A method and device for reducing pollutants entering a river and predicting water quality of a river section based on a water environment mathematical model

Abstract

The present invention discloses a method for reducing pollutants entering a river and predicting water quality of a river section based on a water environment mathematical model, which makes up for the lack of monitoring time and space, and can simulate and predict the change of water quality concentration of a river section under multi-parameter conditions such as different rain types, different diversion and drainage flows of control gates, and pollutant output regularity characteristics under different rainfall and rain types. The method comprises the following steps: S1. Constructing a mathematical model of river network water environment; S2. Determining predicted pollutants; S3. Inputting the diversion and drainage conditions of the control gates, the dispatching conditions of the gate pumps, and the predicted pollutant information discharged by the pumping stations along the way into the mathematical model of river network water environment; S4. Determining the degree of influence of pollutants on the river section; S5. Determining the prediction scheme of the influence of pollutants on the water quality of the river section; S6. Based on the established mathematical model of river network water environment, the migration and diffusion of pollutants under different rain types, different diversion and drainage of control gates and pumping station drainage conditions are simulated to determine the degree of influence of predicted pollutants on the water quality of the river section. The present invention has certain practicality and can provide a scientific basis for the stable compliance of water quality of river sections.

Description

Technical Field

[0001] The invention relates to a method and a device for reducing pollutants entering a river and predicting water quality of a river section based on a water environment mathematical model, and belongs to the technical field of regional river water environment management. Background Art

[0002] With the vigorous promotion of black and odorous water treatment, many urban water bodies have eliminated the black and odorous on sunny days, but the black and odorous rivers on rainy days have returned. The blackening, odorization and deterioration of urban water bodies on rainy days have become a bottleneck for river water treatment and water environment quality improvement. The pollution of outflow from drainage outlets on rainy days has become the fundamental reason why urban water bodies "turn black when it rains" or "exceed the standard when it rains".

[0003] Therefore, strengthening outlet management, improving the quality of drainage pipe networks, and reducing the pollution load of overflow during rainy days are important measures to achieve the goal of improving water environment quality and promote the consolidation and improvement of water environment quality.

[0004] However, field monitoring has certain limitations in time and space. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a method and device for reducing pollutants entering a river and predicting water quality in a river section based on a mathematical model of the water environment. The method and device can simulate and predict the changes in water quality concentration in a river section under multi-parameter conditions such as different rainfall types, different diversion and drainage flow rates of regulating gates, and characteristics of pollutant output rules under different rainfall types, thereby providing a scientific basis for ensuring that the water quality of the river section meets the standards.

[0006] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0007] In a first aspect, the present invention provides a method for reducing pollutants entering a river and predicting water quality of a river section based on a water environment mathematical model, comprising the following steps:

[0008] Identify predicted pollutants in the study area;

[0009] Obtain the diversion and drainage flow, sluice pump scheduling and predicted pollutant information discharged by pump stations along the way in the study area, and input the diversion and drainage flow, sluice pump scheduling and predicted pollutant information discharged by pump stations along the way into the river network water environment mathematical model to obtain hydrodynamic and water quality simulation results;

[0010] Compare the hydrodynamic and water quality simulation results with the key assessment sections in the study area, the water function zones in the study area, or the water quality standards of the river to determine the impact of pollutants on the river section;

[0011] In the constructed water environment mathematical model, the pump station drainage and pump station drainage water volume under different rainfall conditions are set, and the model operation results are compared with the key assessment sections, water function zones or river water quality standards in the study area to determine the prediction scheme of the impact of regulating gate drainage and pump station drainage on the water quality of the river section under different rainfall types;

[0012] Based on the established mathematical model of the river network water environment in the study area, a comprehensive simulation is conducted on the migration and diffusion of pollutants under different rainfall types and different regulating gate drainage and pump station drainage conditions to determine the impact of the predicted pollutants in the study area on the water quality of the river section, that is, the predicted water quality results.

[0013] Furthermore, the hydrodynamic model calculation of the river network water environment mathematical model adopts the Saint-Venant equations describing the one-dimensional unsteady flow in the open channel, including the continuity equation and the momentum equation, and additionally considers the floodplain and lateral inflow. The calculation formula of the model hydrodynamic calculation model is as follows:

[0014]

[0015] Where: Q is the flow rate; x is the spatial coordinate along the direction of water flow; b is the storage width, which refers to the total river width including the beach; h is the water level; t is the time coordinate; q is the lateral inflow flow, inflow is positive and outflow is negative; α is the momentum correction coefficient; A is the cross-sectional area of ​​the main channel; g is the gravitational acceleration; C is the Xie Cai coefficient; R is the hydraulic radius;

[0016] The water quality model calculation of the river network water environment mathematical model adopts a one-dimensional convection diffusion equation, and the calculation formula of the model water quality calculation model is as follows:

[0017]

[0018] In the formula: x is the spatial coordinate along the water flow direction; t is the time coordinate; Q is the flow rate; C is the substance concentration; A is the cross-sectional area of ​​the main channel; D is the longitudinal diffusion coefficient; K is the linear attenuation coefficient; C2 is the source-sink concentration; q is the side inflow flow;

[0019] There are a large number of structures in the river channel, and the scheduling operation of the structures has a great impact on the hydraulic elements, so the impact of the scheduling of the structures cannot be ignored. Hydraulic structures include gate outlet flow types (such as spillways), overflow types (such as rubber dams), flow types (such as pumps), etc. Complex scheduling rules can be set for the operation of hydraulic structures. The operation of hydraulic structures can be controlled according to dozens of logical judgment conditions such as water level or flow at a certain point in the river channel, water level difference or flow difference, water storage capacity, time, etc. Hydraulic structures are used to calculate the flow between two water points (hpoint) upstream and downstream. The flow through the hydraulic structure is determined by the upstream and downstream water levels and the parameters of the structure itself (such as: related dimensions of the structure, etc.), which can be abbreviated as Q=f(h). Since the energy equation Q=f(h) of hydraulic structures varies greatly in expression, and there are also expressions involving different flow states, only one of them is described here.

