Groundwater flow velocity meter

Abstract

To provide a ground water flow direction / flow rate meter capable of three-dimensionally measuring the flow direction and flow rate of ground water.SOLUTION: A ground water flow direction / flow rate meter has a sensor unit that comprises a cylindrical paper cylinder mounted on an outer periphery of a cylindrical member, and a cylindrical water-permeable sponge mounted on the outer periphery of the paper cylinder. The paper cylinder is provided with a plurality of dots printed with water-soluble ink over at least the entire circumference in a circumferential direction. The sensor unit is installed in a ground water observation well, so that the flow direction and flow rate of ground water can be three-dimensionally obtained, based on the tailing of the ink eluted from the plurality of dots and drawn on the paper cylinder.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a simplified groundwater flow direction and velocity meter. [Background technology]

[0002] Measurement of groundwater flow direction and velocity is used for various purposes, such as predicting the impact of soil and groundwater contamination and understanding groundwater flow in landslide areas. However, conventional groundwater flow meters are expensive and have a complicated configuration.

[0003] Therefore, the present inventors previously proposed a paper disc type groundwater flow direction and velocity meter as a simple groundwater flow direction and velocity meter (see Patent Document 1).

[0004] The groundwater flow direction and velocity meter described in Patent Document 1 uses dye ink printed on paper as a tracer and measures the flow direction and velocity of groundwater by capturing the transport of the ink on a plane.It is inexpensive and has a simple configuration, and does not require a power source for measurement work in groundwater observation wells. However, the groundwater flow direction and velocity meter described in Patent Document 1 has a problem in that although it can measure horizontal flow, it cannot measure vertical flow. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5471624 Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, an object of the present invention is to provide a simple groundwater flow direction and velocity meter that can measure the flow direction and velocity of groundwater three-dimensionally. [Means for solving the problem]

[0007] In order to achieve the above object, the groundwater flow direction and velocity meter of the present invention comprises: a cylindrical paper cylinder attached to the outer periphery of the cylindrical member; a cylindrical water-permeable sponge attached to the outer periphery of the paper cylinder; A drain hole is provided in the upper part of the cylindrical member above the position where the paper cylinder is attached, an upper disk fixed to the upper part of the cylindrical member and a lower disk fixed to the lower part of the cylindrical member to position the paper cylinder and the water-permeable sponge in the axial direction of the cylindrical member; The drainage hole provided in the upper part of the cylindrical member is located above a height at which the upper disk is fixed, The paper cylinder is provided with a plurality of dots printed with water-soluble ink at least along the entire circumference, By leaving the sensor unit stationary in a groundwater observation well for a predetermined period of time, it becomes possible to determine the flow direction and flow velocity of groundwater in three dimensions based on the tailing of the ink that dissolves from the multiple point-like dots and is drawn on the paper cylinder.

[0008] The groundwater flow direction and velocity meter of the present invention comprises: This makes it possible to determine the horizontal flow direction and flow velocity of groundwater based on the horizontal component (horizontal length) of the length of the ink tailing that dissolves from the multiple point dots and is drawn on the paper cylinder.

[0009] The groundwater flow direction and velocity meter of the present invention comprises: It is preferable to determine the horizontal flow direction and flow velocity of groundwater based on the relationship between the horizontal component of the length of the ink tailing of the plurality of point-like dots and the angle (azimuth angle) from a reference direction.

[0010] The groundwater flow direction and velocity meter of the present invention comprises: graphing the relationship between the horizontal component of the length of the ink tail of the plurality of point-like dots and the angle (azimuth angle) from a reference orientation; It is preferable to determine the horizontal flow direction of groundwater based on the azimuth angle at which the horizontal component of the length of the tailings becomes zero (intersects with zero).

[0011] The groundwater flow direction and velocity meter of the present invention comprises: It is preferable that the direction connecting two points on the paper cylinder at an azimuth angle at which the horizontal component of the length of the tailings is zero is taken as the horizontal flow direction of the groundwater.

[0012] The groundwater flow direction and velocity meter of the present invention comprises: graphing the relationship between the horizontal component of the length of the ink tail of the plurality of point-like dots and the angle (azimuth angle) from a reference orientation; It is preferable to determine the horizontal flow direction of groundwater based on the azimuth angle at which the horizontal component of the length of the tailings is at its maximum.

[0013] The groundwater flow direction and velocity meter of the present invention comprises: It is preferable that the horizontal tangent direction on the paper cylinder at the azimuth angle at which the horizontal component of the length of the tailings is maximum is taken as the horizontal flow direction of the groundwater.

