CN113297814B

CN113297814B - River basin dynamic water environment capacity calculation method and system based on river and lake water quality limit value

Info

Publication number: CN113297814B
Application number: CN202110558425.4A
Authority: CN
Inventors: 夏瑞; 陈焰; 王强; 王璐; 贾蕊宁; 张凯; 杨中文; 马淑芹; 王晓; 后希康; 段平洲; 塔拉; 张晓娇
Original assignee: Chinese Research Academy of Environmental Sciences
Current assignee: Chinese Research Academy of Environmental Sciences
Priority date: 2021-05-21
Filing date: 2021-05-21
Publication date: 2023-09-26
Anticipated expiration: 2041-05-21
Also published as: CN113297814A; AU2021106591A4

Abstract

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

Description

River basin dynamic water environment capacity calculation method and system based on river and lake water quality limit value

Technical Field

The invention relates to the technical field of river and lake basin water environment, in particular to a basin dynamic water environment capacity calculation method and system based on river and lake water quality limit value.

Background

At present, the requirement of a water functional area is mainly considered when the water environment capacity is calculated, and the water quality target of the water functional area does not necessarily meet the water quality control requirement of rivers by rivers, lakes and seas according to the requirements of 'fixing rivers by lakes and fixing rivers by seas'. The method is characterized in that the existing water quality standard is difficult to meet the requirement of regional variability, different regions have different requirements on river water quality, the phenomenon of too tight or too loose water quality easily occurs when the river water quality is managed according to the unified standard, and the differentiated river water quality limit value is formulated as the water quality target for calculating the water environment capacity according to the regional characteristics and the river, lake and sea water quality protection target. And secondly, the linear or nonlinear relation between the water quantity and the meteorological conditions is not considered, the result of the change of the water quantity along with the meteorological conditions is lacking in water quantity input, and the calculation result of the water environment capacity cannot realize dynamic change. Meanwhile, the influence 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 the point sources and the non-point sources are not performed on the river basin where the river is located, only the water body is taken as a research object, and the influence of rainfall runoff is not considered. The method has the defects that the existing river water environment capacity calculation method is low in precision and cannot be used for solving and estimating the dynamic water environment capacity.

Disclosure of Invention

Therefore, the river basin dynamic water environment capacity calculating method and system based on the river and lake water quality limit value provided by the invention overcome the defects that the existing river water environment capacity calculating method is low in precision and can not solve and estimate the dynamic water environment capacity.

In order to achieve the above purpose, the present invention provides the following technical solutions:

in a first aspect, an embodiment of the present invention provides a river basin dynamic water environment capacity calculation method based on a river and lake water quality limit value, including:

obtaining basic data of a river basin to be calculated, wherein the basic data comprises the following steps: geospatial data, pollution source data, water quality monitoring data, hydrologic data, and meteorological data;

dividing a river basin to be calculated into a plurality of production and collection units according to geographic space data and meteorological data, constructing a river basin distributed hydrological model based on basic data, and calibrating the river basin distributed hydrological model according to actual measurement flow data until the river basin distributed hydrological model meets the precision requirement;

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

Constructing 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 the river and lake water inflow limit value meeting the lake water quality standard condition by using the river and lake water quality response model;

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

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

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

Optionally, the in-cell contaminant degradation amount includes: upstream input pollutant degradation amount W _dS The pollutant degradation amount W is input into the branch _dZ Degradation amount W of point source pollutant _dP Degradation amount W of non-point source pollutant _dM ，

The degradation amount of the pollutants in the cell body is calculated by the following formula respectively:

wherein K represents a rate constant of contaminant degradation, Q _aij The flow rate of the j-th branch flow; c (C) _aij Contaminant concentration for the j-th substream; l (L) _j The distance between the inlet of the jth tributary and the end of the river reach is the j tributary; TL is the total length of the river reach; w (W) _dG The degradation amount of pollutants at the sewage outlet is generalized; l (L) _G The tail distance of the drain outlet from the river reach is generalized; u is the average river flow rate.

Optionally, before the step of coupling the basin distributed hydrological model with the one-dimensional water quality model by using the preset conversion model to obtain the basin distributed water quantity water quality model, the method further includes:

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

Optionally, the process of constructing a river and lake water quality response model using the base data includes: selecting a corresponding model according to the requirements of the simulation indexes, and setting global parameters, local parameters and tributary parameters 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 drainage basin range;

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

the tributary parameters include: the flow area of the lake inlet branch flow, the lake inlet flow and the lake inlet water mass concentration.

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

Wherein K represents the rate constant of contaminant degradation, C _si Indicating a water quality limit.

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

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

the system comprises a drainage basin distributed hydrological model construction module, a drainage basin distributed hydrological model generation module and a measurement module, wherein the drainage basin distributed hydrological model construction module is used for dividing a drainage basin to be calculated into a plurality of production converging units according to geographic space data and meteorological data, constructing a drainage basin distributed hydrological model based on basic data, and calibrating the drainage basin distributed hydrological model according to actual measurement flow data until the drainage basin distributed hydrological model meets the precision requirement;

the system comprises a river basin distributed water quantity and water quality model construction module, a water basin distributed water quantity and water quality model analysis module and a water basin distributed water quantity and water quality model analysis module, wherein the river basin distributed water quantity and water quality model construction module is used for coupling a river basin distributed hydrological model with a one-dimensional water quality model by utilizing a preset conversion model to obtain a river basin distributed water quantity and water quality model, calibrating the river basin distributed water quantity and water quality model according to water quality actual measurement data until the river basin distributed water quantity and water quality model meets the precision requirement, and calculating the outlet water quality concentration of each converging unit by utilizing the river basin distributed water quantity and water quality model;

The river and lake water quality response model construction module is used for constructing a river and lake water quality response model by utilizing 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 the river and lake water quality limit value meeting the lake water quality standard condition by utilizing the river and lake water quality response model;

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

In a third aspect, an embodiment of the present invention provides a terminal, including: the river basin dynamic water environment capacity calculating method based on the river basin water quality limit value comprises at least one processor and a memory in communication connection with 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 so that the at least one processor can execute the river basin dynamic water environment capacity calculating method based on the river basin water quality limit value according to the first aspect of the embodiment of the 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, where the computer instructions are configured to cause the computer to execute the river basin dynamic water environment capacity calculation method based on the river basin water quality limit value according to the first aspect of the present invention.

