JPH0517975A - Rainwater inflow amount estimating device - Google Patents

Abstract

PURPOSE:To improve accuracy of estimating an inflow amount of rainwater by reflecting rain fall distribution, making the best use of a narrow band property of a rainwater radar, as a rainfall amount in an equiarrival time region of an RRL method. CONSTITUTION:Power received by a radar transceiving device 2 is converted into a mesh-shaped rain amount distribution by a mesh rain amount data converting device 3 and also giving a flow down speed of rain water in a sewage trunk line or a branch pipe, obtained from an observed water level or flow amount, to an equiarrival time curve creating device 6 to create an equiarrival time curve such that a flow arrival time to a flow amount calculating point in an objective flow area becomes a predetermined inflow amount arithmetic period. These equiarrival time curve and mesh rain amount data are given to an area rainfall amount calculating device 4 to calculate an area rainfall amount in an equiarrival time region by performing area distribution of the mesh rain amount data relating to the equiarrival time region. This area rainfall amount is given to an outflow analyzer 5 and overlapped with a rainfall record in the past to calculate an inflow amount at each time corresponding to the inflow amount arithmetic period displayed in a display device 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump operation support device for a sewer pumping station or a treatment plant for the purpose of draining rainwater, and in particular, rainwater inflow prediction by a rainwater runoff analysis method considering the rainfall distribution in a basin by a radar rain gauge. Regarding the device.

[0002]

2. Description of the Related Art Conventionally, in a sewer pump facility intended for drainage of rainwater, an operator has determined the number of pumps to be operated and the timing of starting and stopping according to the state of rainwater inflow due to rainfall. The operator made the above decision based on his experience and intuition for many years, based on the rainfall conditions and the pump well water level.

However, with the progress of urbanization and sewerage development in recent years, most of the rainfall will flow into the pump facility,
It has become necessary to deal with the sudden inflow of rainwater due to torrential rain, typhoons, and thunderstorms.

Therefore, recently, a method has been introduced in which rainfall information is linked to a rainwater outflow analysis method to quantitatively predict the amount of rainwater inflow into the pump facility (hereinafter simply referred to as inflow prediction). This inflow prediction method makes it possible to predict the pump operation time and the number of pumps with respect to the inflow amount several tens of minutes ahead of the current time, and eventually to support the pump operation to reduce the load on the operator during rainfall, such as preparations for starting the private generator It is moving toward the system.

By the way, as a rainfall runoff analysis method, RRL which is often used to calculate runoff of sewer pipes in urban areas.
There is a method (R0ad Resarch Laboratory). Below this RRL
The method will be briefly explained.

First, the delivery time to the inflow calculation point P is
Obtained and calculated at each equal time interval Δt
Has been achieved. The delivery time is calculated when the sewer pipe is full.
Assuming that there is, the flow velocity is calculated from the hydraulic formula and
Calculates distance and time domain boundary line L_iCan create
It Next rainfall intensity I in the basin_iAs shown in Figure 3
Rainwater inflow P_iIs calculated by the following formula, P0 = 0 P₁= I₁・ A₁  P₂= I₁・ A₂＋ I₂・ A₁  P₃= I₁・ A₃＋ I₂・ A₂＋ I₃  : …… (1): P_n= I₁・ A_n＋ I₂・ A_n-1+ ... I_n・ A₁  And this is shown as the change in rainwater inflow over time.
And the curve becomes as shown in FIG. Here, in the above formula (1),
And A_iIs the equal arrival time area. The next rain
It does not immediately flow out, but once it is stored in the basin, it flows out
Therefore, as shown in FIG. 6 via the stored flow rate-outflow rate function shown in FIG.
The outflow function Q shown is obtained.

When the target watershed is relatively large and the ratio of the flow rate flowing in from a distance is relatively larger than that in the vicinity of the pump facility, calculation is performed based on the rainfall that has occurred up to the current time without performing rainfall prediction. Even if it is within the range of short time prediction of several tens of minutes, no large error will occur.

[0008]

As described above, in the method based on the RRL method, the equal arrival time region is not in a full state and the delivery time tends to be estimated earlier. This causes a mistake in predicting the rising waveform of the inflow amount, which is a problem in accuracy.

Conventionally, as a method of rainfall observation, a ground rain gauge has been mainly used in the past, but a radar rain gauge is planned to be introduced mainly in large cities as a means for grasping the regional rainfall distribution, that is, the surface rainfall distribution situation. Therefore, in the RRL method, it is necessary to emphasize the rainfall distribution on the equal arrival time domain curve. That is, although a uniform rainfall distribution in the target watershed was conventionally assumed, in the case of a radar rain gauge, a mesh unit (for example,
Since the information is given in (500 m × 500 m), it is important to improve the accuracy by calculating the area rainfall within the equal arrival time by making the best use of the detailed rainfall distribution information amount. An object of the present invention is to provide a rainwater inflow prediction device that solves the above-mentioned problems and can improve the inflow prediction accuracy based on a radar rain gauge.

