CN113297814A - River lake water quality limit value-based watershed dynamic water environment capacity calculation method and system - Google Patents

Abstract

The invention discloses a river and lake water quality limit-based watershed dynamic water environment capacity calculation method and system, wherein the method comprises the following steps: constructing a basin distributed hydrological model based on basic data, coupling the basin distributed hydrological model with a flow and flow rate conversion model, a pollution load model and a one-dimensional water quality model to obtain a basin distributed water quality model, and calculating the outlet water quality concentration of each confluence unit according to the basin distributed water quality model; constructing a river and lake water quality response model by using the basic data, and calculating a river and lake water quality limit value meeting the standard conditions of lake water quality; and calculating the dynamic water environment capacity of each production confluence unit and the whole watershed according to the outlet water quality concentration of each production confluence unit and the river lake-entering water quality limit value, so that the calculation precision of the water environment capacity of the watershed is improved, and the method is used for fine control of river pollution.

Description

Calculation method and system of dynamic water environment capacity of river basin based on water quality limit of river and lake

technical field

The invention relates to the technical field of water environment in rivers and lakes, in particular to a method and system for calculating the dynamic water environment capacity of a river basin based on water quality limits of rivers and lakes.

Background technique

At present, the requirements of water function zones are mainly considered when calculating the water environment capacity. According to the requirement of “setting rivers by lakes and rivers by sea”, the water quality targets of water function zones may not necessarily meet the water quality control requirements of rivers, lakes and seas for rivers. The reason is that the existing water quality standards are difficult to meet the needs of regional differences. Different regions have different requirements for river water quality. Management according to unified standards is prone to excessively strict or loose water quality. Water quality protection goals, and formulate differentiated river water quality limits as water quality goals for water environment capacity calculations. Secondly, the linear or non-linear relationship between water volume and meteorological conditions is not considered. As a result of the change of water volume with meteorological conditions, without the input of water volume, the calculation results of water environment capacity cannot achieve dynamic changes. At the same time, the impact of interval point sources and non-point sources on the water environment capacity is not considered, the control unit division and the statistical accounting distribution of point sources and non-point sources are not carried out for the river basin where the river is located. Impact. The existing methods for calculating the water environmental capacity of rivers have the defects of low precision and inability to solve and estimate the dynamic water environmental capacity.

SUMMARY OF THE INVENTION

Therefore, the present invention provides a watershed dynamic water environment capacity calculation method and system based on river and lake water quality limits, which overcomes the defects of low precision and inability to solve and estimate the dynamic water environment capacity of the existing river water environment capacity calculation methods.

To achieve the above object, the present invention provides the following technical solutions:

In the first aspect, an embodiment of the present invention provides a method for calculating the dynamic water environment capacity of a river basin based on the water quality limit value of rivers and lakes, including:

Obtain the basic data of the watershed to be calculated, the basic data includes: geospatial data, pollution source data, water quality monitoring data, hydrological data and meteorological data;

According to geospatial data and meteorological data, the basin to be calculated is divided into several production-convergence units, the basin distributed hydrological model is constructed based on the basic data, and the basin distributed hydrological model is calibrated according to the measured flow data, until the basin distributed hydrological model meets the accuracy Require;

Using the preset conversion model, the distributed water quality model of the watershed is coupled with the one-dimensional water quality model to obtain the distributed water quality and water quality model of the watershed. Meet the accuracy requirements, and use the distributed water quantity and water quality model of the basin to calculate the water quality concentration at the outlet of each production and confluence unit;

Use basic data to build a river and lake water quality response model, calibrate the river and lake water quality response model according to the preset river and lake water quality observation data, until the river and lake water quality response model meets the accuracy requirements, and use the river and lake water quality response model to calculate to meet the lake water quality response model. Water quality limits for river inflows to lakes under water quality standard conditions;

According to the water quality concentration at the outlet of each production-convergence unit and the water quality limit of the river entering the lake, the dynamic water environment capacity of each production-convergence unit and the dynamic water environment capacity of the river basin are calculated.

Optionally, the preset conversion model includes: a flow rate conversion model and a pollution load distribution model.

Optionally, a watershed distributed water quantity and quality model is constructed through the DTVGM model.

Optionally, the pollutant degradation amount in the unit includes: the upstream input pollutant degradation amount W _dS , the tributary input pollutant degradation amount W _dZ , the point source pollutant degradation amount W _dP , the non-point source pollutant degradation amount W _dM ,

The amount of pollutant degradation in the unit was calculated by the following formulas:

Among them, K is the rate constant of pollutant degradation, Q _aij is the flow rate of the jth tributary; C _aij is the pollutant concentration of the jth tributary; L _j is the distance from the jth tributary entering the confluence to the end of the river reach; TL is the The total length of the river reach; W _dG is the degradation amount of pollutants at the generalized sewage outlet; L _G is the distance between the generalized sewage outlet and the end of the river reach; u is the average flow velocity of the river.

Optionally, before the step of using the preset conversion model to couple the watershed distributed hydrological model and the one-dimensional water quality model to obtain the watershed distributed water quantity and water quality model, the method further includes:

The point sources and non-point sources of the watershed to be calculated are counted and distributed to each production and sink unit of the watershed distributed water volume model.

Optionally, the process of using basic data to construct a water quality response model for rivers and lakes includes: selecting a corresponding model according to the requirements of the simulation indicators, and setting global parameters, local parameters and tributary parameters of the model to build a water quality response model for rivers and lakes; wherein ,

Global parameters include: basin-wide rainfall, evaporation, water level changes, and atmospheric external loads;

Local parameters include: the water surface area of the lake area, the average depth of the lake area, the depth of the mixed layer, the non-algal turbidity and the average water quality of the lake area;

The tributary parameters include: the basin area of the tributaries entering the lake, the flow into the lake, and the water quality concentration in the lake.

Optionally, the dynamic water environment capacity of each generation and confluence unit is calculated by the following formula:

where K is the rate constant of pollutant degradation and _Csi is the water quality limit.