The technical scheme of the invention has the following advantages:

1. according to the river basin dynamic water environment capacity calculation method and system based on the river and lake water quality limit value, the pollution source is dynamically distributed according to the time dimension through the pollution load distribution model. Meanwhile, the river basin distributed water quantity model is coupled with the one-dimensional water quality model through the flow rate and flow velocity conversion model, and the water quantity and the water quality are coupled, so that the construction of the river basin distributed water quantity and water quality model is completed.

2. According to the river basin dynamic water environment capacity calculation method and system based on the river and lake water quality limit value, as the water quality actual measurement data and the preset river and lake water quality observation data are changed in real time, the water quantity, the water quality and the water environment capacity of each confluence unit under different rainfall conditions are synchronously obtained, and the dynamic calculation of the water environment capacities of the confluence units and the river basin is realized.

3. According to the river basin dynamic water environment capacity calculation method and system based on the river and lake water quality limit value, the river and lake water quality limit value is obtained according to the river and lake water quality response model, the river and lake water quality limit value is different from the requirements of the existing surface water quality standard, the water quality requirements of different areas on the river and lake water entering are different, the river water quality limit value of different areas can be determined according to the river and lake water quality response model, and the water environment capacity is different from the calculation of the water environment capacity based on the water quality target and the water quality standard in the past.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

FIG. 1 is a flowchart of a specific example of a river basin dynamic water environment capacity calculation method based on river and lake water quality limit values provided by an embodiment of the invention;

FIG. 2 is a schematic diagram of water volume and quality balance of a water body of a confluence unit according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of Bathtub model construction data of a river basin dynamic water environment capacity calculation method based on river and lake water quality limit values provided by the embodiment of the invention;

FIG. 4 is a schematic diagram of a month runoff of a lake-entering hydrologic control station (S1, S2, S3, S4, S5) provided by an embodiment of the invention;

FIGS. 5 (a) -5 (e) are diagrams of 5 tributary month runoff control hydrologic station rate periodic and verification period month runoff observations and simulated value runoff processes provided by embodiments of the present invention;

FIGS. 6 (a) -6 (h) are graphs showing comparison between observed values and simulated values of TP concentrations at regular and verification periods of a portion of water quality control sites according to embodiments of the present invention;

FIG. 7 is a schematic diagram of a simulation process of the TP concentration in a lake region according to an embodiment of the present invention;

FIGS. 8 (a) -8 (e) are schematic diagrams of dynamic change curves of the TP water environment capacity of each river basin in the year according to the embodiments of the present invention;

FIG. 9 is a block diagram of a river basin dynamic water environment capacity calculation system based on river and lake water quality limit values provided by the embodiment of the invention;

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

Detailed Description

The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; the two components can be directly connected or indirectly connected through an intermediate medium, or can be communicated inside the two components, or can be connected wirelessly or in a wired way. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.

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

Example 1

The river basin dynamic water environment capacity calculation method based on the river and lake water quality limit value provided by the embodiment of the invention, as shown in fig. 1, comprises the following steps:

step S1: obtaining basic data of a river basin to be calculated, wherein the basic data comprises the following steps: geospatial data, pollution source data, water quality monitoring data, hydrologic data, and meteorological data.

In the embodiment of the invention, the basic data in the preset time period is acquired, and the preset time period is selected correspondingly according to the actual calculation, which is not limited herein. The obtained basic data are shown in the following table, which is only used as an example, but not limited to, and the corresponding basic data are obtained according to actual requirements in practical application.

Step S2: dividing the basin to be calculated into a plurality of production converging units according to the geospatial data and the meteorological data, constructing a basin distributed hydrological model based on the basic data, and calibrating the basin distributed hydrological model according to the actually measured flow data until the basin distributed hydrological model meets the precision requirement.

In the embodiment of the invention, based on spatial data such as a digital elevation model (Digital Elevation Model, DEM), a hydrologic station, a water quality station, land utilization, soil type and the like of a river basin research area to be calculated, the spatial data are selected according to actual demands in practical application by way of example only and not limitation. The GIS platform is utilized to obtain the spatial variation information such as the unit gradient, the flow direction, the water flow path, the water system distribution, the river basin, the confluence boundary, the land cover, the hydrological input variable and the like of the river basin land surface, and the spatial variation information is not limited herein. Meanwhile, each production and collection unit at least comprises 1-2 water quality stations for water quality boundary control, and a corresponding relation between a administrative area, a river entering sewage outlet and a land collection area is established by using a superposition technology; and reasonably analyzing and dividing the production and confluence units by combining the hydrologic production and confluence characteristics of the natural river basin with the natural characteristics and the space differences of the river basin of the water ecological system.

In the embodiment of the invention, the drainage basin distributed hydrologic model is an existing geographic data model, the drainage basin distributed hydrologic model constructed based on basic data can comprehensively utilize the space distribution information of rainfall, and the space distribution of model parameters can reflect the space change of the natural condition of the underlying surface.

In the embodiment of the invention, the spatial basin land digital information and the hydrologic information are used as the framework of a basin distributed hydrologic model, rainfall data of a research area are input, basin runoff and confluence simulation is carried out, the flow of a simulated basin outlet is obtained, the flow is compared with the runoff actual measurement value of a corresponding hydrologic station for analysis and evaluation, a Nash efficiency coefficient NSE, a deterministic coefficient R2 and a relative error Bias are selected as evaluation indexes of the model, and the simulation value and the actual measurement value are compared until the basin distributed hydrologic model meets the precision requirement, and corresponding model parameters are selected, so that the method is not limited by the limitation, and corresponding evaluation indexes are selected according to actual requirements in practical application. The evaluation index was calculated by the following formula, respectively:

nash efficiency coefficient:

deterministic coefficient:

relative error:

wherein: n is the length of the runoff sequence, Q _i,sim and Q_i,obs Respectively a runoff simulation value and an observation value at the ith moment,is the average observed value of runoff.