[0010]

In order to achieve the above-mentioned object, the present invention is directed to the operation of a sewer pump for the purpose of draining rainwater, and the inflow of rainwater by a rainwater runoff analysis method considering the rainfall distribution in the basin by a radar rain gauge. In the amount prediction device, radar transmitting / receiving means for emitting radio waves from a radar antenna and receiving radio waves reflected by raindrops as electric power, and mesh rainfall data for converting the electric power received by the radar transmitting / receiving means into a mesh-shaped rainfall distribution A conversion means, a flow velocity calculation means for calculating the flow velocity of rainwater from the sewer trunk line or branch pipe from the observed water level or flow rate, and the flow to the flow rate calculation point in the target basin based on the flow velocity calculated by this flow velocity calculation means. The equal arrival time curve creating means for creating an equal arrival time curve whose time becomes a predetermined inflow amount calculation cycle, and the equal arrival time curve creating means The area rainfall calculation means for calculating the area rainfall within the equal arrival time area by performing the area distribution of the mesh rainfall data obtained by the mesh rainfall data conversion means to the equal arrival time area, and the area rainfall amount. Outflow analysis means that calculates the inflow at each time corresponding to the inflow calculation cycle by superposing past rainfall history using the area rainfall obtained by the calculation means, and each time calculated by this outflow analysis means Inflow prediction display means for displaying the time change of the rainwater inflow in

[0011]

In the rainwater inflow predicting apparatus having such a structure, the mesh obtained by the mesh rainfall data converting means for the equal arrival time range obtained by the equal arrival time curve creating means by the area rainfall calculating means The area distribution of the rainfall data is performed to calculate the area rainfall within the equal arrival time area, and this area rainfall is used to calculate the inflow rate at each time corresponding to the inflow rate calculation cycle by combining with the past rainfall history. Therefore, it is possible to accurately reflect the rainfall distribution that makes use of the narrow range of the radar as the rainfall amount within the equal arrival time region of the RRL method, and improve the precision of the inflow forecast value. Further, since the equal arrival time region is not fixed but variable depending on the flow velocity, the rainwater arrival time corresponding to the flow rate can be estimated, and the accuracy of the inflow waveform prediction value can be improved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a structural example of the entire apparatus of the present invention. This apparatus is provided with a radar rain gauge consisting of a radar antenna 1 and a radar transmitter / receiver 2. At least the radar antenna 1 of the radar rain gauge is installed in a place where the visibility is relatively good in the vicinity of the urban area, and operates under the control of the radar transmitter / receiver 2.
The radar transmitter / receiver 2 generates a signal to be transmitted, emits it from the radar antenna 1 as a radio wave, and returns the radio wave backscattered by raindrops falling from a rain cloud to the radar antenna 1 again.
It is received as radar reception power data corresponding to the rainfall distribution data.

Since the received power of the radar transmitter / receiver 2 cannot be used as rainfall data as it is, it is applied to the mesh rainfall data converter 3 to convert the received power into mesh-shaped rainfall distribution data. The mesh rainfall distribution data converted by the mesh rainfall data conversion device 3 is input to the area rainfall calculation device 4.

On the other hand, the water level is measured by a water level gauge installed in the pump facility 10, and the measured value is given to the flow velocity calculation device 7 to calculate the flow velocity of rainwater. This flow velocity calculation device 7
The downflow velocity obtained in step 1 is added to the equal arrival time curve creation device 6, where an equal arrival time curve is created and given to the area rainfall amount calculation device 4.

The area rainfall calculation device 4 distributes the area of the mesh rainfall data within the equal arrival time region, and calculates the area rainfall by the calculation which will be described in detail later. The area rainfall calculated by the area rainfall calculator 4 is given to the runoff analyzer 5, where the past rainfall history is superposed using the area rainfall, and the inflow at each time is analyzed in detail later. Find by law. The result obtained by the outflow analysis device 5 is displayed as a required graph on the inflow prediction display device 8. Next, the operation of the rainwater inflow prediction device configured as described above will be described.

Now, when the water level is measured by the water level gauge installed in the pump facility and the measured value is input to the flow velocity calculation device 7, the flow velocity calculation device 7 substitutes the measured water depth h into the following equal flow equation. Then, the flow velocity v is obtained and input to the equal arrival time curve creation device 6. In this equal arrival time curve creation device 6,
Using this flow velocity v, an equal arrival time curve is created by the following method.

