JPH10300622A - Leak water detection system of waste disposal ground - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mask construction easily possible and the specification of a leakage portion possible with high accuracy. SOLUTION: The title system for detecting a leakage of water-barrier sheet in a waste disposal ground where the water-barrier sheet is laid on the hollow of the ground and waste matter is thrown away on the water barrier sheet to be accumulated, comprises the resistance wire 24 of a known resistance value per a unit length, laid on the reverse side of a water-barrier sheet 6, a conductive wire 28 laid on the opposite side against the resistance wire 24 with the water-barrier sheet 6 between, and to about the same direction as the resistance wire 24 close to the resistance wire 24, a constant current source 36 connected through an ammeter 40 between an end of the conductive wire 28 and an end of the resistance wire 24, and a voltmeter 42 for measuring the voltage between both the ends of the resistance wire 24. A plurality of sets of the resistance wire 24 and the conductive wire 28 are mounted along the water-barrier sheet with intervals. When a torn hole 70 occurs, water 72 leaks, and the conductive wire 28 and resistance wire 24 are connected electrically in the portion thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for detecting water leakage of a seepage control sheet at a waste disposal site where a seepage control sheet is laid in a concave portion of the ground, and waste is dumped and deposited on the seepage control sheet. It is.

[0002]

2. Description of the Related Art As one method of disposing a large amount of waste generated in an urban area or the like, a water-impervious sheet is laid in a concave portion of the ground, and the waste is dumped and deposited on the water-impervious sheet. The method of burying it in the soil is adopted. Waste may contain substances harmful to the human body, and some chemical reaction may occur in the deposited waste to generate harmful substances. When these harmful substances are mixed with rainwater and soak into the ground, the groundwater is polluted,
May cause environmental destruction. The water impermeable sheet is provided to prevent such harmful substances from seeping into the ground.

[0003] The impermeable sheet is made of synthetic resin or synthetic rubber, has a sufficient strength, and is further strengthened by being duplexed, but is still damaged by dumped waste. It is safer to assume that the battery will degrade or break due to aging. When such damage occurs, water leaks through the location, and it becomes impossible to prevent harmful substances.

Therefore, it is important to detect the breakage of the impermeable sheet at an early stage and take measures to prevent water leakage.
As a system to detect water leakage through the impermeable sheet,
There is known a system that detects the presence or absence of water leakage by passing an electric current across a water-impervious sheet, and further specifies a water leakage location. That is, a plurality of conductive wires are laid in parallel below the impermeable sheet at intervals, and a plurality of conductive wires are arranged above the impermeable sheet at intervals and orthogonal to the lower conductive wires. I do. Then, a voltage is applied between the upper and lower conductive lines, and it is checked whether or not a current flows. As a result, if a current flows between the specific conductive line on the upper side and the specific conductive line on the lower side, the water impermeable sheet may be damaged near the intersection of these conductive lines. I understand. Also, as another system, electrodes are arranged in a matrix on the upper side of the impermeable sheet, and the electric field strength when a voltage is applied above and below the impermeable sheet is measured by each electrode to calculate the distribution of the current intensity. Such a system has been devised.

[0005]

However, in the above-mentioned water leak detection system in which conductive wires are laid, it is necessary to lay the upper and lower conductive wires crossing each other, and it takes time and effort to lay the conductive wires. In addition, the accuracy of specifying the leak location cannot be increased beyond the interval between the intersections of the upper and lower conductive wires. On the other hand, in a system for measuring electric field strength, a large number of electrodes must be arranged in a matrix, which takes time and effort in arranging the electrodes, and the number of cables connecting each electrode to related equipment is enormous. Become. In addition, it is necessary to measure the distribution of the specific resistance, and to obtain the electric field strength from the measurement result,
Complex calculations must be performed. The present invention has been made to solve such a problem, and its purpose is to
An object of the present invention is to provide a leak detection system for a waste disposal site that can be easily constructed and that can identify a leak point with high accuracy.

[0006]