[0020] In order to maintain consistency and compatibility with the discretized format of the hydrodynamic Saint-Venant equations in the above formula 1, the discretized form of Q=f(h) at the hydraulic structure is like the momentum equation form, that is:

[0021]

[0022] The above equation is the discrete form of the energy equation of hydraulic structures, which will replace the momentum equation in the discretized Saint-Venant equations;

[0023] The flow through hydraulic structures is discretely formatted as follows:

[0024]

[0025] Comparing the above two equations, we can get:

[0026]

[0027] In the formula, α j , β j , γ j , δ j All of them are intermediate parameters, Q is the flow rate, h represents the gate opening height, and n is the power number.

[0028] Furthermore, the method for constructing the river network water environment mathematical model includes:

[0029] Generalize the internal river channels to form a generalized river network with river channels and nodes;

[0030] The natural river network is merged and generalized, and the river channel is generalized into a horizontal bottom slope and a trapezoidal section. The generalized section is described by the three elements of bottom height, bottom width and side slope.

[0031] The water quality boundary conditions of the river network water environment mathematical model are set at the inflow of the river in the river network model;

[0032] The data needed to establish a mathematical model of the river network water environment include: water system maps of the study area, river topography data, design parameters and dispatching operation rules of hydraulic structures, hydrological information data, pump station discharge and pollutant concentrations.

[0033] Further, the methods for determining the predicted pollutants in the study area include:

[0034] Based on the water quality requirements of key river monitoring sections in the study area and the main exceeding factors of the monitoring sections under the current situation, combined with the "Surface Water Environmental Quality Standards", conventional water quality influencing pollutants are determined.

[0035] Furthermore, the method of inputting the diversion and drainage flow, the sluice pump scheduling situation and the predicted pollutant information discharged by the pumping stations along the way into the river network water environment mathematical model includes:

[0036] The diversion and drainage flow of the control gate and pump station is input into the mathematical model of river network water environment as the internal boundary conditions. The required data include diversion and drainage flow and time.

[0037] The sluice pump dispatching situation is input into the river network water environment mathematical model as a controllable hydraulic structure. The required data include the inherent condition parameters of the controllable hydraulic structure and the number, height and time of the sluice opening holes. The inherent condition parameters include the sluice height, width and opening speed.

[0038] The predicted pollutant information discharged from the pumping stations along the way is input into the mathematical model of the river network water environment in the form of point source pollution. The required data include the discharge volume and pollutant emission concentration based on time series.

[0039] Furthermore, the calculated results are compared with the key assessment sections in the study area, the water function zones in the study area or the water quality standards of the river. The methods for determining the impact of pollutants on the river section include:

[0040] Calibrate and verify the river roughness in the hydrodynamic calculation model and water quality calculation model in the water environment mathematical model and the predicted pollutant degradation coefficient in the study area;

[0041] Based on actual hydrological information, sluice and pump scheduling, pump station discharge volume and concentration, and the Surface Water Environmental Quality Standards, the calculated results are compared with the key assessment sections, water functional zones, or river water quality standards in the study area to determine the extent of the impact of pollutants on river sections.

[0042] Furthermore, the method for determining the prediction scheme of the impact of the diversion and drainage of the regulating sluice and the drainage of the pump station on the water quality of the river section under different rainfall patterns includes:

[0043] The rainfall level is determined by comprehensively considering the rainfall, the scheduling of sluice pumps in the study area, the drainage volume of the regulating sluice, the drainage volume of the pumping stations along the way based on the time series, and the pollutant emission concentration. The rainfall is divided into 6 levels: Level 1 light rain: rainfall less than 10 mm in 24 hours, Level 2 moderate rain: rainfall 10-25 mm in 24 hours, Level 3 heavy rain: rainfall 25-50 mm in 24 hours, Level 4 torrential rain: rainfall greater than 50 mm in 24 hours.

[0044] Furthermore, the method for determining the impact of the predicted pollutants in the study area on the water quality of the river section includes:

[0045] By inputting the control gate diversion and drainage data, the gate pump opening and closing status data in the study area, the river hydrological information, the pump station discharge and the pollutant concentration into the river network water environment mathematical model, the river network water environment mathematical model automatically runs and calculates the hydrodynamic and water quality simulation results;

[0046] Based on the water quality simulation results of the model, determine the extent and duration of the impact of pollutants on the river section.

[0047] In a second aspect, an embodiment of the present invention provides a device for reducing pollutants entering a river and predicting water quality of a river section based on a water environment mathematical model, the device comprising:

[0048] Pollutant determination module: used to determine the predicted pollutants in the study area;

[0049] Calculation module: used to obtain the diversion and drainage flow, sluice pump scheduling and predicted pollutant information discharged by pump stations along the way in the study area, and input the diversion and drainage flow, sluice pump scheduling and predicted pollutant information discharged by pump stations along the way into the river network water environment mathematical model to calculate the hydrodynamic and water quality simulation results;

[0050] Section impact module: used to compare the calculated results with the key assessment sections, water function zones or river water quality standards in the study area to determine the impact of pollutants on the river sections;

[0051] Prediction scheme module: used to set the pump station drainage and pump station drainage water volume under different rainfall conditions in the constructed water environment mathematical model, compare the model operation results with the key assessment sections, water function zones or river water quality standards in the study area, and determine the prediction scheme of the impact of regulating gate drainage and pump station drainage on the water quality of the river section under different rainfall types;

[0052] Output module: It is used to comprehensively simulate the migration and diffusion of pollutants under different rainfall types, different regulating gate drainage and pump station drainage conditions based on the established mathematical model of the river network water environment in the study area, and determine the impact of the predicted pollutants in the study area on the water quality of the river section, that is, the predicted water quality results.

