A method for regulating multiple water sources in lakes based on a hydrodynamic-water quality-ecological model

Abstract

The present invention provides a method for regulating multiple water sources in a lake based on a hydrodynamic-water quality-ecological model, which relates to the field of water source regulation technology, including steps of obtaining data, clarifying the occurrence mechanism of spatiotemporal heterogeneity of lake water environment, establishing a model, determining the water quality control threshold for maintaining the health of lake water ecology, and proposing the best multi-water source regulation scheme. The present invention, by improving the BLOOM module, incorporates the phytoplankton characterization into the simulation of the competition mechanism of lake phytoplankton, creates a hydrodynamic-water quality-ecological comprehensive model suitable for lake water environment simulation, improves the accuracy of lake water environment simulation, and thus can better accurately determine the water quality control target of lake water environment health; secondly, by using a variety of water resources for comprehensive regulation of multiple water sources, the water quality of the lake is improved while also improving the comprehensive utilization of regional water resources. The results of the present invention provide scientific and technological support for the water quality management of Chagan Lake, and are also the requirements for implementing the "one lake, one policy" precise governance.

Description

Technical Field

[0001] The invention relates to the technical field of water source regulation, and in particular to a lake multi-water source regulation method based on a hydrodynamic-water quality-ecological model. Background Art

[0002] Comprehensive regulation of multiple water sources is a key technical means to solve the shortage of lake water resources and deterioration of water quality in arid and semi-arid areas. How to jointly use multiple water sources including precipitation, irrigation area drainage and water diversion to maintain the ecological water quantity and water quality requirements of lakes is a key technical problem that needs to be urgently solved in the practice of lake ecological protection and restoration. However, the multi-water source regulation method based on the hydrodynamic-water quality-ecological comprehensive model is often overlooked in the restoration and improvement of lake water environment, and the scientific determination of water quality thresholds and multi-water source ratios in the multi-water source regulation of lakes is difficult to quantify, which in turn affects the simulation accuracy of lake water environment indicators and the precise regulation and decision-making of multiple water sources.

[0003] Based on the analysis of the eco-hydrological process of the watershed and the determination of the protection goals of the lake water quality or water ecology, scholars often use a single clean water source to restore and improve the lake water quality and water ecology, and lack the comprehensive use of precipitation, irrigation area drainage, water diversion and floods and other water resources for joint regulation. In addition, the application of existing lake hydrodynamics-water quality models or water quality-ecological models in the process of multi-water source regulation lacks the organic combination of the three research objects of hydrodynamics, water quality and water ecology, and most ecological models are often characterized at the functional group level, lacking in the representation level. This is because: ① Research on the improvement and restoration of lake water quality and water ecology by diverting water from a single water source ① Due to water source restrictions, a variety of water resources are also wasted, making it difficult to restore the water environment while improving the efficiency of water resource utilization; ② There is a lack of a comprehensive simulation model for the coupling of hydrodynamics, water quality and ecology, and the ecological module lacks an effective description of the biological phenotype level, which makes it difficult to accurately determine the water quality and water ecological goals of multi-water source regulation, and it is difficult to quantify the effectiveness and scientificity of multi-water source regulation. The shortcomings of existing research make it difficult to scientifically determine the water quality and water ecological goals of lakes, and it is difficult to scientifically determine the ratio of multiple water sources, which makes it difficult for lake managers to propose accurate multi-water source regulation plans. It can be seen that there is currently a lack of a more scientific method for multi-water source regulation of lakes based on a hydrodynamics-water quality-ecological model. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a lake multi-water source regulation method based on a hydrodynamic-water quality-ecological model.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a method for regulating multiple water sources in a lake based on a hydrodynamic-water quality-ecological model, the method for regulating multiple water sources in a lake based on a hydrodynamic-water quality-ecological model comprising the following steps:

[0006] S1: Prepare the database for the lake hydrodynamics-water quality-ecological integrated model and obtain various monitoring data required for the lake hydrodynamics-water quality-ecological integrated model;

