CN105224772A - A kind of Nenjiang representative region Ecology methods of risk assessment based on system dynamics decision model - Google Patents

Abstract

Based on a Nenjiang representative region Ecology methods of risk assessment for system dynamics decision model, it relates to a kind of Nenjiang representative region Ecology methods of risk assessment.Method of the present invention is: by the influential branch afflux of pollution source amount of putting in storage Nierji reservoir, non-point source discharges, upland water and riverine emission factor are by system dynamics decision model, simulate the effect that different resolutions reduces reservoir ecological risk, implementation decision-making, and on the basis of Ecology risk indicator system, evaluate the Ecology risk status of different times difference position in storehouse, lake, based on the sample space of Netica software building Bayesian network, calculate the probability to ecological risk generation in various degree when each index changes, thus realize the risk assessment of Nenjiang representative region Ecology.The present invention is applied to the representative region Ecology risk assessment of basin, river.

Description

A kind of Nenjiang representative region Ecology methods of risk assessment based on system dynamics decision model

Technical field

The present invention relates to a kind of Nenjiang representative region Ecology methods of risk assessment.

Background technology

System dynamics (Systemdynamics, SD), taught by Massachusetts Institute of Technology (MIT) professor J.W.Forrester at first and propose with the 1950's, the Resolving probiems being devoted to Industrial Management is caused in early days what study, and be called as industrial dynamics, through the development of 20 century 70s, day by day move to maturity, WORLDII and WORLDIII model based on system dynamics has derived the scientific payoffs that world dynamics and " increment multiplier " etc. have great significance to development of human history respectively, phase also adopts the method for system dynamics to analyze to the socioeconomic problem of the U.S. to professor Forrester at this moment, explain the inherent mechanism etc. of the economic Long-term Fluctuation of the U.S. and western countries.To the nineties in 20th century, a large amount of system dynamics scientific payoffss occurs, the application of system dynamics is throughout the every field of research and production, the scientists of Club of Rome to 1970 on the basis that the data of nineteen ninety are tested, WORLDIII model is revised, publish thus " exceeding the maximum: face global collapse and look forward to a continuable future ", attempt the tight relationship fundamentally breaking through man and nature, R.F.Nail then adopts the national energy policy plan of system dynamics model to the U.S. to assess, and estimated the cost that the energy policy that the U.S. is intended to strengthen global warming spends accordingly.And domestic at us, the experts and scholars such as from 20 century 70s, introduce the concept of system dynamics gradually, and progressively launch the research and apply to it, wherein emerging large quantities of such as poplar leads to friendship, Wang Qifan, Tao Piao and Hu Yukui.

(1) intension: system dynamics is the subject of an analysis and research information feedback system, also be a recognition system problem and intercrossing, the comprehensive branch of learning solving system problem, from the angle of system methodology, system dynamics is an entity about system architecture, function and historical approach, it with the theory of systematology for core, be the form of expression with kybernetics, combine closely with technical development of computer, the problem of resolution system feedback arrangement and behavior.Have above feature just because of system dynamics, the relation between the variable that model is different from real life just can adopt the feedback mechanism of system dynamics to make an explanation and analysis, such as arms race etc.

(2) form: system dynamics is for the angle of problem, be starting point from the pass of the interdependence between system action and its inner principle, and show with the form of mathematical model, progressively find, understand problem Emergence and Development and change because of, fruit relation and causal directivity, the namely structure of problem.Problem itself is then made up of structures different one by one, the network that its cause-effect relationship all linked with one another or decision rule are formed, and this institutional framework determines the characteristic of system action.Just because of this, system dynamics has the ability and universality that process most of information feedback system problem.Different structure in different problem is divided into following main element according to its variation pattern by system dynamics, is respectively flow variable, level variable and auxiliary variable.

Level variable: be also called storehouse variable, refer to the amount that Commodity flow etc. is accumulated in internal system, tank farm stock even population etc. such as, in solution in the liquid level of liquid, commercial production, its amount of accumulating within certain time interval should be relevant with the change of flow variable in this time period.

Flow variable: the description being system activity itself is the change of material amount in system in the unit interval, and because level variable is only by the impact of flow variable, therefore flow variable is also referred to as decision function.

Auxiliary variable: auxiliary variable is the data of the maximum existed in system dynamics research, it is different from level variable and flow variable, it both can be constant also can be variable, be mainly used in representing the pilot process of consulting process, the different parameters value of model, and for the input test function etc. of pattern.

Conserved: also become Commodity flow, represents the material flowed in systems in which.Material needs the time in flow process, therefore there is delay phenomenon.

Non-conservation stream: also claim information flow is the information channel of connection status variable and rate variable.Conserved is controlled device but not Conserved then belongs to decision-making foundation.

Source point and meeting point: source point and meeting point represent the inside of system, relative to the real system having accumulation that we are concerned about, source point and meeting point represent those parts beyond our your Study system boundary.

(3) modeling process:

1. the problem that will solve is expressed clearly, the border of certainty annuity:

In order to how its feature occurs and describe expression problem, the time limit should trace back to history enough far away, and the time also should extend to future enough far away, to catch the remote effect of the policy that may take.Namely one large defect of universal model is that we tend to cause-effect relationship is envisioned as local with immediately, but in dynamic complex system, cause and effect may a good distance off over time and space, great majority cause spinoff that is that decision-making was lost efficacy and that do not expect etc. to comprise the feedback of long delay, therefore the understandability of the problem of impact should be taken into full account in the selection realized, and for the evaluation of policy.

2. propose about the causal dynamic hypothesis of problem or theory:

Endogenous to explain: the endogenous theoretical reciprocation by the variable in model and factor produces the dynamic behaviour of system, therefore by associating the decision rule of impact between the structure of define system inside and different element, can predict and the system action that this decision rule responds mutually, and study under the hypothesis changing system architecture and decision rule, the dynamic law of system action.Just because of this, we need drawing system structural drawing to help us to carry out combing and understanding for internal system domain relation.

Drawing system structural drawing: model boundary figure---a model boundary figure by listing endogenous variable, exogenous variable and storage discharge diagram, wherein should not there is obvious feedback arrangement in exogenous variable; The one-piece construction that subsystem figure---subsystem figure shows model comprises logistics, cash flow and information flow between subsystem, by showing quantity and the type of representative different tissues, subsystem graph expression about model border and summarize the information of degree, also to pass on information that is raw in some and exogenous variable; Casual loop diagram---model boundary figure and subsystem figure shows border and the system of model, but the relation do not shown between variable, and a flexible useful instrument of casual loop diagram to be any field delineate feedback arrangement aspect, be causal figure between display variable; Storage discharge diagram---casual loop diagram highlights the feedback arrangement of system, storage discharge diagram then highlights the physical arrangement of its behind, as previously mentioned, what storage discharge diagram was followed the trail of is the accumulation of internal system logistics, cash flow and information flow, storage comprises stock, the population and finance account etc. of product, and flow is the speed that storage increases or reduces, storage characterizes the state of system and produces as the information of decision basis.Decision-making changes the speed of flow, changes the backfeed loop in storage and loop system; Policy structure figure---policy structure figure shows the cause-and-effect diagram of specific decision rule information input, policy structure figure pays close attention to modeling person and supposes that decision makers uses the information of flow in control system, there is shown the causal structure and time delay that design in specific decision-making, instead of the feedback arrangement of whole system.

3. equation is write:

Proceed to the quantitative model of fully definition from the field of concept map, it should possess all formula, parameter and starting condition etc.

4. test:

Part test be that the simulation behavior of model and the real behavior of system are compared, but test than representation of the historical behavior relate to more.Model must under extreme conditions be tested: extreme condition test becomes the key tool finding model defect, and provides possibility to the deep understanding of model.

5. policy design and assessment:

Redesign storage flow structure, eliminate time delay, change the information quality and information flow that utilize in the decision point of key, even fundamentally reformulate the decision process of actor in system.Therefore must assess the interaction between the sensitivity of model parameter and structural uncertainty and different policy policy robustness and they.

6. the principle of system dynamic modeling:

A. solve specific problem, instead of be system modelling; B. from modeling is combined with whole problem; C. suspection attitude is held all the time to the value of modeling; D. system dynamics is not single isolated, in appropriate circumstances, additive method should be used to combine with system dynamics with instrument; E. the implementation process of decision-making is noticed; F. client and modeling person query repeatedly to modeling process jointly; G. black-box modeling should be avoided in the process of modeling; H. model is carried out to the inspection of continuation; I. available rudimentary model is set up as early as possible; J. the border of model should be roomy as much as possible; K. should take into full account that policy affects for the persistence of model.