Step S3: and coupling the drainage basin distributed hydrologic model with the one-dimensional water quality model by using a preset conversion model to obtain a drainage basin distributed water quantity water quality model, calibrating the drainage basin distributed water quantity water quality model according to water quality actual measurement data until the drainage basin distributed water quantity water quality model meets the precision requirement, and calculating the outlet water quality concentration of each converging unit by using the drainage basin distributed water quantity water quality model.

In the embodiment of the invention, the step of coupling the drainage basin distributed hydrological model with the one-dimensional water quality model by using the preset conversion model to obtain the drainage basin distributed water quantity water quality model further comprises the following steps: the method comprises the steps of counting point sources and non-point sources of a water environment of a river basin to be calculated, distributing the point sources and the non-point sources to all production and convergence units of a distributed hydrological model of the river basin, counting and calculating and distributing the point sources and the non-point sources of a control unit of the river basin where the river is located, and considering the influence of rainfall runoff. According to the embodiment of the invention, the space distribution of the pollution source accounting results is carried out according to the production and convergence unit or the administrative area, the influence of the space-time distribution characteristics of the pollution source on the water quality of the river basin is reflected, the distribution of the pollution source accounting results is not limited, and the corresponding distribution is carried out according to the requirements. The pollution load distribution is adopted to distribute the pollution sources on a time scale, so that the pollution sources can be finely controlled in time and space from the time dimension from the perspective of pollution treatment.

In the embodiment of the invention, the one-dimensional water quality model is a water quality model established under a steady state condition of a river, and the steady state condition is that the cross-sectional area, the flow velocity, the flow rate and the input quantity of pollutants of the river are not changed with time after the pollutants enter the water body under a steady pollution discharge condition of the river of a uniform river section. After sewage is discharged into a river channel, the transverse mixing length is far smaller than the calculation flow length of the river, pollutants can be basically and uniformly mixed in a short time, the concentration gradient of the pollutants in the vertical direction and the transverse direction is negligible, and only the concentration change of the river along the longitudinal direction is considered, so that the one-dimensional water quality model is adopted as the basis of the coupling model. The one-dimensional water quality model is represented by the following formula:

in the formula,C₀ To calculate the concentration of the initial cross-section contaminant (mg/L); v is river flow rate (m/s). Wherein K is ₁ For the rate constant of contaminant degradation, x is the calculated section distance (m) from the starting section.

In the embodiment of the invention, the basin distributed water quantity and water quality model is based on a basin distributed hydrologic model and a one-dimensional water quality model, and is constructed by a DTVGM model. The output result of the hydrologic model is used as the input boundary of the water quality model, so that the key for realizing the coupling of the hydrologic model and the water quality model is the conversion of model parameters. The parameters output by the drainage basin distributed hydrological model are the water quantity and the water quality of the outlets of each production converging unit and the drainage basin outlet, the boundary condition that a one-dimensional water quality model needs to be input is the flow velocity, and in the condition of lacking flow velocity actual measurement data, the invention utilizes a preset conversion model to realize the coupling of the two: the flow rate conversion model and the pollution load distribution model are only examples, but not limited to, and the proper conversion model is selected according to actual conditions in practical application. The method and the device can be used for converting the water yield result of the watershed distributed water yield water quality model into the flow speed boundary required by the one-dimensional water quality model, and can provide a simple and effective solution idea for the same type of model coupling.

In a specific embodiment, since the Distributed time-varying gain model (DTVGM) model cannot output the flow rate, the output flow data needs to be converted, and in the coupling construction process of the watershed Distributed hydrologic model and the one-dimensional water quality model, the point source and the non-point source are Distributed in the time dimension by constructing the pollution load distribution model, so as to realize the dynamic change of the pollution load.

The flow and the flow velocity are converted by adopting a calibration formula method, the flow and the flow velocity relation of each river reach is linearly fitted according to the historical observation data of the hydrologic site, a flow and flow velocity conversion model is obtained, and the dynamic flow obtained by the river basin distributed hydrologic model is updated into dynamic flow velocity data. The average river flow velocity u and the average river cross-section water depth H are calculated by the following formula:

u＝aQ ^b

H＝αQ ^β

wherein Q is river section flow (m ³ S); a. b, alpha and beta are empirical parameters for determining the flow rate and flow relationship and the water level and flow rate relationship, and can be determined according to historical data.

The water cross-sectional area A is calculated by the following formula _c Average water surface width B:

in the embodiment of the invention, due to the requirement of the watershed distributed water quantity and water quality model on the input boundary, the calculated pollution load is required to be distributed according to the time dimension. For example: the Total Phosphorus (TP) pollution load of a pollutant calculated in a certain year is W, and W is allocated to each month or each day according to a time scale (month scale or day scale, etc., which is merely by way of example, but not by way of limitation, and a corresponding time scale is selected according to actual requirements in practical application), and W is correspondingly divided into 12 values or 365 values according to certain conditions and is input into a model in a time sequence form as a boundary condition.

In a specific embodiment, a pollution load month distribution model is built by combining actual conditions, and the month 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 )

wherein ,L_m,i A monthly load for pollution source i; l (L) _a,i Annual load for pollution source i; l (L) _g,j The flow rate of groundwater entering the river in month j; q (Q) _s , _j The flow rate of the surface runoff entering the river in the j month; q (Q) _s,a Is annual surface runoff; q (Q) _g , _a Is annual underground runoff.