[0007] S2: Comprehensively analyze the evolution characteristics and laws of lake water environment based on monitoring data, and clarify the occurrence mechanism of spatiotemporal heterogeneity of lake water environment;

[0008] S3: Based on the evolution mechanism of lake water environment, a comprehensive hydrodynamic-water quality-ecological model suitable for describing lake water environment is constructed;

[0009] S4: Based on the lake hydrodynamics-water quality-ecology integrated model, study the evolution characteristics of phytoplankton and water quality under the development and changes of different irrigation areas, reveal the competition mechanism of lake phytoplankton under the stress of multiple environmental factors, and determine the water quality control threshold to maintain the health of lake water ecology;

[0010] S5: Based on the lake water quality control threshold, propose the optimal multi-water source regulation plan to maintain the health of lake water ecology.

[0011] In order to obtain various monitoring data, the present invention has been improved in that the various monitoring data required in step S1 include collecting hourly flow data from hydrological monitoring stations at the entrances and exits of the lake, hourly meteorological observation data in the catchment area, digital elevation data (DEM), monthly water quality data and plankton data of the lake, and then establishing a model database and preparing various input data using Notepad software.

[0012] In order to clarify the occurrence mechanism of spatiotemporal heterogeneity of lake water environment, the present invention has the following improvements: the specific steps of step S2 are to clarify the evolution characteristics of water cycle elements based on long-term meteorological, hydrological, water quality and other data, and clarify the water supply source of the lake; divide the water quality evolution stages of the lake, and clarify the spatiotemporal characteristics and evolution laws of nutrient factors and non-nutrient factors in the current water quality evolution stage; evaluate the eutrophication degree of the lake, and provide a mechanism basis for the construction of a comprehensive model of lake hydrodynamics, water quality and water ecology; when statistically analyzing the basic data of the database, Person correlation analysis method and Mann-Kendall mutation detection method are used, and the eutrophication index calculation comprehensively utilizes Trophic State Index (TSI), Trophic Level Index (TLI) and Eutrophication Index (EI) indices for calculation.

[0013] In order to establish the model, the improvement of the present invention is that the step S3 specifically includes the following steps:

[0014] a: Preprocessing of hydrological, meteorological, water quality and ecological observation data and digital elevation data;

[0015] b: Acquisition and construction of model parameters;

[0016] c: Model fitting and validation.

[0017] In order to establish the model, the present invention has been improved in that step a requires collecting hourly hydrological flow data at the lake entrance and exit, monthly water quality and plankton data, hourly meteorological observation data in the catchment area, and digital elevation data, and preprocessing these data.

[0018] In order to establish the model, the present invention has the following improvements: in the step b, the Delft3d platform is used to carry out the simulation of the lake hydrodynamics-water quality-ecological model. First, the grid generation module (Delft3D-Rgfgrid) is used to grid the DEM data and the simulation boundary obtained by remote sensing and actual measurement, and a land-water boundary suitable for hydrodynamic simulation is constructed, and a grid suitable for operation is divided. Secondly, the initial value generation module (Delft3D-Quickin) is used to superimpose the bottom topography and the roughness to set the initial conditions of the Flow module to generate the initial bottom topography, and then the input parameters of the model are localized and calibrated. Subsequently, the hydrodynamic calculation module (Delft3D-Flow) is used to combine the acquired grid and the lake bottom topography, and the specific parameters are set before calculation; the hydrodynamic coupling module (Coupling) is used to couple the input hydrodynamic data into the process library module (Process Library) and water quality simulation modules (Waq-1 and Waq-2) are used to simulate pollutant transport. The hydrodynamic coupling module (Coupling) mainly converts the orthogonal grid into a water quality simulation transport grid, changes the original 1h time step to 1 day time step, and directly calls the simulation results (Communication file) of the hydrodynamic simulation. The process library module (Process Library) needs to simulate the reaction process of the substance in detail. The water quality simulation module (Waq-1 and Waq-2) starts the specific simulation. The model integrates atmospheric deposition, endogenous and exogenous inputs, and the competition mechanism between species. The ecological module (BLOOM) is nested in the water quality module. It mainly adds the characterization of phytoplankton phenotype level based on the characterization of three phytoplankton functional groups.