Domestic research in ecology language at present is still mainly present in ecological security of water environment warning aspect, mainly utilizes " state one pressure one responds " model, sets up Environment Ecological Safe assessment indicator system.He Yan takes composite index law to compare effectively evaluating index in conjunction with its set up for Ecological security assessment of water environment, on the basis that this analyzes, in conjunction with quantitative method, the alert of ecological security of water environment is differentiated from the change profile of horizontal and vertical aspect.Wen Jun constructs warning index method about sustainable utilization of water resource and system, and the mathematical method that application is relevant carries out modeling, build water resource at the regional level in be able to the Early-warning Model of sustainable use.In addition, in the technical research of ecology language, Zhou Xiaohui etc., referring in ecology language to the technical monitoring of the ecosystem, classify to ecosystem monitoring target, build index system, predict its development trend.Liu Pu luckily carries out risk assessment by the Ecological and environmental warning assessment indicator system of analytical hierarchy process to the oasis, Jiuquan that it builds, and has made Alarm Assessment analysis to its state of ecological environment, and proposes the prophylactico-therapeutic measures of main ecological problem on this basis.And, be directed to Ecology risk assessment not a kind of effective method of Nenjiang.

Summary of the invention

The present invention is directed to above-mentioned Problems existing, and propose a kind of Nenjiang representative region Ecology methods of risk assessment based on system dynamics decision model.

A kind of Nenjiang representative region Ecology methods of risk assessment based on system dynamics decision model of the present invention, it carries out according to following content: by the influential branch afflux of pollution source amount of putting in storage Nierji reservoir, non-point source discharges, upland water and riverine emission factor are by system dynamics decision model, simulate the effect that different resolutions reduces reservoir ecological risk, realize implementation decision-making, and on the basis of Ecology risk indicator system, evaluate the Ecology risk status of different times difference position in storehouse, lake, based on the sample space of Netica software building Bayesian network, calculate the probability to ecological risk generation in various degree when each index changes, thus realize the risk assessment of Nenjiang representative region Ecology.

The present invention comprises following beneficial effect:

The present invention utilizes the Nenjiang representative region Ecology Risk Assessment Index System established, ecological risk assessment is carried out to Nierji reservoir, and utilize system dynamics to set up the Nenjiang County socio-economic development of Nierji reservoir upstream, and the interactive response relation between the Nierji reservoir Ecology risk of downstream, finally sets up early warning mechanism and the theoretical foundation of Nenjiang Typical Areas with Bayesian network.

Thus enrich both at home and abroad about the research field of ecological risk assessment, research and decision-making, accelerate the practical engineering application of ecological risk assessment, innovate the method for Ecology risk assessment, analyze the relation of Ecology risk assessment and Nierji reservoir Ecology risk status, propose the Ecology risk assessment for Nenjiang Typical Areas, for follow-up foundation evaluation-early warning-decision-making platform provides theoretical foundation and technical support.

The present invention is on the basis constructing Nenjiang representative region Ecology Risk Assessment Index System, consider upland water, all key elements such as branch afflux (Gan He) and socio-economic development are on the impact of Nierji reservoir Ecology risk, adopt Ithink software platform, construct the socio-economic development of reservoir upstream area, upstream branching flow imports, storehouse, lake surrounding landscape changes the system dynamics model with the interactive corresponding relation of the Ecology risk of reservoir.By the setting to system dynamics model correlation parameter, simulate the effect that different resolutions reduces reservoir ecological risk, contrast optimal case, implementation decision-making;

The present invention on the basis of Ecology risk indicator system, evaluate the Ecology risk status of different times difference position in storehouse, lake, based on the sample space of Netica software building Bayesian network, calculate to the probability that ecological risk in various degree occurs when each index changes, thus realize completing early warning to ecological risk probability of happening in various degree by monitoring relevant ecological risk assessment index.

Accompanying drawing explanation

Fig. 1 is Technology Roadmap of the present invention;

Fig. 2 is population Population number dynamic imitation result figure;

Fig. 3 is GDP Population number dynamic imitation result figure;

Fig. 4 is agriculture GDP and agriculture GDP accounting analog result figure;

Fig. 5 is end, Fasten Joint Bolt storehouse COD concentration of analog result figure;

Fig. 6 is end, Nierji reservoir storehouse COD concentration of analog result figure under the COD bleed strategy of control life source;

Fig. 7 is end, Nierji reservoir storehouse COD concentration of analog result figure under control industrial source COD bleed strategy;

Fig. 8 is end, Nierji reservoir storehouse COD concentration of analog result figure under control upland water strategy;

Fig. 9 imports strategy lower Nierji reservoir storehouse end COD concentration of analog result figure for controlling direct current;

Figure 10 is end, Nierji reservoir storehouse COD concentration of analog result figure under adjustment land use strategy;

Figure 11 is Nierji reservoir ammonia nitrogen concentration analog result figure under Different Strategies;

Figure 12 is Nierji reservoir total nitrogen concentration analog result figure under Different Strategies;

Figure 13 is Nierji reservoir total phosphorus analog result figure under Different Strategies;

Figure 14 is characteristic contamination emission transaction result figure under adjustment land use strategy.

Embodiment

Embodiment one: a kind of Nenjiang representative region Ecology methods of risk assessment based on system dynamics decision model of present embodiment, it carries out according to following content:

By the influential branch afflux of pollution source amount of putting in storage Nierji reservoir, non-point source discharges, upland water and riverine emission factor are by system dynamics decision model, simulate the effect that different resolutions reduces reservoir ecological risk, realize implementation decision-making, and on the basis of Ecology risk indicator system, evaluate the Ecology risk status of different times difference position in storehouse, lake, based on the sample space of Netica software building Bayesian network, calculate the probability to ecological risk generation in various degree when each index changes, thus realize the risk assessment of Nenjiang representative region Ecology.

Embodiment two: present embodiment and embodiment one unlike: described riverine blowdown formula is:

PSICODNJ＝PSICOD×PSICODCR

PSICOD＝IGDP×CODpIGDP×ICODDR

In formula, PSICODNJ is that Nenjiang Model of The Labahe sewage draining exit COD enters river amount;

PSICOD is Nenjiang County Model of The Labahe sewage draining exit discharge capacity;

PSICODCR is that industrial point source COD discharges river pollutant sources;

CODpIGDP is ten thousand yuan of industrial added value COD discharge capacitys

ICODDR is that Model of The Labahe sewage draining exit discharge COD accounts for Nenjiang County industrial sites source emission COD ratio.Other is identical with embodiment one.

Embodiment three: present embodiment and embodiment one are unlike Nierji reservoir upstream, blowdown point main in master stream, Nenjiang is the sanitary sewage discharge of Nenjiang County sewage treatment plant and the industrial wastewater discharge of Nenjiang County Model of The Labahe sewage draining exit, the two all comes from the socio-economic development of Nenjiang County, is subject to the impact of Nenjiang County population and socio-economic development.Other is identical with embodiment one.

Embodiment four: present embodiment and embodiment one unlike: the quantity of Nenjiang County population should be following formula:

POP(t)＝POP(t-1)+increase+Decrease

In formula, POP (t) is Nenjiang County population during t, and POP (t-1) is the population during t-1 of Nenjiang County;

Increase is the population recruitment in Nenjiang County year from t-1 to t

Decrease is the population decline amount in Nenjiang County year from t-1 to t;

Under not considering the prerequisite of urbanization rate year border, Nenjiang County change conditions, Nenjiang County nonagricultural population's quantity can be expressed by following formula:

UP＝POP×UR

In formula, UP is nonagricultural population's quantity of Nenjiang County t

UR is the urbanization rate of Nenjiang County t.

Other is identical with embodiment one.