According to the present invention, in order to achieve the above-mentioned object, a water-impervious sheet is laid in a concave portion of the ground, and the wastewater is dumped and deposited on the water-impervious sheet in a waste disposal site. A system for detecting leakage of a water sheet, wherein the resistance line per unit length is laid on the upper or lower side of the impermeable sheet, and a resistance wire having a known resistance per unit length, and the resistance wire sandwiching the impermeable sheet. And a conductor laid on the opposite side,
A constant current source that supplies a constant current between the conductor and the resistance wire; and a voltage measurement unit that measures a voltage at both ends of the resistance wire. The resistance wire is provided in a plurality at intervals. It is characterized by the following. The present invention is also a system for detecting water leakage of the water-impervious sheet at a waste disposal site where a water-impervious sheet is laid in a concave portion of the ground, and waste is dumped and deposited on the water-impervious sheet, A resistance wire having a known resistance value per unit length laid on the upper side or the lower side of the water sheet, a conductor laid on the opposite side of the resistance wire across the water shielding sheet, and the conductor And a current source that supplies a current between the resistance lines, a current measurement unit that measures a current flowing through the resistance lines, and a voltage measurement unit that measures voltages at both ends of the resistance lines. It is characterized in that a plurality are provided at intervals. The present invention also provides
The impermeable sheet is double, the resistance wire is laid between the two impermeable sheets, an upper side of the upper impermeable sheet, and a lower side of the lower impermeable sheet, The invention is characterized in that the conductor is laid. The present invention is also a system for detecting water leakage of the water-impervious sheet at a waste disposal site where a water-impervious sheet is laid in a concave portion of the ground, and waste is dumped and deposited on the water-impervious sheet, A resistance wire having a known resistance value per unit length laid on the upper side or the lower side of the water sheet, a conductive line laid on the opposite side of the resistance line across the impermeable sheet, and the conductive line A constant current source connected between one end of the resistance wire and one end of the resistance wire, and voltage measuring means for measuring a voltage at both ends of the resistance wire. , And a plurality thereof is provided.

[0007] The present invention is also a system for detecting water leakage of the water-impervious sheet at a waste disposal site where a water-impervious sheet is laid in a concave portion of the ground and waste is dumped and deposited on the water-impervious sheet. Laid on the upper or lower side of the impermeable sheet, a resistance wire having a known resistance value per unit length, and a conductive wire laid on the opposite side to the resistance wire across the impermeable sheet, A current source connected between one end of the conductive wire and one end of the resistance wire, current measurement means for measuring a current flowing through the resistance wire, and voltage measurement means for measuring a voltage at both ends of the resistance wire; And a plurality of pairs of the resistance line and the conductive line are provided at intervals. In the present invention, the impermeable sheet is double, the resistance wire is laid between the two impermeable sheets, an upper side of the upper impermeable sheet, and a lower side of the impermeable sheet. On the lower side, the conductive wires each forming a pair with one of the resistance wires are laid. In the present invention, the water-impervious sheet is double, the conductive wire is laid between the two water-impervious sheets, the upper side of the upper water-impervious sheet and the lower side of the water-impervious sheet. The resistive wires respectively forming a pair with the one conductive wire are laid on the lower side. The present invention also includes a current supply unit that supplies a current to the resistance line, and a current detection unit that detects whether a current flows through the resistance line when the current supply unit supplies a current to the resistance line. It is further characterized by being provided.

In the water leakage detection system for a waste disposal site according to the present invention, when the waterproof sheet is damaged and water leakage occurs, the resistance wire and the conductor are electrically connected at that location. As a result, a current flows through the resistance wire and a voltage drop occurs in the resistance wire, so that the voltage measurement result by the voltage measurement means is not zero. As a result, first, it can be determined in which vicinity of the resistance wire the water leakage is occurring. When the voltage measured by the voltage measuring means is V and the current supplied by the constant current source is I, the resistance value between the location of the resistance wire near the water leakage location and the end of the resistance wire is V / I. Therefore, if the resistance value per unit length of the resistance wire is r, the distance from the end of the resistance wire to the leak location is V
/ (Ir).

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described based on embodiments with reference to the drawings. FIG. 1 is a principle diagram for explaining the principle of specifying a water leakage point in the water leakage detection system according to the embodiment, FIG. 2 is a cross-sectional side view showing a main part of an example of the water leakage detection system according to the embodiment, FIG. FIG. 4 is a circuit diagram of the water leakage detection system of the embodiment, and FIG. 5 is a cross-sectional side view showing the entire waste disposal site provided with the water leakage detection system of the embodiment.

As shown in FIG. 5, the water leakage detection system for a waste disposal site according to the present embodiment has a double water-impervious sheet, ie, first and second water-impervious sheets 4, 6 in a concave portion 2 of the ground. Are provided at a waste disposal site 10 where the waste 8 is dumped and deposited on these impermeable sheets.

FIG. 2 is a cross-sectional view showing an enlarged part of the seepage control sheet. First, the first felt layer 1 is placed on the ground 12.
4 are formed, on which the first impermeable sheet 4 is laid. The second impermeable sheet 6 is laid on the first impermeable sheet 4 with the second felt layer 16 interposed therebetween, and further on the second impermeable sheet 6 is a third felt layer 18. Is formed, and a soil covering layer 20 is formed on the third felt layer 18.