The invention eliminates the traditional calculation of river water environment capacity by taking the water function area as a basic unit, adopts the sub-watershed divided by the watershed distributed hydrologic model as a calculation basic unit, and is coupled with a one-dimensional water quality model to construct a distributed water quantity and water quality model. As shown in fig. 2, for a water body i of a confluence unit, the water quantity and quality balancing process is as follows:

producing the equation of confluence unit hydrologic balance:

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

equation for water concentration balance of confluence unit:

wherein ,ΔV_i The change amount of the water storage amount in the time period for the unit i; q (Q) _i-1 and Q_i The inflow and outflow amounts of water are respectively the units; q _i Taking water for human beings; r is R _i The interval water yield of the unit i; q (Q) _ai Is the amount of branch. V (V) _i The water storage capacity of unit i; c (C) _Ri Concentration of contaminants in the interval product stream (closely related to non-point source contamination); c (C) _ai Is the concentration of the tributary water quality; c (C) _i-1 and C_i The water quality concentrations are respectively input and output by the unit; c (C) _qi Taking the water contaminant concentration for a human; w (W) _p Negative pollution of point source of unit iSummation of the charges; w (W) _d Is the degradation amount of pollutants in the unit body.

In an embodiment of the invention, W _d For producing the self-cleaning ability of the water body in the converging unit, comprising: upstream input pollutant degradation amount W _dS The method comprises the steps of carrying out a first treatment on the surface of the The pollutant degradation amount W of the branch flow _dZ The method comprises the steps of carrying out a first treatment on the surface of the Degradation amount W of point source pollutant _dP The method comprises the steps of carrying out a first treatment on the surface of the Degradation amount W of non-point source pollutant _dM By way of example only, and not by way of limitation, corresponding in-cell pollutant degradation amount data are selected according to actual requirements in practical application. The degradation amount of the pollutants in the cell body is calculated by the following formula respectively:

wherein n is the total number of river reach branches; q (Q) _aij The flow rate of the j-th branch flow; c (C) _aij Contaminant concentration for the j-th substream; l (L) _j The distance between the j-th branch inlet and the end of the river reach is the j-th branch inlet; TL is the total length of the river reach.

The degradation amount of the non-point source pollutant of the point source is related to the inflow amount of the pollutant and the pollutant discharge mode, and the simplified pollution discharge mode of the simplified pollution discharge outlet can be considered, so that:

wherein ,W_dG The degradation amount of pollutants at the sewage outlet is generalized; l (L) _G To generalize the tail distance of the drain outlet from the river reach. The concrete position of the generalized sewage outlet can be determined according to the river entering amount of the point source and non-point source pollutants and the sewage characteristic analysis. The two extreme cases are first-stage sewage disposal and second-stage sewage disposal, the former L _G TL, the contaminant degradation amount is maximal; the latter L _G =0, degradation ofThe amount is minimal.

In the embodiment of the invention, based on a watershed distributed water quantity and water quality model, the water quality of a watershed outlet is calculated in a simulation mode, the water quality is compared with the measured value of a corresponding water quality station for analysis and evaluation, a correlation coefficient CC and an average error MRE are selected as model evaluation indexes, the applicability of the model is judged by comparing the water quality simulation value with the measured value, and the evaluation indexes are calculated by the following formulas:

in the formula,C_i,sim The water quality simulation value at the i time; c (C) _i,obs The water quality observation value at the i-th moment;is the average value of the water quality observation values; />Is the average value of the water quality simulation values; n is the number of samples.

Step S4: and constructing a river and lake water quality response model by utilizing 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 accuracy requirement, and calculating the river and lake water inflow limit value meeting the lake water quality standard condition by utilizing the river and lake water quality response model.

In one embodiment, the river and lake water quality response model is constructed mainly by using the Bathtub simulation software, and as shown in FIG. 3, the data required for constructing the Bathtub model include: the global parameters, the local parameters and the tributary parameters are only exemplified, but not limited to, and corresponding data are selected according to actual requirements in practical application.

The global parameter is data of a river basin scope, and comprises the following steps: the rainfall, evaporation, water level change, external load of atmosphere, etc. are only examples, but not limited to, and the corresponding global parameters are selected according to the actual requirements in practical application.

The local parameters are water parameters of the lake region, and the method comprises the following steps: the surface area of the lake region, the average depth of the lake region, the depth of the mixed layer, the turbidity of the non-algae and the average water quality of the lake region are merely examples, but not limited thereto, and the corresponding local parameters are selected according to the actual requirements in the practical application.

The tributary parameters are data of the lake-entering tributary, and include: the area of the flow field of the lake-entering tributary, the flow rate of the lake-entering flow and the water concentration of the lake-entering flow are only exemplified, but not limited to, and corresponding tributary parameters are selected according to actual requirements in practical application.

In one embodiment, the river and lake water quality response model construction step comprises: the method comprises five parts of model selection, global parameter setting, local parameter setting, tributary parameter setting and model calibration verification, and specifically comprises the following steps:

(1) Selection of a model: according to the requirement of the simulation index, determining the simulation time, and selecting a corresponding Model at a Model Selector interface, for example: the P model, the N model, the Chl-a model, the transparency model, and the like are only examples, but not limited thereto, and the corresponding model is selected according to actual requirements in practical application. For example: the calculation formula of the P model is divided into a first-order model and a second-order model, and the specific calculation formula is as follows:

a first order model:

second order model:

wherein: p is the total phosphorus output concentration (mg/m) of the lake ³ )，P _i For total phosphorus concentration (mg/m) in the river ³ ) K is a correction factor, A ₁ For the phosphorus sedimentation term intercept, T is the hydraulic retention time(year).

(2) Global parameter setting

The global parameter setting interface needs to define the simulated time (average period), 1 is input when the average period is one year, 0.5 is input when the average period is half year, and the other same reason is that; in addition, parameters of average rainfall, evaporation capacity, average water storage depth and atmospheric load (total phosphorus, total nitrogen, etc.) in the average period time need to be input, which are only by way of example, but not by way of limitation, and corresponding global parameters are set according to actual requirements in practical application.

