JP2003057228A - Method of predictive calculation of pickup of organic matter, and method of predictive calculation of water quality - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new method of predictive calculation of pickup of organic matter, by which the pickup of an organic matter from sludge can be calculated predictively, and to provide a new method of predictive calculation of water quality. SOLUTION: The method of predictive calculation of pickup of organic matter includes a step of predictively calculation the pickup of a suspended matter from the sludge, and a step of converting the predictively calculated pickup of the suspended matter into the pickup of the organic matter from the sludge, based on the relational expression expressing the concentration of the picked-up suspended matter and the concentration of the organic matter contained in the picked-up suspended matter, as a function of the concentration of the suspended matter picked-up.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention of the present application relates to a method for predicting and calculating rolled-up organic matter amount and a method for predicting and calculating water quality. More specifically, the invention of this application relates to a new method for predicting the amount of wound organic matter and a new method for predicting water quality, which is useful for elucidating the mechanism of fluctuations in water quality in coastal waters and the like and for preserving the water quality / sediment environment.

[0002]

2. Description of the Related Art Conventionally, the prediction calculation of the amount of bottom mud wound up in water by waves and currents (hereinafter referred to as the amount of bottom sediment) is a predictive calculation of beach topography changes due to drift sand for coastal conservation measures. Also, it has been actively researched and developed, and is being put to practical use in predicting calculation of channel burial due to hoisting and transportation of small-diameter mud for the purpose of channel burial countermeasures (also called siltation countermeasures). .

[0003]

However, in the conventional predictive calculation of the amount of rolled-up sludge, the target substance to be predicted is a suspended substance (also called suspended sand) in the sludge, and only organic matter in the suspended substance is calculated. There was a problem that it was not targeted.

That is, the prediction calculation of the amount of bottom sediments is carried out by predicting the amount of suspended matter (hereinafter referred to as the amount of suspended matter) from the bottom sediment which is rolled up into water by waves and flows. On the other hand, of course, both inorganic and organic substances are present in the suspended solids, so even if the amount of rolled-up suspended solids including both is predicted, for example, a water quality prediction calculation that models organic substance generation / decomposition processes The accuracy is not sufficiently high in the water quality prediction calculation using the model.

The invention of this application has been made in view of the above-mentioned circumstances, solves the problems of the prior art, and reduces the amount of organic matter to be rolled up from the bottom mud (hereinafter referred to as the amount of rolled up organic matter). A new method for predicting and calculating the amount of rolled-up organic matter that enables predictive calculation, as well as organic matter generation and
It is an object of the present invention to provide a new water quality prediction calculation method that enables more accurate water quality prediction calculation using a water quality prediction calculation model that models a decomposition process.

[0006]

Means for Solving the Problems In order to solve the above problems, the invention of this application comprises a step of predicting and calculating the amount of suspended suspended matter from bottom mud, the concentration of suspended suspended matter and the suspended suspended matter in the suspended matter. And a step of converting the predicted calculation value of the amount of the suspended suspended matter into the amount of the suspended organic matter from the bottom mud by the relational expression expressing the concentration of the organic matter as a function of the concentration of the suspended suspended matter. An amount prediction calculation method (claim 1) is provided.

In the invention of this application, the step of predicting and calculating the amount of the suspended suspended matter from the bottom mud, the concentration of the suspended suspended matter and the concentration of the organic matter in the suspended suspended matter are calculated as a function of the concentration of the suspended suspended matter. The step of converting the predicted calculation value of the amount of suspended suspended matter into the amount of organic matter rolled up from the bottom mud, and the step of predicting and calculating the water quality using the calculated value of the amount of organic matter rolled up A water quality prediction calculation method (claim 2) is also provided, and in the step of predicting and calculating the water quality in this prediction calculation method, a water quality prediction calculation model that models organic matter generation and decomposition processes is used (claim Item 3) is provided.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The invention of this application is that the relational expression between the concentration of the suspended suspended matter and the concentration of the organic matter in the suspended suspended matter can be expressed as a function of the concentration of the suspended suspended matter. The present invention has been made on the basis of a completely new finding by the inventors, and the relational expression is used to realize the prediction calculation of the amount of rolled organic matter.