As shown in FIGS. 2 and 3, the water leakage detection system 22 of the present embodiment comprises a resistance wire 24 and first and second conductive wires 26 and 28 (the conductor and the conductive wire in the claims). And equivalent). The resistance wire 24 has a known resistance value per unit length, and is laid between the first and second waterproof sheets 4 and 6. Further, the first conductive wire 26 is provided on the lower side of the first water-impervious sheet 4, that is, on the opposite side to the resistance wire 24 with the first water-impervious sheet 4 interposed therebetween, in the vicinity of the resistance wire 24. 24 are laid in almost the same direction. On the other hand, the second conductive wire 28 is located above the second water-impervious sheet 6, and thus on the opposite side of the resistance line 24 with the second water-impervious sheet 6 interposed therebetween.
It is laid in almost the same direction. A covered conductive wire 30 is also laid between the first and second water shielding sheets 4 and 6 in the same direction as the resistance wire 24 in the vicinity of the resistance wire 24, and one end thereof is one end of the resistance wire 24. Part is electrically connected. In the present embodiment, as shown in FIG. 3, ten resistance wires 24 are provided at intervals (for example, about 10 m) together with the first and second conductive wires 26 and 28 and the covered conductive wire 30 that make up the pair. Laid almost parallel).

[0013] The water leakage detection system 22 of this waste disposal site
Further includes, as shown in FIG. 4, first and second current sources 34 and 36, first and second ammeters 38 and 40, a voltmeter 42, and a changeover switch 44. First and second current sources 34 and 36 are provided for flowing current through first and second conductive lines 26 and 28, and first and second ammeters 38 and 40 measure the current values. On the other hand, the voltmeter 42 is for measuring the voltage at both ends of each resistance wire 24.

One terminal 64 of the first current source 34 is connected to the first terminal
And the other terminal 50 of the first ammeter 38 is connected to the first conductive line 26 via the changeover switch 44. Also, the second
One terminal 66 of the constant current source 36 is connected to one terminal 56 of the second ammeter 40, and the other terminal 58 of the second ammeter 40 is connected to the second conductive wire via the changeover switch 44. 28. The other terminal 60 of the voltmeter 42 is connected to one end 62 of each coated conductive wire 30 via the changeover switch 44. The other end of the covered conductive wire 30 is connected to the other end of each resistance wire 24 as described above.

The changeover switch 44 includes first and second switches.
The first and second current sources 3 through the ammeters 38, 40 of
, And voltmeter 42 are connected to the resistance line 24 and the first and second conductive lines 26,
28 and each of the covered conductive wires 30 for switching and connecting, and has a configuration of four circuits and ten contacts.

Then, through the changeover switch 44, the terminal 64 of the first current source 34 is connected to one end of each first conductive wire 26 through the first ammeter 38, and the terminal 66 of the second current source 36 is connected. Are connected to each second through the second ammeter 40.
Is connected to one end of the conductive line 28. At the same time, the terminal 52 of the voltmeter 42 is connected to one end 68 of each resistance wire 24 and the minus terminal 71 of the current sources 34 and 36, and the other terminal 60 of the voltmeter 42
0 is connected to one end 62. In addition, the coated conductive wire 3
The other end of 0 is connected to the other end 32 of the same set of resistance wires 24 as described above.

Next, how to identify a leak location of the impermeable sheet will be described in detail. FIG. 1 shows a simplified side cross section around the second water-impervious sheet 6. Here, an example in which a damaged portion generated in the second water-impervious sheet 6 is specified will be described. Therefore, in FIG. 1, the first impermeable sheet 4, the first conductive wire 26, the first current source 34, and the like are omitted to avoid unnecessary complication. Further, for the same reason, the changeover switch 44 is also omitted, and a state is shown in which the specific resistance wire 24 and the related conductive wire shown in FIG. 1 are connected to a current source or the like.
Although the connection position of the ammeter 40 is different between FIG. 1 and FIG. 4, any connection position may be used as long as the current flowing through the resistance wire 24 can be measured.

As shown in FIG. 1, the second impermeable sheet 6
Is damaged and the break 70 occurs, the second impermeable sheet 6
The upper water 72 leaks to the lower side of the second impermeable sheet 6 through the break 70. As a result, the water 72 causes the second water-impervious sheet 6 above the second
Is electrically connected to the lower resistance wire 24, the second constant current source 36, a part of the second conductive wire 28, a part of the resistance wire 24, and a second ammeter. An electric series circuit is formed by 40, and the current supplied by the second current source 36 flows as shown by the dotted line A. The current from the second current source 36 also flows through the resistance wire 24 from the location of the break 70 toward the end 32. However, since the input impedance of the voltmeter 42 is sufficiently large, this current can be ignored. Of the degree.