In a second aspect, an embodiment of the present invention provides a watershed dynamic water environment capacity calculation system based on river and lake water quality limits, including:

a data acquisition module for acquiring basic data of the watershed to be calculated, the basic data including: geospatial data, pollution source data, water quality monitoring data, hydrological data and meteorological data;

The watershed distributed hydrological model building module is used to divide the watershed to be calculated into several production-convergence units according to geospatial data and meteorological data, build a watershed distributed hydrological model based on basic data, and carry out the calculation of the watershed distributed hydrological model according to the measured flow data. until the distributed hydrological model of the basin meets the accuracy requirements;

The watershed distributed water quantity and quality model building module is used to use the preset conversion model to couple the watershed distributed hydrological model with the one-dimensional water quality model to obtain the watershed distributed water quantity and quality model. Carry out calibration until the watershed distributed water quantity and quality model meets the accuracy requirements, and use the watershed distributed water quantity and quality model to calculate the outlet water quality concentration of each production and confluence unit;

The river and lake water quality response model building module is used to construct a river and lake water quality response model using basic data. The water quality response model of the river and lake calculates the water quality limit of the river entering the lake that meets the standard conditions of the lake water quality;

The dynamic water environment capacity calculation module is used to calculate the dynamic water environment capacity of each production and confluence unit and the dynamic water environment capacity of the river basin according to the water quality concentration at the outlet of each production and confluence unit and the water quality limit of the river entering the lake.

In a third aspect, an embodiment of the present invention provides a terminal, including: at least one processor, and a memory communicatively connected to the at least one processor, wherein the memory stores a program executable by the at least one processor. The instruction is executed by the at least one processor, so that the at least one processor executes the method for calculating the dynamic water environment capacity of a river basin based on the water quality limit of the river and lake according to the first aspect of the embodiment of the present invention.

In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, where the computer-readable storage medium stores computer instructions, and the computer instructions are used to cause the computer to execute the first aspect of the embodiment of the present invention. Calculation method of dynamic water environment capacity of river basin based on water quality limit of river and lake.

The technical scheme of the present invention has the following advantages:

1. The method and system for calculating the dynamic water environment capacity of a river basin based on the water quality limit of rivers and lakes provided by the present invention realizes the dynamic allocation of pollution sources according to the time dimension through the pollution load allocation model. At the same time, through the flow rate conversion model, the distributed water quantity model of the basin is coupled with the one-dimensional water quality model, and the water quantity and water quality are coupled to complete the construction of the basin distributed water quantity and quality model.

2. The method and system for calculating the dynamic water environment capacity of the river basin based on the water quality limit of rivers and lakes provided by the present invention, because the measured water quality data and the preset water quality observation data of rivers and lakes are changed in real time, synchronously obtain the different rainfall of each production and confluence unit. Under the condition of water quality, water quality and water environment capacity, the dynamic calculation of the production and confluence unit and the water environment capacity of the basin can be realized.

3. The method and system for calculating the dynamic water environment capacity of a river basin based on the water quality limit of rivers and lakes provided by the present invention, wherein the result obtained according to the water quality response model of rivers and lakes is the water quality limit of rivers entering the lake, which is different from the existing surface water quality According to the requirements of the standard, different regions have different requirements for the water quality of rivers entering the lake. According to the water quality response model of rivers and lakes, the water quality limit of rivers in different regions can be determined, which is different from the previous calculation of water environment capacity based on water quality goals and water quality standards.

Description of drawings

In order to illustrate the specific embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the specific embodiments or the prior art. Obviously, the accompanying drawings in the following description The drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

Fig. 1 is a flow chart of a specific example of a method for calculating the dynamic water environment capacity of a river basin based on a river and lake water quality limit value provided by an embodiment of the present invention;

FIG. 2 is a schematic diagram of the water quantity and water quality balance of a water body of a production-convergence unit according to an embodiment of the present invention;

3 is a schematic diagram of the Bathtub model construction data of a method for calculating the dynamic water environment capacity of a river basin based on a river and lake water quality limit value provided by an embodiment of the present invention;

FIG. 4 is a schematic diagram of monthly runoff at the inflow hydrological control station (S1, S2, S3, S4, S5) provided by an embodiment of the present invention;

Figures 5(a)-5(e) are runoff process diagrams of monthly runoff observation values and simulated values of 5 tributaries provided by the embodiment of the present invention;

Figures 6(a)-6(h) are comparison diagrams of observed values and simulated values of TP concentration at regular and monthly verification periods for some water quality control sites provided by the embodiment of the present invention;

7 is a schematic diagram of a curve of a lake area TP concentration simulation process provided by an embodiment of the present invention;

Figures 8(a)-8(e) are schematic diagrams of dynamic change curves of TP water environmental capacity in each basin within a year provided by an embodiment of the present invention;

Fig. 9 is the module composition diagram of a kind of basin dynamic water environment capacity calculation system based on river and lake water quality limit value provided by the embodiment of the present invention;

FIG. 10 is a composition diagram of a specific example of a terminal according to an embodiment of the present invention.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation or a specific orientation. construction and operation, and therefore should not be construed as limiting the invention. Furthermore, the terms "first", "second", and "third" are used for descriptive purposes only and should not be construed to indicate or imply relative importance.

In the description of the present invention, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense, unless otherwise expressly specified and limited, for example, it may be a fixed connection or a detachable connection connection, or integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal connection of two components, which can be a wireless connection or a wired connection connect. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific situations.

In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

Example 1

A method for calculating the dynamic water environment capacity of a river basin based on the water quality limit of rivers and lakes provided by an embodiment of the present invention, as shown in FIG. 1 , includes the following steps:

Step S1: Acquire basic data of the watershed to be calculated, the basic data includes: geospatial data, pollution source data, water quality monitoring data, hydrological data and meteorological data.

In this embodiment of the present invention, basic data within a preset time period is acquired, and the preset time period is selected according to actual calculations, which is not limited herein. The obtained basic data is shown in the following table, which is only an example, not limited to this, and the corresponding basic data is obtained according to actual needs in practical applications.

Step S2: According to the geospatial data and meteorological data, divide the basin to be calculated into several production-convergence units, build a basin distributed hydrological model based on the basic data, and calibrate the basin distributed hydrological model according to the measured flow data, until the basin distributed hydrological model is reached. The model meets the accuracy requirements.

In the embodiment of the present invention, based on spatial data such as digital elevation model (Digital Elevation Model, DEM), hydrological site, water quality site, land use and soil type of the watershed research area to be calculated, this is only an example, not limited to this. In practical applications, the corresponding spatial data is selected according to actual needs. The GIS platform is used to obtain spatial variation information such as unit slope, flow direction, water flow path, water system distribution, watershed and runoff boundary, land cover, and hydrometeorological input variables on the land surface of the basin. The spatial variation information is not limited here. At the same time, it is necessary to ensure that each production and confluence unit contains at least 1-2 water quality stations for water quality boundary control, and the superposition technology is used to establish the corresponding relationship between the administrative area - the sewage outlet into the river - the land confluence area; combine the hydrological production and confluence characteristics of natural river basins With the natural characteristics and spatial differences of the water ecosystem, the divided runoff and runoff units are reasonably analyzed.