[0053] In a third aspect, the present invention provides a device for reducing pollutants entering a river and predicting water quality of a river section based on a water environment mathematical model, including a processor and a storage medium;

[0054] The storage medium is used to store instructions;

[0055] The processor is used to operate according to the instructions to execute the steps of the method described in the first aspect.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] The present invention discloses a method for reducing pollutants entering a river and predicting water quality of a river section based on a mathematical model of water environment, aiming to simulate and predict the change of water quality concentration of a river section under multi-parameter conditions such as different rain types, different diversion and drainage flow rates of regulating gates, and regular characteristics of pollutant output under different rainfall types, thereby providing a scientific basis for the stable compliance of water quality of a river section. The present invention makes up for the deficiency of monitoring time and space, and can simulate and predict the change of water quality concentration of a river section under multi-parameter conditions such as different rain types, different diversion and drainage flow rates of regulating gates, and regular characteristics of pollutant output under different rainfall types. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 is the position of the hydraulic structure in the calculation grid point;

[0059] Figure 2 This is the effect of water diversion during light rain, drainage from the pumping station, and reduction in pollutant concentration on the water quality of section A;

[0060] Figure 3 This is the effect of water diversion, pump station discharge, and pollutant concentration reduction on the water quality of section A during moderate rain.

[0061] Figure 4 This is the effect of water diversion, pump station discharge, and pollutant concentration reduction on the water quality of section A during heavy rain;

[0062] Figure 5 This is the effect of water diversion, pump station discharge, and pollutant concentration reduction on the water quality of section A during heavy rain;

[0063] Figure 6 This is the effect of the reduction in the discharge concentration of the pumping station on the water quality of section A during light rain when the gate discharges water;

[0064] Figure 7 This is a diagram showing the effect of the reduction in pump station drainage concentration on the water quality of section A during rainy season when the sluice gate is draining water;

[0065] Figure 8 This is a diagram showing the effect of the reduction in discharge concentration of the pumping station on the water quality of section A during heavy rain when the gate is draining water;

[0066] Fig. 9 This is a diagram showing the effect of the reduction in pumping station discharge concentration on the water quality of section A during heavy rains when the gate is used to control the discharge;

[0067] Fig.10 This is a map of the Nanjing water system;

[0068] Fig.11 The map of water diversion for the outer Qinhuai River;

[0069] Fig.12 It is an operation flow chart of the present invention. DETAILED DESCRIPTION

[0070] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0071] Embodiment 1:

[0072] This embodiment provides a method for reducing pollutants entering a river and predicting water quality of a river section based on a water environment mathematical model, comprising the following steps:

[0073] Step S1. Construct a mathematical model of the river network water environment. In order to facilitate calculation, the internal river channels must first be generalized to form a generalized river network with river channels and nodes. The natural river network is merged and generalized. The generalized river channels are horizontal bottom slopes and trapezoidal sections. The generalized sections are described by three elements: bottom height, bottom width and side slopes. Since the hydrodynamic boundary conditions can be divided into two categories: flow boundaries and water level boundaries, the external river channels are also divided into two categories, one is a river channel with flow-type boundary conditions, and the other is a river channel with water level-type boundary conditions. The water quality boundary conditions are set at the inflow of the river in the river network model. The model is successfully built and used for the calculation of the following steps.

[0074] Step S2. Determine the predicted pollutants in the study area by consulting recent water environment survey data in the study area;

[0075] Step S3. Input the diversion and drainage flow, sluice pump dispatching conditions and the predicted pollutant information discharged by the pumping stations along the way into the river network water environment mathematical model, and automatically calculate the water dynamics and water quality simulation results through the water environment mathematical model constructed in S1;

[0076] Step S4. Compare the results automatically calculated by the water environment mathematical model in step S3 with the key assessment sections of the study area, the water function zones of the study area or the water quality standards of the river to determine the impact of the pollutants on the river section;

[0077] Step S5. Set the pump station drainage and pump station drainage water volume under different rainfall conditions in the constructed water environment mathematical model, compare the model operation results with the key assessment sections of the study area, the water function zones of the study area or the river water quality standards, and determine the prediction scheme of the impact of the control gate drainage and pump station drainage on the water quality of the river section under different rainfall types;

[0078] Step S6. Based on the established mathematical model of the river network water environment in the study area, a comprehensive simulation is performed on the migration and diffusion of pollutants under different rainfall types, different control gate drainage and pump station drainage conditions to determine the impact of the predicted pollutants on the water quality of the river section in the study area determined in step S2;

[0079] Specifically, the hydrodynamic model calculation in the river network water environment mathematical model established in step S1 adopts the Saint-Venant equations describing the one-dimensional unsteady flow in the open channel, including the continuity equation and the momentum equation, and additionally considers the floodplain and lateral inflow. The calculation formula of the model hydrodynamic calculation model is as follows:

[0080]

[0081] In the formula: Q is the flow rate; x is the spatial coordinate along the direction of water flow; b is the storage width, which refers to the total river width including the beach; h is the water level; t is the time coordinate; q is the lateral inflow flow, inflow is positive and outflow is negative; α is the momentum correction coefficient; A is the cross-sectional area of ​​the main channel; g is the gravitational acceleration; C is the Xie Cai coefficient; R is the hydraulic radius.