[0019] In order to establish the model, the present invention has the following improvements: in step c, the lake hydrodynamic module needs to be calibrated and verified using water temperature, water depth and salinity, the water quality module needs to be calibrated and verified using water quality parameters such as total nitrogen, total phosphorus, dissolved oxygen and chlorophyll, and the calibration effect is evaluated using the Nash coefficient (Nash-Sutcliffe Efficiency, NSE), standard deviation (standard regression percent bias, PBIAS) and visual interpretation. The ecological module is calibrated and verified using algae biomass and proportion, and the simulation effect is evaluated using the average standard deviation (Average Standard Deviation, ARD%) and visual interpretation, and finally a hydrodynamic-water quality-water ecology comprehensive model suitable for lake water environment simulation is constructed.

[0020] In order to determine the water quality control threshold for maintaining the health of lake water ecology, the improvements of the present invention are as follows: in step S4, in order to accurately determine the water quality control target for maintaining the health of lake water ecology, the constructed lake hydrodynamics-water quality-ecology comprehensive model is used to simulate the biomass of phytoplankton under different water input scenarios and water quality discharge scenarios, and through the revelation of the competition mechanism under the synergistic effect of multiple environmental factors, multi-scenario simulation is carried out with low biomass and low proportion of harmful cyanobacteria as constraints.

[0021] In order to obtain the best multi-water source regulation scheme, the present invention has the following improvements: in step S5, the water quality control target (TN and TP concentrations) for maintaining the ecological health of lake water is determined as a constraint condition, different hydrological years, different irrigation area withdrawal scenarios and different improved hydrodynamic conditions are set as regulation measures, a variety of combined scenarios are designed, and the water quality improvement rate (Improvement of Water Quality) and available water volume are used as constraints to determine the best multi-water source regulation scheme for maintaining the health of lake water environment, thereby providing technical support and decision-making basis for lake water quality management and ecological water replenishment.

[0022] Compared with the prior art, the advantages and positive effects of the present invention are:

[0023] In the present invention, by improving the BLOOM module, the phytoplankton characterization is incorporated into the simulation of the competition mechanism of lake phytoplankton, and a hydrodynamic-water quality-ecological comprehensive model suitable for lake water environment simulation is created, which improves the accuracy of lake water environment simulation, so that the water quality control target of the lake water environment health can be better and more accurately determined; secondly, a variety of water resources are used for comprehensive regulation of multiple water sources, which improves the water quality of the lake and also improves the comprehensive utilization of regional water resources. The results of the present invention provide scientific and technological support for the water quality management of Chagan Lake, and are also the requirements for practicing the "one lake, one policy" precise governance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention proposes an operation step diagram of a method for regulating multiple water sources in lakes based on a hydrodynamic-water quality-ecological model;

[0025] Figure 2 A technical flow chart of a method for regulating multiple water sources in lakes based on a hydrodynamic-water quality-ecological model is proposed for the present invention;

[0026] Figure 3 A schematic diagram of the construction mechanism of a lake hydrodynamics-water quality-ecological model for a lake multi-water source regulation method based on a hydrodynamics-water quality-ecological model is provided for the present invention;

[0027] Figure 4 The main parameter diagram of the hydrodynamics-water quality-water ecology model of a lake multi-water source regulation method based on the hydrodynamics-water quality-ecological model is proposed for the present invention;

[0028] Figure 5 The present invention proposes a multi-scenario simulation diagram of a lake multi-water source regulation method based on a hydrodynamic-water quality-ecological model. DETAILED DESCRIPTION