[0014] The groundwater flow direction and velocity meter of the present invention comprises: graphing the relationship between the horizontal component of the length of the ink tail of the plurality of point-like dots and the angle (azimuth angle) from a reference orientation; It is preferable to determine the horizontal flow velocity of the groundwater based on the maximum value of the horizontal component of the length of the tailings and a calibration curve obtained in advance through an experiment at the time the sensor unit is placed in the groundwater observation well.

[0015] The groundwater flow direction and velocity meter of the present invention comprises: It is preferable that the horizontal flow velocity of the groundwater be a function of the maximum value of the horizontal component of the length of the tailings divided by the time the sensor unit is left stationary in the groundwater observation well.

[0016] The groundwater flow direction and velocity meter of the present invention further comprises: This makes it possible to determine the vertical flow direction and flow velocity of groundwater based on the horizontal component (horizontal length) and vertical component (vertical length) of the length of the ink tailing that dissolves from the multiple point dots and is drawn on the paper cylinder.

[0017] Here, in the groundwater flow direction and velocity meter of the present invention, the flow direction of groundwater in the vertical direction means the elevation and depression angle, which is the angle in the up and down direction with respect to the horizontal.

[0018] The groundwater flow direction and velocity meter of the present invention comprises: It is preferable to determine the vertical flow direction and flow velocity of groundwater based on the relationship between the horizontal component of the length of the ink tailing of the multiple point dots and the angle (azimuth angle) from the reference direction, and the relationship between the vertical component of the length of the ink tailing of the multiple point dots and the angle (azimuth angle) from the reference direction.

[0019] The groundwater flow direction and velocity meter of the present invention comprises: graphing the relationship between the horizontal component of the length of the ink tailing of the plurality of dots and the angle (azimuth angle) from a reference orientation, and the relationship between the vertical component of the length of the ink tailing of the plurality of dots and the angle (azimuth angle) from a reference orientation; It is preferable to determine the vertical flow direction of groundwater based on the maximum value of the horizontal component of the length of the tailings and the value of the vertical component of the length of the tailings.

[0020] The groundwater flow direction and velocity meter of the present invention comprises: graphing the relationship between the vertical component of the length of the ink tail of the plurality of point-like dots and the angle (azimuth angle) from a reference orientation; It is preferable to determine the vertical flow velocity of the groundwater based on the vertical component value of the length of the tailings and a calibration curve obtained in advance through an experiment at the time the sensor unit is placed in the groundwater observation well.

[0021] The groundwater flow direction and velocity meter of the present invention comprises: It is preferable that the vertical flow velocity of the groundwater be a function of the vertical component of the length of the tailings divided by the time the sensor unit is left stationary in the groundwater observation well. [Effects of the Invention]

[0023] The groundwater flow direction and velocity meter of the present invention comprises a sensor unit having a cylindrical paper cylinder attached to the outer periphery of a cylindrical member and a cylindrical water-permeable sponge attached to the outer periphery of the paper cylinder, and the paper cylinder has a plurality of point-like dots printed with water-soluble ink at least around the entire circumference.By leaving the sensor unit in a groundwater observation well for a predetermined period of time, it is possible to determine the flow direction and velocity of groundwater in three dimensions based on the tailing of the ink that dissolves from the plurality of point-like dots and is drawn on the paper cylinder, and therefore it is possible to provide a simple groundwater flow direction and velocity meter that can measure the flow direction and velocity of groundwater in three dimensions.

[0024] Furthermore, the groundwater flow direction and velocity meter of the present invention is a simple type that is inexpensive and has a simple configuration, and does not require a power source for measurement work in groundwater observation wells. Therefore, it is possible to perform three-dimensional measurement of groundwater flow direction and velocity even in places with poor environments such as mountainous regions where it is difficult to obtain power. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a front view of a groundwater flow direction and velocity meter according to an embodiment of the present invention. [Figure 2] FIG. 2 is an exploded explanatory view of the groundwater flow direction and velocity meter according to the embodiment of the present invention. [Figure 3] FIG. 2 is an explanatory diagram of the measurement mechanism of the groundwater flow direction and velocity meter according to the embodiment of the present invention. [Figure 4] An explanatory diagram of the unfolded paper cylinder before measurement. [Figure 5] FIG. 10 is an explanatory diagram of the occurrence of tailing in a paper cylinder after measurement. [Figure 6]Illustration of groundwater flow model on a paper cylinder. [Figure 7] FIG. 6 is an explanatory diagram of the detection status of tailing in FIG. 5. [Figure 8] An explanatory diagram of the azimuth distribution and approximate curve of the horizontal component Lx of the tailing length. [Figure 9] An explanatory diagram of the orientation distribution of the vertical component Lz of the tailing length and an approximate straight line. [Figure 10] An illustration of the relationship between groundwater flow velocity V and tailing length L on the paper cylinder. DETAILED DESCRIPTION OF THE INVENTION