In the embodiment of the present invention, the watershed distributed hydrological model is an existing geographic data model. The watershed distributed hydrological model constructed based on basic data can fully utilize the spatial distribution information of rainfall, and the spatial distribution of the model parameters can Reflect the spatial changes of the natural conditions of the underlying surface.

In the embodiment of the present invention, the spatialized land surface digital information and hydrological information of the watershed are used as the framework of the distributed hydrological model of the watershed, the rainfall data in the study area are input, and the simulation of the watershed runoff and confluence is performed to obtain the simulated watershed outlet flow, Comparing, analyzing and evaluating with the measured runoff value of the corresponding hydrological station, selecting Nash efficiency coefficient NSE, certainty coefficient R2 and relative error Bias as the evaluation indicators of the model, by comparing the simulated value and the measured value, until the distributed hydrological model of the basin meets the accuracy requirements , select the corresponding model parameters, this is only an example, not limited to this, in practical applications, select the corresponding evaluation indicators according to the actual needs. The evaluation indicators are calculated by the following formulas:

Nash efficiency coefficient:

Certainty factor:

Relative error:

为径流平均观测值。Where: n is the length of the runoff sequence, Qi _,sim and Qi _,obs are the simulated and observed runoff values at the i-th time, respectively,

is the average observed value of runoff.

Step S3: Use the preset conversion model to couple the watershed distributed hydrological model and the one-dimensional water quality model to obtain a watershed distributed water quantity and quality model, and calibrate the watershed distributed water quantity and quality model according to the measured water quality data until the watershed distributed water quality model is obtained. The water quantity and quality model meets the accuracy requirements, and the water quality concentration at the outlet of each production and confluence unit is calculated by using the distributed water quantity and quality model of the basin.

In the embodiment of the present invention, before the step of obtaining the distributed water quantity and water quality model of the watershed, the step of coupling the distributed hydrological model of the watershed with the one-dimensional water quality model by using the preset conversion model further includes: the point source and the water environment of the watershed to be calculated. The non-point sources are counted and distributed to each production-convergence unit of the watershed distributed hydrological model, and the control unit is divided into point sources and non-point sources for the river basin. In the embodiment of the present invention, the pollution source accounting results are spatially allocated according to the production and confluence units or administrative regions, and at the same time, the impact of the temporal and spatial distribution characteristics of the pollution sources on the water quality and water quality of the basin is reflected. Pollution load distribution is used to allocate pollution sources on a time scale. From the perspective of pollution control, it is possible to carry out refined time and space control of pollution sources from the time dimension.

In the embodiment of the present invention, the one-dimensional water quality model refers to the water quality model established by the river under steady-state conditions, and the steady-state condition refers to the cross-sectional area of the river after the pollutants enter the water body under steady discharge conditions of a river with a uniform reach. , flow rate, flow, and the input of pollutants do not change with time. After the sewage is discharged into the river, the horizontal mixing length is much smaller than the calculated flow length of the river. The pollutants can basically be mixed evenly in a short time, and the vertical and horizontal pollutant concentration gradients can be ignored. Only the concentration changes along the river are considered. Therefore, the present invention adopts a one-dimensional water quality model as the basis of the coupled model. The one-dimensional water quality model is represented by the following formula:

In the formula, C ₀ is the concentration of pollutants at the initial section of the calculation (mg/L); v is the river velocity (m/s). where K ₁ is the rate constant of pollutant degradation, and x is the distance (m) between the calculated section and the starting section.

In the embodiment of the present invention, the watershed distributed water quantity and quality model is based on the watershed distributed hydrological model and the one-dimensional water quality model, and the watershed distributed water quantity and quality model is constructed through the DTVGM model. The output of the hydrological model is used as the input boundary of the water quality model, so the key to realizing the coupling between the two lies in the conversion of model parameters. The parameters output by the distributed hydrological model of the watershed are the water quantity and quality at the outlet of each production and confluence unit and the outlet of the watershed. The boundary condition that the one-dimensional water quality model needs to input is the flow rate. In the absence of the measured data of the flow rate, the present invention realizes the coupling of the two. , using the preset conversion models: flow rate conversion model, pollution load distribution model, this is only an example, not limited to this, select the appropriate conversion model according to the actual situation in practical applications. By converting the water quantity result of the distributed water quantity and water quality model of the watershed into the flow velocity boundary required by the one-dimensional water quality model, the embodiment of the present invention can provide a simple and effective solution for the coupling of models of the same type.

In a specific embodiment, since the distributed time-varying gain model (Distributed time-varying gain model, DTVGM model) model cannot output the flow velocity, it is necessary to transform the output flow data. In the process of coupling construction, the point source and the non-point source are allocated in the time dimension by constructing the pollution load distribution model, so as to realize the dynamic change of the pollution load.

The flow velocity is converted by the calibration formula method, and the flow velocity relationship of each river reach is linearly fitted according to the historical observation data of the hydrological station, and the flow velocity conversion model is obtained. Calculate the average flow velocity u of the river and the average water depth H of the river section by the following formulas:

u= ^aQb

H= ^αQβ

Among them, Q is the river section flow (m ³ /s); a, b, α and β are empirical parameters for determining the relationship between flow velocity and flow rate and the relationship between water level and flow velocity, which can be determined according to historical data.

Calculate the water-passing cross-sectional area A _c and the average water surface width B by the following formulas:

In the embodiment of the present invention, due to the requirement on the input boundary of the distributed water quantity and quality model of the watershed, the calculated pollution load needs to be distributed according to the time dimension. For example, the total phosphorus (TP) pollution load of pollutants calculated in a certain year is W, which needs to be selected according to the time scale (monthly scale or daily scale, etc.) Corresponding time scale) to assign W to each month or day, correspondingly, W will be divided into 12 values or 365 values according to certain conditions, and input into the model in the form of time series as boundary conditions.