(3) Local parameter setting

The setting of the local parameters mainly considers whether the lake body is partitioned or not, the whole lake area is a section under the condition of no partition, the geographic space information such as the surface area, the average depth, the characteristic length, the depth of the mixed layer and the like of the whole lake area are required to be input, and the parameters such as the average water quality concentration and the correction factor of the lake area are required to be input, so that the method is only limited by the example, and the corresponding local parameters are set according to the actual requirements in the practical application.

(4) Tributary parameter setting

The parameter setting of the tributary mainly considers the information of the tributary entering the lake, the information to be input includes the catchment area, the flow rate, the TP concentration of the tributary and the like, and only by way of example, but not by way of limitation, the corresponding tributary parameters are set according to the actual requirements in the practical application.

(5) Model rating verification

Inputting the water quality with different concentrations of the tributaries into the lake region, calculating the water quality concentration of the lake region based on the model, comparing, analyzing and evaluating the water quality concentration of the lake region with preset water quality observation data of the river and the lake, selecting a correlation coefficient CC and average error MRE as model evaluation indexes, and comparing the water quality simulation value with standard data until the water quality response model of the river and the lake meets the precision requirement, wherein the preset water quality observation data of the river and the lake are correspondingly selected according to the actual requirement, so that the method is not limited. And calculating the river-to-lake water quality limit value meeting the lake water quality standard condition by using the river-to-lake water quality response model.

In the embodiment of the invention, the water quality limit value of the side stream entering the lake is determinedIn the process, mainly taking lake water quality standard as a target, setting gradient water quality concentration of a tributary, calculating the lake water quality concentration and the reverse-pushing tributary water quality concentration under different situations based on a built Bathtub model, and analyzing the water quality limit value of the lake tributary under various water quality standard conditions of the lake. The following table shows the inlet conditions of the lake inlet tributaries and the water quality concentration results in the lake region. When the lake water quality reaches the standard, the tributary is set to be the condition (C ₁ ～C ₅ ) In the input model, the water quality concentration (C) of the lake is calculated ₁₁ ～C ₅₁ ) And determining the corresponding water quality category, comparing the water quality category with the lake water quality standard, analyzing whether the lake water quality can reach the standard, and if the lake water quality reaches the standard, determining that the tributary input concentration is the tributary water quality limit value.

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Step S5: and calculating the dynamic water environment capacity of each confluence unit and the dynamic water environment capacity of the river basin according to the outlet water quality concentration of each confluence unit and the river lake entering water quality limit value.

In the embodiment of the invention, the dynamic water environment capacity model takes the production and collection units as the calculation basic units, and the dynamic water environment capacity of the river basin is calculated according to the dynamic water environment capacity of each production and collection unit. The dynamic water environment capacity can be estimated through a distributed water quantity and water quality coupling model, wherein hydrologic factors such as the upper section inflow, the interval output, the branch inflow and the lower section outflow of the calculation unit can be obtained through a river basin distributed hydrologic model. The flow rate can be indirectly obtained by using a flow rate-flow rate conversion relationship. The water quality concentration of the upper section and the inflow concentration of the tributaries can be obtained through a water quality coupling model. The river water quality limit value calculated by the Bathtub model is determined by the lower section water quality target and the artificial water taking water quality target. Therefore, the river basin dynamic water environment capacity accounting mainly uses the river water quality limit value calculated by the Bathtub model and the water quality obtained by the river basin distributed water quality coupling model as boundary conditions, uses rainfall data as driving, and calculates the dynamic water environment capacity, including annual changes and annual changes.

According to a 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

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

In a specific embodiment, a river basin in the south of China is taken as a case, and typical pollutant Total Phosphorus (TP) is taken as an index, so that dynamic capacity calculation of dynamic TP water environment of the river basin is carried out.

Basic data collection processing

For a river basin, the collected data comprise geographical space data such as water system distribution, pollution source space distribution, weather station space distribution, hydrological water quality station space distribution, land utilization, DEM, lake area, characteristic length and the like, pollution source data such as point source and point source load and the like, water quality monitoring data such as rivers and lakes and the like, hydrological data such as river flow and water level and meteorological data such as rainfall evaporation and the like, and the time span is 2009-2018.

(II) basin distributed hydrological model construction

1. Yield confluence unit division

Based on ARCGIS10.2 platform, 86 production convergence calculation units are obtained by dividing according to basic geographic information data such as water system, administrative division, land utilization, DEM, hydrologic site, water quality control section and the like of a certain river basin, each calculation unit is ensured to have 1-2 water quality control sites to control water quality boundaries. When the calculation unit is divided, the hydrologic production converging characteristic of the natural river basin and the space difference of the water ecological system are comprehensively analyzed, the natural characteristic of the river basin of the ecological system is considered, meanwhile, the double scale conversion analysis of the river basin and the administrative region can be supported by overlapping administrative regions, and the calculation unit can be used as a basic calculation unit of the water environment capacity of a certain river basin TP.

2. Model rating verification

According to the collected data related to a certain river basin, the rainfall data of the certain river basin in 2009-2018 are used for carrying out hydrologic simulation on the runoffs of the main lake entering hydrologic control stations (S1, S2, S3, S4 and S5) in FIG. 4, wherein 2010-2015 are the rate period, and 2016-2018 are the verification period. Fig. 5 (a) -5 (e) are diagrams of measured and simulated value runoff processes for 5 tributary month runoff control hydrologic station rate periods (2010-2015) and verification periods (2016-2018), respectively, in sequence.

The simulation results of the drainage basin distributed water quantity model meet the runoff simulation requirements and show good precision, so that the model can simulate the natural distribution condition of water resources of a drainage basin, and lays a foundation for further developing water quality simulation of the drainage basin and TP water environment capacity accounting.