[0026] An embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows a front view of a groundwater flow direction and velocity meter according to an embodiment of the present invention, and Fig. 2 shows an exploded explanatory view of the groundwater flow direction and velocity meter according to an embodiment of the present invention. The groundwater flow direction and velocity meter 1 in the embodiment of the present invention is a single-hole groundwater flow direction and velocity measuring device for measuring groundwater flow in a groundwater observation well, and has a cylindrical member 2 such as a hard resin pipe, a cylindrical paper cylinder 3, and a cylindrical water-permeable sponge 4. The groundwater flow direction and velocity meter 1 comprises a cylindrical paper cylinder 3 attached to the outer periphery of the cylindrical member 2, and a cylindrical water-permeable sponge 4 attached to the outer periphery of the paper cylinder 3, thereby forming a sensor section.

[0027] The cylindrical member 2 is, for example, a polyvinyl chloride resin pipe (for example, VP20 (outer diameter 26 mm, thickness 3 mm)), and is provided with a drain hole 21 at the top. By connecting a support member (not shown) or the like to the cylindrical member 2, the length of the groundwater flow direction and velocity meter 1 can be adjusted.

[0028] The paper cylinder 3 is, for example, drawing paper, and has a plurality of point-like dots 5 (e.g., 2 to 3 mm) printed at equal intervals (e.g., 16 at 22.5° central angle intervals, 12 at 30° central angle intervals, etc.) printed on it using water-soluble dye ink by an inkjet printer at least around the entire circumference. The paper cylinder 3 is made of paper that is resistant to water and suitable for ink transfer, and other paper types than drawing paper may also be used. The paper cylinder 3 (for example, total length (axial length) 180 mm) is made by wrapping the paper sheet 3a described below in a cylindrical shape around the outer surface of the cylindrical member 2, and here we show an example in which the point-like dots 5 are printed circumferentially around the entire circumference and arranged in four rows in the axial direction. The paper cylinder 3 can also be attached by fitting a cylindrical paper sheet 3 a onto the outer circumferential surface of the cylindrical member 2 .

[0029] The water-permeable sponge 4 is, for example, a melamine sponge (for example, outer diameter 50 mm, inner diameter 26 mm) made by processing melamine foam into a cylindrical shape, and is attached to the paper cylinder 3 so as to cover the entire outer periphery thereof. Here, the water-permeable sponge 4 has an axial length that is approximately the same as that of the paper cylinder 3, but it can also be configured by stacking six layers of sponges with an axial length of 30 mm, for example.

[0030] When assembling the groundwater flow direction and velocity meter 1, the paper sheet 3a is wrapped cylindrically around the outer circumferential surface of the cylindrical member 2 to attach the paper cylinder 3. Then, the water-permeable sponge 4 is fitted and attached to the outer circumferential surface of the paper cylinder 3. An upper disk 22 is fixed to the upper part of the cylindrical member 2, and the paper cylinder 3 and the water-permeable sponge 4 can be positioned in the axial direction. After the paper cylinder 3 and the water-permeable sponge 4 are attached to the cylindrical member 2, the lower disk 23 is fixed to the bottom of the cylindrical member 2 by screwing or the like, and the paper cylinder 3 and the water-permeable sponge 4 are positioned and fixed to the outer peripheral surface of the cylindrical member 2, thereby forming the sensor unit. The drainage hole 21 provided in the upper part of the cylindrical member 2 is located above the height at which the upper disk 22 is fixed.

[0031] Next, a procedure for measuring the flow direction and flow velocity of groundwater using a groundwater flow direction and velocity meter according to an embodiment of the present invention will be described. The groundwater flow direction and velocity meter 1 in the embodiment of the present invention is a single-hole groundwater flow direction and velocity measuring device that measures groundwater flow in a groundwater observation well (for example, about 3 to 10 m deep) drilled vertically from the ground surface. A cylinder (with an inner diameter of about 70 mm) made of, for example, hard plastic is installed inside an observation well drilled at the ground surface, and many small holes are drilled uniformly around the circumference near the observation depth. Groundwater flows through these small holes and passes through the interior of the cylinder.