In a specific embodiment, a pollution load monthly distribution model is constructed in combination with the actual situation, and the monthly pollution load distribution is calculated by the following formula:

L _m,i =(Q _s,j +Q _g,j )×L _a,i /(Q _s,a +Q _g,a )

Among them, L _m,i is the monthly load of pollution source i; L _a,i is the annual load of pollution source i; L _g,j is the flow of groundwater into the river in the jth month; Q _s , _j is the inflow of surface runoff in the jth month The flow of the river; Q _s,a is the annual surface runoff; Q _g , _a is the annual underground runoff.

The invention abandons the traditional calculation of river water environment capacity with the water function area as the basic unit, adopts the sub-basins divided by the distributed hydrological model of the watershed as the basic calculation unit, and couples the one-dimensional water quality model to construct a distributed water quantity and water quality model. As shown in Figure 2, for a water body i of a catchment unit, the process of water quality and water quality balance:

The equation of the hydrological balance of the production-confluence unit:

ΔV _i =Q _i-1 +R _i +Q _ai -q _i -Q _i

The equation of the water quality concentration balance in the production-confluence unit:

Among them, ΔV _i is the change of water storage volume of unit i in the period; Qi _-1 and Qi are the inflow and outflow water volume of the unit, respectively; q _i is the water consumption of human beings; R _i is the interval water production of unit _i ; Q _ai is the inflow of tributaries. _Vi is the water storage capacity of unit i; C _Ri is the pollutant concentration in the interval runoff (closely related to non-point source pollution); C _ai is the tributary water quality concentration; C _i-1 and C _i are the unit input and output, respectively C _qi is the concentration of pollutants in human water; W _p is the sum of the pollution load of the unit i point source; W _d is the degradation amount of pollutants in the unit.

In the embodiment of the present invention, W _d is the self-purification capacity of the water body in the production-convergence unit, including: the degradation amount of upstream input pollutants W _dS ; the degradation amount of tributary input pollutants W _dZ ; the degradation amount of point source pollutants W _dP ; The degradation amount W _dM is only taken as an example, not limited to this. In practical applications, the corresponding data on the degradation amount of pollutants in the unit is selected according to actual needs. The calculation of the model is more accurate. The amount of pollutant degradation in the unit was calculated by the following formulas:

Among them, n is the total number of tributaries; Q _aij is the flow of the jth tributary; C _aij is the pollutant concentration of the jth tributary; L _j is the distance from the jth tributary to the end of the river reach; TL is the river reach total length.

The degradation amount of point source and non-point source pollutants is related to the amount of pollutants entering the river and the method of pollutant discharge. It can be considered to be simplified as a generalized sewage outlet discharge form. Therefore:

Among them, W _dG is the degradation amount of pollutants in the generalized sewage outlet; L _G is the distance between the generalized sewage outlet and the end of the river reach. The specific location of the generalized sewage outlet can be determined according to the analysis of point source and non-point source pollutants entering the river and the characteristics of sewage discharge. The two extreme cases are the first section discharge and the section discharge. The former is L _G =TL, and the degradation amount of pollutants is the largest; the latter is L _G =0, and the degradation amount is the smallest.

In the embodiment of the present invention, based on the distributed water quantity and water quality model of the watershed, the water quality at the outlet of the watershed is simulated and calculated, and is compared and evaluated with the measured value of the corresponding water quality station, and the correlation coefficient CC and the average relative error MRE are selected as the model evaluation indicators. The applicability of the model is judged by using the simulated and measured values of water quality, and the evaluation index is calculated by the following formula:

为水质观测值的平均值；

为水质模拟值的平均值；n为样本个数。In the formula, C _i,sim is the simulated water quality value at the ith moment; C _i,obs is the water quality observation value at the ith moment;

is the average value of water quality observations;

is the average value of water quality simulation values; n is the number of samples.

Step S4: constructing a river and lake water quality response model using basic data, and calibrating the river and lake water quality response model according to the preset river and lake water quality observation data until the river and lake water quality response model meets the accuracy requirements, and using the river and lake water quality response model Calculate the water quality limits for river inflows that meet the lake water quality standard conditions.

In a specific embodiment, the water quality response model of rivers and lakes is mainly constructed with the help of the Bathtub simulation software. As shown in Figure 3, the data required for the construction of the Bathtub model includes: global parameters, local parameters and tributary parameters. As a limit, in practical applications, select the corresponding data according to the actual needs.

The global parameters are the data of the watershed, including: rainfall, evaporation, water level changes, and atmospheric external load, etc. This is only an example, not limited to this, and the corresponding global parameters are selected according to actual needs in practical applications.

The local parameters are the water parameters of the lake area, including: the surface area of the lake area, the average depth of the lake area, the depth of the mixed layer, the non-algal turbidity, and the average water quality of the lake area. This is just an example, not limited to this, and is selected according to actual needs in practical applications. the corresponding local parameters.

The tributary parameters are the data of the tributaries entering the lake, including: the watershed area of the tributaries entering the lake, the flow rate and the water quality concentration. .

In a specific embodiment, the steps of building a water quality response model for rivers and lakes include five parts: model selection, global parameter setting, local parameter setting, tributary parameter setting, and model calibration verification, as follows:

(1) Model selection: According to the requirements of the simulation indicators, determine the simulation time, and select the corresponding model in the Model Selector interface, such as: P model, N model, Chl-a model and transparency model, etc. This is only an example, not a model This is limited, in practical applications, select the corresponding model according to the actual needs. For example, the calculation formula of the P model is divided into a first-order model and a second-order model. The specific calculation formula is as follows:

First order model:

Second order model:

Among them: P is the total phosphorus output concentration of the lake (mg/m ³ ), P _i is the total phosphorus concentration of the river entering the lake (mg/m ³ ), k is the correction factor, A ₁ is the intercept of the phosphorus sedimentation term, and T is the hydraulic retention time (year).

(2) Global parameter settings

The global parameter setting interface needs to define the simulation time (average period). When the average period is one year, enter 1. When the average period is half a year, enter 0.5. The parameters of rainfall, evaporation, average water storage depth and atmospheric load (total phosphorus, total nitrogen, etc.) are only examples, not limited to this. In practical applications, set corresponding global parameters according to actual needs.

(3) Local parameter setting

The setting of local parameters mainly considers whether the lake body is partitioned or not. Without partitioning, the entire lake area is a segment. Geospatial information such as the surface area, average depth, characteristic length, and mixed layer depth of the entire lake area needs to be input. Input parameters such as the average concentration of water quality and correction factor in the lake area. This is only an example, not limited to this. In practical applications, set the corresponding local parameters according to actual needs.