Embodiment five: present embodiment and embodiment one unlike: Nenjiang County sanitary sewage drains into the computing formula measured in river and can calculate according to following formula:

PSLCODNJ＝PSLCOD×PSLCODCR

PSLCOD＝UP×CODpUP×SPDR

In formula, PSLCODNJ is that Nenjiang County sanitary sewage drains into river COD and measures;

PSLCODCR is life point source COD discharge river pollutant sources;

CODpUP is the amount that annual unit nonagricultural population discharges COD;

SPDR is the ratio that Nenjiang County sewage treatment plant discharge capacity accounts for Nenjiang County total emission volumn;

Nenjiang County industrial added value change formula is as follows:

IGDP(t)＝IGDP(t-1)+IGDPI(t)

IGDPI(t)＝IGDP(t-1)×IGDPR

In formula, IGDP (t) is the industrial added value amount of Nenjiang County t;

The industrial added value amount that IGDP (t-1) is Nenjiang County t-1;

IGDPI (t) is t Nenjiang County industrial added value increment;

IGDPR is Nenjiang County industrial added value rate of growth.

Other is identical with embodiment one.

Embodiment six: present embodiment and embodiment one unlike: described non-point pollution formula is:

NPSCODE＝NPSCOD×NPSCODC

NPSCOD＝CODDL+CODFL+TreeL×CODpTc+GrassL×CODpGC+UncoverL×CODpUCC+UrbanL×CODpUC

CODDL＝DLA×CODpDLC+DLA×FUS×FUScr

CODFL＝FLA×CODpFLC+FLA×FUS×FUScrF

In formula, NPSCODE is that non-point source COD drains into river amount;

NPSCOD is that non-point source COD creates;

NPSCODC is non-point pollution discharge river pollutant sources;

CODDL is that dry land produces COD amount;

CODFL is that paddy field produces COD amount;

TreeL is study area forest land area;

CODpTC is forest land COD output coefficient;

GrassL is study area grassland area:

CODpGC is meadow COD output coefficient;

UncoverL is the waste ground area in study area;

CODpUCC is wasteland COD output coefficient;

UrbanL is study area construction land area;

GDPpUC is construction land COD output coefficient;

DLA is study area dry land area;

CODpDLC is dry land output coefficient;

FUS is unit arable land applying quantity of chemical fertilizer in study area;

FUScr is study area dry land chemical fertilizer efficiency;

FLA is paddy field, study area area;

CODpFLC is paddy field output coefficient;

FUScr is paddy field, study area chemical fertilizer efficiency.

Other is identical with embodiment one.

Embodiment seven: present embodiment and embodiment one unlike: described branch afflux formula is as follows:

$CODPW=\frac{(CODUT\×QUT+PSLCODNJ\×NJLQ+PSICODNJ\×NJIQ)}{(NJLQ+NJIQ+QUT)}$

$CODGH=CODPW\×\exp (-\frac{k1+l1}{v1})$

$CODGHHUI=\frac{(CODGH\×QUTT+CODLJT\×QLJT)}{(QUTT+QLJT)}$

QUTT＝QUT+NJLQ+NJIQ

$endPSCOD=CODGHHUI\×\exp \left(\frac{-k2\×l2}{v2}\right)$

endCOD＝endPSCOD×(QUTT+QLJT)+NPSCOD

In formula, CODPW is the COD concentration at sewage draining exit place, Nenjiang County;

CODUT is upland water concentration;

QUT is upland water flow;

PSLCODNJ is Nenjiang County Sewage Plant sewage draining exit concentration of emission;

NJLQ is Nenjiang County Sewage Plant quantity of wastewater effluent;

PSICODNJ is Nenjiang County Model of The Labahe sewage draining exit concentration of emission;

NJIQ is Nenjiang County Model of The Labahe sewage draining exit discharge capacity;

CODGH is the COD concentration of Gan He remittance place;

K1 is the COD degradation coefficient of section between upland water section to sewage draining exit;

L1 is that the river of section between upland water section to sewage draining exit is long;

V1 is the flow velocity of section between upland water section to sewage draining exit;

CODGHHUI is that Gan He imports some place COD concentration;

QUTT is that upland water converges Nenjiang County blowdown sewage quantity;

CODLJT is sweet river COD concentration;

QLJT is sweet river flow;

EndPSCOD is end, Fasten Joint Bolt storehouse COD point source concentration;

K2 is the COD degradation coefficient that Gan He imports section between point to end, Fasten Joint Bolt storehouse;

L2 is that the river of section between Gan He remittance point to end, Fasten Joint Bolt storehouse is long;

V2 is the flow velocity that Gan He imports section between point to end, Fasten Joint Bolt storehouse.

Other is identical with embodiment one.

Embodiment eight: present embodiment and embodiment one unlike: branch afflux formula obtains based on under type: the water of Nierji reservoir imports from the non-point source in the water of limekiln, upstream section and the water of upstream branching flow and region, master stream, and main pollution source is that downstream Gan He imports, upland water and non-point source import; To import as major pollutants source builds model with upland water water quality and Gan He remittance, riverine discharge, non-point source.Other is identical with embodiment one.

Embodiment nine: present embodiment and embodiment one unlike: described characteristic contamination formula is:

NPCE＝NPC×NPCC

NPC＝DLA×CUS×CUSr+FLA×CUS×CUSrF

In formula, NPCE is characteristic contamination discharge capacity;

NPC is characteristic contamination generation;

NPCC is characteristic contamination discharge river pollutant sources;

CUS is the amount of application in every mu, agricultural chemicals farmland;

CUSr is dry land residues of pesticides coefficients;

CUSrF is paddy field residues of pesticides coefficient.

Other is identical with embodiment one.

Embodiment ten: present embodiment and embodiment one unlike: characteristic contamination be based on paddy field, the dry land applications of pesticide residual with discharge for index carries out calculating.Other is identical with embodiment one.

Content of the present invention is not limited only to the content of the respective embodiments described above, and the combination of one of them or several embodiment equally also can realize the object of inventing.

Effect of the present invention is verified by following examples:

Embodiment 1

1, model construction

Based on the analysis in Fasten Joint Bolt upstream TP, TN source, the known pollution source amount impact on Nierji reservoir warehouse-in is larger is branch afflux, non-point source discharge, upland water and riverine blowdown, therefore the present embodiment inquires into its origin cause of formation from above four aspects, its system dynamics decision model of the components such as main influence factor.

(1) riverine blowdown

Nierji reservoir upstream, blowdown point main in master stream, Nenjiang is the sanitary sewage discharge of Nenjiang County sewage treatment plant and the industrial wastewater discharge of Nenjiang County Model of The Labahe sewage draining exit, the two all comes from the socio-economic development of Nenjiang County, is subject to the impact of Nenjiang County population and socio-economic development.Therefore we construct following system dynamics model to simulate the impact of socio-economic development on Nenjiang County sewage draining exit, thus realize optimizing Nenjiang County socio-economic development form control Nenjiang County blowdown flow rate, reduce the Nierji reservoir Ecology risk caused by a source emission.

Population variety is subject to population and increases and unpeopled impact, and do not consider the change conditions of population growth rate and population decline rate, so the quantity of Nenjiang County population should be following formula:

POP(t)＝POP(t-1)+increase+Decrease

In formula, POP (t) is Nenjiang County population during t, and POP (t-1) is the population during t-1 of Nenjiang County;

Increase is the population recruitment in Nenjiang County year from t-1 to t

Decrease is the population decline amount in Nenjiang County year from t-1 to t.

And under not considering the prerequisite of urbanization rate year border, Nenjiang County change conditions, Nenjiang County nonagricultural population's quantity can be expressed by following formula:

UP＝POP×UR

In formula, UP is nonagricultural population's quantity of Nenjiang County t

UR is the urbanization rate of Nenjiang County t.

And agricultural population is different from the day discharge coefficient of nonagricultural population, when known nonagricultural population's quantity and nonagricultural population's pollutant discharge coefficient, the amount of pollutant discharged in the sanitary sewage discharge process of Nenjiang County can be calculated, simultaneously discharge how coefficient and Nenjiang County Sewage Plant blowdown flow rate according to sanitary sewage and account for the ratio of Nenjiang County total amount of pollutants discharged, Nenjiang County Sewage Plant blowdown flow rate can be calculated.

The computing formula that Nenjiang County sanitary sewage drains into river amount can calculate according to following formula:

PSLCODNJ＝PSLCOD×PSLCODCR

PSLCOD＝UP×CODpUP×SPDR

In formula, PSLCODNJ is that Nenjiang County sanitary sewage drains into river COD and measures;

PSLCODCR is life point source COD discharge river pollutant sources;

CODpUP is the amount that annual unit nonagricultural population discharges COD;

SPDR is the ratio that Nenjiang County sewage treatment plant discharge capacity accounts for Nenjiang County total emission volumn;

And put source emission except sanitary sewage, the contaminant capacity of the generation of industrial production wastewater is the large source of another of source emission, and in model, we adopt ten thousand yuan of industrial added values and unit industrial added value pollutant discharge amount to be main index.