[0032] When the groundwater flow direction and velocity meter 1 is inserted into a groundwater observation well, a Netron cover (tangerine net) is placed over the sensor to protect it. Furthermore, when the groundwater flow direction and velocity meter 1 is inserted into a groundwater observation well, water that flows into the interior of the cylindrical member 2 from the lower end opening of the cylindrical member 2 is drained through the drainage hole 21, thereby making it possible to equalize the water levels inside and outside the cylindrical member 2. The length of the groundwater flow direction and velocity meter 1 is adjusted by connecting a support member (not shown) to the cylindrical member 2, for example.

[0033] When measuring the flow direction and flow velocity of groundwater, the groundwater flow direction and velocity meter 1 is left standing for a predetermined time, for example, 15 to 60 minutes, after the sensor unit reaches the target depth of the observation well. Meanwhile, ink dissolves from the dots 5 printed on the paper cylinder 3 due to the groundwater flow and diffuses within the permeable sponge 4, leaving a trail (trajectory) of the dissolved ink on the paper cylinder 3. After the predetermined time has elapsed, the groundwater flow direction and velocity meter 1 is pulled up from the observation well, and the paper cylinder 3 is recovered from the sensor unit.

[0034] FIG. 3 is an explanatory diagram of the measurement mechanism of the groundwater flow direction and velocity meter according to the embodiment of the present invention. As shown in Figure 3, for example, in the case of a three-dimensional groundwater flow that includes a vertically upward component, the groundwater flow will create ink tails 51 on the surface of the paper cylinder 3, extending diagonally upward from the multiple point dots 5.

[0035] FIG. 4 shows an explanatory diagram of the unfolded paper cylinder before measurement. Figure 4 shows an example of a paper sheet 3a in which the paper cylinder 3 is unfolded before measurement, and shows an example in which multiple point-like dots 5 are printed around the entire circumference of the paper cylinder 3 in eight axial rows.

[0036] FIG. 5 is an explanatory diagram of the state of the paper cylinder unfolded after measurement, showing the state of tailing occurring in the paper cylinder after measurement. Figure 5 shows an example of a paper sheet 3a formed by unfolding the paper cylinder 3 after measurement, in which the groundwater flow direction and velocity meter 1, which had been left stationary in a groundwater observation well for a predetermined time as shown in Figure 3, was pulled out of the observation well and recovered from the sensor unit, and shows an example of a situation in which ink tailing 51 has occurred from the multiple point-like dots 5 printed around the entire circumference of the paper cylinder 3.

[0037] Figure 6 is an explanatory diagram of an example of a groundwater flow model on a paper cylinder, where (a) shows a plan view and (b) shows a side view (for convenience of explanation, the side view is shown tilted). The tailings 51 drawn on the surface of the paper sheet 3a in Figure 5 can be modeled as shown in Figure 6, with groundwater passing in a straight line through the permeable sponge 4 provided around the sensor unit.

[0038] On the surface of the paper cylinder 3, the horizontal tangential direction of the paper is x, and the vertical upward direction is z. The horizontal tangential flow velocity Vx and the vertical upward flow velocity Vz of the groundwater are expressed as follows, where φ is the direction from north (reference direction) on the paper, ψ is the upwind direction of the flow, V is the groundwater flow velocity, and θ is the vertical flow direction (angle of elevation and depression):

number

number

[0039] Therefore, the lengths Lx and Lz of the tailing in the x and z directions are

number

number

[0040] The groundwater flow velocity V is approximated by the above equations (3) and (4),

number

number

[0041] Here, strictly speaking, Vx should be the circumferential flow velocity in the above, but if Vx is sufficiently small, there is no problem in practice in considering it as the tangential flow velocity. Therefore, the length of the tailing drawn on the paper cylinder 3 can be regarded as the length L of the tailing corresponding to the flow velocity V, and the horizontal component (horizontal length) of the length L of the tailing on the paper cylinder 3 can be considered as Lx, and the vertical component (vertical length) can be considered as Lz.