(4) tributary parameter setting

The parameter setting of the tributaries mainly considers the information of the tributaries entering the lake. The information to be input includes the catchment area, flow, and TP concentration of the tributaries, etc. This is only an example, not limited to this, in practical applications according to the actual situation The corresponding tributary parameters need to be set.

(5) Model calibration verification

The water quality of different concentrations of tributaries is input into the lake area, and the water quality concentration of the lake area is calculated based on the model, and the comparison analysis and evaluation are carried out with the pre-set river and lake water quality observation data, and the correlation coefficient CC and the average relative error MRE are selected as the model evaluation indicators. Standard data, until the river and lake water quality response model meets the accuracy requirements, the preset river and lake water quality observation data are selected according to actual needs, and there is no limit here. And use the river and lake water quality response model to calculate the river inflow water quality limit that meets the lake water quality standard conditions.

In the embodiment of the present invention, in the process of determining the water quality limit value of the tributaries entering the lake, the water quality standard of the lake is mainly used as the target, the gradient water quality concentration of the tributaries is set, and the lake water quality concentration under different scenarios is calculated based on the constructed Bathtub model and the backward calculation The water quality concentration of the tributaries is analyzed, and the water quality limits of the tributaries entering the lake under the conditions of various water quality standards of the lake are analyzed. The following table shows the input conditions of the tributaries entering the lake and the results of water quality concentration in the lake area. When the goal is to meet the water quality of the lake, input the tributary setting conditions (C ₁ to C ₅ ) into the model, calculate the water quality concentration (C ₁₁ to C ₅₁ ) of the lake, determine the corresponding water quality category, and compare it with the lake water quality standard to analyze whether The water quality of the lake can meet the standard. If the standard is met, the input concentration of the tributary is determined as the water quality limit of the tributary.

Step S5: Calculate the dynamic water environment capacity of each production-convergence unit and the dynamic water environment capacity of the river basin according to the water quality concentration at the outlet of each production-convergence unit and the water quality limit of the river entering the lake.

In the embodiment of the present invention, the dynamic water environment capacity model takes the production-convergence unit as the basic calculation unit, and calculates the dynamic water environment capacity of the basin according to the dynamic water environment capacity of each production-convergence unit. The dynamic water environment capacity can be estimated through the distributed water quantity and water quality coupling model, in which the hydrological elements such as the upper section inflow, the interval runoff, the tributary inflow and the sink, and the lower section outflow of the calculation unit can be obtained through the basin distributed hydrological model. The flow velocity can be obtained indirectly by using the flow velocity conversion relationship. The water quality concentration of the upper section and the tributary inflow concentration can be obtained through the coupled model of water quality and water quality. The water quality target of the lower section and the water quality target of artificial water intake are determined by the river water quality limit calculated by the Bathtub model. Therefore, the dynamic water environment capacity accounting of the basin mainly uses the river water quality limit calculated by the Bathtub model and the water quantity and quality obtained by the distributed water quality and water quality coupling model as the boundary conditions, and the rainfall data as the driving force to calculate the dynamic water environment capacity, including interannual changes. and year-to-year changes.

According to the one-dimensional water quality model balance equation, the water environment capacity can be expressed as:

W _i =W _p +R _i C _Ri

=C _si (ΔV _i +Q _i )-Q _i-1 C _i-1 -Q _ai C _ai +C _qi q _i +W _d

=(C _si -C _i-1 )Q _i-1 +C _si R _i +(C _si -C _ai )Q _ai +(C _qi -C _si )q _i +W _d

Substituting the pollutant degradation amount W _d in the calculation unit estimated based on the one-dimensional water quality model into the formula above, the dynamic water environment capacity of each production and confluence unit can be expressed as:

where K is the rate constant of pollutant degradation and _Csi is the water quality limit.

In a specific embodiment, taking a watershed in southern China as an example, and taking the typical pollutant total phosphorus (TP) as an indicator, the dynamic capacity calculation of the water environment of the watershed's dynamic TP is carried out.

(1) Basic data collection and processing

For a certain watershed, the collected data includes geospatial data such as water system distribution, spatial distribution of pollution sources, spatial distribution of meteorological stations, spatial distribution of hydrology and water quality stations, land use, DEM, lake area and characteristic length, and pollution source data such as point sources and point source loads. , water quality monitoring data such as rivers and lakes, hydrological data such as river flow and water level, and meteorological data such as rainfall evaporation, with a time span of 2009-2018.

(2) Construction of the distributed hydrological model of the watershed

1. Division of production and confluence units

According to the basic geographic information data such as the water system, administrative division, land use, DEM, hydrological site, water quality control section of a certain basin, and based on the ArcGIS 10.2 platform, a total of 86 calculation units of production and confluence are obtained, ensuring that each calculation unit has 1 - 2 water quality control sites control water quality boundaries. When dividing the calculation unit, it comprehensively analyzes the characteristics of hydrological production and confluence of natural watersheds and the spatial differences of water ecosystems, and considers the natural characteristics of the watersheds of ecosystems. At the same time, it can support overlapping administrative divisions for double-scale conversion analysis of watersheds and administrative regions. , which can be used as the basic calculation unit of TP water environment capacity in a certain watershed.

2. Model calibration verification

According to the collected data of a certain watershed, with the rainfall data of a certain watershed from 2009 to 2018, as shown in Figure 4, a hydrological simulation was carried out on the monthly runoff of the main inflow hydrological control stations (S1, S2, S3, S4, S5), of which 2010-2015 The year is the regular period, and 2016-2018 is the verification period. Figures 5(a)-5(e) are the runoff process diagrams of the measured and simulated monthly runoff values of the five tributaries, respectively, at regular (2010-2015) and verification (2016-2018) monthly runoff rates.

Based on the judgment and evaluation indicators of the simulation effect such as NSE, R2 and Bias, it can be seen that the simulation results of the distributed water volume model in the basin meet the requirements of runoff simulation and show good accuracy, indicating that the model can simulate the natural distribution of water resources in a certain basin, which is Lay the foundation for further water quality simulation in a certain watershed and TP water environmental capacity accounting.

(3) Coupling model of distributed water quantity and water quality in the basin

The present invention uses the monthly total phosphorus concentration data of a main water quality control station in a certain watershed to carry out water quality simulation of the tributaries entering the lake, and selects 2015-2017 for simulation, wherein 2015-2016 is the regular period, and 2017 is the verification period. According to the calibration verification index calculated by the formula, the results are shown in the following table. Figure 6(a)-(h) shows the comparison between the measured and simulated values of TP concentration in the regular (2015-2016) and verification period (2017) months of some water quality control sites.