Nenjiang County industrial added value change is subject to the impact that Nenjiang County industrial added value increases, and when increment is timing, its total amount rises, otherwise total amount declines, and is expressed as following formula by formula:

IGDP(t)＝IGDP(t-1)+IGDPI(t)

IGDPI(t)＝IGDP(t-1)×IGDPR

In formula, IGDP (t) is the industrial added value amount of Nenjiang County t;

The industrial added value amount that IGDP (t-1) is Nenjiang County t-1;

IGDPI (t) is t Nenjiang County industrial added value increment;

IGDPR is Nenjiang County industrial added value rate of growth.

The COD amount of Nenjiang County industrial sites source emission is subject to Nenjiang County industrial added value, ten thousand yuan, Nenjiang County industrial added value pollutant discharge amount, Model of The Labahe sewage draining exit discharge capacity accounts for the ratio of Nenjiang County industrial sites source emission amount, and the impact of industrial sites source emission river pollutant sources, and computing formula is as follows:

PSICODNJ＝PSICOD×PSICODCR

PSICOD＝IGDP×CODpIGDP×ICODDR

In formula, PSICODNJ is that Nenjiang Model of The Labahe sewage draining exit COD enters river amount;

PSICOD is Nenjiang County Model of The Labahe sewage draining exit discharge capacity;

PSICODCR is that industrial point source COD discharges river pollutant sources;

CODpIGDP is ten thousand yuan of industrial added value COD discharge capacitys

ICODDR is that Model of The Labahe sewage draining exit discharge COD accounts for Nenjiang County industrial sites source emission COD ratio.

The riverine discharge capacity of ammonia nitrogen, total phosphorus and total nitrogen can be calculated according to above model and method.

(2) non-point pollution

The rainwash that non-point pollution mainly comes from precipitation generation washes away, and the ground mulching impact being subject to study area is comparatively obvious, and therefore during Modling model, we mainly consider the pollutant output coefficient of different land use type and different land use type.It should be noted that socio-economic development is on to exist during the affecting of land use change survey herein, but because our time and space yardstick of model is less, and the process that the change of land use pattern just can manifest under the long-time span of large spatial scale often, therefore, in this model, land use change survey situation is considered to constant.

The non-point source discharge of COD comprises farmland, paddy field with farmland, forest land, meadow, Urban Construction Land_use and wasteland are main, wherein farmland includes output coefficient and the content ratio due to pollutant in the consumption of using chemical fertilizer and chemical fertilizer, and therefore the discharge of its non-point source can according to following formulae discovery.

NPSCODE＝NPSCOD×NPSCODC

NPSCOD＝CODDL+CODFL+TreeL×CODpTc+GrassL×CODpGC+UncoverL×CODpUCC+UrbanL×CODpUC

CODDL＝DLA×CODpDLC+DLA×FUS×FUScr

CODFL＝FLA×CODpFLC+FLA×FUS×FUScrF

In formula, NPSCODE is that non-point source COD drains into river amount;

NPSCOD is that non-point source COD creates;

NPSCODC is non-point pollution discharge river pollutant sources;

CODDL is that dry land produces COD amount;

CODFL is that paddy field produces COD amount;

TreeL is study area forest land area;

CODpTC is forest land COD output coefficient;

GrassL is study area grassland area:

CODpGC is meadow COD output coefficient;

UncoverL is the waste ground area in study area;

CODpUCC is wasteland COD output coefficient;

UrbanL is study area construction land area;

GDPpUC is construction land COD output coefficient;

DLA is study area dry land area;

CODpDLC is dry land output coefficient;

FUS is unit arable land applying quantity of chemical fertilizer in study area;

FUScr is study area dry land chemical fertilizer efficiency;

FLA is paddy field, study area area;

CODpFLC is paddy field output coefficient;

FUScr is paddy field, study area chemical fertilizer efficiency.

The situation that the model of the non-point source discharge of ammonia nitrogen, total phosphorus, total nitrogen, formula and COD pollute is similar, therefore can simulate the discharge of ammonia nitrogen, total nitrogen and total phosphorus according to above model structure and formula.

(3) upland water and upstream branching flow import

The water of Nierji reservoir imports from the non-point source in the water of limekiln, upstream section and the water of upstream branching flow and region, master stream, by TP, TN pollution source analysis before, can recognize, main pollution source is that downstream Gan He remittance, upland water and non-point source import.Therefore we import as major pollutants source builds model with upland water water quality and Gan He remittance, riverine discharge, non-point source.

The water quality to Nenjiang County sewage draining exit is gone out according to quality and water balanced calculation by upland water water quality and flow, and have the discharge capacity of sewage draining exit and sewage effluent amount to go out the water quality to Gan He remittance place according to one dimension water quality formulae discovery, and continue according to Gan He remittance water quality and sweet river flow the amount of pollutant extrapolating end, Fasten Joint Bolt storehouse, and the amount of the pollutant discharged with non-point source combines, and calculates the pollutant load in Nierji reservoir according to the storage capacity of Nierji reservoir.And can calculate according to the following formula.

$CODPW=\frac{(CODUT\×QUT+PSLCODNJ\×NJLQ+PSICODNJ\×NJIQ)}{(NJLQ+NJIQ+QUT)}$

$CODGH=CODPW\×\exp (-\frac{k1\×l1}{v1})$

$CODGHHUI=\frac{(CODGH\×QUTT+CODLJT\×QLJT)}{(QUTT+QLJT)}$

QUTT＝QUT+NJLQ+NJIQ

$endPSCOD=CODGHHUI\×\exp \left(\frac{-k2\×l2}{v2}\right)$

endCOD＝endPSCOD×(QUTT+QLJT)+NPSCOD

In formula, CODPW is the COD concentration at sewage draining exit place, Nenjiang County;

CODUT is upland water concentration;

QUT is upland water flow;

PSLCODNJ is Nenjiang County Sewage Plant sewage draining exit concentration of emission;

NJLQ is Nenjiang County Sewage Plant quantity of wastewater effluent;

PSICODNJ is Nenjiang County Model of The Labahe sewage draining exit concentration of emission;

NJIQ is Nenjiang County Model of The Labahe sewage draining exit discharge capacity;

CODGH is the COD concentration of Gan He remittance place;

K1 is the COD degradation coefficient of section between upland water section to sewage draining exit;

L1 is that the river of section between upland water section to sewage draining exit is long;

V1 is the flow velocity of section between upland water section to sewage draining exit;

CODGHHUI is that Gan He imports some place COD concentration;

QUTT is that upland water converges Nenjiang County blowdown sewage quantity;

CODLJT is sweet river COD concentration;

QLJT is sweet river flow;

EndPSCOD is end, Fasten Joint Bolt storehouse COD point source concentration;

K2 is the COD degradation coefficient that Gan He imports section between point to end, Fasten Joint Bolt storehouse;

L2 is that the river of section between Gan He remittance point to end, Fasten Joint Bolt storehouse is long;

V2 is the flow velocity that Gan He imports section between point to end, Fasten Joint Bolt storehouse.

The situation that the model of the simulation of water quality of ammonia nitrogen, total phosphorus, total nitrogen, formula and COD pollute is similar, therefore can simulate the water quality condition of ammonia nitrogen, total nitrogen and total phosphorus according to above model structure and formula.

(4) simulation of characteristic contamination

The data of characteristic contamination are not had in Monitoring Data due to upland water, Gan He remittance, sewage draining exit, therefore cannot consider the research of this part characteristic contamination in modeling, in this research of source of therefore characteristic contamination, be thought of as the residual and discharge of paddy field, the dry land applications of pesticide.

NPCE＝NPC×NPCC

NPC＝DLA×CUS×CUSr+FLA×CUS×CUSrF

In formula, NPCE is characteristic contamination discharge capacity;

NPC is characteristic contamination generation;

NPCC is characteristic contamination discharge river pollutant sources;

CUS is the amount of application in every mu, agricultural chemicals farmland;

CUSr is dry land residues of pesticides coefficients;

CUSrF is paddy field residues of pesticides coefficient.

By the discharge capacity of above formulae discovery characteristic contamination, simultaneously because characteristic contamination is comparatively difficult to degraded, therefore in pollutant emission process, do not consider its degraded situation.