[0042] FIG. 7 shows the outline of the tailing on the paper cylinder of FIG. 5, illustrating the detection of the tailing. As shown in FIG. 7, the outline of the tailing 51 can be determined by visual inspection, for example, from the tailing 51 drawn on the surface of the paper sheet 3a in FIG. 5, and the length and direction of the tailing 51 can be read. In addition, in Figure 5, the surface of the paper sheet 3a is scanned and subjected to binarization processing, thereby defining the outline of the tailing 51 using machine learning, etc., and the length and direction of the tailing 51 can be read based on features such as the line segment connecting the center of gravity of the point-like dot 5 and the center of gravity of the tailing 51, and the Feret's diameter of the tailing 51 (the long side of the rectangle circumscribing the outline of the tailing).

[0043] FIG. 8 shows an explanatory diagram of the azimuth distribution and approximation curve of the horizontal component Lx of the tailing length. Figure 8 shows the results of an experiment in which a groundwater flow direction and velocity meter 1 according to an embodiment of the present invention was inserted into an observation well inclined at 30° to the vertical axis, and a vertical flow was assumed to occur.The relationship between the horizontal component Lx of the length L of the ink tailing of multiple point-like dots and the angle (azimuth angle) of the multiple point-like dots from a reference orientation was graphed, and an approximate curve was calculated. The experimental conditions for the model shown in Figure 6 were: flow direction (downwind) = 180° (ψ = 0°), set flow velocity V = 0.3 cm / min, and vertical flow direction (elevation angle) θ = 30°. From the graph in Figure 8, it can be seen that the approximation curve intersects with the horizontal axis at an azimuth angle of approximately 200° to 210°, and the horizontal component Lx of the tailing length L becomes zero, which roughly coincides with the set flow direction (downwind direction) = 180°.

[0044] Therefore, according to the groundwater flow direction and velocity meter 1 in the embodiment of the present invention, the direction connecting two points on the paper cylinder at the azimuth angle where the horizontal component Lx of the tailing length L is zero can be taken as the horizontal flow direction of the groundwater.

[0045] Furthermore, according to the groundwater flow direction and velocity meter 1 in the embodiment of the present invention, the azimuth angle at which the horizontal component Lx of the length L of the tailings is maximum can be read from the graph in Figure 8, and the horizontal tangent direction on the paper cylinder at that azimuth angle can be determined as the horizontal flow direction of the groundwater.

[0046] Furthermore, according to the groundwater flow direction and velocity meter 1 in the embodiment of the present invention, the maximum value of the horizontal component Lx of the tailing length L is read from the graph in Figure 8, divided by the sine of the elevation and depression angle, and substituted into the calibration curve (see Figure 10) described below for the time period during which the sensor unit is placed in the groundwater observation well, and further multiplied by the sine of the elevation and depression angle to obtain the horizontal flow velocity of the groundwater.

[0047] FIG. 9 shows an explanatory diagram of the orientation distribution of the vertical component Lz of the tailing length and the approximation line. Figure 9 shows a graph of the relationship between the vertical component Lz of the length L of the ink tailing of multiple point dots and the angle (azimuth angle) of the multiple point dots from the reference orientation in the experiment of Figure 8, and an approximate straight line was obtained. From the graph in Figure 9, it can be seen that the vertical component Lz of the tailing length L is on the positive side overall, indicating that there is a vertical upward flow in the groundwater as expected.

[0048] According to the groundwater flow direction and velocity meter 1 of the embodiment of the present invention, the maximum value of the horizontal component Lx of the length of the tailings is read from the graph in FIG. 8, the vertical component Lz of the length L of the tailings is read from the graph in FIG. 9, and the vertical flow direction of the groundwater can be determined by dividing Lz by Lx and finding its arc tangent.

[0049] Furthermore, according to the groundwater flow direction and velocity meter 1 in the embodiment of the present invention, the vertical component Lz of the length L of the tailing is read from the graph in Figure 9, and this is divided by the sine of the elevation and depression angle. After that, this is substituted into the calibration curve (see Figure 10) in paragraph 0051 below, which was created in advance at the time when the sensor unit was placed in the groundwater observation well, and further multiplied by the sine of the elevation and depression angle, thereby obtaining the vertical flow velocity V of the groundwater.

[0050] The groundwater flow direction and flow velocity can be calculated manually or by using image analysis software.