[0029] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0030] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, in the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0031] See also Figure 1-5 The present invention provides a method for regulating multiple water sources in a lake based on a hydrodynamic-water quality-ecological model. The method for regulating multiple water sources in a lake based on a hydrodynamic-water quality-ecological model comprises the following steps:

[0032] S1: Prepare the database for the lake hydrodynamics-water quality-ecological integrated model and obtain various monitoring data required for the lake hydrodynamics-water quality-ecological integrated model;

[0033] S2: Comprehensively analyze the evolution characteristics and laws of lake water environment based on monitoring data, and clarify the occurrence mechanism of spatiotemporal heterogeneity of lake water environment;

[0034] S3: Based on the evolution mechanism of lake water environment, a comprehensive hydrodynamic-water quality-ecological model suitable for describing lake water environment is constructed;

[0035] S4: Based on the lake hydrodynamics-water quality-ecology integrated model, study the evolution characteristics of phytoplankton and water quality under the development and changes of different irrigation areas, reveal the competition mechanism of lake phytoplankton under the stress of multiple environmental factors, and determine the water quality control threshold to maintain the health of lake water ecology;

[0036] S5: Based on the lake water quality control threshold, propose the optimal multi-water source regulation plan to maintain the health of lake water ecology.

[0037] The various monitoring data required in step S1 include collecting hourly flow data from the hydrological monitoring stations at the entrance and exit of the lake, hourly meteorological observation data in the catchment area, digital elevation data (DEM), monthly water quality data and plankton data of the lake, and then establishing a model database and preparing various input data using Notepad software.

[0038] The specific steps of step S2 are to clarify the evolution characteristics of water cycle elements based on long-term meteorological, hydrological, water quality and other data, and clarify the water supply source of the lake; divide the water quality evolution stage of the lake, clarify the temporal and spatial characteristics and evolution laws of nutrient factors and non-nutrient factors in the current water quality evolution stage; evaluate the eutrophication degree of the lake, and provide a mechanism basis for the construction of a comprehensive model of lake hydrodynamics, water quality and water ecology. When statistically analyzing the basic data of the database, the Person correlation analysis method and the Mann-Kendall mutation detection method are used. The eutrophication index calculation comprehensively utilizes the Trophic State Index (TSI), Trophic Level Index (TLI) and Eutrophication Index (EI) indices for calculation.

[0039] Step S3 specifically includes the following steps:

[0040] a: Preprocessing of hydrological, meteorological, water quality and ecological observation data and digital elevation data requires collecting hourly hydrological flow data at the lake entrance and exit, monthly water quality and plankton data, hourly meteorological observation data in the catchment area, and digital elevation data, and preprocessing these data;

[0041] b: Acquisition and construction of model parameters. The Delft3d platform is used to simulate the lake hydrodynamics-water quality-ecological model. First, the grid generation module (Delft3D-Rgfgrid) is used to grid the DEM data and simulation boundaries obtained by remote sensing and field measurement, to construct a land-water boundary suitable for hydrodynamic simulation, and to divide the grid suitable for operation. Secondly, the initial numerical generation module (Delft3D-Quickin) is used to superimpose the bottom topography and roughness to set the initial conditions of the Flow module to generate the initial bottom topography. After that, the input parameters of the model are localized and calibrated. The main parameters are shown in the attached figure of the manual. Subsequently, the hydrodynamic calculation module (Delft3D-Flow) is used to combine the acquired grid and lake bottom topography, and the calculation is performed after the specific parameters are set; the hydrodynamic coupling module (Coupling) is used to couple the input hydrodynamic data into the process library module (Process Library) and water quality simulation modules (Waq-1 and Waq-2) are used to simulate the transport of pollutants. The hydrodynamic coupling module (Coupling) mainly converts the orthogonal grid into a water quality simulation transport grid, modifies the original 1h time step to 1 day time step, and directly calls the simulation results (Communication file) of the hydrodynamic simulation. The process library module (Process Library) needs to simulate the reaction process of the substance in detail. The water quality simulation module (Waq-1 and Waq-2) starts the specific simulation. The model integrates atmospheric deposition, endogenous and exogenous inputs, and the competition mechanism between species. The ecological module (BLOOM) is nested in the water quality module. It mainly describes the three phytoplankton functional groups and adds the description of the phytoplankton phenotypic level. In summary, the schematic diagram of the construction mechanism of the lake hydrodynamic-water quality-ecological model is shown in the attached figure of the specification.