Comprehensively considering the evaluation results of the model, the water quality simulation results of the distributed water quantity and water quality coupling model are good, and the errors in most monitoring sections are less than 20%, indicating that the model is suitable for the water quality simulation of a certain river basin, and lays a foundation for the further development of the water environment capacity accounting of a certain river basin. Base.

(4) Response model of river and lake water quality

(1) Model selection

According to the requirements for TP management and control in a certain watershed, select the phosphorus second-order model on the Model Selector interface. The model construction time is from April to September every year from 2014 to 2018.

(2) Global parameter settings

Since the construction time of the river-lake response relationship model is every month, the average period is set to 1/12, which is 0.083; the average rainfall, evaporation, and average water storage depth in different months are input according to the actual situation.

(3) Local parameter setting

The water quality response model of the river and lake of the present invention does not consider the division of the lake body, and counts the physical properties of the lake body according to different months, including the surface area, average depth, characteristic length, mixed layer depth, TP average concentration of the lake area and correction of the lake area. Factors, etc., are input into the model according to the actual situation. where the correction factor is used for model calibration.

(4) tributary parameter setting

The tributary input information includes tributary catchment area, flow rate, and tributary TP concentration.

(5) Model calibration verification

The water quality of the tributaries with different TP concentrations was input into the lake area, and the TP concentration in the lake area was calculated based on the model, and the TP measured values of the corresponding monitoring sections in the lake area were compared, analyzed and evaluated, and the correlation coefficient CC and the average relative error MRE were selected as the model evaluation indicators. value and measured value to judge the applicability of the model. The model evaluation index correlation coefficient CC and the average relative error MRE are 0.99 and 0.004, respectively. The simulation process curve is shown in Figure 7. The R2 values of the regular period and the verification period are 0.6772 and 0.7848, respectively. The simulation results of the river and lake water quality response model are good, indicating that the The model is suitable for TP simulation of rivers and lakes in a certain watershed, and lays the foundation for carrying out TP water environment capacity accounting in a certain watershed.

(5) River TP limit

In the process of determining the TP limit value of the tributaries entering the lake, it mainly includes three steps. The first is that the tributaries entering the lake implement the "Surface Water Environmental Quality Standard" (GB3838-2002) river TP standard. Environmental Quality Standard (GB3838-2002) lake TP standard, the third is to set the lake TP standard as the goal, set the gradient TP concentration of the tributaries, and calculate the lake TP concentration and backward tributaries under different scenarios based on the constructed river and lake water quality response model TP concentration, analyze the TP limit of the tributaries entering the lake under various standard conditions of the lake.

(3) Tributary input gradient TP concentration

When the goal of lake TP compliance is set, the tributary setting conditions are input into the model, the TP concentration of the lake is calculated, the corresponding water quality category is determined, and compared with the lake TP standard, it is analyzed whether the lake TP can reach the standard. is the tributary TP limit. The input conditions and results are shown in the table below. When the TP concentration of lakes takes the standard limit of class I-V lakes in the "Surface Water Environmental Quality Standard" (GB3838-2002), the trial calculation limit of TP concentration in the rivers entering the lake is 0.02. ~0.4mg/L, between the lake and river control limits. When the TP concentration of the lake is taken as the standard limit value of class III (0.05mg/L), the calculated TP concentration control limit of the river entering the lake is 0.075mg/L, which is equivalent to the water quality of class II of the river.

(6) Dynamic TP water environment capacity of the watershed

(1) Hydrological frequency analysis and rainfall distribution

The daily precipitation data of each rainfall station in a certain watershed is analyzed, and the annual precipitation data is obtained by statistics. The frequency analysis is carried out with the commonly used Pearson III curve as the theoretical frequency curve, taking 10%, 25%, 50%, 75%, and 90% respectively. Guaranteed rate rainfall is used as the annual rainfall of extra-rich, high-water, medium-water, low-water and extra-dry water, and precipitation distribution is carried out for the precipitation with different guarantee rates. After entering the distributed water quality model of the basin, the conditions of different guarantee rates are obtained. The process of sewage quantity and water quality, and then calculate the water environment capacity.

(2) Dynamic TP water environment capacity accounting

Based on the water quantity and quality process calculated by the distributed water quantity and quality coupled model and the river TP limit (0.075mg/l) calculated by the river and lake water quality response model, the TP water environment capacity of the basin is calculated, and the calculation results include the basin under different hydrological years. Dynamic water environment capacity and annual watershed dynamic water environment capacity. The calculation results of the dynamic water environmental capacity of the watershed under different hydrological years are shown in the following table, and the annual dynamic change curve of the TP water environmental capacity of each watershed is shown in Figures 8(a)-8(e).

In the method for calculating the dynamic water environment capacity of a river basin based on the water quality limit of rivers and lakes provided in the embodiment of the present invention, the dynamic distribution of pollution sources according to the time dimension is realized through the pollution load distribution model. At the same time, the distributed water volume model of the basin is coupled with the one-dimensional water quality model through the flow rate conversion model, and the water volume and water quality are coupled. Through the measured flow velocity data, the coupling of water quality and water quality models in the basin is completed. Since the measured water quality data and the preset water quality observation data of rivers and lakes change in real time, the water quality, water quality and water environment capacity of each production-convergence unit under different rainfall conditions are obtained simultaneously, so as to realize the dynamic calculation of the production-convergence unit and the water environment capacity of the basin. The result obtained according to the river and lake water quality response model is the water quality limit of the river entering the lake, which is different from the requirements of the existing surface water quality standards. Different regions have different requirements for the water quality of the river entering the lake. The determination of water quality limits for rivers in different regions is different from the previous calculation of water environment capacity based on water quality targets and water quality standards. The calculation accuracy of the water environment capacity of the basin is improved, and it is used for the refined management and control of river pollution.

Example 2

The embodiment of the present invention provides a watershed dynamic water environment capacity calculation system based on river and lake water quality limits, as shown in FIG. 9 , including:

The data acquisition module 1 is used to acquire the basic data of the preset time of the water environment of the river basin to be calculated, the basic data includes: geospatial data, pollution source data, water quality monitoring data, hydrological data and meteorological data; The method described in step S1 is not repeated here.

