CN105115538A - Estimation method for endogenous pollution of wetland lake in estuarine delta region - Google Patents

Abstract

The invention discloses an estimation method for endogenous pollution of a wetland lake in an estuarine delta region, and the method comprises the main steps: A) measuring the nutrient contents (TN, TP) of the wetland lake in the estuarine delta region; B) extracting a water-soluble organic matter, and calculating and measuring a dissolved oxygen content (DO); C) selecting and measuring position temperature values of a constant temperature layer, a jump temperature layer and an isothermal layer, and a sea level, wave intensity and flow speed of the estuarine delta region, and other related parameters of a hydrodynamic force process; D) building a temperature and tidal wave process coupling model; E) solving the model; F) carrying out the comprehensive evaluation of the endogenous pollution of the wetland lake in the estuarine delta region.

Description

A kind of estuarine delta area wetland lake endogenous pollution evaluation method

Technical field

The invention belongs to water environment pollution assessment and management application, be specifically related to a kind of by estuarine delta area wetland lake temperature model and tidal wave model multiple-quality water water amount parameters index is fitted to the integrated evaluating method that can be carried out estuarine delta wetland lake endogenous pollution.

Background technology

Water body layering is that water body is due to the condition difference such as temperature or salinity, thus produce density stratification change phenomenon, summer typical forward water temperature delamination structure be followed successively by epilimnion from top to bottom, jump warm layer (or being called thermocline) and isothermal layer (or being called thermostat layer).Can know, the formation of warm layer of jumping blocks the exchange of the upper and lower material in estuarine delta wetland lake, area, after thermal stratification is formed, bottom water body is in anaerobic state, the sediment of bottom is made to pass through biochemical method, produce a certain amount of polluter, when entering winter, top water temperature drop is low, the water temperature of levels reaches unanimity, the warm layer that now jumps is destroyed, after entering spring, the heat effect of the solar radiation that the water surface is continued, high temperature water body is made to run into low temperature water body and immixture occurs, the polluter in the bed mud of bottom is caused to translate into top, pollutant is mixed in whole water body, cause the deteriorating water quality of water body, produce endogenous pollution problem.

Control for estuarine delta area wetland lake endogenous pollution is usually monitor based on the water quality parameter of long-term sequence, and adopt aeration mode to destroy layering, water body is made to reach abundant oxygen supply mixing, mostly belong to end treatment link, also do not have by front end management and comprehensive evaluation, control the integrated evaluating method that estuarine delta area wetland is lake endogenous.

Three class indexs are mainly contained for estuarine delta area wetland lake endogenous pollution comprehensive evaluation:

The first kind is total nitrogen and total phosphorus (TN, TP), and this kind of index reflects content and the estuarine delta area wetland Lake Eutrophication of wetland lake, estuarine delta area Middle nutrition salt.

Equations of The Second Kind is dissolved oxygen content (DO), and this kind of index reflects the contaminated degree of water quality.

3rd class is water temperature, due to the impact of the energy input and output change that wetland lake, estuarine delta area produces by external condition, be reflected to wetland lake, estuarine delta area inner, be the gradient disparities of temperature, the change of water temperature can suppress water body planktonic organism amount, thus produces DO and total phosphorus and total nitrogen change quantitatively.

4th class is estuarine tide intensity, and this kind of index has reacted the disturbance that tidal wave process produces water body, and pollutant when intensity is larger in bed mud stirs, and causes endogenous pollution problem

In real work, the normally discontinuous monitoring of this three classes index, and the correlation analysis between index is less, to the comprehensive analysis between index and management process less, therefore need the comprehensive evaluation of a kind of estuarine delta area wetland lake endogenous pollution problem and the foundation of management system.

Summary of the invention

The object of the present invention is to provide the integrated evaluating method of a kind of estuarine delta area wetland lake endogenous pollution, by water temperature delamination model, set up an estuarine delta area wetland lake endogenous pollution overall target.