In the above relational expression, a field survey is carried out for each actual sea area subject to the amount of winding and water quality prediction, and the water quality at a large winding location (for example, a shallow water location) and a small water location in the ocean area due to waves and currents. It can be obtained by analyzing data (eg suspended matter, loss on ignition of suspended matter, suspended organic carbon, chlorophyll concentration, etc.) and can be used to model the winding process of rolled organic matter. Perform forecast calculation of the amount of organic matter rolled up for each forecasted sea area.

More specifically, first, the winding and settling process of suspended matter from the bottom mud due to waves and flows will be described. For example, as shown in FIG. 1, the winding process (Up in the figure).
In the above, a layer directly above the bottom surface containing a high concentration of suspended substances is formed immediately above the bottom surface of the mud layer composed of bottom mud, and the suspended substances are wound up from the layer directly above the bottom surface into water.

In the sedimentation process (W1 and W2 in the figure), the organic matter contained in the suspended material suspended in water (SSbm) is the organic matter (SSorg-b) combined with the inorganic matter (SSin-bm) such as soil particles.
m1) and organic matter (SSorg-bm2) separated from inorganic matter are separated and settled, and transported by flow. The sedimentation rate of the organic matter (SSorg-bm1) combined with the inorganic matter depends on the sedimentation rate of the inorganic matter, and the organic matter released from the inorganic matter (SSor-bm1)
It becomes larger than the sedimentation velocity of g-bm2). In the suspended suspended matter (SSbm) containing these organic matters, the composition of the organic matter changes with the passage of time in the transportation process, and the average sedimentation rate of the suspended matter composed of the mixed particle size of inorganic matter and organic matter also changes. It is thought to do.

Modeling of the winding process of the organic material is as follows:
Based on the winding and sedimentation process of this suspended matter, the above relational expression, and the existing model for predicting the amount of suspended suspended matter (for example, the model for calculating the amount of floating mud floating and the model for predicting suspended sediment) and the water quality prediction model Based on the consistency with, for example, the following is performed.

First, the layer just above the bottom surface is an extremely thin layer and is a virtual layer because it is difficult to measure in an actual sea area and contains many uncertain elements. Next, the suspended suspended matter is converted into the suspended organic matter by the relational expression between the suspended suspended matter concentration and the organic matter concentration obtained by the analysis of the field survey water quality data. For this conversion, there are a method to be performed after winding up in water and a method to calculate the winding up in water by performing conversion in the layer immediately above the bottom surface according to the conversion timing. Thereby, the winding process model as illustrated in FIG. 2 is obtained.

That is, the winding process model of the rolled-up organic matter is a predictive calculation model of the amount of rolled-up organic matter, and based on this, the existing suspended-cracked substance amount prediction calculation model is used to predictively calculate the concentration of the rolled-up suspended matter. By converting it into the amount of organic matter rolled up by the above relational expression, the amount of organic matter rolled up from the bottom mud can be accurately predicted and calculated.

Further, according to the invention of this application,
By using the amount of rolled-up organic matter predicted and calculated as described above, it is possible to more accurately perform the water quality prediction calculation by the water quality prediction calculation model that models the biochemical generation / decomposition process of the organic matter.

In this case, in order to make it possible to perform the prediction calculation of the amount of wound organic matter at the same time as the water quality prediction calculation, assuming that the wound organic matter is decomposed and consumed (corroded) like organic matter of water origin. The predictive calculation model of the amount of organic matter may be incorporated into the water quality predictive calculation model.

The invention of this application has the characteristics as described above, and the embodiments will be described in more detail below.

[0018]

[Examples] [Example 1] As an example, the preparation of a relational expression between the concentration of suspended suspended matter and the concentration of organic matter based on field survey water quality data in the actual target sea area will be described.

<1. Field survey water quality data> The field survey water quality data used to create the relational expressions are as follows.・ Survey place: Inage beach and Kemigawa beach breaking wave zone (measurement points: S1 to S6, N1 to N5) and offshore water area (measurement points: offshore 1 to 5) (see Fig. 3) ・ Survey time: 1999 July 28, September 26, 10
Total of 3 times on 29th month ・ Survey layer: 2 layers or 3 layers from the sea floor + 0.3m or + 0.5m to the sea surface ・ Survey items: Suspended substances in water (SS), loss on ignition (I
L), suspended organic carbon (POC), chlorophyll concentration

<2. Calculation of Organic Substance and Inorganic Substance in Suspended Substance> Based on this water quality data, first, the organic substance (SSorg) and inorganic substance (SSin) contained in the suspended substance (SS) are calculated. It converts suspended solids (SS) in water into organic matter (SS or
g) and inorganic substances (SSin). SSorg = SS × IL SSin = SS-SSorg

<3. Calculation of Suspended Suspended Substances> Next, the suspended suspended substances (SSbm: SS component rolled up from the bottom mud due to waves and currents) are used as follows, using the water quality data for large and small winding locations. calculate.