As shown in FIG. 7, the iso-arrival time curve is obtained from arbitrary points x ₁ to P with respect to the outflow calculation point P at the end of the main line.
Respect, between the x ₁ arbitrary point to P, the distance proceeds in i-th time interval Delta] t · i as reaching the flow at a flow rate v ₁ l
₁ becomes l ₁ = Δt · i · v ₁ (2). Considering the point x ₂ on the sewage trunk line, when flowing down at the flow velocity v ₂ , the distance l ₂ to P is l ₂ = Δt · i · v ₂ (3). Generally, at a point x ₃ along the main line, the sum of the time t _A for reaching the watershed and the time t _B for flowing down the main line t = t _A + t _B (4) forms an equal arrival time region. Become. That is, t = l _A / v ₁ + l _B / v ₂ (5) Now, pay attention to the flow velocities v ₁ and v ₂ . Usually, when flowing down in the sewer pipe at a water depth h as shown in FIG. 8, the flow velocity v can be obtained by using the uniform flow equation and the Manning equation. A = (1/2) · r ² ・ (Θ-sin θ) (6) S = r ・ θ (7) θ = 2cos ^-1 (1-h / r) (8) R = A / S = (r / 2)・ (1-sin θ / θ) …… (9) v = (1 / n) ・ i ^1/2 ・ R ^2/3 …… (10) Q = Av …… (11)

Here, A: accumulated product (m ² ), R: pipe radius (m), θ: angle, S: wet side length, h: water depth (m), R:
Diameter (m), v: flow velocity (m / sec), n: roughness count, i:
Pipe slope, Q: Flow rate (m ³ / Sec)

Numerical examples of the water depth H, the flow rate Q, and the flow velocity v when the pipe diameter is 7 m are shown in FIGS. 9 and 10. Further, FIG. 11 is a diagram of the main line flow-down time, and it can be seen that the time required to flow down a predetermined distance becomes shorter as the flow rate increases.

To facilitate understanding, consider a watershed surrounded by a circle with a main line passing through the center. According to the isokinetic equation using the Manning equation, the flow rate (m ³ / S) or the water depth (m) is given, it is possible to create the equal arrival time curve L _i corresponding thereto. For example, when the flow rate is small, the Δt time intervals become close as shown in FIG. 12,
It is considered that the flow rate becomes sparse as shown in FIG. 13 as the flow rate increases.

A water level gauge is often installed at the flow rate calculation point P, which is a pump facility or a water diversion facility, and the main arrival speed v ₁ changes the equal arrival time curve based on the measured water level _every moment. Let On the other hand, in most cases, a water level gauge is not installed to estimate the reaching velocity v ₂ of the branch pipes in the basin, so that it is obtained as a function of the water level gauge information at the flow rate calculation point P. That is, V ₂ = f (v ₁ ) (12) where f is a function that relates the water level measurement value of the main line and the reaching velocity v _{2 The} equal arrival time curve thus obtained is the area rainfall. It is input to the quantity calculation device 4.

On the other hand, when the reception power received by the radar transmitter / receiver 2 is converted into a mesh rainfall distribution by the mesh rainfall data converter 3 and input to the area rainfall calculator 4, the area rainfall calculator 4 Radar rainfall mesh data is emphasized on the equal arrival time curve by the following method.

FIG. 13 is a diagram in which the equal arrival time curve of the basin and the mesh data are superimposed. For the calculation of the area rainfall, the area distribution of the mesh data (n pieces) within the equal arrival time area is used. That is, IA _i (t) = Σa _j · r _j (t) · Δt / 1000 (13) where j = 1 to n, A _i : Area rainfall at the i-th time interval Δt time, a _j : mesh j over the area of equal arrival time curve L _i-1
Area of (m ² ) R _j (t): rainfall intensity (mm) of mesh j at time t
/ hr) Δt: Time interval (hr)

In this way, the area rainfall calculation device 4 distributes the area of the mesh rainfall data within the equal arrival time region, and the area rainfall is calculated by the equation (13).
The inflow amount at each time is obtained by the outflow analysis device 5 using the area rainfall amount calculated by the area rainfall amount calculation device 4 as follows. For example, the area rainfall surrounded by L ₂ and L ₃ in FIG. 13 is IA ₃ = Σa _j · r _j · Δt / 1000 (14) where j = 1 to 10 is represented. That is, P ₁ = IA ₁ (t) P ₂ = IA ₂ (t-1) + IA ₁ (t) P ₃ = IA ₃ (t-2) + IA ₂ (t-1) ) + IA ₁ (t): (15): P _m = IA _m (t-m + 1) + ... + IA ₁ (t).

The inflow amount obtained here is a virtual inflow amount, and an outflow amount curve is obtained by using a well-known storage amount-outflow amount function. In this case, if there is only one pump facility in the target basin, the outflow amount will be the estimated inflow value to the pump facility. The result obtained by the analysis device 5 is displayed on the inflow prediction display device 8 as a necessary graph.