In order to realize above-mentioned target, estuarine delta area provided by the invention wetland lake endogenous pollution integrated evaluating method, key step is wherein:

A) water source estuarine delta area wetland Lakes in Nutrition material content (TN, TP) is measured;

B) extract water soluble organic substance, calculate and measure dissolved oxygen content (DO);

C) choose and measure thermostat layer, the correlation parameter of the Hydrodynamic Process such as the warm layer that jumps, isothermal layer position temperature value and Hekou District tidal level, ripple are strong, flow velocity;

D) coupling model of temperature and tidal wave process is set up;

E) model solution;

F) estuarine delta area wetland lake endogenous pollution comprehensive evaluation.

According to integrated evaluating method, steps A adopts alkaline chitinase to clear up ultraviolet spectrophotometry and alkaline potassium per-sulfate digestion ammonium molybdate spectrophotometric method.

According to integrated evaluating method, step B adopts continous way septum electrode method.

According to integrated evaluating method, step C adopts distributed optical fiber temperature measuring instrument (DTS), SBY2-1 acoustic wave instrument and GlobalWater current meter.

According to integrated evaluating method, the heat exchange amount (Q that step D adopts water body heat transfer model sign water surface to conduct heat total _s) be long-wave radiation amount (Q _r), water surface evaporation (Q _w), water surface sensible heat is to flow (Q _h), its process formula is: Q _s=Q _r+ Q _w+ Q _h

Long-wave radiation amount (Q _r):

The radiation wavelength distributed due to air is longer relative to sun incident wavelength, and main energetic concentrates between 4 ~ 120 μm, therefore belongs to long-wave radiation scope; The process formula of the long-wave radiation of air is:

$Q^R={-\mathrm{\ϵ}}_{\left(\mathrm{water}\right)}{\mathrm{\δT}}_{\left(\mathrm{water}\right)}^4+{\mathrm{\ϵ}}_{\left(\mathrm{air}\right)}{{\mathrm{\δT}}_{\left(\mathrm{air}2\right)}}^4(1-R_{t\left(w\right)})(1+{{0.17C}_{\left(\mathrm{cloud}\right)}}^2)$

In formula: T _(water), ε _(air), ε _(water), R _{t (w)}, σ, T _(air), C _(cloud)be respectively water surface 0m place temperature, the radiation coefficient of water, the radiation coefficient of air, water surface longwave radiation reflection rate, ripple hereby Germania constant, be 2m place temperature, cloud cover rate on the water surface.

Evaporation from water surface thermal loss (Q _w):

Evaporation directly embodies contacting of heat and water quality exchanges process, and processing formula is:

$Q_w=L{C}_w{u}_{\left(\mathrm{wind}\right)}{\mathrm{\ρ}}_{\left(\mathrm{air}\right)}\frac{{0.622\×12}^{\{\frac{0.7859+0.03477T}{1+0.00412T}-3\}}}{P}(R_h-1)$

In formula: L, C _w, ρ _(air), P, R _hbe respectively evaporation latent heat, evaporation heat transfer coefficient, atmospheric density (gets 1.225kg/m ³), standard atmospheric pressure, a relative humidity.

Sensible heat is to flow (Q _h):

Thermal convection refers to that heat is by flow media, is propagated into the phenomenon at another place by one of space.Water surface thermoflux be on the occasion of time, top layer is in intensification situation, and water temperature is high compared with the following layer of water body, otherwise density stratification is stablized., in cooling situation, surface temperature then may lower than following layer, form non-steady state, at this moment levels generation thermal convection, its process formula is:

Q _h＝C _Hc _p(air)ρ _(air)u _(wind)(T _(air-r)-T _(water))

In formula: C _h, c _{p (air)}, u _(wind), T ( _{air_r)}be respectively the dry-bulb temperature of air on sensible heat conduction volume factor (getting 0.0014), the specific heat at constant pressure (getting 1003) of water, the wind speed at water surface place, the water surface, all the other are the same.

According to integrated evaluating method, step D calculates on the other hand and penetrates the total heat exchange amount of diabatic process, and its process formula is:

Q _sw(s)＝Q _{(sw_surface)}(1-0.65C _(cloud) ²)(1-R _t(sw))

Q _sw(z)＝Q _sw(s)exp{-η _e(S-z)}

In formula: Q _sWand Q (S) _sW(Z) water surface solar shortwave radiation amount and shortwave radiation amount change procedure is under water respectively, wherein, R _{t (sw)}, Q ( _{sw_surface)}, Q _sw, η _e(m ^-1) be respectively nondimensional shortwave radiation surface reflectivity, total shortwave radiation amount, the net solar radiation through the water surface, attenuation coefficient by the water surface.