(III) river basin distributed water quantity and quality coupling model

The invention utilizes the total phosphorus concentration data of a main water quality control station in a certain river basin to respectively simulate the water quality of the lake inlet tributaries, and selects 2015-2017 for simulation, wherein 2015-2016 is the rate period, and 2017 is the verification period. And calibrating the verification index according to the formula calculation, wherein the result is shown in the following table. FIGS. 6 (a) - (h) are graphs comparing measured and simulated values of TP concentration at regular intervals (2015-2016) and during a validation period (2017) for a portion of water quality control site.

The evaluation result of the model is comprehensively considered, the water quality simulation result of the distributed water quantity and water quality coupling model is good, and the error of most monitoring sections is less than 20%, so that the model is suitable for water quality simulation of a certain river basin, and a foundation is laid for further carrying out water environment capacity accounting of the certain river basin.

(IV) river and lake water quality response model

(1) Model selection

And selecting a phosphorus second-order Model at a Model Selector interface according to the TP management and control requirements of a certain river basin. The model is built for 4-9 months each year from 2014-2018.

(2) Global parameter setting

Because the construction time of the river and lake response relation model is each month, the average period is set to be 1/12, namely 0.083; the average rainfall, evaporation capacity, average water storage depth and the like of different months are input according to actual conditions.

(3) Local parameter setting

The river and lake water quality response model does not consider the partitioning of the lake body, and the physical properties of the lake body are counted according to different months, wherein the physical properties comprise the surface area, the average depth, the characteristic length, the mixed layer depth, the TP average concentration of the lake region, the correction factor and the like, and the physical properties are input into the model according to actual conditions. Wherein correction factors are used for model calibration.

(4) Tributary parameter setting

The information entered by the tributaries includes the catchment area of the tributaries, the flow rate, and the TP concentration of the tributaries.

(5) Model rating verification

Inputting water quality with different TP concentrations in a lake region, calculating the TP concentration in the lake region based on the model, performing comparative analysis and evaluation with TP actual measurement values of monitoring sections corresponding to the lake region, selecting a correlation coefficient CC and average mean error MRE as model evaluation indexes, and judging the applicability of the model by comparing TP simulation values and actual measurement values. The model evaluation index correlation coefficient CC and average mean error MRE are respectively 0.99 and 0.004, the simulation process curves are shown in figure 7, the rate periodic time and the verification period R2 value are respectively 0.6772 and 0.7848, and the river and lake water quality response model simulation result is good, so that the model is suitable for river and lake TP simulation of a certain river basin, and a foundation is laid for carrying out TP water environment capacity accounting of the certain river basin.

(V) river TP limit

In the process of determining the TP limit value of the lake inlet branch, the method mainly comprises three steps, wherein the first step is that the lake inlet branch executes the river TP standard of the surface water environment quality standard (GB 3838-2002), the second step is that the lake inlet branch executes the lake TP standard of the surface water environment quality standard (GB 3838-2002), the third step is that the lake TP standard is taken as a target, gradient TP concentration of the branch is set, the lake TP concentration and the reverse pushing branch TP concentration under different scenes are calculated based on a constructed river and lake water quality response model, and the TP limit value of the lake inlet branch under various standard conditions of the lake is analyzed.

(3) Tributary input gradient TP concentration

When the lake TP reaches the standard, the tributary setting conditions are input into a model, the TP concentration of the lake is calculated, the corresponding water quality class is determined, the lake TP standard is compared with the corresponding water quality class, whether the lake TP reaches the standard is analyzed, and if the lake TP reaches the standard, the tributary TP limit value is indicated as the tributary input concentration. The following table shows the input conditions and results, when the lake TP concentration takes the lake I-V standard limit value of the surface water environment quality standard (GB 3838-2002), the calculated lake inlet river TP concentration control limit value is 0.02-0.4 mg/L, and is between the lake and river control limit values. When the lake TP concentration takes the lake III standard limit value (0.05 mg/L), the calculated lake entering river TP concentration control limit value is 0.075mg/L, which is equivalent to river II water quality.

(VI) river basin dynamic TP Water Environment Capacity

(1) Hydrologic frequency analysis and rainfall distribution

Analyzing daily rainfall data of each rainfall station in a certain river basin, carrying out statistics to obtain annual rainfall data, carrying out frequency analysis by taking a pearson III type curve which is commonly used in China as a theoretical frequency curve, respectively taking 10%, 25%, 50%, 75% and 90% of guaranteed rate rainfall as special-abundant, reclaimed, withered and special-withered annual rainfall, spreading rainfall distribution on the rainfall with different guaranteed rates, and obtaining water quantity and water quality processes under different guaranteed rate conditions after inputting a river basin distributed water quantity and water quality model, thereby accounting water environment capacity.

(2) Dynamic TP water environment capacity accounting

And calculating the river basin TP water environment capacity based on the water quantity and water quality process calculated by the distributed water quantity and water quality coupling model and the river TP limit value (0.075 mg/l) calculated by the river lake water quality response model, wherein the calculation result comprises the river basin dynamic water environment capacity under different hydrologic year conditions and the annual river basin dynamic water environment capacity. The calculation results of the dynamic water environment capacity of the watershed under different hydrologic year conditions are shown in the following table, and are shown in dynamic change curves of the water environment capacity of each watershed TP in the year in the figures 8 (a) -8 (e).

According to the river basin dynamic water environment capacity calculation method based on the river and lake water quality limit value, provided by the embodiment of the invention, the pollution source is dynamically distributed according to the time dimension through the pollution load distribution model. Meanwhile, the river basin distributed water quantity model is coupled with the one-dimensional water quality model through the flow rate and flow velocity conversion model, and water quantity and water quality are coupled. And (3) coupling the basin water quantity and water quality model through actually measuring the flow rate data. Because the measured water quality data and the preset river and lake water quality observation data are changed in real time, the water quantity, the water quality and the water environment capacity of each production and collection unit under different rainfall conditions are synchronously obtained, and the dynamic calculation of the water environment capacities of the production and collection units and the river basin is realized. The water quality limit value of the river entering the lake is obtained according to the water quality response model of the river and the lake, the water quality limit value is different from the requirement of the existing surface water quality standard, the water quality requirement of different areas on the river entering the lake is different, the water quality limit value of the river in different areas can be determined according to the water quality response model of the river and the lake, and the water environment capacity is different from the calculation of the water environment capacity based on the water quality target and the water quality standard in the past. The calculation accuracy of the water environment capacity of the river basin is improved, and the river basin water environment capacity calculation method is used for fine management and control of river pollution.