[0082] Specifically, the water quality model calculation in the river network water environment mathematical model established in step S1 adopts a one-dimensional convection-diffusion equation, and the calculation formula of the model water quality calculation model is as follows:

[0083]

[0084] In the formula: x is the spatial coordinate along the water flow direction; t is the time coordinate; Q is the flow rate; C is the substance concentration; A is the cross-sectional area of ​​the main channel; D is the longitudinal diffusion coefficient; K is the linear attenuation coefficient; C2 is the source-sink concentration; q is the lateral inflow flow.

[0085] Specifically, the controllable hydraulic structures in the river network water environment mathematical model established in step S1 are used to calculate the flow between the two water points (hpoint) upstream and downstream, that is, the hydraulic structures are placed at the flow points of the calculation grid points, and the flow through the hydraulic structures is determined by the upstream and downstream water levels and the parameters of the structures themselves (such as: related dimensions of the structures, etc.). That is, the flow of hydraulic structures such as gates and pumps in the river network model is determined by the upstream and downstream water levels.

[0086] There are a large number of structures in the river channel, and the scheduling operation of the structures has a great impact on the hydraulic elements, so the impact of the scheduling of the structures cannot be ignored. Hydraulic structures include gate outlet flow types (such as spillways), overflow types (such as rubber dams), flow types (such as pumps), etc. Complex scheduling rules can be set for the operation of hydraulic structures. The operation of hydraulic structures can be controlled according to dozens of logical judgment conditions such as water level or flow at a certain point in the river channel, water level difference or flow difference, water storage capacity, time, etc. Hydraulic structures are used to calculate the flow between two water points (hpoint) upstream and downstream. The flow through the hydraulic structure is determined by the upstream and downstream water levels and the parameters of the structure itself (such as: related dimensions of the structure, etc.), which can be abbreviated as Q=f(h). Since the energy equation Q=f(h) of hydraulic structures varies greatly in expression, and there are also expressions involving different flow states, only one of them is described here.

[0087] In order to maintain the consistency and compatibility of the discrete format of the Saint-Venant equations, the discretized form of Q = f(h) at the hydraulic structure is like the momentum equation form, that is:

[0088]

[0089] The above formula is the discrete form of the energy equation of hydraulic structures, which will replace the momentum equation in the discretized Saint-Venant equations. In addition, the flow through hydraulic structures is discretely formatted as follows:

[0090]

[0091] Comparing the above two equations, we can get:

[0092]

[0093] Specifically, the data required for the river network water environment mathematical model established in step S1 include: water system map of the study area, river terrain data, hydraulic structure design parameters and dispatching operation rules, hydrological information data, pump station discharge and pollutant concentration.

[0094] Specifically, the steps for determining the predicted pollutants in step S2 are as follows: based on the water quality requirements of the key river monitoring sections in the study area and the main exceeding factors of the monitoring sections under the current situation, combined with the "Surface Water Environmental Quality Standard" (GB 3838-2002), determine the conventional water quality affecting pollutants.

[0095] Specifically, in the S3 step, the control gate and pump station drainage flow is input into the model as the internal boundary condition, and the required data includes the drainage flow and time; the gate pump scheduling situation is input into the river network model as a controllable hydraulic structure, and the required data includes the condition parameters of the controllable hydraulic structure itself, such as gate height, width, opening speed, etc., and the required data also includes the number of gate opening holes, height and time; the drainage of the pump station along the way is input into the model in the form of point source pollution, and the required data includes the drainage volume and pollutant emission concentration based on the time series.

[0096] Specifically, before the S4 step, it is also necessary to calibrate and verify parameters such as the river roughness in the hydrodynamic calculation model and the water quality calculation model in the water environment mathematical model and the predicted pollutant degradation coefficient in the study area; the impact of pollutants on the river section in the S4 step should be determined in combination with actual hydrological information, sluice pump scheduling, pump station discharge and discharge concentration, and the "Surface Water Environmental Quality Standard" (GB3838-2002).

[0097] Specifically, the prediction scheme for the impact of pollutants on the water quality of the river section determined in step S5 needs to comprehensively consider factors such as rainfall, the scheduling of sluice pumps in the study area, the drainage volume of the regulating sluice, the drainage volume of the pumping stations along the way based on time series, and the pollutant emission concentration. The rainfall is divided into 6 levels, level 1 light rain: 24-hour rainfall is less than 10 mm, level 2 moderate rain: 24-hour rainfall is 10-25 mm, level 3 heavy rain: 24-hour rainfall is 25-50 mm, level 4 torrential rain: 24-hour rainfall is greater than 50 mm.

[0098] Specifically, the method for determining the degree of influence of pollutants on the water quality of the river section in step S6 is: by inputting the control gate diversion and drainage data, the gate pump opening and closing status data in the study area, the river hydrological information, the pump station discharge and the pollutant concentration into the model, the model automatically runs and calculates the hydrodynamics (water level, flow) and water quality (predicted pollutant concentration in the study area) according to the above formulas 1-5, and determines the degree and time of the influence of pollutants on the river section according to the water quality simulation results of the model. The model will automatically run the processing calculation, and you can see the time required for the water quality to reach the standard water quality concentration.