Apply two-dimentional equation of tide hudge in addition to characterize the impact that coastal region wetland lake is subject to sea tide:

The tidal level (ξ) in somewhere:

$\mathrm{\ξ}\left(t\right)=a_0+\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{R}_j\cos ({\mathrm{\σ}}_{j}t-{\mathrm{\θ}}_j)+r\left(t\right)$

In above formula, a ₀for mean sea level; R _jfor tidal wave amplitude; θ _jfor the initial phase of tidal wave; σ _jfor tidal wave angular velocity; R (t) is non-astronomical tidal level, makes a general reference because the hydrology, meteorological condition change the SEA LEVEL VARIATION caused.

Trend (u):

$u=U_0+\underset{i}{\mathrm{\Σ}}{U}_i\cos (v_i-{\mathrm{\ξ}}_i)=U_0+\underset{i}{\mathrm{\Σ}}{U}_i\cos ({\mathrm{\σ}}_{i}t+v_{0i}-{\mathrm{\ξ}}_i)$

$v=V_0+\underset{i}{\mathrm{\Σ}}{V}_i\cos (v_i-{\mathrm{\η}}_i)=V_0+\underset{i}{\mathrm{\Σ}}{V}_i\cos ({\mathrm{\σ}}_{i}t+v_{0i}-{\mathrm{\η}}_i)$

Wherein u, v are respectively the northern component of flow velocity and eastern component; U ₀, V ₀for Euler residual current; U _i, ξ _ifor the harmonic constant of northern component; V _i, η _ifor the harmonic constant of eastern component.

Two dimension equation of tide hudge:

$\frac{\∂}{\∂x}\left(\mathrm{UD}\right)+\frac{\∂}{\∂y}\left(\mathrm{VD}\right)+\frac{\∂\mathrm{\ξ}}{\∂t}=0$

$\frac{\∂U}{\∂t}+U\frac{\∂U}{\∂x}+V\frac{\∂U}{\∂y}=\mathrm{fV}-g\frac{\∂}{\∂x}(\mathrm{\ξ}-\stackrel{\‾}{\mathrm{\ξ}})+A_H(\frac{{\∂}^{2}U}{{\∂x}^2}+\frac{{\∂}^{2}U}{{\∂y}^2})-k_{b}U$

$\frac{\∂V}{\∂t}+U\frac{\∂V}{\∂x}+V\frac{\∂V}{\∂y}=\mathrm{fU}-g\frac{\∂}{\∂y}(\mathrm{\ξ}-\stackrel{\‾}{\mathrm{\ξ}})+A_H(\frac{{\∂}^{2}V}{{\∂x}^2}+\frac{{\∂}^{2}V}{{\∂y}^2})-k_{b}V$

In above formula, D is total depth of water, x, y be east, the north to, U, V are east, the north component of trend, A _hfor horizontal eddy viscosity, k _bfor bottom-friction factor.

Described integrated evaluating method, the model solution in step e, is adopt finite element volume method to calculate, and is realized by commercial CFD code.

Described integrated evaluating method, integrated evaluating method in step F, obtain different water temperature condition by model solution, and bring steps A into, step B, related data measured by step C, coupling water quality model and dissolved oxygen DO model, coupling temperature model and estuarine tide wave pattern, thus try to achieve the impact of index of correlation along with seasonal form change condition and the inherent trend of existence in wetland lake, estuarine delta area, study area, and estuarine delta area wetland lake endogenous pollution degree is graded, estuarine delta area wetland lake endogenous pollution problem can be predicted timely, and related management in addition.

The invention provides the integrated evaluating method of estuarine delta area wetland lake endogenous pollution, simple to operate, with low cost, evaluation speed is fast, evaluation result considers dissolved oxygen DO, the indexs such as total nitrogen total phosphorus, evaluation precision is high, effectively can control the body eutrophication that caused by thermal stratification and other endogenous pollution problems.