2, system dynamics model and data

Concrete model formation and data as follows:

AGDP(t)＝AGDP(t-dt)+(AGDPI)*dt

INITAGDP＝645107

INFLOWS:

AGDPI＝AGDP*AGDPR

CropP(t)＝CropP(t-dt)+(CropPI)*dt

INITCropP＝1506622

INFLOWS:

CropPI＝CropP*CropPIR

IGDP(t)＝IGDP(t-dt)+(IGDPI)*dt

INITIGDP＝215405

INFLOWS:

IGDPI＝IGDP*IGDPR

pop(t)＝pop(t-dt)+(increase-Decrease)*dt

INITpop＝504345

INFLOWS:

increase＝pop*IR

OUTFLOWS:

Decrease＝pop*DR

SGDP(t)＝SGDP(t-dt)+(SGDPI)*dt

INITSGDP＝439703

INFLOWS:

SGDPI＝SGDP*SGDPR

AGDPCR＝AGDP/GDP

AGDPR＝(0.0044*(CropP/10000)^2+0.0092*(CropP/10000)+0.1246)/10000

CODDL＝DLA*CODpDLC+DLA*FUS*FUScr

CODFL＝FLA*CODpFLC+FLA*FUScrF*FUS

CODGH＝CODPW*EXP(-K1*L1/V1)

CODGHHUI＝(CODGH*QUTT+QLJT*CODLJT)/(QUTT+QLJT)

CODLJT＝10920

CODpDLC＝17000000

CODpFLC＝20000000

CODpGC＝17000000

CODpIGDP＝21295148

CODpTC＝17000000

CODpUC＝14500000

CODpUCC＝17000000

CODpUP＝95295955.67

CODPW＝(PSLCODNJ*NJLQ+PSICODNJ*NJIQ+QUT*CODUT)/(NJIQ+NJLQ+QUT)

CODUT＝19720

CropL＝416548

CropPIR＝(CropPP-CropP)/CropP

CropPP＝-26.371*(CropL*FUS+CUS*0)^2+1357*(CropL*FUS+CUS*0)+34784

CUS＝CUSC*(1+GDPCR)

CUSC＝0.0025

CUSr＝1

CUSrF＝1

DLA＝271017

DR＝0.0048

endCODT＝(NPSCOD+endPSCOD*(QUTT+QLJT))

endNHNT＝endPSNHN*(QLJT+QUTT)+NPSNHN

endPSCOD＝CODGHHUI*EXP(-K2*L2/V2)

endPSNHN＝NHNGHHUI*EXP(-KNH2*L2/V2)

endPSTN＝TNGHHUI*EXP(-KTN2*L2/V2)

endPSTP＝TPGHHUI*EXP(-KTP2*L2/V2)

endTNT＝NPSTN+endPSTN*(QLJT+QUTT)

endTPT＝endPSTP*(QLJT+QUTT)+NPSTP

FLA＝1773

FUS＝FUSC*(1+GDPCR)

FUSC＝0.073

FUScr＝0

FUScrF＝0

FUSnr＝0

FUSnrF＝0

FUStnr＝0

FUStnrF＝0

FUStpr＝0

FUStprF＝0

GDP＝AGDP+IGDP+SGDP

GDPCR＝AGDPCR/9

GrassL＝157986

ICODDR＝0.89

IGDPR＝0.12

INHNDR＝0.93

IR＝0.007

ITNDR＝0.9

ITPDR＝0.8

K1＝0.00001

K2＝0.001

KNH1＝0.05

KNH2＝0.05

KTN1＝0.015

KTN2＝0.015

KTP1＝0.016

KTP2＝0.016

L1＝7000

L2＝8000

LNHNDR＝0.82

LTNDR＝0.8

LTPDR＝0.8

NEJendCOD＝endCODT/NEJV

NEJendNHN＝endNHNT/NEJV

NEJendTN＝endTNT/NEJV

NEJendTP＝endTPT/NEJV

NEJV＝6456000000

NHNDL＝DLA*NHNpDLC+DLA*FUS*FUSnr

NHNFL＝FLA*NHNpFLC+FLA*FUS*FUSnrF

NHNGH＝NHNPW*EXP(-KNH1*L1/V1)

NHNGHHUI＝(NHNLJT*QLJT+NHNGH*QUTT)/(QLJT+QUTT)

NHNLJT＝479

NHNpDLC＝1850000

NHNpFLC＝1800000

NHNpGC＝1850000

NHNpIGDP＝131015.26

NHNpTC＝1850000

NHNpUC＝1200000

NHNpUCC＝1850000

NHNpUP＝1417302

NHNPW＝(QUT*NHNUT+NJIQ*PSINHN+NJLQ*PSLNHN)/(NJIQ+NJLQ+QUT)

NHNUT＝577

NJIQ＝3890000*(1+IGDPR)

NJLQ＝5475000*(1+IR-DR)

NPC＝DLA*CUS*CUSr+FLA*CUS*CUSrF

NPCC＝0.9

NPCE＝NPCC*NPC

NPSCOD＝UrbanL*CODpUC+UncoverL*CODpUCC+TreeL*CODpTC+GrassL*CODpGC+CODDL+CODFL

NPSCODC＝1

NPSCODE＝NPSCOD*NPSCODC

NPSNHN＝UrbanL*NHNpUC+UncoverL*NHNpUCC+TreeL*NHNpTC+GrassL*NHNpGC+NHNDL+NHNFL

NPSNHNC＝1

NPSNHNE＝NPSNHN*NPSNHNC

NPSTN＝UrbanL*TNpUC+UncoverL*TNpUCC+TreeL*TNpTC+GrassL*TNpGC+TNDL+TNFL

NPSTNC＝1

NPSTNE＝NPSTN*NPSTNC

NPSTP＝UrbanL*TPpUC+UncoverL*TPpUCC+TreeL*TPpTC+GrassL*TPpGC+TPFL+TPDL

NPSTPC＝1

NPSTPE＝NPSTP*NPSTPC

PSICOD＝IGDP*CODpIGDP*ICODDR

PSICODC＝PSICODNJ/NJIQ

PSICODCR＝0.156

PSICODNJ＝PSICOD*PSICODCR

PSINHN＝IGDP*INHNDR*NHNpIGDP

PSINHNC＝PSINHNNJ/NJIQ

PSINHNCR＝0.131

PSINHNNJ＝PSINHNCR*PSINHN

PSITN＝IGDP*TNpIGDP*ITNDR

PSITNC＝PSINHNNJ/NJIQ

PSITNCR＝0.209

PSITNNJ＝PSITN*PSITNCR

PSITP＝IGDP*TPpIGDP*ITPDR

PSITPC＝PSITPNJ/NJIQ

PSITPCR＝0.092

PSITPNJ＝PSITP*PSITPCR

PSLCOD＝UP*CODpUP*SPDR

PSLCODC＝PSLCODNJ/NJLQ

PSLCODCR＝0.622

PSLCODNJ＝PSLCOD*PSLCODCR

PSLNHN＝UP*NHNpUP*LNHNDR

PSLNHNC＝PSLNHNNJ/NJLQ

PSLNHNCR＝0.424

PSLNHNNJ＝PSLNHN*PSLNHNCR

PSLTN＝UP*TNpUP*LTNDR

PSLTNC＝PSLTNNJ/NJLQ

PSLTNCR＝0.437

PSLTNNJ＝PSLTN*PSLTNCR

PSLTP＝UP*TPpUP*LTPDR

PSLTPC＝PSLTPNJ/NJLQ

PSLTPCR＝0.434

PSLTPNJ＝PSLTP*PSLTPCR

QLJT＝91.7

QUT＝144

QUTT＝NJIQ+NJLQ+QUT

SGDPR＝0.12

SPDR＝0.82

TNDL＝DLA*TNpDLC+DLA*FUS*FUStnr

TNFL＝FLA*TNpFLC+FLA*FUS*FUStnrF

TNGH＝TNPW*EXP(-KTN1*L1/V1)

TNGHHUI＝(TNLJT*QLJT+TNGH*QUTT)/(QLJT+QUTT)

TNLJT＝1107

TNpDLC＝29000000

TNpFLC＝29000000

TNpGC＝10000000

TNpIGDP＝451273

TNpTC＝2380000

TNpUC＝11000000

TNpUCC＝14900000

TNpUP＝4964000

TNPW＝(TNUT*QUT+PSITNNJ*NJIQ+PSLTNNJ*NJLQ)/(QUT+NJIQ+NJLQ)