[0042] The mechanism formula and intrinsic parameters of the state module (BLOOM) are as follows:

[0043] A: Dynamic equilibrium equation of matter:

[0044]

[0045]

[0046]

[0047]

[0048]

[0049] Where i is 1-6 algae functional groups

[0050]

[0051]

[0052]

[0053] Where X represents carbon, nitrogen, and phosphorus

[0054] B: Algae phenotype, growth and competition equations:

[0055]

[0056]

[0057]

[0058]

[0059]

[0060] k min，i ≤k d ≤k max，i Energy restriction (14)

[0061] Competition process:

[0062]

[0063] mrt i =m i *Phy i (16)

[0064] m i =m i，0 *(kt m，i ) t (17)

[0065] k d =k b +k SPM +k POM +k Phy +k HUM Photodigestion process (18)

[0066] nit=k nit *NH 4 *f T，nit Nitrification process (19)

[0067] den=k den *NO 3 *f T，den Denitrification process (20)

[0068] Where: Phy i For phytoplankton type, and is the mass of nutrient salt used for simulation, is the change in the migration process, The amount of change in physical, chemical and biological reactions, gro refers to the net growth of phytoplankton, mrt is the mortality rate of phytoplankton, M i is the mortality rate of type i algae, k tmi is the temperature coefficient of type i algae mortality, k d is the total extinction coefficient, k b is the background extinction, k SPM refers to the disappearance of inorganic suspended matter, k POM It is the death of dead particulate matter and organic matter, k Phy It is completely destroyed due to phytoplankton, and the humus input from fresh water leads to its destruction. Nit is nitrification, den is denitrification, k nit and k den are the nitrification rate and denitrification rate, respectively, T，nit 、f T，den are the temperature functions of the nitrification and denitrification processes, sed is the sedimentation, v is the sedimentation velocity, X is the carbon, nitrogen, phosphorus and silicate elements, POX is the particulate organic elements carbon, nitrogen, phosphorus and silicate, grz is being eaten by filter feeders, up is the absorption rate of organic matter by animals, S N,i is the stoichiometric characteristics of the nutrient N in type i phytoplankton, S P,i The stoichiometric characteristics of the nutrient P in type i phytoplankton.

[0069] The intrinsic formation mechanism of the lake BLOOM module includes the material balance principle of nutrient input, includes different algal functional groups and characterization types in the lake, and also calculates the growth and competition process of algae, coupling the algal growth process, death process, sedimentation process, nitrification and denitrification process, light degradation process, sediment resuspension process and food chain feeding process;

[0070] c: Model fitting and verification. The lake hydrodynamic module is calibrated and verified using water temperature, water depth and salinity. The water quality module is calibrated and verified using water quality parameters such as total nitrogen, total phosphorus, dissolved oxygen and chlorophyll. The calibration effect is evaluated using the Nash coefficient (Nash-Sutcliffe Efficiency, NSE), standard deviation (standard regression percent bias, PBIAS) and visual interpretation. The ecological module is calibrated and verified using algae biomass and proportion, and the simulation effect is evaluated using the average standard deviation (Average Standard Deviation, ARD%) and visual interpretation. Finally, a comprehensive hydrodynamic-water quality-water ecology model suitable for lake water environment simulation is constructed.