<3-. Calculation of Inorganic Component in Rolled Suspended Substance> The inorganic component (SSin-bm) contained in the rolled suspended substance (SSbm) is extracted. This is performed by the following equation, using the average value of the inorganic matter (SSin) in the offshore surface layer, which is less affected by winding, as the background (SSin-off). SSin-bm = SSin-SSin-off

<3-. Calculation of Organic Component in Rolled-up Suspended Substance> The organic component (SSorg-bm) contained in the rolled-up suspended substance (SSbm) is extracted. Organic matter (SSorg) contains phytoplankton-derived internally-produced components, but the amount of chlorophyll (Chla) serves as an indicator of the amount of phytoplankton. ) And the following linear expression [SSorg = a · Chla + b]
It was found that it can be expressed by (see FIG. 4).

July Y = 0.0382X + 2.164
(R = 0.777) September Y = 0.0308X + 0.7121 (R =
0.914) October Y = 0.1179X + 1.5971 (R =
0.876) where: X: Chla concentration [μg / l] Y: SSorg concentration [mg / l] R: Correlation coefficient

Organic matter calculated by using this linear equation (SS
org) as the background (SSorg-off), and organic components (SSorg-b) contained in the suspended material (SSbm)
m) is calculated by the following formula. SSorg-bm = SSorg-SSorg-off

<4. Calculation of Concentration of Suspended Material> From the above, the concentration of suspended material (SSbm) from bottom mud is calculated as SSbm = SSin-bm + SSorg-bm.

<5. Concentration distribution of rolled-up suspended matter> When analyzing the distribution of rolled-up suspended matter concentration (SSbm) thus obtained, the characteristic of the concentration distribution in July when the rolling phenomenon due to waves was clear was as follows. It was as it was.

That is, the SSbm of the offshore surface layer assuming no winding is in the range of about 0 to 1.6 (mg / l), and it is considered that this degree of error is included in the calculation of SSbm. SSbm at Inage beach, which was expected to be rolled up by waves due to the difference in beach nourishment structure such as jetty
Indicates a high value, and the lower layer of the sea area near the shore (shoreline to about 200 m offshore) was in the range of about 20 to 200 (mg / l). On the other hand, SSbm on the beach of Kemigawa, which was expected to be rolled up, was about 1/10 of the beach of Inage.

<6. Relationship between rolled-up suspended matter and organic components>
Next, when the ratio of the organic component (SSorg-bm) contained in the suspended material (SSbm) was examined, it was observed that the higher the concentration of SSbm, the smaller the ratio of SSorg-bm. The relation with bm is the following expression [SSor
g-bm = a * log (SSbm) + b or Log (SSorg-
bm) = a · log (SSbm) + b] (see FIGS. 5A, 5B, and 5C).

July Yorg-bm = 0.5163exp
(1.4819Log ₁₀ (Xbm)) (R ² = 0.6294) September Yorg-bm = 1.5272Log ₁₀ (Xbm) +
0.1478 (R ² = 0.4263) Oct Yorg-bm = 2.0514 Log ₁₀ (Xbm) +
0.0557 (R ² = 0.7296) where: Xbm: Concentration of suspended material in suspension [mg / l] Yorg-bm: Concentration of organic substance in suspended material in suspension [mg / l] R ² : Coefficient of determination

<7. Relationship between Organic Components of Rolled Suspended Substances and Organic Carbon Content> Here, since a model that expresses organic matter in terms of carbon amount is used as a water quality prediction model, the organic components of rolled suspended solids (SSbm) calculated by the above method ( SSorg-
bm) needs to be converted to organic carbon content (POCbm).

The construction of the water quality prediction model for the target sea area was carried out in July when the winding phenomenon was clear, so the organic carbon content (POCbm) of the organic component (SSorg-bm) of the suspended suspended matter (SSbm) The following relational expression obtained from the analysis and analysis of the water quality data for July was used for the conversion to ().