[0099] Specifically, taking a section A of the Qinhuai River as an example, the specific implementation steps of the present invention are described:

[0100] S1. Construct a mathematical model of river network water environment;

[0101] The distribution of water systems in Nanjing is shown in the attached figure. Figure 1As shown. The Qinhuai River system has two sources, north and south, and is divided into the Qinhuai New River and the Outer Qinhuai River at Dongshan Bridge, which flow into the Yangtze River respectively. The water allocation methods of the Outer Qinhuai River: "six gates linkage" and "time-sharing water diversion" are adopted. "Six gates linkage" refers to the use of the Tianshengqiao Gate, Wudingmen Gate, Qinhuai New River Hub, Lianhua Gate, Nanhe Gate and Sanchahe Estuary Gate that have been built in the Qinhuai River Basin to form a centralized control system. According to the water level (high tide level) of the Yangtze River Xiaguan, the six gates are uniformly dispatched, and water is diverted to the Outer Qinhuai River through various water diversion methods. Time-sharing water diversion mainly refers to the use of rainwater resources and the water level difference between Shijiu Lake and the Qinhuai River Basin for gravity diversion during the flood season, and the use of the Qinhuai New River Hub Pump Station to draw water during the non-flood season, as shown in the attached Figure 2 Through the above measures, the water quality of Qinhuai River and the main urban area has been improved.

[0102] The hydrodynamic model calculation in the mathematical model of river network water environment adopts the Saint-Venant equations describing one-dimensional unsteady flow in open channels, including the continuity equation and momentum equation, and additionally considers the floodplain and lateral inflow:

[0103]

[0104] In the formula: Q is the flow rate; x is the spatial coordinate along the direction of water flow; b is the storage width, which refers to the total river width including the beach; h is the water level; t is the time coordinate; q is the lateral inflow flow, inflow is positive and outflow is negative; α is the momentum correction coefficient; A is the cross-sectional area of ​​the main channel; g is the gravitational acceleration; C is the Xie Cai coefficient; R is the hydraulic radius.

[0105] The water quality model calculation in the river network water environment mathematical model adopts the one-dimensional convection diffusion equation:

[0106]

[0107] In the formula: x is the spatial coordinate along the water flow direction; t is the time coordinate; Q is the flow rate; C is the substance concentration; A is the cross-sectional area of ​​the main channel; D is the longitudinal diffusion coefficient; K is the linear attenuation coefficient; C2 is the source-sink concentration; q is the lateral inflow flow.

[0108] The numerical solution of the convection-diffusion equation is similar to that of the hydrodynamic equations, which is solved by a six-point implicit difference scheme and finally solved by the Thomas chase method.

[0109] In the mathematical model of river network water environment, controllable hydraulic structures are used to calculate the flow between two water points (hpoint) upstream and downstream, as follows Figure 1 shown.

[0110] In order to maintain the consistency and compatibility of the discrete format of the Saint-Venant equations, the discretized form of Q = f(h) at the hydraulic structure is like the momentum equation form, that is:

[0111]

[0112] The above formula is the discrete form of the energy equation of hydraulic structures, which will replace the momentum equation in the discretized Saint-Venant equations. In addition, the flow through hydraulic structures is discretely formatted as follows:

[0113]

[0114] Comparing the above two equations, we can get:

[0115]

[0116] S2. Determine the predicted pollutants;

[0117] Since the water quality requirement of a certain section A of the Qinhuai River is to stably meet the Class III water standard, the ammonia nitrogen has occasionally exceeded the Class III water standard in recent years, and the situation is even worse on rainy days. Therefore, in combination with the "Surface Water Environmental Quality Standard" (GB 3838-2002), it is determined that the conventional water quality influencing pollutants are ammonia nitrogen.

[0118] S3. Input the diversion and drainage flow, sluice pump dispatching conditions and the predicted pollutant information discharged by the pumping stations along the way into the river network water environment mathematical model;

[0119] The control gate and pump station drainage flow is input into the model as the internal boundary condition, and the required data includes the gate / pump drainage flow and time; the gate pump scheduling situation is input into the river network model as a controllable hydraulic structure, and the required data includes the condition parameters of the controllable hydraulic structure itself, such as gate height, width, opening speed, etc. The required data also includes the number, height and time of gate opening holes; the drainage of pump stations along the way is input into the model in the form of point source pollution, and the required data includes the drainage volume and pollutant emission concentration based on time series.

[0120] Table 1 Regulating gate and pump station drainage flow

[0121]

[0122]

[0123] Table 2 Discharge volume and discharge concentration of pumping stations along the way

[0124]

[0125] S4. Determine the extent of the impact of pollutants on the river section;

[0126] Before step S4, the parameters of the hydrodynamic calculation model and the water quality calculation model need to be calibrated and verified; at the same time, the impact of pollutants on the river section in step S4 should be determined in combination with actual hydrological information, sluice pump scheduling, pump station discharge volume and discharge concentration, and the "Surface Water Environmental Quality Standard" (GB 3838-2002).

[0127] Table 3 Water quality of section A from September 1 to 7

[0128] date Ammonia nitrogen concentration in section A (㎎ / L) September 1 0.22 September 2 0.23 September 3 0.25 September 4 0.30 September 5 0.70 September 6 0.55 September 7 0.36

[0129] S5. Determine the prediction scheme of the impact of the diversion and drainage flow of the regulating gate and the drainage of the pumping station on the water quality of the river section under different rainfall patterns;

[0130] The prediction scheme for determining the impact of pollutants on the water quality of river sections needs to comprehensively consider factors such as rainfall, sluice pump scheduling in the study area, control sluice drainage, time series-based drainage of pumping stations along the way, and pollutant emission concentrations.

[0131] ① The rainfall is divided into 6 levels: Level 1: 24-hour rainfall is less than 10mm, Level 2: 24-hour rainfall is 10-25mm, Level 3: 24-hour rainfall is 25-50mm, Level 4: 24-hour rainfall is greater than 50mm.