[0071] In step S4, in order to accurately determine the water quality control target for maintaining the health of lake water ecology, the constructed lake hydrodynamics-water quality-ecology integrated model is used to simulate the biomass of phytoplankton under different water input scenarios and water quality discharge scenarios. By revealing the competition mechanism under the synergistic effect of multiple environmental factors, multi-scenario simulation is carried out with low biomass and low proportion of harmful cyanobacteria as constraints. Ten scenarios are designed, as shown in the attached figure of the specification, where III and IV represent the surface water classification standards; "Observed value" represents the average observed value of TN, TP and TSS concentrations. ; “Inversion value” represents the inversion value of TSS concentration, so as to evaluate the effects of nitrogen-phosphorus ratio (N:P), total nitrogen (TN), total phosphorus (TP) and total suspended particles (TSS) on phytoplankton biomass and proportion, and describe the growth limitation and dynamic competition of phytoplankton in Chagan Lake. In these 10 scenarios (Table 2), N:P was set to 5, 10, 15, 20 or 30 to simulate the changes of phytoplankton in clear water and turbid water. The nutrient (TN and TP) concentrations and TSS were obtained according to the China Surface Water Environmental Quality III and IV Standards (GB 3838-2002) and inversion data, respectively. In these scenarios, only the concentrations of TN, TP and TSS were changed, and the flow rate remained unchanged. Scenarios 1 and 2 were used as basic scenarios for comparison, aiming to explore the effects of N:P and nutrient concentrations (TN and TP) and TSS on phytoplankton biomass and species succession. The determination of clear water and turbid water was based on the observed values ​​and correlation between TSS and SD.

[0072] In step S5, the water quality control target (TN and TP concentrations) for maintaining the ecological health of lake water is taken as a constraint condition, different hydrological years, different irrigation area withdrawal scenarios and different improved hydrodynamic conditions are set as control measures, and a variety of combined scenarios are designed. Using the water quality improvement rate (Improvement of Water Quality) and available water volume as constraints, the optimal multi-water source control plan for maintaining the health of the lake water environment is determined, providing technical support and decision-making basis for lake water quality management and ecological water replenishment.

[0073] In the present invention, by improving the BLOOM module, the phytoplankton characterization is incorporated into the simulation of the competition mechanism of lake phytoplankton, and a hydrodynamic-water quality-ecological comprehensive model suitable for lake water environment simulation is created, which improves the accuracy of lake water environment simulation, so that the water quality control target of the lake water environment health can be better and more accurately determined; secondly, a variety of water resources are used for comprehensive regulation of multiple water sources, which improves the water quality of the lake and also improves the comprehensive utilization of regional water resources. The results of the present invention provide scientific and technological support for the water quality management of Chagan Lake, and are also the requirements for practicing the "one lake, one policy" precise governance.