Accompanying drawing explanation

Fig. 1 is schematic flow sheet of the present invention, and Fig. 2 is the sample distribution figure of patent specific implementation process in the Huanghe delta.

Embodiment

The invention provides a kind of comprehensive endogenous pollution evaluation method based on estuarine delta area wetland lake model, its main method is as follows:

A) top layer water sampling and preservation: first use clean water bucket to draw water in sample point, is then transferred in the labeled vinyon sampling bottle of preprepared by water sample, often place's sampling about 2.8L.The sign spot such as water temperature, intensity of illumination, DO measure, and record the parameters such as sampling time on the same day, weather conditions, estuarine delta area wetland lake level, trend size for experimental study reference, sample frequency is that sampling should be carried out in every 2 ~ 3 days, the mensuration with completing other chemical index in same laboratory same day after sampling.

B) longitudinal water sampling and preservation: according to wetland lake, estuarine delta area lineament, at representative point position selection sampling spot, use along the depth of water direction organic glass fixed-depth water sampler every 5 ~ 10 meters of samplings once, laboratory is taken back in the preservation of water sample brown, wide-mouth vial and preserves at 4 DEG C or measure in good time.Sample record requires the same.This research near the wetland lake entrance of estuarine delta area, wetland lake, estuarine delta area different depth, former channel thread district, the different representative points position such as estuary have chosen 10 sampled points.

C) collection of upstream runoff water sample: according to the topographic features of upstream, wetland lake, estuarine delta area, respectively in the place of the comparatively intensive village place of tributary meet, population and a segment distance of being separated by, 9-10 sampled point is set, sampling uses vinyon bottle, in river course, the place of smooth in water flow draws water, and avoids sampling in slough, bank.The index such as Simultaneously test water temperature, total phosphorus and total nitrogen of sampling.

Concrete sample distribution is shown in accompanying drawing.

The result of sampling is carried out data analysis and arrangement, make the instantaneous Distribution Value of survey region estuarine delta area wetland lake total phosphorus total nitrogen and DO, in conjunction with transient temperature distribution scenario, the distribution of index of correlation under description stratified condition, this research continues to sample in March, 2009 to Dec and monitors the water quality condition in master library district, there is obvious total nitrogen and exceed standard in result display wetland lake, study area, average of the whole year detection level 1.4mg/L, exceeds standard 31%.

According to associated temperature parameter, import water body heat transfer model, solve, make the vertical temperature distribution image in estuarine delta wetland lake, area, energy equation and RNGk-ε model is utilized to carry out couple solution, time step is 0.01s, and time step number is 500s, calculates the Distribution dynamics of correlation parameter under thermal stratification condition.

Estuarine delta area wetland lake endogenous pollution comprehensive evaluation:

Under temperature stratification condition there is obvious seasonal variety in DO, and 4, in the May process that formed gradually in thermal stratification, dissolved oxygen DO longitudinally also form the high basic distribution bent down.But due to the mixing reoxygenation of upper and lower water body in winter, dissolved oxygen concentration entirety is higher, and bottom is also at about 7 ~ 8mg/L, and now lake does not exist anoxic or anaerobic zone substantially.Layering in July is stablized, and water body defines the vertical gradient of DO: surface water 8 ~ 9mg/L, substantially close to saturation concentration; Along with the increase of the depth of water, dissolved oxygen concentration reduce, and thermocline depth of water scope have to go to the toilet reduce sharply little; The dissolved oxygen DO of bottom water body is reduced to about 4mg/L.Bottom dissolved oxygen DO constantly declined along with the time, and September is 2.1mg/L, and 10 the end of month were only 0.5mg/L, were in anaerobic environment completely.After entering January, thermal stratification disappears.

Study area estuarine delta area wetland water body in lake vertical nutrients distribution characteristics is not obvious, but also there is the phenomenon that concentration raises in the total nitrogen in wetland lake, estuarine delta in flood season area within the scope of 20 ~ 40m depth of water, this is because river, upstream flush period river total nitrogen concentration significantly increases, and cause with wetland lake, the form of undercurrent remittance estuarine delta area.And in this depth range there is not obvious rising in total phosphorus.