Example 2

The embodiment of the invention provides a river basin dynamic water environment capacity calculation system based on river and lake water quality limit value, which is shown in fig. 9 and comprises the following steps:

the data acquisition module 1 is used for acquiring basic data of the water environment preset time of the river basin to be calculated, and the basic data comprise: geospatial data, pollution source data, water quality monitoring data, hydrologic data, and meteorological data; this module performs the method described in step S1 in embodiment 1, and will not be described here again.

The drainage basin distributed hydrological model construction module 2 is used for dividing the drainage basin water environment to be calculated into a plurality of production and confluence units according to the geographic space data and the meteorological data, constructing a drainage basin distributed hydrological model based on the basic data, and calibrating the drainage basin distributed hydrological model according to the actually measured flow data until the drainage basin distributed hydrological model meets the precision requirement; this module performs the method described in step S2 in embodiment 1, and will not be described here.

The river basin distributed water quantity and water quality model construction module 3 is used for coupling the river basin distributed hydrologic model with the one-dimensional water quality model by utilizing a preset conversion model to obtain a river basin distributed water quantity and water quality model, calibrating the river basin distributed water quantity and water quality model according to water quality actual measurement data until the river basin distributed water quantity and water quality model meets the precision requirement, and calculating the outlet water quality concentration of each confluence unit by utilizing the river basin distributed water quantity and water quality model; this module performs the method described in step S3 in embodiment 1, and will not be described here.

The river and lake water quality response model construction module 4 is used for constructing a river and lake water quality response model by utilizing 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 the river and lake water quality limit value meeting the lake water quality standard condition by utilizing the river and lake water quality response model; this module performs the method described in step S4 in embodiment 1, and will not be described here.

The dynamic water environment capacity calculation module 5 is used for calculating the dynamic water environment capacity of each confluence unit and the dynamic water environment capacity of the river basin according to the outlet water quality concentration of each confluence unit and the river lake inlet water quality limit value; this module performs the method described in step S5 in embodiment 1, and will not be described here.

The embodiment of the invention provides a river basin dynamic water environment capacity calculation system based on river basin water quality limit value, which constructs a river basin distributed hydrologic model based on basic data, wherein the dynamic water environment capacity model takes a confluence unit as a calculation basic unit, the river basin distributed hydrologic model is coupled with a one-dimensional water quality model to obtain a river basin distributed water quantity water quality model, and outlet water quality concentration of each confluence unit is calculated according to the river basin distributed water quantity water quality model; constructing 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 lake water quality standard data, and calculating a river and lake inlet water quality limit value meeting the lake water quality standard condition by using the river and lake water quality response model; according to the outlet water quality concentration of each yielding and converging unit and the river lake entering water quality limit value, the dynamic water environment capacity of each yielding and converging unit and the river basin is calculated, the accuracy of calculating the river water environment capacity is improved, and the capacity of the dynamic water environment can be estimated.

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 ), at least one communication interface 403, a memory 404, at least one communication bus 402. Wherein communication bus 402 is used to enable connected communications between these components. The communication interface 403 may include a Display screen (Display) and a Keyboard (Keyboard), and the optional communication interface 403 may further include a standard wired interface and a wireless interface. The memory 404 may be a high-speed RAM memory (Random Access Memory) or a nonvolatile memory (nonvolatile memory), such as at least one magnetic disk memory. The memory 404 may also optionally be at least one storage device located remotely from the aforementioned processor 401. Wherein the processor 401 may perform the river basin dynamic water environment capacity calculation method based on the river and lake water quality limit value in embodiment 1. A set of program codes is stored in the memory 404, and the processor 401 calls the program codes stored in the memory 404 for executing the river basin dynamic water environment capacity calculating method based on the river and lake water quality limit value in embodiment 1. The communication bus 402 may be a peripheral component interconnect standard (peripheral component interconnect, PCI) bus or an extended industry standard architecture (extended industry standard architecture, EISA) bus, among others. Communication bus 402 may be divided into an address bus, a data bus, a control bus, and the like. For ease of illustration, only one line is shown in fig. 10, but not only one bus or one type of bus. Wherein the memory 404 may include volatile memory (English) such as random-access memory (RAM); the memory may also include a nonvolatile memory (english: non-volatile memory), such as a flash memory (english: flash memory), a hard disk (english: hard disk drive, abbreviated as HDD) or a solid-state drive (english: SSD); memory 404 may also include a combination of the above types of memory. The processor 401 may be a central processor (English: central processing unit, abbreviated: CPU), a network processor (English: network processor, abbreviated: NP) or a combination of CPU and NP.

Wherein the memory 404 may include volatile memory (English) such as random-access memory (RAM); the memory may also include a nonvolatile memory (english: non-volatile memory), such as a flash memory (english: flash memory), a hard disk (english: hard disk drive, abbreviated as HDD) or a solid state disk (english: solid-state drive, abbreviated as SSD); memory 404 may also include a combination of the above types of memory.

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

Wherein the processor 401 may further comprise a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a Programmable Logic Device (PLD), or a combination thereof (English: programmable logic device). The PLD may be a complex programmable logic device (English: complex programmable logic device, abbreviated: CPLD), a field programmable gate array (English: field-programmable gate array, abbreviated: FPGA), a general-purpose array logic (English: generic array logic, abbreviated: GAL), or any combination thereof.

Optionally, the memory 404 is also used for storing program instructions. The processor 401 may call program instructions to implement the river basin dynamic water environment capacity calculation method based on the river and lake water quality limit value in embodiment 1 according to the present application.