[0074] The above are only preferred embodiments of the present invention and are not intended to limit the present invention in other forms. Any technician familiar with the profession may use the technical contents disclosed above to change or modify them into equivalent embodiments with equivalent changes and apply them to other fields. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for regulating multiple water sources in lakes based on a hydrodynamic-water quality-ecological model, characterized by: The method for regulating multiple water sources in lakes based on the hydrodynamics-water quality-ecological model comprises the following steps: S1: Prepare the database for the lake hydrodynamics-water quality-ecological integrated model and obtain various monitoring data required for the lake hydrodynamics-water quality-ecological integrated model; S2: Comprehensively analyze the evolution characteristics and laws of lake water environment based on monitoring data, and clarify the occurrence mechanism of spatiotemporal heterogeneity of lake water environment; S3: Based on the evolution mechanism of lake water environment, a comprehensive hydrodynamic-water quality-ecological model suitable for describing lake water environment is constructed; S4: Based on the lake hydrodynamics-water quality-ecology integrated model, study the evolution characteristics of phytoplankton and water quality under the development and changes of different irrigation areas, reveal the competition mechanism of lake phytoplankton under the stress of multiple environmental factors, and determine the water quality control threshold to maintain the health of lake water ecology; S5: Based on the lake water quality control threshold, propose the best multi-water source regulation scheme to maintain the health of lake water ecology; The step S3 specifically comprises the following steps: a: Preprocessing of hydrological, meteorological, water quality and ecological observation data and digital elevation data; b: Acquisition and construction of model parameters; c: Model fitting and validation; In the step a, it is necessary to collect hourly hydrological flow data at the lake entrance and exit, monthly water quality and plankton data, hourly meteorological observation data in the catchment area, and digital elevation data, and pre-process these data; In the step b, the Delft3d platform is used to carry out the simulation of the lake hydrodynamics-water quality-ecological model. First, the DEM data and simulation boundaries obtained by remote sensing and field measurement are gridded using the grid generation module Delft3D-Rgfgrid to construct a land-water boundary suitable for hydrodynamic simulation, and the grid suitable for operation is divided. Secondly, the initial value generation module Delft3D-Quickin is used to superimpose the bottom topography and roughness to set the initial conditions of the Flow module to generate the initial bottom topography. After that, the input parameters of the model are localized and calibrated. Subsequently, the hydrodynamic calculation module Delft3D-Flow is used to combine the acquired grid and lake bottom topography, and the specific parameters are set before calculation. The hydrodynamic coupling module Couplin is used to couple the input hydrodynamic data into the process library module Process Library and water quality simulation modules Waq-1 and Waq-2 are used to simulate the transport of pollutants. The hydrodynamic coupling module Coupling converts the orthogonal grid into a water quality simulation transport grid, changes the original 1h time step to a 1-day time step, and directly calls the Communication file of the hydrodynamic simulation. The process library module Process Library needs to simulate the reaction process of the substance in detail. The water quality simulation modules Waq-1 and Waq-2 start the specific simulation. The model integrates atmospheric deposition, endogenous and exogenous inputs, and the competition mechanism between species. The ecological module BLOOM is nested in the water quality module. On the basis of describing the three phytoplankton functional groups, the description of the phytoplankton phenotype level is added. In the step c, the lake hydrodynamic module needs to be calibrated and verified using water temperature, water depth and salinity, the water quality module needs to be calibrated and verified using water quality parameters including total nitrogen, total phosphorus, dissolved oxygen and chlorophyll, the calibration effect needs to be evaluated using Nash-Sutcliffe Efficiency (NSE), standard regression percent bias (PBIAS) and visual interpretation, the ecological module needs to be calibrated and verified using algae biomass and proportion, the simulation effect needs to be evaluated using Average Standard Deviation (ARD%) and visual interpretation, and finally a hydrodynamic-water quality-water ecology comprehensive model applicable to lake water environment simulation is constructed; The mechanism formula and intrinsic parameters of the ecological module BLOOM reflect the mechanism and process of the model as follows: A: Dynamic equilibrium equation of matter: Where i is 1-6 algae functional groups Where X represents carbon, nitrogen, and phosphorus B: Algae phenotype, growth and competition equations: k min，i ≤k d ≤k max,i Energy restriction (14) Competition process: mr t =m i *Phy i (16) m i =m i，0 *(kt m,i ) t (17) k d =k b +k SPM +k POM +k Phy +k HUM Photodigestion process (18) nit=k nit *NH4*f T，nit Nitrification process (19) den=k den *NO3*f T,den Denitrification process (20) Where: Phyi is the phytoplankton type, and is the mass of nutrient salt used for simulation, is the change in the migration process, The amount of change in physical, chemical and biological reactions, The change in the pollution source is gro, which is the net growth of phytoplankton, mrt is the mortality rate of phytoplankton, and M i is the mortality rate of type i algae, k tmi is the temperature coefficient of type i algae mortality, k d is the total extinction coefficient, k b is the background extinction, k SPM refers to the disappearance of inorganic suspended matter, k POM It is the death of dead particulate matter and organic matter, k Phy It is completely destroyed due to phytoplankton, and the humus input from fresh water leads to its destruction. Nit is nitrification, den is denitrification, k nit and k den are the nitrification rate and denitrification rate, respectively, T,nit 、f T,den are the temperature functions of the nitrification and denitrification processes, sed is the sedimentation, v is the sedimentation velocity, X is the carbon, nitrogen, phosphorus and silicate elements, POX is the particulate organic elements carbon, nitrogen, phosphorus and silicate, grz is being eaten by filter feeders, up is the absorption rate of organic matter by animals, S N,i is the stoichiometric characteristics of the nutrient N in type i phytoplankton, S P,i is the stoichiometric characteristics of the nutrient P in type i phytoplankton; The intrinsic formation mechanism of the lake BLOOM module includes the material balance principle of nutrient input, includes different algal functional groups and characterization types in the lake, and also calculates the growth and competition process of algae, coupling the algal growth process, death process, sedimentation process, nitrification and denitrification process, light degradation process, sediment resuspension process and food chain feeding process; c: Model fitting and verification. The lake hydrodynamic module was calibrated and verified using water temperature, water depth and salinity. The water quality module was calibrated and verified using water quality parameters: total nitrogen, total phosphorus, dissolved oxygen and chlorophyll. The calibration effect was evaluated using the Nash-Sutcliffe Efficiency (NSE), standard regression percent bias (PBIAS) and visual interpretation. The ecological module was calibrated and verified using algal biomass and proportion. The simulation effect was evaluated using the Average Standard Deviation (ARD%) and visual interpretation. Finally, a comprehensive hydrodynamic-water quality-water ecology model suitable for lake water environment simulation was constructed.