TNUT＝1511

TPDL＝DLA*TPpDLC+DLA*FUS*FUStpr

TPFL＝FLA*TPpFLC+FLA*FUS*FUStprF

TPGH＝TPPW*EXP(-KTP1*L1/V1)

TPGHHUI＝(TPLJT*QLJT+TPGH*QUTT)/(QLJT+QUTT)

TPLJT＝40

TPpDLC＝900000

TPpFLC＝900000

TPpGC＝200000

TPpIGDP＝33336

TPpTC＝150000

TPpUC＝240000

TPpUCC＝510000

TPpUP＝346750

TPPW＝(TPUT*QUT+PSLTP*NJLQ+PSITP*NJIQ)/(NJIQ+NJLQ+QUT)

TPUT＝40

TreeL＝271359

UncoverL＝19692

UP＝pop*UR

UR＝0.53

UrbanL＝4230

V1＝0.586

V2＝0.586

3, analog result

3.1 model simulation results

3.1.1 Bayesian network Early-warning Model

According to end, Nierji reservoir in May, 2014 storehouse Monitoring Data, its five-day BOD is I class water, ammonia nitrogen is II class water, total phosphorus is III class water, total nitrogen is III class water, permanganate indices is II class water, by above water quality condition input Bayesian network model, pollutant sources is calculated.

When the potassium permanganate water quality situation in prosperity Village is II class water, the water quality condition of limekiln water quality condition to be the probability of I class water be 13.3%, II class water is 26.3%, III class water water quality is 27%, IV class water Water-quality Probability is 20%, V class water Water-quality Probability is 13.3%; The probability distribution of the water quality situation of Nenjiang pontoon bridge section is, when water quality condition is I class water, probability is 17.1%, II class water water quality be 17.1%, III class water water quality be 32.4%, IV class water water quality be 31.4%, V class water water quality is 1.92%; Gan He imports, and the probability of to be the probability of I class water be 22.8%, II class water quality that Liu Jia collects section is the Water-quality Probability of 22.8%, III class water be 17.9%, IV class water water quality be 22.8%, V class water Water-quality Probability is 13.7%; The probability of to be 13.3%, II class water quality be 20%, III class water quality that Nenjiang sewage draining exit probability is I class water probability is 27%, IV class Water-quality Probability be 26%, V class water water quality is 13.7%.

When end, Fasten Joint Bolt storehouse ammonia nitrogen water quality is II class, when the probability distribution situation of the water quality condition of limekiln section is I class water, probability is 15.8%, during II class water, probability is 32.6%, probability during III class water is 32.6%, the probability of III class water is 20%, IV class water probability is 15.8%, V class water probability is 15.8%; Nenjiang pontoon bridge section I class water, IV class water, V class water probability are 15.8%, II class water probability be 29.9%, III class water probability is 22.7%; The ammonia nitrogen water quality probability distribution situation of Liu Jia village section is I class water is that 33.6%, II class water Water-quality Probability is 17.5%, III class water, IV class water, V class water probability scenarios are respectively 16.7%, 16.2%, 16%.The probability of the probability of Nenjiang County sewage draining exit water quality to be the probability of I class water be 13.3%, II class water to be the probability of 20%, III class water be 27%, IV class water is the probability of 26%, V class water is 13.7%.

When end, Nierji reservoir storehouse total phosphorus water quality is III class, the probability distribution of the water quality condition of limekiln section is I class water water quality 20%, II class water water quality is 77.1%, III class water water quality, IV class water water quality, V class water water quality are 0.96%, Nenjiang pontoon bridge probability I, II class water is 48.6%, III class water to V class water probability is that to collect section be I class water probability 27.6% to 0.96%, Liu Jia, II class water probability is 69.5%, III class water, IV class water, V class water probability are 0.96%; And the probability distribution I class water probability of Nenjiang County Sewage Plant discharge total phosphorus concentration be 13.3%, II class water probability be 20%, III class water probability be 27%, IV class water probability be 26.3%, V class water probability is 13.3%.

By above probability distribution situation analysis, can see, in May, 2014, Nierji reservoir water quality condition was better, only there is the water quality condition of total nitrogen total phosphorus more than II class water water quality, and from the water quality condition analysis of upstream section, can see that the situation that exceeds standard of ammonia nitrogen, total phosphorus is not remarkable, only there is the water quality condition of Nenjiang County sewage draining exit poor, and carry out source distribution by pollution source above and can see, Nenjiang County blowdown only occupies a very little part for pollutant in Nierji reservoir, therefore can think that the discharge of total phosphorus and total nitrogen more and come from non-point source discharge.

And according in August, 2014, the water quality monitoring situation in each tributary of Upper Reaches of The Nenjiang River, china, can know that the water quality of limekiln section be permanganate indices grade is III class water, ammonia nitrogen water quality grade is III class water, total phosphorus water grade is II class water, BOD5 water grade is III class water; Nenjiang pontoon bridge water quality condition, potassium permanganate grade is III class water, ammonia nitrogen water quality grade is III class water, total phosphorus water grade is II class water, BOD5 water grade is III class water; A Gan He remittance point Liu Jia village section water quality condition is permanganate indices is II class water, BOD5 water grade is II class water, ammonia nitrogen water quality grade is II class water, total phosphorus water grade is II class water; And Nenjiang sewage draining exit to go out water quality poor, the indexes such as BOD5, permanganate indices, ammonia nitrogen, total phosphorus are all V class.

By above each section water quality condition input Bayesian network, early warning can be carried out to end, Nierji reservoir storehouse water quality, result shows: the probability distribution of prosperity Village section permanganate indices is the probability of I class water is 0.31%, II class water probability is 34.8%, III class water probability is 39.6%, IV class water probability is 25.1%, V class water probability is 0.16%; And the water quality condition I class water probability of BOD5 is 48.9%, II class water water quality be 46.1%, III class water water quality be 2.59%, IV class water water quality be 2.14%, V class water water quality is 0.31%; The probability of ammonia nitrogen water quality probability situation to be the probability of I class water be 0.37%, II class water is 43.4%, III class water water quality be 53.4%, IV class water Water-quality Probability be 2.48%, V class water Water-quality Probability is 0.36%; Total phosphorus water quality condition, the probability for I class water is the probability of 11.6%, II class water be 59.7%, III class water Water-quality Probability be 10.6%, IV class water Water-quality Probability be 15.8%, V class water Water-quality Probability is 2.26%.

Can see according to above result, the possibility of the water quality condition of prosperity Village section to be permanganate indices be III class water is the highest, and probability reaches 39.6; The probability that BOD5 reaches I class water is 48.9%, the probability of II class water is 46.1%, it is 43.4% that ammonia nitrogen reaches II class water water quality, III class water water quality is 53.4%, total phosphorus is the probability of II class water is 59.7%, and according to the actual conditions of monitoring, can see and reach III class water water quality at prosperity Village section permanganate indices, BOD5 concentration is I class water water quality, ammonia nitrogen is II class water water quality, total phosphorus is II class water water quality, consistent with the result that Bayesian network model is simulated on the whole, illustrates that Bayesian network model is more consistent.

3.1.2 system dynamics decision model

By related data input system kinetic model, Nierji reservoir water quality condition is simulated, wherein model socioeconomic data adopts Nenjiang County social economy publication in 2013, water quality condition is employing water monitoring data in 2013, pollutant emission have employed sewage draining exit Monitoring Data, and land utilization then adopts remote sensing image interpret data etc.The time boundary of model is 2013 to 2024, totally 12 years, and geographical frontier is Nierji reservoir and water catchment area, Upper Reaches of The Nenjiang River, china master stream, and operational system dynamics decision model, can obtain following analog result, as shown in Figure 2.

Population analog result shows, the size of population rises gradually, the size of population in 2013 is 504345 people, be 517833 people to the size of population in 2024, increment is 13000 people, population size presents ascendant trend gradually, this also illustrates social economy and present the trend developed gradually, under the prerequisite that Urbanization Rate does not rise appreciably, nonagricultural population's total amount rises, and life point source pollutant discharge capacity also can rise thereupon, simultaneously along with the size of population rises, socio-economic development is also comparatively obvious, and concrete variation tendency as shown in Figure 3 and Figure 4.