[0132] ② The discharge volume and pollutant discharge concentration of different pumping stations under the 90% guarantee rate design hydrological conditions and different rain types with 90% guarantee rate are as follows:

[0133] Table 4 Average discharge of pumping station 1, pumping station 2 and pumping station 3 under different rainfall patterns

[0134]

[0135] Table 5 Pollutant emission concentrations of pumping stations 1, 2 and 3 under different rainfall patterns

[0136]

[0137] The forecast scenario is shown in the following table:

[0138] Table 6 Summary of the regulation plan for water diversion at the control gate

[0139]

[0140] Table 7 Summary of the regulation plan for regulating gate drainage

[0141]

[0142]

[0143] S6. Based on the established mathematical model of river network water environment, the migration and diffusion of pollutants under different rainfall types and different regulating gate drainage and pump station drainage conditions are simulated to determine the predicted impact of pollutants on the water quality of river sections.

[0144] Water quality simulation results of section A under different water diversion conditions of the regulating gate:

[0145] Figure 1 is the position of the hydraulic structure in the calculation grid point;

[0146] Figure 2 This is the effect of water diversion during light rain, drainage from the pumping station, and reduction in pollutant concentration on the water quality of section A;

[0147] Figure 3 This is the effect of water diversion, pump station discharge, and pollutant concentration reduction on the water quality of section A during moderate rain.

[0148] Figure 4 This is the effect of water diversion, pump station discharge, and pollutant concentration reduction on the water quality of section A during heavy rain;

[0149] Figure 5 This is the effect of water diversion, pump station discharge, and pollutant concentration reduction on the water quality of section A during heavy rain;

[0150] Figure 6 This is the effect of the reduction in the discharge concentration of the pumping station on the water quality of section A during light rain when the gate discharges water;

[0151] Figure 7 This is a diagram showing the effect of the reduction in pump station drainage concentration on the water quality of section A during rainy season when the sluice gate is draining water;

[0152] Figure 8 This is a diagram showing the effect of the reduction in discharge concentration of the pumping station on the water quality of section A during heavy rain when the gate is draining water;

[0153] Fig. 9 This is a diagram showing the impact of the reduction in discharge concentration from the pumping station on the water quality of section A during heavy rains when the sluice gate is used to control discharge.

[0154] Embodiment 2:

[0155] The embodiment of the present invention provides a device for reducing pollutants entering a river and predicting water quality of a river section based on a water environment mathematical model, the device comprising:

[0156] Pollutant determination module: used to determine the predicted pollutants in the study area;

[0157] Calculation module: used to obtain the diversion and drainage flow, sluice pump scheduling and predicted pollutant information discharged by pump stations along the way in the study area, and input the diversion and drainage flow, sluice pump scheduling and predicted pollutant information discharged by pump stations along the way into the river network water environment mathematical model to calculate the hydrodynamic and water quality simulation results;

[0158] Section impact module: used to compare the calculated results with the key assessment sections, water function zones or river water quality standards in the study area to determine the impact of pollutants on the river sections;

[0159] Prediction scheme module: used to set the pump station drainage and pump station drainage water volume under different rainfall conditions in the constructed water environment mathematical model, compare the model operation results with the key assessment sections, water function zones or river water quality standards in the study area, and determine the prediction scheme of the impact of regulating gate drainage and pump station drainage on the water quality of the river section under different rainfall types;

[0160] Output module: It is used to comprehensively simulate the migration and diffusion of pollutants under different rainfall types, different regulating gate drainage and pump station drainage conditions based on the established mathematical model of the river network water environment in the study area, and determine the impact of the predicted pollutants in the study area on the water quality of the river section, that is, the predicted water quality results.

[0161] The device of this embodiment can be used to implement the method described in the first embodiment.

[0162] Embodiment three:

[0163] This embodiment provides a device for reducing pollutants entering a river and predicting water quality of a river section based on a water environment mathematical model, including a processor and a storage medium;

[0164] The storage medium is used to store instructions;

[0165] The processor is used to operate according to the instructions to execute the steps of the method described in embodiment 1.