2. The method for controlling multiple water sources in lakes based on a hydrodynamic-water quality-ecological model according to claim 1, characterized in that: The various monitoring data required in step S1 include collecting hourly flow data from the hydrological monitoring stations at the entrance and exit of the lake, hourly meteorological observation data in the catchment area, digital elevation data DEM, monthly water quality data and plankton data of the lake, and then establishing a model database and preparing various input data using Notepad software.

3. The method for controlling multiple water sources in lakes based on a hydrodynamic-water quality-ecological model according to claim 1, characterized in that: The specific steps of step S2 are as follows: based on long-term meteorological, hydrological and water quality data, the evolution characteristics of water cycle elements are clarified, and the water supply source of the lake is clarified; the water quality evolution stage of the lake is divided, and the spatiotemporal characteristics and evolution laws of trophic factors and non-trophic factors in the current water quality evolution stage are clarified; the eutrophication degree of the lake is evaluated, and a mechanism basis is provided for the construction of a comprehensive model of lake hydrodynamics, water quality and water ecology. When statistically analyzing the basic data of the database, the Person correlation analysis method and the Mann-Kendall mutation detection method are used, and the eutrophication index calculation comprehensively utilizes the Trophic State Index TSI, Trophic Level Index TLI and Eutrophication Index EI indices for calculation.

4. The method for controlling multiple water sources in lakes based on a hydrodynamic-water quality-ecological model according to claim 1, characterized in that: In step S4, in order to accurately determine the water quality control target for maintaining the health of the lake water ecology, the constructed lake hydrodynamics-water quality-ecology comprehensive model is used to simulate the biomass of phytoplankton under different water input scenarios and water quality discharge scenarios. By revealing the competition mechanism under the synergistic effect of multiple environmental factors, multi-scenario simulation is carried out with low biomass and low proportion of harmful cyanobacteria as constraints.

5. The method for controlling multiple water sources in lakes based on a hydrodynamic-water quality-ecological model according to claim 1, characterized in that: In step S5, the water quality control target TN and TP concentrations for maintaining the ecological health of lake water are determined as constraints, different hydrological years, different irrigation area withdrawal scenarios and different improved hydrodynamic conditions are set as control measures, and a variety of combined scenarios are designed. Using the water quality improvement rate and available water volume as constraints, the optimal multi-water source control plan for maintaining the health of the lake water environment is determined, providing technical support and decision-making basis for lake water quality management and ecological water replenishment.

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