Claims (8)

1. an estuarine delta area wetland lake endogenous pollution integrated evaluating method, key step is wherein:

A) water source estuarine delta area wetland Lakes in Nutrition material content (TN, TP) is measured;

B) extract water soluble organic substance, calculate and measure dissolved oxygen content (DO);

C) choose and measure thermostat layer, the correlation parameter of the Hydrodynamic Process such as the warm layer that jumps, isothermal layer position temperature value and Hekou District tidal level, ripple are strong, flow velocity;

D) coupling model of temperature and tidal wave process is set up;

E) model solution;

F) estuarine delta area wetland lake endogenous pollution comprehensive evaluation.

2., according to integrated evaluating method, steps A adopts alkaline chitinase to clear up ultraviolet spectrophotometry and alkaline potassium per-sulfate digestion ammonium molybdate spectrophotometric method.

3., according to integrated evaluating method, step B adopts continous way septum electrode method.

4., according to integrated evaluating method, step C adopts distributed optical fiber temperature measuring instrument (DTS), SBY2-1 acoustic wave instrument and GlobalWater current meter.

5. according to integrated evaluating method, the heat exchange amount (Q that step D adopts water body heat transfer model sign water surface to conduct heat total _s) be long-wave radiation amount (Q _r), water surface evaporation (Q _w), water surface sensible heat is to flow (Q _h), its process formula is: Q _s=Q _r+ Q _w+ Q _h

A. long-wave radiation amount (Q _r):

The radiation wavelength distributed due to air is longer relative to sun incident wavelength, and main energetic concentrates between 4 ~ 120 μm, therefore belongs to long-wave radiation scope; The process formula of the long-wave radiation of air is:

$Q_R=-{\mathrm{\ϵ}}_{\left(\mathrm{water}\right)}{\mathrm{\δT}}_{\left(\mathrm{water}\right)}^4+{\mathrm{\ϵ}}_{\left(\mathrm{air}\right)}{{\mathrm{\δT}}_{\left(\mathrm{air}2\right)}}^4(1-R_{t\left(w\right)})(1+0.17{C_{\left(\mathrm{cloud}\right)}}^2)$

In formula: T _(water), ε _(air), ε _(water), R _{t (w)}, σ, T _(air), C _(cloud)be respectively water surface 0m place temperature, the radiation coefficient of water, the radiation coefficient of air, water surface longwave radiation reflection rate, ripple hereby Germania constant, be 2m place temperature, cloud cover rate on the water surface.

B. evaporation from water surface thermal loss (Q _w):

Evaporation directly embodies contacting of heat and water quality exchanges process, and processing formula is:

$Q_w=L{C}_w{u}_{\left(\mathrm{wind}\right)}{\mathrm{\ρ}}_{\left(\mathrm{air}\right)}\frac{0.622\×{10}^{\{\frac{0.7859+0.03477T}{1+0.00412T}-3\}}}{P}(R_h-1)$

In formula: L, C _w, ρ _(air), P, R _ltbe respectively evaporation latent heat, evaporation heat transfer coefficient, atmospheric density (gets 1.225kg/m ³), standard atmospheric pressure, a relative humidity.

C. sensible heat is to flow (Q _h):

Thermal convection refers to that heat is by flow media, is propagated into the phenomenon at another place by one of space.Water surface thermoflux be on the occasion of time, top layer is in intensification situation, and water temperature is high compared with the following layer of water body, otherwise density stratification is stablized., in cooling situation, surface temperature then may lower than following layer, form non-steady state, at this moment levels generation thermal convection, its process formula is:

Q _h＝C _Hc _p(air)ρ _(air)u _(wind)(T _(air-r)-T _(watcr))

In formula: C _h, c _{p (air)}, u _(wind), T _{(air_r)}be respectively the dry-bulb temperature of air on sensible heat conduction volume factor (getting 0.0014), the specific heat at constant pressure (getting 1003) of water, the wind speed at water surface place, the water surface, all the other are the same.