[0166] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0167] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0168] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0169] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0170] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for reducing pollutants entering a river and predicting water quality of a river section based on a water environment mathematical model, characterized in that: The following steps are involved: Identify predicted pollutants in the study area; Obtain the diversion and drainage flow, sluice pump scheduling and predicted pollutant information discharged by pump stations along the way in the study area, and input the diversion and drainage flow, sluice pump scheduling and predicted pollutant information discharged by pump stations along the way into the river network water environment mathematical model to obtain hydrodynamic and water quality simulation results; Compare the hydrodynamic and water quality simulation results with the key assessment sections in the study area, the water function zones in the study area, or the water quality standards of the river to determine the impact of pollutants on the river section; In the constructed water environment mathematical model, the pump station drainage and pump station drainage water volume under different rainfall conditions are set, and the model operation results are compared with the key assessment sections, water function zones or river water quality standards in the study area to determine the prediction scheme of the impact of regulating gate drainage and pump station drainage on the water quality of the river section under different rainfall types; Based on the established mathematical model of the river network water environment in the study area, the migration and diffusion of pollutants under different rainfall types, different control gate drainage and pump station drainage conditions are fully simulated to determine the impact of the predicted pollutants in the study area on the water quality of the river section, that is, the predicted water quality results; The hydrodynamic model calculation of the river network water environment mathematical model adopts the Saint-Venant equations describing the one-dimensional unsteady flow in the open channel, including the continuity equation and the momentum equation, and supplements the floodplain and lateral inflow. The calculation formula of the model hydrodynamic calculation model is as follows: Where: Q is the flow rate; x is the spatial coordinate along the direction of water flow; b is the storage width, which refers to the total river width including the beach; h is the water level; t is the time coordinate; q is the lateral inflow flow, inflow is positive and outflow is negative; α is the momentum correction coefficient; A is the cross-sectional area of ​​the main channel; g is the gravitational acceleration; C is the Xie Cai coefficient; R is the hydraulic radius; The water quality model calculation of the river network water environment mathematical model adopts a one-dimensional convection diffusion equation, and the calculation formula of the model water quality calculation model is as follows: In the formula: x is the spatial coordinate along the water flow direction; t is the time coordinate; Q is the flow rate; C is the substance concentration; A is the cross-sectional area of ​​the main channel; D is the longitudinal diffusion coefficient; K is the linear attenuation coefficient; C2 is the source-sink concentration; q is the side inflow flow; The discretized form of Q=f(h) at the hydraulic structure of the river network water environment mathematical model is the momentum equation form, that is: The above equation is the discrete form of the energy equation of hydraulic structures, which will replace the momentum equation in the discretized Saint-Venant equations; The flow through hydraulic structures is discretely formatted as follows: Comparing Formula 3 and Formula 4, we can get: β j ＝1 In the formula, α j , β j , γ j , δ j All are intermediate parameters, Q is the flow rate, h represents the gate opening height, and n is the power number; The method for constructing the river network water environment mathematical model includes: Generalize the internal river channels to form a generalized river network with river channels and nodes; The natural river network is merged and generalized, and the river channel is generalized into a horizontal bottom slope and a trapezoidal section. The generalized section is described by the three elements of bottom height, bottom width and side slope. The water quality boundary conditions of the river network water environment mathematical model are set at the inflow of the river in the river network model; The data needed to establish a mathematical model of river network water environment include: water system map of the study area, river topography data, hydraulic structure design parameters and dispatching operation rules, hydrological information data, pump station discharge and pollutant concentration; The method of inputting the diversion and drainage flow, the sluice pump dispatching conditions and the predicted pollutant information discharged by the pumping stations along the way into the river network water environment mathematical model includes: The diversion and drainage flow of the control gate and pump station is input into the mathematical model of river network water environment as the internal boundary conditions. The required data include diversion and drainage flow and time. The sluice pump dispatching situation is input into the river network water environment mathematical model as a controllable hydraulic structure. The required data include the inherent condition parameters of the controllable hydraulic structure and the number, height and time of the sluice opening holes. The inherent condition parameters include the sluice height, width and opening speed. Inputting the predicted pollutant information discharged by the pumping stations along the way into the river network water environment mathematical model in the form of point source pollution, the required data includes the drainage volume and pollutant emission concentration based on the time series; the method of inputting the diversion and drainage flow, the sluice pump scheduling situation and the predicted pollutant information discharged by the pumping stations along the way into the river network water environment mathematical model includes: The diversion and drainage flow of the control gate and pump station is input into the mathematical model of river network water environment as the internal boundary conditions. The required data include diversion and drainage flow and time. The sluice pump dispatching situation is input into the river network water environment mathematical model as a controllable hydraulic structure. The required data include the inherent condition parameters of the controllable hydraulic structure and the number, height and time of the sluice opening holes. The inherent condition parameters include the sluice height, width and opening speed. The predicted pollutant information discharged from the pumping stations along the way is input into the mathematical model of the river network water environment in the form of point source pollution. The required data include the discharge volume and pollutant emission concentration based on time series.

2. The method for reducing pollutants entering a river and predicting water quality of a river section based on a water environment mathematical model according to claim 1 is characterized in that: Methods for determining predicted pollutants for the study area include: Based on the water quality requirements of key river monitoring sections in the study area and the main exceeding-standard factors of the monitoring sections under the current situation, combined with the "Surface Water Environmental Quality Standard GB 3838-2002", conventional water quality influencing pollutants are determined.

3. The method for reducing pollutants entering a river and predicting water quality of a river section based on a water environment mathematical model according to claim 1, characterized in that: The calculated results are compared with the key assessment sections, water function zones or river water quality standards in the study area. Methods for determining the impact of pollutants on river sections include: Calibrate and verify the river roughness in the hydrodynamic calculation model and water quality calculation model in the water environment mathematical model and the predicted pollutant degradation coefficient in the study area; Based on the actual hydrological information, sluice pump scheduling, pump station discharge volume and discharge concentration, and the "Surface Water Environmental Quality Standard GB 3838-2002", the calculated results are compared with the key assessment sections, water functional zones or river water quality standards in the study area to determine the impact of pollutants on river sections.

4. The method for reducing pollutants entering a river and predicting water quality of a river section based on a water environment mathematical model according to claim 1, characterized in that: Methods for determining the prediction scheme of the impact of sluice gate drainage and pump station drainage on river section water quality under different rainfall patterns include: The rainfall level is determined by comprehensively considering the rainfall, the scheduling of sluice pumps in the study area, the drainage volume of the regulating sluice, the drainage volume of the pumping stations along the way based on the time series, and the pollutant emission concentration. The rainfall is divided into 6 levels: Level 1 light rain: rainfall less than 10 mm in 24 hours, Level 2 moderate rain: rainfall 10-25 mm in 24 hours, Level 3 heavy rain: rainfall 25-50 mm in 24 hours, Level 4 torrential rain: rainfall greater than 50 mm in 24 hours.