By shown in Fig. 3 and Fig. 4, GDP total amount presents its speedup between 2013 to 2016 of trend steadily risen and slows down, speedup goes up gradually afterwards, by 2024, GDP total amount 34,300,000,000 yuan can be realized, and the main mainstay industry in Nenjiang County is agricultural, wherein agriculture GDP in 2013 proportion that occupies whole GDP is larger, it is overall that close to 1, total amount is 6,400,000,000 yuan, and along with socio-economic development, the proportion that agricultural GDP occupies GDP declines gradually, by 2024, occupy 21% of whole GDP, total amount reaches 73.5 hundred million yuan.

Known according to Fig. 5, can see along with socioeconomic development according to analog result, the pollutant levels of Nierji reservoir also present the trend slowly risen, its COD concentration rises to 16mg/L gradually from 14mg/L, ammonia nitrogen concentration is then at about 0.5mg/L, total nitrogen concentration is then at 1.6mg/L, total phosphorus concentration is then at 0.07mg/L, according to the Monitoring Data of prosperity Village section in 2014, permanganate indices is 5.68mg/L, be permanganate indices about 3 times calculating according to COD, should be 16.8mg/L, ammonia nitrogen concentration is 0.66mg/L, total nitrogen concentration is 1.8mg/L, total phosphorus concentration is 0.09mg/L, comparative simulation result and actual detected value, can see that the analog result of model is comparatively accurate.

By controlling pollutant discharge amount, the life source emission controlled in riverine some source emission per capita, and the industrial discharge reduced in industry growth, by the water quality that monitoring upland water and Gan He import, be decreased through the amount that upland water and branch afflux enter the pollutant of Nierji reservoir, and utilize changing condition to reduce non-point pollution situation by research on adjustment land region, control the amount of application of fertilizer and pesticide in farmland simultaneously, and then reduce because agricultural chemicals and the excessive of chemical fertilizer are used, the excessive residual agricultural chemicals caused and chemical fertilizer enter water body by rainwash.Design parameter can adjust according to following table 1.

Table 1 model parameter table

The parameter that the correlation parameter of ammonia nitrogen, total nitrogen, total phosphorus also calculates according to above COD adjusts, and carry out program decisions, relevant analog result as shown in Figure 6.

In Fig. 6, Line 1 is when not adopting any control strategy, the COD concentration change situation at end, Nierji reservoir storehouse, No. 2 lines are under the strategy of control domestic pollution source emission, the analog result of end, Nierji reservoir storehouse COD concentration, as can see from Figure 6, the main source that COD pollutes should be the some source emission of domestic pollution, when cities and towns discharge capacity drop to 40 kilograms/(people × year) time, end, storehouse COD concentration is that decline is about 50%, it is the strategy of comparatively effectively control COD concentration, and in Fig. 7, No. 2 lines are the result of end, Nierji reservoir storehouse COD concentration of analog under controlling industrial source COD bleed strategy, when ten thousand yuan of industrial added value COD discharge capacitys drop to 10 kilograms/ten thousand yuan, the value of end, Nierji reservoir storehouse COD concentration is between 13.5mg/L to 15mg/L, still there is the risk of III class water.

Be shown as in Fig. 8 and control end, Nierji reservoir storehouse COD concentration of analog result under upland water strategy, wherein No. 2 lines are strictly control the result of upland water water quality in end, the tactful Imitating Nierji reservoir storehouse COD concentration change of 10mg/L, showing its value is change between 13mg/L to 15mg/L, has certain risk reaching III class water; What show in Fig. 9 is then the COD concentration of analog result at the lower end, Nierji reservoir storehouse of control Gan He remittance strategy, wherein No. 2 lines are that strictly control Gan He imports water quality under the strategy of 10mg/L, to the analog result of end, Nierji reservoir storehouse COD concentration change, show from figure and can see, the effect that control Gan He imports strategy is better than control upland water, mainly due to the difference in geographic position, it is nearer that Gan He converges mouth distance end, Nierji reservoir storehouse, thus hydraulic detention time is shorter, and degradation amount is less.

End, Nierji reservoir storehouse COD concentration of analog result under adjustment land use strategy is shown as by Figure 10, wherein No. 2 lines are farmland area is reduced dry land area and paddy field area all reduces the analog result after 50%, it is noted herein that farmland is only reduced by modeling scheme, and be not farmland is converted into other land-use style, therefore, its analog result is the concentration value be less than under the actual performance of policy, can find out by adjustment Land_use change situation from the same, concentration for control COD has certain effect, but it is not remarkable, its variation range is between 13.5mg/L to 15.5mg/L, warehouse-in water quality can not be effectively avoided to reach III class water.

Therefore with regard to the control of COD, effective method is the discharge capacity controlling Nenjiang County Sewage Plant the most, reduce the content of COD pollutant in life source, secondly import for control Gan He, because Gan He imports mouth distance Fasten Joint Bolt reservoir area comparatively closely, and its flow is larger, in addition master stream, Nenjiang upstream flow rate is very fast, if do not controlled Gan He, a large amount of sweet river upstream contaminant directly imports reservoir area under the prerequisite without degraded, has considerable influence to the Ecology risk of Nierji reservoir.

Equally, we are for above five kinds of strategies, to ammonia nitrogen, total nitrogen, the Conventional pollution such as total phosphorus are simulated, the characteristic contamination situation simultaneously contrasted in farmland adjustment situation is simulated, at total nitrogen, total phosphorus, in the simulation of ammonia nitrogen, Line 1 represents according to pollutant levels analog result under As-Is, No. 2 lines represent the pollutant levels under control life source emission strategy, No. 3 lines represent the pollutant levels under control industrial source bleed strategy, No. 4 lines represent the pollutant levels under control upland water strategy, No. 5 lines represent the pollutant levels under control Gan He remittance strategy, No. 6 lines represent the analog result of end, Nierji reservoir storehouse pollutant levels under adjustment land use strategy.

Can see by showing result in Figure 11, end, Nierji reservoir storehouse ammonia nitrogen concentration analog result situation under Different Strategies, wherein according to current strategy, Fasten Joint Bolt ammonia nitrogen concentration analog result is at 0.52mg/L, for III class water water quality, and in five kinds of strategies, the most effective is soil adjustable strategies, consistent with COD situation, the analogue value is the ammonia nitrogen concentration under the actual conditions being less than policy execution in theory herein, be about 0.41mg/L, lower than III class water water quality standard, source, same control life source imports with Gan He and Nierji reservoir ammonia nitrogen concentration also can be made lower than III class water water quality standard, wherein control life source emission, Nierji reservoir concentration can be made to be 0.46mg/L, control Gan He imports and end, Nierji reservoir storehouse ammonia nitrogen concentration then can be made at 0.47mg/L.And due to industrial source ammonia nitrogen discharge capacity less, upstream section distance Nierji reservoir is distant, therefore its impact for ammonia nitrogen concentration not obvious.

Result is shown in Figure 12, can see that the optimal strategy of total nitrogen concentration is consistent with ammonia nitrogen situation, control non-point source discharge best to the control effects of total nitrogen concentration, next make a living work-source and Gan He remittance, and the control effects of industrial source and upland water discharge is poor.Result is shown in Figure 13, can see that the optimal strategy of total phosphorus concentration is consistent with total nitrogen status, control non-point source discharge best to the control effects of total phosphorus concentration, next make a living work-source and Gan He remittance, and the control effects of industrial source and upland water discharge is poor.

Due to the reason of model structure, can see when farmland area drop by half, its characteristic contamination discharge capacity drop by half, but it is consistent with the situation of Conventional pollution before, only consider that farmland reduces 50% herein, and do not consider that land type changes other types into, therefore its analog result should be less than the discharge capacity under actual policy.As can be seen from above result, the major control means of COD are for controlling Nenjiang County domestic pollution source emission, and the Gan He that tightens control imports water quality, the control device of ammonia nitrogen, total nitrogen, total phosphorus is then for controlling Land_use change situation, or the amount of application reducing farmland fertilizer reduces the non-point source remittance of nutrient, the Gan He that simultaneously tightens control imports water quality, thus reduces end, Nierji reservoir storehouse water pollutant concentration, thus reduces Ecology risk.

Claims (10)

1., based on a Nenjiang representative region Ecology methods of risk assessment for system dynamics decision model, it is characterized in that it carries out according to following content:

By the influential branch afflux of pollution source amount of putting in storage Nierji reservoir, non-point source discharges, upland water and riverine emission factor are by system dynamics decision model, simulate the effect that different resolutions reduces reservoir ecological risk, realize implementation decision-making, and on the basis of Ecology risk indicator system, evaluate the Ecology risk status of different times difference position in storehouse, lake, based on the sample space of Netica software building Bayesian network, calculate the probability to ecological risk generation in various degree when each index changes, thus realize the risk assessment of Nenjiang representative region Ecology.