POCbm / SSorg-bm = 0.1576 (S
Sorg-bm) ^-0.2976 (R ² = 0.4423) POCbm = POC × (SSorg-bm / SSorg) where SSorg-bm: Organic component of hoisting suspension substance POCbm: Organic component of hoisting suspension substance Organic carbon amount

<8. Relational expression> The above <6> and <7>
The relational expression in is a relational expression between the concentration of suspended suspended matter (SSbm) and the concentration of organic matter in the suspended suspended matter (SSorg-bm) created based on the field survey water quality data, and the concentration of suspended suspended matter ( It can be seen that it is expressed as a function of SSbm). Therefore, in the same way as above,
By obtaining the relational expression for each prediction target sea area, it is possible to realize an accurate prediction calculation of the amount of rolled organic matter.

[Embodiment 2] Here, based on the amount of wound organic matter obtained by the relational expression of Example 1, formation of organic matter
An example of incorporating a rolled-up organic matter amount prediction calculation model and a water quality prediction calculation model, which is performed when calculating the water quality prediction using the water quality prediction calculation model that models the decomposition process, will be described.

<1. Incorporation into organic matter generation / decomposition process in water quality prediction model><1-. Classification of suspended organic matter> First, as in the following equation,
Suspended organic matter (POM) in water, suspended organic matter (POMwa) and suspended organic matter (POMbm)
Divide into. POM = POMwa + POMbm

Each of these suspended organic substances (POMwa, POM
The biochemical production and decomposition process of bm) can be modeled as follows.

<1-. Modeling of suspended organic matter originating in water> dPOMwa / dt = [death (PHY, ZOO)] + [feces (ZOO)]-[decomposition (POMwa)]-[feeding (ZO
O, F-Bent)]-[settling (POMwa)] where dPOMwa / dt: Suspended organic matter of water origin (POMw)
a) Time variation [Death (PHY, ZOO)]: Phytoplankton (PH
Y) death, zooplankton (ZOO) mortality [feces (ZOO)]: Zooplankton (ZOO) feces [decomposition (POMwa)]: POMwa decomposition [feeding (ZOO, F-Bent) )]: PO of zooplankton (ZOO) and mud-layer benthic animals (F-Bent)
Mwa intake [POMwa]: POMwa sediment

<1-. Modeling of suspended organic matter)> dPOMbm / dt =-[decomposition (POMbm)]-[feeding (ZOO, F-Bent)]-[sedimentation (POMbm)] +
[Winding (POMbm)] where: dPOMbm / dt: Suspended organic matter (POMb) originating from hoisting
m) temporal change [decomposition (POMbm)]: Decomposition amount of POMbm [feeding (ZOO, F-Bent)]: PO of zooplankton (ZOO) and mud layer benthos (F-Bent)
Mbm food intake [precipitation (POMbm)]: POMbm precipitation [winding (POMbm)]: POMbm winding

<2. Incorporation of hoisting process of organic matter> Field survey of forecasted sea area The conversion formula of hoisted suspended matter obtained from water quality data into the amount of hoisted organic matter (see Example 1) is intended for hoisted suspended matter in water. Therefore, when constructing a water quality prediction model for the target sea area,
The method of converting the suspended matter into the organic matter to be rolled up is a method which is carried out after being rolled up in water.

The amount of organic matter to be rolled up is calculated as follows by using the calculation result of the amount of suspended matter in the layer immediately above the bottom surface based on the conditions of wave and flow fields.

<2-. Calculation of the amount of suspended solids in water> First, it is assumed that the transport from the layer directly above the bottom surface to water is by vertical diffusion, and the vertical diffusion amount D of the suspended substance from the layer directly above the bottom surface to the water, that is, the amount D Is calculated.

D = Kzb (dSSbm / dz) where: Kzb: vertical diffusion coefficient dSSbm / dz: concentration gradient of the vertically suspended substance (SSbm) between the water immediately above the bottom surface and the water above.

<2-. Calculation of Volume of Rolled Organic Matter> The volume of suspended organic matter in water (POMbm) is calculated by using the relational expression (see Example 1) obtained by the analysis of the field survey water quality data of the target sea area. It is calculated by converting the winding amount D of turbid substances.

As described above, by incorporating the predictive calculation model of the amount of rolled-up organic matter into the water quality prediction calculation model, the calculated amount of rolled-up organic matter is decomposed / consumed (corroded) in the same manner as the organic matter derived from water. It can be done at the same time as the water quality prediction calculation.