5. The method for reducing pollutants entering a river and predicting water quality of a river section based on a water environment mathematical model according to claim 1, characterized in that: Methods for determining the extent to which the predicted pollutants in the study area will affect the water quality of the river section include: By inputting the control gate diversion and drainage data, the gate pump opening and closing status data in the study area, the river hydrological information, the pump station discharge and the pollutant concentration into the river network water environment mathematical model, the river network water environment mathematical model automatically runs and calculates the hydrodynamic and water quality simulation results; Based on the water quality simulation results of the model, determine the extent and duration of the impact of pollutants on the river section.

6. A device for reducing pollutants entering a river and predicting water quality of a river section based on a water environment mathematical model, characterized in that: The device comprises: Pollutant determination module: used to determine the predicted pollutants in the study area; Calculation module: used to obtain the diversion and drainage flow, sluice pump scheduling and predicted pollutant information discharged by pump stations along the way in the study area, and input the diversion and drainage flow, sluice pump scheduling and predicted pollutant information discharged by pump stations along the way into the river network water environment mathematical model to calculate the hydrodynamic and water quality simulation results; Section impact module: used to compare the calculated results with the key assessment sections, water function zones or river water quality standards in the study area to determine the impact of pollutants on the river sections; Prediction scheme module: used to set the pump station drainage and pump station drainage water volume under different rainfall conditions in the constructed water environment mathematical model, compare the model operation results with the key assessment sections, water function zones or river water quality standards in the study area, and determine the prediction scheme of the impact of regulating gate drainage and pump station drainage on the water quality of the river section under different rainfall types; Output module: used to comprehensively simulate the migration and diffusion of pollutants under different rainfall types, different control gate drainage and pump station drainage conditions based on the established mathematical model of river network water environment in the study area, and determine the impact of the predicted pollutants in the study area on the water quality of the river section, that is, the predicted water quality results; The hydrodynamic model calculation of the river network water environment mathematical model adopts the Saint-Venant equations describing the one-dimensional unsteady flow in the open channel, including the continuity equation and the momentum equation, and supplements the floodplain and lateral inflow. The calculation formula of the model hydrodynamic calculation model is as follows: Where: Q is the flow rate; x is the spatial coordinate along the direction of water flow; b is the storage width, which refers to the total river width including the beach; h is the water level; t is the time coordinate; q is the lateral inflow flow, inflow is positive and outflow is negative; α is the momentum correction coefficient; A is the cross-sectional area of ​​the main channel; g is the gravitational acceleration; C is the Xie Cai coefficient; R is the hydraulic radius; The water quality model calculation of the river network water environment mathematical model adopts a one-dimensional convection diffusion equation, and the calculation formula of the model water quality calculation model is as follows: In the formula: x is the spatial coordinate along the water flow direction; t is the time coordinate; Q is the flow rate; C is the substance concentration; A is the cross-sectional area of ​​the main channel; D is the longitudinal diffusion coefficient; K is the linear attenuation coefficient; C2 is the source-sink concentration; q is the side inflow flow; The discretized form of Q=f(h) at the hydraulic structure of the river network water environment mathematical model is the momentum equation form, that is: The above equation is the discrete form of the energy equation of hydraulic structures, which will replace the momentum equation in the discretized Saint-Venant equations; The flow through hydraulic structures is discretely formatted as follows: Comparing Formula 3 and Formula 4, we can get: β j ＝1 In the formula, α j , β j , γ j , δ j All are intermediate parameters, Q is the flow rate, h represents the gate opening height, and n is the power number; The method for constructing the river network water environment mathematical model includes: Generalize the internal river channels to form a generalized river network with river channels and nodes; The natural river network is merged and generalized, and the river channel is generalized into a horizontal bottom slope and a trapezoidal section. The generalized section is described by the three elements of bottom height, bottom width and side slope. The water quality boundary conditions of the river network water environment mathematical model are set at the inflow of the river in the river network model; The data needed to establish a mathematical model of river network water environment include: water system map of the study area, river topography data, hydraulic structure design parameters and dispatching operation rules, hydrological information data, pump station discharge and pollutant concentration; The method of inputting the diversion and drainage flow, the sluice pump dispatching conditions and the predicted pollutant information discharged by the pumping stations along the way into the river network water environment mathematical model includes: The diversion and drainage flow of the control gate and pump station is input into the mathematical model of river network water environment as the internal boundary conditions. The required data include diversion and drainage flow and time. The sluice pump dispatching situation is input into the river network water environment mathematical model as a controllable hydraulic structure. The required data include the inherent condition parameters of the controllable hydraulic structure and the number, height and time of the sluice opening holes. The inherent condition parameters include the sluice height, width and opening speed. Inputting the predicted pollutant information discharged by the pumping stations along the way into the river network water environment mathematical model in the form of point source pollution, the required data includes the drainage volume and pollutant emission concentration based on the time series; the method of inputting the diversion and drainage flow, the sluice pump scheduling situation and the predicted pollutant information discharged by the pumping stations along the way into the river network water environment mathematical model includes: The diversion and drainage flow of the control gate and pump station is input into the mathematical model of river network water environment as the internal boundary conditions. The required data include diversion and drainage flow and time. The sluice pump dispatching situation is input into the river network water environment mathematical model as a controllable hydraulic structure. The required data include the inherent condition parameters of the controllable hydraulic structure and the number, height and time of the sluice opening holes. The inherent condition parameters include the sluice height, width and opening speed. The predicted pollutant information discharged from the pumping stations along the way is input into the mathematical model of the river network water environment in the form of point source pollution. The required data include the discharge volume and pollutant emission concentration based on time series.

7. A device for reducing pollutants entering a river and predicting water quality of a river section based on a water environment mathematical model, characterized in that: including processor and storage medium; The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method according to any one of claims 1 to 5.

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