The embodiment of the application also provides a computer readable storage medium, and the computer readable storage medium is stored with computer executable instructions, and the computer executable instructions can execute the river basin dynamic water environment capacity calculation method based on the river and lake water quality limit value in the embodiment 1. Wherein the storage medium may be a magnetic Disk, an optical Disk, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), a Flash Memory (Flash Memory), a Hard Disk (HDD), or a Solid State Drive (SSD); the storage medium may also comprise a combination of memories of the kind described above.

It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. And obvious variations or modifications thereof are contemplated as falling within the scope of the present application.

Claims

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

coupling the drainage basin distributed hydrologic model with a one-dimensional water quality model by using a preset conversion model to obtain a drainage basin distributed water quantity water quality model, constructing the drainage basin distributed water quantity water quality model by using a DTVGM model, calibrating the drainage basin distributed water quantity water quality model according to water quality actual measurement data until the drainage basin distributed water quantity water quality model meets the precision requirement, and calculating the outlet water quality concentration of each confluence unit by using the drainage basin distributed water quantity water quality model, wherein the preset conversion model comprises the following steps: a flow rate and flow velocity conversion model and a pollution load distribution model; the water quantity and water quality balancing process comprises the following steps:

Producing the equation of confluence unit hydrologic balance:

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

equation for water concentration balance of confluence unit:

wherein ,ΔV_i The change amount of the water storage amount in the time period for the unit i; q (Q) _i-1 and Q_i The inflow and outflow amounts of water are respectively the units; q _i Taking water for human beings; r is R _i The interval water yield of the unit i;Q _ai for branch inflow, V _i The water storage capacity of unit i; c (C) _Ri Contaminant concentration in the interval product stream; c (C) _ai Is the concentration of the tributary water quality; c (C) _i-1 and C_i The water quality concentrations are respectively input and output by the unit; c (C) _qi Taking the water contaminant concentration for a human; w (W) _p The unit i is the sum of the point source pollution loads; w (W) _d The degradation amount of pollutants in the unit body;

the degradation amount of the pollutants in the unit body comprises: upstream input pollutant degradation amount W _dS The pollutant degradation amount W is input into the branch _dZ Degradation amount W of point source pollutant _dP Degradation amount W of non-point source pollutant _dM ，

wherein K represents a rate constant of contaminant degradation, Q _aij The flow rate of the j-th branch flow; c (C) _aij Contaminant concentration for the j-th substream; l (L) _j The distance between the inlet of the jth tributary and the end of the river reach is the j tributary; TL is the total length of the river reach; w (W) _dG The degradation amount of pollutants at the sewage outlet is generalized; l (L) _G The tail distance of the drain outlet from the river reach is generalized; u is the average river flow rate;

according to the outlet water quality concentration of each confluence unit and the river lake-entering water quality limit value, calculating the dynamic water environment capacity of each confluence unit and the dynamic water environment capacity of a river basin, and calculating the dynamic water environment capacity of each confluence unit through the following formula:

2. The river basin dynamic water environment capacity calculating method based on river basin water quality limit value according to claim 1, wherein the step of coupling the river basin distributed hydrologic model with the one-dimensional water quality model by using a preset conversion model to obtain the river basin distributed water quantity water quality model further comprises:

3. The river basin dynamic water environment capacity calculating method based on the river and lake water quality limit value according to claim 1, wherein the process of constructing the river and lake water quality response model by utilizing the basic data comprises the following steps: selecting a corresponding model according to the requirements of the simulation indexes, and setting global parameters, local parameters and tributary parameters of the model to construct a river and lake water quality response model; wherein,

4. River basin dynamic water environment capacity calculation system based on river and lake water quality limit value, which is characterized by comprising:

the system comprises a basin distributed water quantity and water quality model construction module, a basin distributed water quantity and water quality model calculation module and a basin distributed water quality model calculation module, wherein the basin distributed water quantity and water quality model construction module is used for coupling a basin distributed hydrologic model with a one-dimensional water quality model by utilizing a preset conversion model to obtain a basin distributed water quantity and water quality model, constructing the basin distributed water quantity and water quality model by using a DTVGM 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 outlet water quality concentration of each confluence unit by utilizing the basin distributed water quantity and water quality model, wherein the preset conversion model comprises the following steps: a flow rate and flow velocity conversion model and a pollution load distribution model; the water quantity and water quality balancing process comprises the following steps:

Producing the equation of confluence unit hydrologic balance:

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

equation for water concentration balance of confluence unit:

wherein ,ΔV_i The change amount of the water storage amount in the time period for the unit i; q (Q) _i-1 and Q_i The inflow and outflow amounts of water are respectively the units; q _i Taking water for human beings; r is R _i Interval of unit iWater yield; q (Q) _ai For branch inflow, V _i The water storage capacity of unit i; c (C) _Ri Contaminant concentration in the interval product stream; c (C) _ai Is the concentration of the tributary water quality; c (C) _i-1 and C_i The water quality concentrations are respectively input and output by the unit; c (C) _qi Taking the water contaminant concentration for a human; w (W) _p The unit i is the sum of the point source pollution loads; w (W) _d The degradation amount of pollutants in the unit body;

the dynamic water environment capacity calculation module is used for calculating the dynamic water environment capacity of each confluence unit and the dynamic water environment capacity of the river basin according to the outlet water quality concentration of each confluence unit and the river water inflow and lake water quality limit value, and the dynamic water environment capacity of each confluence unit is calculated through the following formula:

5. A computer terminal device, comprising: at least one processor, and a memory communicatively coupled to the at least one processor, wherein the memory stores instructions executable by the at least one processor to cause the at least one processor to perform the river basin dynamic water environment capacity calculation method based on river and lake water quality limits of any one of claims 1-3.

6. A computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions for causing the computer to perform the river basin dynamic water environment capacity calculation method based on river basin water quality limit values according to any one of claims 1 to 3.