[Embodiment 3] FIG. 6 exemplifies the whole flow from the prediction calculation of the amount of organic matter to be wound up to the prediction calculation of water quality according to the invention of this application as an embodiment. In this embodiment, the coastal sea area having a structure such as a jetty and the tidal flat portion is the prediction target sea area.

<1. Prediction calculation of amount of rolled-up organic matter><1-> First, since the external force that causes the suspended substance to be rolled up is a wave and a flow, in the present embodiment, the wave and the flow are
The calculation is performed using the following existing wave prediction model and flow field prediction calculation model.

A. Wave Prediction Calculation Model There are structures such as jetty in the prediction target sea area, and it is necessary to accurately reproduce the reflection and diffraction phenomena of the structure for wave deformation calculation. Therefore, in the present embodiment, an existing predictive calculation model, which is extended to treat irregular waves based on the unsteady gentle gradient equation, is used.

B. Predictive calculation model of flow field The existing two-dimensional single layer model corresponding to tidal flat is used for tidal flow calculation. In addition, the beach current is calculated from the wave calculation results using the existing formula, and the combined current with the tidal current is obtained.

<1-> Next, using the calculation result of the wave and the calculation result of the flow field as input conditions, an existing calculation model for predicting the amount of floating mud (W.Bijker, Sedimentation is Channels)
andTreaanches., conf.coastal Eng. pp1708-1718, 198
Predict the amount of suspended solids according to (see 0).

<1-> Then, the predicted calculation value of the amount of suspended organic matter is calculated from the relational expression between the concentration of suspended suspended matter and the concentration of organic matter prepared based on the field survey water quality data in the target sea area. Convert to quantity.

From the above, an accurate prediction calculation of the amount of wound organic matter is realized.

<2. Water Quality Prediction Calculation> As the water quality prediction calculation model, an existing ecosystem (low-order) model type that models the generation and decomposition processes of organic matter is used. Existing ecosystem (low-order) model types will be adopted for important mud systems in sandy areas such as tidal flats. It should be noted that the water quality prediction calculation here also includes the bottom quality prediction calculation.

Then, a model of a winding process of organic matter from bottom mud, that is, a predictive calculation model of the amount of rolled organic matter is incorporated into this water quality prediction calculation model, and the water quality is predicted and calculated based on this combined model.

From the above, highly accurate water quality prediction calculation considering only the amount of organic matter rolled up can be realized.

Of course, the present invention is not limited to the above examples, and various aspects are possible in details.

[0057]

As described in detail above, according to the invention of this application, a new method for predicting the amount of organic matter to be wound up from the bottom mud, and a method for predicting the organic matter generation / decomposition process are provided. Provided is a new water quality prediction calculation method capable of more accurately performing a water quality prediction calculation using a calculation model.

[Brief description of drawings]

FIG. 1 is a conceptual diagram exemplifying a winding and sedimentation process of suspended matter from bottom mud.

FIG. 2 is a conceptual diagram exemplifying a predictive calculation model of the amount of wound organic matter.

FIG. 3 is a schematic diagram showing field survey points in a prediction target sea area as one example.

FIG. 4 is a diagram showing a relationship between an amount of chlorophyll and an organic substance in a suspended substance as one example.

FIG. 5 is a diagram showing a relationship between a rolled-up suspended substance and an organic component as one example, (a) is July survey data,
(B) is the September survey data, and (c) is the October survey data.

FIG. 6 is a flow chart for explaining the prediction calculation of the amount of wound organic matter and water quality according to the invention of this application as an example.

Claims (3)

[Claims] 1. A step of predicting and calculating the amount of suspended suspended matter from bottom mud, and a relational expression expressing the suspended suspended matter concentration and the organic matter concentration in the suspended suspended matter as a function of the suspended suspended matter concentration. And a step of converting the predicted calculation value of the amount of suspended solids into the amount of organic matter rolled up from the bottom mud. 2. The step of predicting and calculating the amount of suspended suspended matter from the bottom mud, and the relational expression expressing the suspended suspended matter concentration and the organic matter concentration in the suspended suspended matter as a function of the suspended suspended matter concentration. , A step of converting the predicted calculation value of the amount of suspended suspended matter into the amount of organic matter rolled up from the bottom mud, and a step of predicting and calculating water quality using the calculated value of the amount of rolled organic matter. Water quality prediction calculation method. 3. In the step of predicting and calculating water quality,
The water quality prediction calculation method according to claim 2, wherein a water quality prediction calculation model modeling the organic matter generation / decomposition process is used.