6. according to integrated evaluating method, step D calculates on the other hand and penetrates the total heat exchange amount of diabatic process, and its process formula is:

Q _sw(s)＝Q _{(sw_surface)}(1-0.65C _(cloud) ²)(1-R _t(sw))

Q _sw(z)＝Q _sw(s)exp{-η _e(S-z)}

In formula: Q _sWand Q (S) _sW(Z) water surface solar shortwave radiation amount and shortwave radiation amount change procedure is under water respectively, wherein, R _{t (sw),}q _{(sw_surface)}, Q _sw, η _e(m ^-1) be respectively nondimensional shortwave radiation surface reflectivity, total shortwave radiation amount, the net solar radiation through the water surface, attenuation coefficient by the water surface.

Apply two-dimentional equation of tide hudge in addition to characterize the impact that coastal region wetland lake is subject to sea tide:

The tidal level (ξ) in a somewhere:

$\mathrm{\ξ}\left(t\right)=a_0+\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{R}_j\cos ({\mathrm{\σ}}_{j}t-{\mathrm{\θ}}_j)+r\left(t\right)$

In above formula, a ₀for mean sea level; R _jfor tidal wave amplitude; θ _jfor the initial phase of tidal wave; σ _jfor tidal wave angular velocity; R (t) is non-astronomical tidal level, makes a general reference because the hydrology, meteorological condition change the SEA LEVEL VARIATION caused.

B. trend (u):

$u=U_0+\underset{i}{\mathrm{\Σ}}{U}_i\cos (v_i-{\mathrm{\ξ}}_i)=U_0+\underset{i}{\mathrm{\Σ}}{U}_i\cos ({\mathrm{\σ}}_{i}t+v_{0i}-{\mathrm{\ξ}}_i)$

$v=V_0+\underset{i}{\mathrm{\Σ}}{V}_i\cos (v_i-{\mathrm{\η}}_i)=V_0+\underset{i}{\mathrm{\Σ}}{V}_i\cos ({\mathrm{\σ}}_{i}t+v_{0i}-{\mathrm{\η}}_i)$

Wherein u, v are respectively the northern component of flow velocity and eastern component; U ₀, V ₀for Euler residual current; U _i, ξ _ifor the harmonic constant of northern component; V _i, η _ifor the harmonic constant of eastern component.

C. two-dimentional equation of tide hudge:

$\frac{\∂}{\∂x}\left(\mathrm{UD}\right)+\frac{\∂}{\∂y}\left(\mathrm{VD}\right)+\frac{\∂\mathrm{\ξ}}{\∂t}=0$

$\frac{\∂U}{\∂t}+U\frac{\∂U}{\∂x}+V\frac{\∂U}{\∂y}=\mathrm{fV}-g\frac{\∂}{\∂x}(\mathrm{\ξ}-\stackrel{\‾}{\mathrm{\ξ}})+A_H(\frac{{\∂}^{2}U}{{\∂x}^2}+\frac{{\∂}^{2}U}{{\∂y}^2})-k_{b}U$

$\frac{\∂V}{\∂t}+U\frac{\∂V}{\∂x}+V\frac{\∂V}{\∂y}=\mathrm{fU}-g\frac{\∂}{\∂y}(\mathrm{\ξ}-\stackrel{\‾}{\mathrm{\ξ}})+A_H(\frac{{\∂}^{2}V}{{\∂x}^2}+\frac{{\∂}^{2}V}{{\∂y}^2})-k_{b}V$

In above formula, D is total depth of water, x, y be east, the north to, U, V are east, the north component of trend, A _hfor horizontal eddy viscosity, k _bfor bottom-friction factor.

7. the integrated evaluating method described in, the model solution in step e, is adopt finite element volume method to calculate, and is realized by commercial CFD code.

8. the integrated evaluating method described in, integrated evaluating method in step F, obtain different water temperature condition by model solution, and bring steps A into, step B, related data measured by step C, coupling water quality model and dissolved oxygen DO model, coupling temperature model and estuarine tide wave pattern, thus try to achieve the impact of index of correlation along with seasonal form change condition and the inherent trend of existence in wetland lake, estuarine delta area, study area, and estuarine delta area wetland lake endogenous pollution degree is graded, estuarine delta area wetland lake endogenous pollution problem can be predicted timely, and related management in addition.