The watershed distributed hydrological model building module 2 is used to divide the water environment of the watershed to be calculated into several production and confluence units according to geospatial data and meteorological data, build a watershed distributed hydrological model based on basic data, and analyze the watershed distributed hydrology based on the measured flow data. The model is calibrated until the watershed distributed hydrological model meets the accuracy requirements; this module executes the method described in step S2 in Embodiment 1, which will not be repeated here.

The watershed distributed water quantity and quality model building module 3 is used to couple the watershed distributed hydrological model with the one-dimensional water quality model by using the preset conversion model to obtain the watershed distributed water quantity and quality model, and based on the measured water quality data of the watershed distributed water quality and quality The model is calibrated until the watershed distributed water quantity and quality model meets the accuracy requirements, and the watershed distributed water quantity and quality model is used to calculate the water quality concentration at the outlet of each production and confluence unit; this module executes the method described in step S3 in Embodiment 1, It is not repeated here.

The river and lake water quality response model building module 4 is used to construct a river and lake water quality response model by using basic data, and calibrate the river and lake water quality response model according to the preset river and lake water quality observation data until the river and lake water quality response model meets the accuracy requirements, and The river and lake water quality response model is used to calculate the river inflow water quality limit that meets the lake water quality standard conditions; this module executes the method described in step S4 in Embodiment 1, and details are not repeated here.

The dynamic water environment capacity calculation module 5 is used to calculate the dynamic water environment capacity of each production and confluence unit and the dynamic water environment capacity of the river basin according to the water quality concentration at the outlet of each production and confluence unit and the water quality limit of the river entering the lake; this module executes Embodiment 1 The method described in step S5 in the above will not be repeated here.

The embodiment of the present invention provides a system for calculating the dynamic water environment capacity of a river basin based on the water quality limits of rivers and lakes. Based on basic data, a distributed hydrological model of the basin is constructed. The distributed water quantity and quality model of the basin is obtained by coupling the one-dimensional hydrological model with the one-dimensional water quality model. According to the distributed water quantity and quality model of the basin, the water quality concentration at the outlet of each production and confluence unit is calculated; the basic data is used to construct the water quality response model of rivers and lakes, and the water quality standards of the lakes are preset according to the water quality standards of the rivers and lakes. The data is used to calibrate the river and lake water quality response model, and the river and lake water quality response model is used to calculate the river inflow water quality limit that meets the lake water quality standard conditions; Calculate the dynamic water environment capacity of each production-convergence unit and watershed, improve the accuracy of river water environment capacity calculation, and can estimate the dynamic water environment capacity.

Example 3

An embodiment of the present invention provides a terminal, as shown in FIG. 10 , including: at least one processor 401 , such as a CPU (Central Processing Unit, central processing unit), at least one communication interface 403 , memory 404 , and at least one communication bus 402 . Among them, the communication bus 402 is used to realize the connection and communication between these components. The communication interface 403 may include a display screen (Display) and a keyboard (Keyboard), and the optional communication interface 403 may also include a standard wired interface and a wireless interface. The memory 404 may be a high-speed RAM memory (Random Access Memory, volatile random access memory), or may be a non-volatile memory (non-volatile memory), such as at least one disk memory. The memory 404 can optionally also be at least one storage device located away from the aforementioned processor 401 . The processor 401 may execute the method for calculating the dynamic water environment capacity of the river basin based on the water quality limit of the river and lake in Embodiment 1. A set of program codes are stored in the memory 404, and the processor 401 calls the program codes stored in the memory 404 for executing the method for calculating the dynamic water environment capacity of the river basin based on the water quality limit of the river and lake in Embodiment 1. The communication bus 402 may be a peripheral component interconnect (PCI for short) bus or an extended industry standard architecture (Extended industry standard architecture, EISA for short) bus or the like. The communication bus 402 can be divided into an address bus, a data bus, a control bus, and the like. For ease of representation, only one line is shown in FIG. 10, but it does not mean that there is only one bus or one type of bus. The memory 404 may include volatile memory (English: volatile memory), such as random-access memory (English: random-access memory, abbreviation: RAM); the memory may also include non-volatile memory (English: non-volatile memory) memory), such as flash memory (English: flash memory), hard disk (English: harddisk drive, abbreviation: HDD) or solid-state drive (English: solid-state drive, abbreviation: SSD); the memory 404 may also include the above types of combination of memory. The processor 401 may be a central processing unit (English: central processing unit, abbreviation: CPU), a network processor (English: network processor, abbreviation: NP), or a combination of CPU and NP.

The memory 404 may include volatile memory (English: volatile memory), such as random-access memory (English: random-access memory, abbreviation: RAM); the memory may also include non-volatile memory (English: non-volatile memory) memory), such as flash memory (English: flash memory), hard disk (English: hard diskdrive, abbreviation: HDD) or solid-state drive (English: solid-state drive, abbreviation: SSD); the memory 404 may also include the above-mentioned types of memory The combination.

The processor 401 may be a central processing unit (English: central processing unit, abbreviation: CPU), a network processor (English: network processor, abbreviation: NP), or a combination of CPU and NP.

The processor 401 may further include a hardware chip. The above-mentioned hardware chip may be an application-specific integrated circuit (English: application-specific integrated circuit, abbreviation: ASIC), a programmable logic device (English: programmable logic device, abbreviation: PLD) or a combination thereof. The above-mentioned PLD may be a complex programmable logic device (English: complex programmable logic device, abbreviation: CPLD), a field programmable gate array (English: field-programmable gate array, abbreviation: FPGA), a general array logic (English: generic arraylogic , abbreviation: GAL) or any combination thereof.

Optionally, memory 404 is also used to store program instructions. The processor 401 may invoke program instructions to implement the method for calculating the dynamic water environment capacity of a river basin based on the water quality limit of rivers and lakes as in the first embodiment of the present application.

Embodiments of the present invention further provide a computer-readable storage medium, where computer-executable instructions are stored on the computer-readable storage medium, and the computer-executable instructions can execute the dynamic water environment of the river basin based on the water quality limit of rivers and lakes in Embodiment 1 Capacity calculation method. Wherein, the storage medium may be a magnetic disk, an optical disk, a read-only memory (Read-Only Memory, ROM), a random access memory (Random Access Memory, RAM), a flash memory (FlashMemory), a hard disk (Hard Disk Drive) , abbreviation: HDD) or solid-state drive (Solid-State Drive, SSD), etc.; the storage medium may also include a combination of the above-mentioned types of memories.