[0051] FIG. 10 shows an explanatory diagram of an example of the relationship (calibration curve) between the groundwater flow velocity V and the tailing length L on the paper cylinder. Figure 10 shows the results of an experiment in which, similar to the experiment in Figure 8, a groundwater flow direction and velocity meter 1 according to an embodiment of the present invention was inserted into an observation well inclined at 30° to the vertical axis, and a vertical flow was assumed to occur.The graph shows the relationship between the length L of the tailing of the ink dots and the flow velocity V at the azimuth angle at which the horizontal component Lx of the tailing length L on the paper cylinder is at its maximum. In the model shown in Figure 6, the experiment was conducted by leaving the groundwater flow direction and velocity meter 1 stationary in the observation well for 15 minutes under the following conditions: flow direction (downwind direction) = 180° (ψ = 0°), vertical flow direction (elevation angle) θ = 30°, and set flow velocities V = 0.05 cm / min, 0.1 cm / min, 0.15 cm / min, 0.2 cm / min, and 0.3 cm / min. The groundwater flow velocity V can be determined by preparing a calibration curve (calibration curve) in advance through experiments showing the relationship between flow velocity V and tailing length L, as shown in Figure 10, and then applying the tailing length L drawn on the paper cylinder 3 to the calibration curve. FIG. 10 shows approximation by a curve, and here it is approximated by a power curve, but it can also be approximated by a straight line.

[0052] A groundwater flow direction and velocity meter 1 in an embodiment of the present invention comprises a sensor unit having a cylindrical paper cylinder 3 attached to the outer periphery of a cylindrical member 2, and a cylindrical water-permeable sponge 4 attached to the outer periphery of the paper cylinder 3, and the paper cylinder 3 is provided with a plurality of point-like dots 5 printed with water-soluble ink at least around the entire circumference, and by leaving the sensor unit in a groundwater observation well for a predetermined period of time, it is possible to determine the flow direction and velocity of groundwater in three dimensions based on the length and direction of the ink tailings 51 that dissolve from the plurality of point-like dots 5 and are drawn on the paper cylinder 3, thereby providing a simple groundwater flow direction and velocity meter that can measure the flow direction and velocity of groundwater in three dimensions.

[0053] Furthermore, the groundwater flow direction and velocity meter 1 in the embodiment of the present invention is a simplified groundwater flow direction and velocity meter that is inexpensive and has a simple configuration, and does not require a power source for measurement work in groundwater observation wells. Therefore, it is possible to perform work to measure groundwater flow direction and velocity in three dimensions even in places such as mountainous regions where the environment is poor and it is difficult to obtain power.

[0054] The groundwater flow direction and velocity meter 1 in the embodiment of the present invention has tailings 51 drawn on a paper cylinder 3, and determines the flow direction and velocity of groundwater based on the length and orientation of the tailings 51. However, the method of determining the flow direction and velocity of groundwater is not limited to the example described in the above embodiment, and various methods can be used.

[0055] The present invention is not limited to the above-described embodiment, and it goes without saying that the configuration can be appropriately modified without departing from the scope of the invention. [Industrial Applicability]

[0056] The groundwater flow direction and velocity meter of the present invention is a simple groundwater flow direction and velocity meter that can measure the flow direction and velocity of groundwater three-dimensionally, and is highly practical. [Explanation of symbols]

[0057] 1 Groundwater current meter (groundwater current measurement tool) 2 Cylindrical members 21 Drainage hole 22 Upper disc 23 Lower disc 3 paper cylinders 3a Paper sheet 4. Permeable sponge 5 dots 51 Tailing

Claims

1. a cylindrical paper cylinder attached to the outer periphery of the cylindrical member; a cylindrical water-permeable sponge attached to the outer periphery of the paper cylinder; A drain hole is provided in the upper part of the cylindrical member above the position where the paper cylinder is attached, an upper disk fixed to the upper part of the cylindrical member and a lower disk fixed to the lower part of the cylindrical member to position the paper cylinder and the water-permeable sponge in the axial direction of the cylindrical member; The drainage hole provided in the upper part of the cylindrical member is located above a height at which the upper disk is fixed, The paper cylinder is provided with a plurality of dots printed with water-soluble ink at least along the entire circumference, By placing the sensor unit in a groundwater observation well, the groundwater flow direction and velocity meter can determine the groundwater flow direction and velocity in three dimensions based on the tailing of the ink that dissolves from the multiple point-like dots and is drawn on the paper cylinder.

2. 2. The groundwater flow direction and velocity meter according to claim 1, which is capable of determining the horizontal flow direction and velocity of groundwater based on the horizontal component of the length of the tailing of the ink eluted from the plurality of point-like dots and drawn on the paper cylinder.

3. 3. The groundwater flow direction and velocity meter according to claim 2, which is capable of determining the vertical flow direction and velocity of groundwater based on the horizontal and vertical components of the length of the tailing of the ink eluted from the plurality of point-like dots and drawn on the paper cylinder.

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