F is the actual infiltration volume; R is the runoff depth; S is the maximum soil storage capacity.

4. The method for optimizing the operation of small and medium-sized reservoirs based on the hydrological and hydrodynamic coupling model according to claim 1 is characterized in that: Specifically, the discharge flow of hydraulic structures is determined by the hydrological conditions upstream and downstream and the opening and closing conditions of weirs and sluice gates. Based on the outflow situation, the corresponding hydraulic formula is used to calculate the flow. When the gate is closed, the flow rate Q = 0; When the gate is open, the flow through the gate is calculated according to the wide crest weir formula. when When , it is free outflow, and the flow rate through the gate is calculated as follows: when When , it is submerged outflow, and the flow through the gate is calculated as follows: Where m is the free outflow coefficient; is the flooding outflow coefficient; B is the total width of the gate opening; Z u is the water level upstream of the gate; Z d H is the water level downstream of the gate; s is the water depth downstream of the sluice gate; g is the acceleration due to gravity.

5. The method for optimizing the operation of small and medium-sized reservoirs based on the hydrological and hydrodynamic coupling model according to claim 1 is characterized in that: During the coupled calculation process of the hydrological and hydrodynamic model, the hydrological and hydrodynamic coupling model uses a combination of finite difference and finite volume methods to discretize the two-dimensional hydrodynamic model; for the case where the conventional grid boundary and the dual grid boundary are orthogonal, the finite difference method is used for numerical discretization, and for the case where the non-dual grid boundaries are orthogonal, the finite volume method is used for numerical discretization.

6. The method for optimizing the operation of small and medium-sized reservoirs based on the hydrological and hydrodynamic coupling model according to claim 1 is characterized in that: Step S4 specifically includes the following contents: S41. Carry out simulation calculation of reservoir operation according to the reservoir operation rules, adjust the boundary conditions, and re-execute step S2 to obtain a new discharge flow to obtain the values ​​of each objective function; S42. Using the NSGA-II algorithm, the scheduling parameters are optimized and adjusted according to the values ​​of each objective function to obtain newly generated scheduling parameters; S43, repeating steps S41 to S42 until a scheduling parameter set and a scheduling solution set that meet the preset conditions are obtained; S44. Using the hierarchical analysis method, the optimal scheduling parameters and scheduling scheme are selected from the scheduling parameter set and the scheduling scheme set.

7. The method for optimizing the operation of small and medium-sized reservoirs based on the hydrological and hydrodynamic coupling model according to claim 1 is characterized in that: Step S1 specifically includes the following contents: S11. Obtain basic data: obtain topographic data of the reservoir basin, real-time or forecast rainfall data, land use data, soil data, existing dispatching rules, and discharge structure parameters; S12. Data processing: (a) Terrain data processing: converting the original terrain data into terrain DEM after processing and correction; (b) Divide the computational grid: Use the grid tool to divide the computational grid based on the terrain DEM and river location; (c) Generate the rainfall grid: Use the GIS tool to assign the rainfall data to the computational grid; (d) Generate the Manning coefficient grid: Calculate the Manning coefficient distribution based on the land use data and assign the Manning coefficient to the computational grid using the GIS tool; (e) Generate the CN2 grid: Calculate the CN2 distribution based on the land use data and soil data and assign the CN2 value to the computational grid using the GIS tool.

8. A small and medium-sized reservoir operation optimization system based on a hydrological and hydrodynamic coupling model, characterized by: The system can implement the method described in any one of claims 1 to 7 above, and the system includes: Basic data acquisition and data processing module: obtains basic data of the reservoir basin; divides the calculation grid based on the basic data of the reservoir basin, and distributes the rainfall data in the basic data and the Manning coefficient and CN2 values ​​obtained from the basic data to the calculation grid to generate the rainfall grid, Manning coefficient grid and CN2 grid respectively, thus realizing data processing; The SCS-CN method is coupled with a two-dimensional hydrodynamic model. This module sets boundary conditions for the reservoir basin and uses the SCS runoff model to calculate runoff for each grid in the reservoir basin. When the reservoir basin has underwater topography, a two-dimensional hydrodynamic model is constructed based on a simplified analysis of the three-dimensional NS equations to implement two-dimensional hydrodynamic calculations. When the runoff of a grid in the reservoir basin exceeds a preset threshold, it is used as a source term in the two-dimensional hydrodynamic model. Combined with zero-dimensional reservoir area calculations and discharge calculations, a reservoir basin hydrological and hydrodynamic coupling model is constructed to implement coupled calculations of the reservoir basin hydrological and hydrodynamic models. Reservoir Basin Multi-Source Water Resource Allocation Module: Based on the water balance relationship in the reservoir basin division, it allocates water sources outside the river among different water users, and optimizes the boundary inflow conditions and water demand upper limit for the scheduling rules; Reservoir real-time and forecast scheduling rule optimization module: Based on the reservoir basin hydrological and hydrodynamic coupling model, combined with the reservoir's objective function, constraints and water demand upper limit, the NSGA-II algorithm is used to optimize the scheduling rules, and the hierarchical analysis method is combined to obtain the optimal scheduling parameters and scheduling plan.

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