Obviously, the above-mentioned embodiments are only examples for clear description, and are not intended to limit the implementation manner. For those of ordinary skill in the art, changes or modifications in other different forms can also be made on the basis of the above description. There is no need and cannot be exhaustive of all implementations here. However, the obvious changes or changes derived from this are still within the protection scope of the present invention.

Claims (10)

1. A river and lake water quality limit-based watershed dynamic water environment capacity calculation method is characterized by comprising the following steps:

acquiring basic data of a watershed to be calculated, wherein the basic data comprises: geospatial data, pollution source data, water quality monitoring data, hydrological data and meteorological data;

dividing a basin to be calculated into a plurality of production convergence units according to geospatial data and meteorological data, constructing a basin distributed hydrological model based on basic data, and calibrating the basin distributed hydrological model according to measured flow data until the basin distributed hydrological model meets the precision requirement;

coupling the basin distributed hydrological model and the one-dimensional water quality model by using a preset conversion model to obtain a basin distributed water quantity and water quality model, calibrating the basin distributed water quantity and water quality model according to water quality actual measurement data until the basin distributed water quantity and water quality model meets the precision requirement, and calculating the outlet water quality concentration of each convergence unit by using the basin distributed water quantity and water quality model;

establishing a river and lake water quality response model by using the basic data, calibrating the river and lake water quality response model according to preset river and lake water quality observation data until the river and lake water quality response model meets the precision requirement, and calculating a river and lake water quality limit value meeting the standard condition of lake water quality by using the river and lake water quality response model;

and calculating the dynamic water environment capacity of each production and confluence unit and the dynamic water environment capacity of the river basin according to the outlet water quality concentration of each production and confluence unit and the river-lake water quality limit value.

2. The method for calculating the watershed dynamic water environment capacity based on the river lake water quality limit value according to claim 1, wherein the preset conversion model comprises: a flow and flow rate conversion model and a pollution load distribution model.

3. The method for calculating the dynamic water environment capacity of the drainage basin based on the river and lake water quality limit value of claim 1, wherein a drainage basin distributed water quantity and water quality model is constructed through a DTVGM model.

4. The method for calculating the watershed dynamic water environment capacity based on the river lake water quality limit value according to claim 3, wherein the degradation amount of pollutants in the unit body comprises: upstream input pollutant degradation amount W_dSThe amount of pollutant degradation W fed into the branch_dZAmount of point source contaminant degradation W_dPAmount of plane-source contaminant degradation W_dM，

Calculating the degradation amount of pollutants in the unit body respectively by the following formulas:

wherein K represents the rate constant for contaminant degradation, Q_aijThe flow rate of the jth branch flow is shown; c_aijThe concentration of the j branch stream pollutants; l is_jThe distance from the j-th branch to the end of the river reach from the junction; TL is the total length of the river reach; w_dGThe pollutant degradation amount of the sewage discharge outlet is generalized; l is_GThe distance between the sewage draining exit and the tail of the river reach is generalized; u is the river average flow rate.

5. The method for calculating the watershed dynamic water environment capacity based on the river and lake water quality limit value according to claim 1, wherein before the step of coupling the watershed distributed hydrological model and the one-dimensional water quality model by using the preset conversion model to obtain the watershed distributed water yield and water quality model, the method further comprises the following steps:

and counting point sources and non-point sources of the watershed to be calculated, and distributing the statistics to each production and convergence unit of the watershed distributed water quantity model.

6. The method for calculating the watershed dynamic water environment capacity based on the river lake water quality limit value according to claim 1, wherein the process of constructing the river lake water quality response model by using basic data comprises the following steps: selecting a corresponding model according to the requirement of the simulation index, and setting the global parameter, the local parameter and the branch parameter of the model to construct a river and lake water quality response model; wherein,

the global parameters include: rainfall, evaporation, water level change and atmospheric external load in the basin range;

the local parameters include: water surface area of lake region, average depth of lake region, depth of mixed layer, turbidity of non-algae and average water quality of lake region;

the tributary parameters included: the flow area of the influent branch, the influent flow rate and the influent water concentration.

7. The method for calculating the dynamic water environment capacity of the river and lake based on the river and lake water quality limit value in the drainage basin according to claim 4, wherein the dynamic water environment capacity of each flow generating and converging unit is calculated through the following formula:

wherein K represents the rate constant for contaminant degradation, C_siIndicates the water quality limit.

8. A river lake water quality limit-based watershed dynamic water environment capacity calculation system is characterized by comprising:

the data acquisition module is used for acquiring basic data of the watershed to be calculated, wherein the basic data comprises: geospatial data, pollution source data, water quality monitoring data, hydrological data and meteorological data;

the watershed distributed hydrological model building module is used for dividing a watershed to be calculated into a plurality of production convergence units according to the geospatial data and the meteorological data, building a watershed distributed hydrological model based on the basic data, and calibrating the watershed distributed hydrological model according to the actually-measured flow data until the watershed distributed hydrological model meets the precision requirement;

the watershed distributed water quantity and water quality model building module is used for coupling a watershed distributed hydrological model and a one-dimensional water quality model by using a preset conversion model to obtain a watershed distributed water quantity and water quality model, calibrating the watershed distributed water quantity and water quality model according to water quality actual measurement data until the watershed distributed water quantity and water quality model meets the precision requirement, and calculating the outlet water quality concentration of each convergence unit by using the watershed distributed water quantity and water quality model;

the river and lake water quality response model building module is used for building a river and lake water quality response model by using the basic data, calibrating the river and lake water quality response model according to preset river and lake water quality observation data until the river and lake water quality response model meets the precision requirement, and calculating a river and lake water quality limit value meeting the lake water quality standard condition by using the river and lake water quality response model;

and the dynamic water environment capacity calculation module is used for calculating the dynamic water environment capacity of each production confluence unit and the dynamic water environment capacity of a river basin according to the outlet water quality concentration of each production confluence unit and the river lake-entering water quality limit value.

9. A terminal, comprising: at least one processor and a memory communicatively connected to the at least one processor, wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to cause the at least one processor to execute the method for calculating the dynamic water environmental capacity of the river and lake based on the river and lake water quality limit according to any one of claims 1 to 7.

10. A computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions for causing the computer to execute the method for calculating the dynamic water environment capacity of the river and lake based on the river and lake water quality limit value according to any one of claims 1 to 7.

Images