As described above, in this embodiment, the mesh rainfall converted by the mesh rainfall data converter 3 is applied to the area rainfall calculator 4, while the coffin water level measured by the water level gauge installed in the pump facility or the like. Is input to the flow velocity calculating device 7 to calculate the flow velocity, and the flow velocity is calculated using the equal arrival time curve creating device 6
To the flow rate calculation point in the target basin, an equal arrival time curve is created so that the inflow time calculation cycle becomes a predetermined inflow calculation period, and this is used together with the mesh rainfall data converted by the mesh rainfall data conversion device 3. The RRL method is applied to the area rainfall amount calculation device 4 to calculate the area rainfall amount, and the RRL method is used to calculate the rainwater outflow amount. Since it is determined, it is possible to improve the inflow prediction accuracy based on the radar rain gauge.

In the above embodiment, the case where the water level in the sewer pipe of the inflow pipe is measured by the water level gauge has been described.
If the water level gauge is aiming at the pump well water level,
The inflow rate may be estimated by converting the water level change into a flow rate from the water level relationship. That is, inflow amount = g (water level change) + pump discharge amount (16) However, g is a function representing the storage amount-water level relationship. Using the inflow amount estimated in this way, the uniform flow equations (6) to (11)
The flow velocity v can be obtained by inputting the flow rate into the equation.

[0029]

As described above, according to the present invention, since the rainfall distribution utilizing the narrowness of the radar is reflected as the rainfall amount within the equal arrival time region of the RRL method, the accuracy of the inflow prediction value is improved. In addition, the equal arrival time range is not fixed and is variable according to the flow velocity, so the rainwater arrival time according to the flow rate can be estimated, and the rainwater inflow amount that can improve the accuracy of the inflow waveform prediction value can be estimated. A prediction device can be provided.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing an embodiment of a rainwater inflow prediction device according to the present invention.

FIG. 2 is a diagram showing a uniform arrival time region for explaining an outflow analysis method.

FIG. 3 is a diagram showing changes in rainfall intensity over time.

FIG. 4 is a diagram showing changes over time in the amount of rainwater inflow.

FIG. 5 is a diagram showing a function of stored amount-outflow amount.

FIG. 6 is a relationship diagram of a virtual inflow flow rate and a flow rate after passing through an SQ function.

FIG. 7 is a diagram for explaining a method of calculating an equal arrival time curve.

FIG. 8 is a sectional view of a sewer pipe for explaining the uniform flow method.

FIG. 9 is a diagram showing the relationship between water depth and flow rate using the uniform flow method.

FIG. 10 is a diagram showing a relationship between water depth and flow velocity.

FIG. 11 is a diagram showing a main running time according to the Manning method.

FIG. 12 is a diagram showing an equal arrival time curve when the flow rate is small.

FIG. 13 is a diagram in which rainfall mesh data and isobaric curves are superimposed.

FIG. 14 is a diagram showing a display example of an inflow prediction result.

[Explanation of symbols]

1 ... Radar antenna, 2 ... Radar transceiver, 3 ...
Mesh rainfall data conversion device, 4 ... Area rainfall calculation device, 5 ... Runoff analysis device, 6 ..., etc. Arrival time curve creation device, 7 ... Velocity calculation device, 8 ... Inflow prediction display device,
9 ... Water gauge, 10 ... Pump facility.

Claims (1)

Claim: What is claimed is: 1. A device for assisting prediction of rainwater inflow by a rainwater runoff analysis method that takes into account rainfall distribution in a basin by a radar rain gauge for operation of a sewer pump for rainwater drainage. A radar transmission / reception means for emitting radio waves from a radar antenna and receiving the radio waves reflected by raindrops as electric power, a mesh rainfall data conversion means for converting the electric power received by the radar transmission / reception means into a mesh-shaped rainfall amount distribution, and observation The flow velocity calculation means for calculating the flow velocity of rainwater on the sewer trunk line or the branch pipe based on the measured water level or flow rate, and the arrival time to the flow rate calculation point in the target basin based on the flow velocity calculated by this flow velocity calculation means Equal arrival time curve creating means for creating an equal arrival time curve such that it becomes a quantity calculation cycle, and equal arrival time obtained by this equal arrival time curve creating means The area rainfall calculation means for calculating the area rainfall within the equal arrival time area by allocating the area of the mesh rainfall data obtained by the mesh rainfall data conversion means to the area, and the area rainfall calculation means Of runoff analysis that calculates the inflow at each time corresponding to the inflow calculation cycle by overlapping the past rainfall history using the area rainfall and the rainwater inflow at each time calculated by this outflow analysis. A rainwater inflow prediction device, comprising: an inflow prediction display means for displaying a change over time.