2. a kind of Nenjiang representative region Ecology methods of risk assessment based on system dynamics decision model according to claim 1, is characterized in that described riverine blowdown formula is:

PSICODNJ＝PSICOD×PSICODCR

PSICOD＝IGDP×CODpIGDP×ICODDR

In formula, PSICODNJ is that Nenjiang Model of The Labahe sewage draining exit COD enters river amount;

PSICOD is Nenjiang County Model of The Labahe sewage draining exit discharge capacity;

PSICODCR is that industrial point source COD discharges river pollutant sources;

CODpIGDP is ten thousand yuan of industrial added value COD discharge capacitys

ICODDR is that Model of The Labahe sewage draining exit discharge COD accounts for Nenjiang County industrial sites source emission COD ratio.

3. a kind of Nenjiang representative region Ecology methods of risk assessment based on system dynamics decision model according to claim 1 and 2, it is characterized in that Nierji reservoir upstream, blowdown point main in master stream, Nenjiang is the sanitary sewage discharge of Nenjiang County sewage treatment plant and the industrial wastewater discharge of Nenjiang County Model of The Labahe sewage draining exit, the two all comes from the socio-economic development of Nenjiang County, is subject to the impact of Nenjiang County population and socio-economic development.

4. a kind of Nenjiang representative region Ecology methods of risk assessment based on system dynamics decision model according to claim 3, is characterized in that the quantity of Nenjiang County population should be following formula:

POP(t)＝POP(t-1)+increase+Decrease

In formula, POP (t) is Nenjiang County population during t, and POP (t-1) is the population during t-1 of Nenjiang County;

Increase is the population recruitment in Nenjiang County year from t-1 to t

Decrease is the population decline amount in Nenjiang County year from t-1 to t;

Under not considering the prerequisite of urbanization rate year border, Nenjiang County change conditions, Nenjiang County nonagricultural population's quantity can be expressed by following formula:

UP＝POP×UR

In formula, UP is nonagricultural population's quantity of Nenjiang County t

UR is the urbanization rate of Nenjiang County t.

5. a kind of Nenjiang representative region Ecology methods of risk assessment based on system dynamics decision model according to claim 3, is characterized in that Nenjiang County sanitary sewage drains into the computing formula measured in river and can calculate according to following formula:

PSLCODNJ＝PSLCOD×PSLCODCR

PSLCOD＝UP×CODpUP×SPDR

In formula, PSLCODNJ is that Nenjiang County sanitary sewage drains into river COD and measures;

PSLCODCR is life point source COD discharge river pollutant sources;

CODpUP is the amount that annual unit nonagricultural population discharges COD;

SPDR is the ratio that Nenjiang County sewage treatment plant discharge capacity accounts for Nenjiang County total emission volumn;

Nenjiang County industrial added value change formula is as follows:

IGDP(t)＝IGDP(t-1)+IGDPI(t)

IGDPI(t)＝IGDP(t-1)×IGDPR

In formula, IGDP (t) is the industrial added value amount of Nenjiang County t;

The industrial added value amount that IGDP (t-1) is Nenjiang County t-1;

IGDPI (t) is t Nenjiang County industrial added value increment;

IGDPR is Nenjiang County industrial added value rate of growth.

6. a kind of Nenjiang representative region Ecology methods of risk assessment based on system dynamics decision model according to claim 1, is characterized in that described non-point pollution formula is:

NPSCODE＝NPSCOD×NPSCODC

NPSCOD＝CODDL+CODFL+TreeL×CODpTc+GrassL×CODpGC+UncoverL×CODpUCC+UrbanL×CODpUC

CODDL＝DLA×CODpDLC+DLA×FUS×FUScr

CODFL＝FLA×CODpFLC+FLA×FUS×FUScrF

In formula, NPSCODE is that non-point source COD drains into river amount;

NPSCOD is that non-point source COD creates;

NPSCODC is non-point pollution discharge river pollutant sources;

CODDL is that dry land produces COD amount;

CODFL is that paddy field produces COD amount;

TreeL is study area forest land area;

CODpTC is forest land COD output coefficient;

GrassL is study area grassland area:

CODpGC is meadow COD output coefficient;

UncoverL is the waste ground area in study area;

CODpUCC is wasteland COD output coefficient;

UrbanL is study area construction land area;

GDPpUC is construction land COD output coefficient;

DLA is study area dry land area;

CODpDLC is dry land output coefficient;

FUS is unit arable land applying quantity of chemical fertilizer in study area;

FUScr is study area dry land chemical fertilizer efficiency;

FLA is paddy field, study area area;

CODpFLC is paddy field output coefficient;

FUScr is paddy field, study area chemical fertilizer efficiency.

7. a kind of Nenjiang representative region Ecology methods of risk assessment based on system dynamics decision model according to claim 1, is characterized in that described branch afflux formula is as follows:

$CODPW=\frac{(CODUT\×QUT+PSLCODNJ\×NJLQ+PSICODNJ\×NJIQ)}{(NJLQ+NJIQ+QUT)}$

$CODGH=CODPW\×\exp (-\frac{k1\×l1}{v1})$

$CODGHHUI=\frac{(CODGH\×QUTT+CODLJT\×QLJT)}{(QUTT+QLJT)}$

QUTT＝QUT+NJLQ+NJIQ

$endPSCOD=CODGHHUI\×\exp \left(\frac{-k2\×l2}{v2}\right)$

endCOD＝endPSCOD×(QUTT+QLJT)+NPSCOD

In formula, CODPW is the COD concentration at sewage draining exit place, Nenjiang County;

CODUT is upland water concentration;

QUT is upland water flow;

PSLCODNJ is Nenjiang County Sewage Plant sewage draining exit concentration of emission;

NJLQ is Nenjiang County Sewage Plant quantity of wastewater effluent;

PSICODNJ is Nenjiang County Model of The Labahe sewage draining exit concentration of emission;

NJIQ is Nenjiang County Model of The Labahe sewage draining exit discharge capacity;

CODGH is the COD concentration of Gan He remittance place;

K1 is the COD degradation coefficient of section between upland water section to sewage draining exit;

L1 is that the river of section between upland water section to sewage draining exit is long;

V1 is the flow velocity of section between upland water section to sewage draining exit;

CODGHHUI is that Gan He imports some place COD concentration;

QUTT is that upland water converges Nenjiang County blowdown sewage quantity;

CODLJT is sweet river COD concentration;

QLJT is sweet river flow;

EndPSCOD is end, Fasten Joint Bolt storehouse COD point source concentration;

K2 is the COD degradation coefficient that Gan He imports section between point to end, Fasten Joint Bolt storehouse;

L2 is that the river of section between Gan He remittance point to end, Fasten Joint Bolt storehouse is long;

V2 is the flow velocity that Gan He imports section between point to end, Fasten Joint Bolt storehouse.

8. a kind of Nenjiang representative region Ecology methods of risk assessment based on system dynamics decision model according to claim 7, it is characterized in that branch afflux formula obtains based on under type: the water of Nierji reservoir imports from the non-point source in the water of limekiln, upstream section and the water of upstream branching flow and region, master stream, main pollution source is that downstream Gan He imports, upland water and non-point source import; To import as major pollutants source builds model with upland water water quality and Gan He remittance, riverine discharge, non-point source.

9. a kind of Nenjiang representative region Ecology methods of risk assessment based on system dynamics decision model according to claim 1, is characterized in that described characteristic contamination formula is:

NPCE＝NPC×NPCC

NPC＝DLA×CUS×CUSr+FLA×CUS×CUSrF

In formula, NPCE is characteristic contamination discharge capacity;

NPC is characteristic contamination generation;

NPCC is characteristic contamination discharge river pollutant sources;

CUS is the amount of application in every mu, agricultural chemicals farmland;

CUSr is dry land residues of pesticides coefficients;

CUSrF is paddy field residues of pesticides coefficient.

10. a kind of Nenjiang representative region Ecology methods of risk assessment based on system dynamics decision model according to claim 1, it is characterized in that characteristic contamination be based on paddy field, the dry land applications of pesticide residual with discharge for index carries out calculating.