As a result of the current flowing as indicated by the dotted line A,
A voltage is generated between the portion near the break 70 of the resistance wire 24 and the end 68. Since the voltmeter 42 is connected to both ends of the resistance wire 24 through the coated conductive wire 30, the voltmeter 42 measures the voltage at both ends of the resistance wire 24. But,
Since substantially no current flows from the location of the break 70 to the end 68 as described above, no voltage drop occurs in this section, and the voltage measured by the voltmeter 42 The voltage is generated between the location near the port 70 and the end 68.

Therefore, when the voltage measured by the voltmeter 42 is V volts and the current measured by the second ammeter 40 is I ampere, the portion of the resistance wire 24 near the break 70 and the end 68
Is V / I ohms. From this, assuming that the resistance value of the resistance wire 24 per unit length is r ohm / meter (known), the distance from the end 68 of the resistance wire 24 to a location near the break 70 is:

[0021]

## EQU1 ## V / (Ir) meter. Here, the case where the second water-impervious sheet 6 is damaged has been described as an example, but with respect to the first water-impervious sheet 4, the resistance wire 24 is on the upper side and the first conductive wire 26 is on the lower side. Although it is laid, the resistance wire 2
4 and the conductive wire are laid in the same manner, so that the first water-impervious sheet 4 can detect the presence or absence of water leakage according to the same principle, and can calculate the distance to the water leakage location. .

Next, a specific procedure for checking for water leakage will be described. First, a changeover switch 44 is provided for each set of conductive wires associated with each resistance wire 24 shown in FIG.
(FIG. 4) to sequentially operate the first and second current sources 3
4, 36, etc. are switched and connected. As a result, if water leakage occurs in the first or second impermeable sheet 4, 6 near any of the resistance wires 24, the measurement results of the first or second ammeter 38, 40 are It is no longer zero. As a result, first, it can be seen that water leakage has occurred at any point along the resistance wire 24. Thereafter, with respect to the resistance wire 24, the first or second ammeter 38,
The distance from the end 68 (FIG. 4) of the resistance wire 24 to the leak location is calculated according to [Equation 1], based on the measurement results of the voltmeter 40 and the voltmeter 42 and the resistance value per unit length of the resistance wire 24.

As described above, in the water leakage detection system 22 of the waste disposal site of the present embodiment, first, the presence or absence of water leakage can be detected based on whether the measurement results of the first and second ammeters 38 and 40 are not zero. When water leakage is detected, the distance from the end portion 62 of the resistance wire 24 to the water leakage point of the first or second water-impervious sheet 4, 6 is measured by the voltmeter 42 and the first
Alternatively, it can be easily calculated from the measurement results of the second ammeters 38 and 40 using a simple calculation formula. Then, in the water leakage detection system 22 of this waste disposal site, the resistance wire 24
Although the accuracy of specifying the location of the water leakage in the arrangement direction is limited by the distance between the resistance wires 24, the accuracy in the direction in which the resistance wire 24 extends is not limited, and the position of the water leakage location can be extremely accurately determined. Can be identified. Further, the resistance wire 24, the first
And second conductive lines 26 and 28, and coated conductive line 3
The 0s do not need to cross each other, but may simply extend in the same direction. Therefore, it is easy to construct the system, and it is possible to reduce the working time and the number of workers. Furthermore, the portion of the water-impervious sheet 6 on which the conductive wire 28 is usually laid may be at the same potential due to the influence of moisture or the covering layer 20, and in this case, the number of the resistance wires 24 may be several. The same effect can be obtained with a single point-like, planar or linear conductor. In this case, one terminal 58 of the ammeter 40 in FIG. 4 may be connected to one conductor without passing through the changeover switch 44. The same can be said for the felt layer 14 side portion of the impermeable sheet 4 on which the conductive wires 26 are laid under the influence of moisture or the ground 12.

The present invention has been described in detail based on the embodiments. However, this is merely an example, and the present invention can be implemented in various forms without being limited to this example.
For example, in the above-described embodiment, two current sources and two ammeters are provided. However, only one of them is connected to one of the first and second conductive wires 26 and 28 by a changeover switch. Of course, it is possible to detect which of the impermeable sheets is damaged at which position when the impermeable sheets 4 and 6 are damaged at substantially the same time. At this time, the same applies when the ammeter is inserted not between the current source and the conductive wire but between the terminal 52 of the voltmeter 42 and the minus terminal 71 of the current source. Also,
If the value of the current supplied by the first and second current sources 34 and 36 is accurately determined (for example, a constant current source), there is no need to measure with an ammeter.
It is also possible to omit the ammeters 38 and 40 of FIG. In that case, the presence or absence of water leakage can be known from whether or not the measured value of the voltmeter 42 is zero.

In the above embodiment, the first and second
It is assumed that the resistance wire 24 is laid between the water impermeable sheets 4 and 6. However, one conductive wire is laid between the first and second water impermeable sheets, and the lower side of the first water impermeable sheet 4. In addition, the same function as the above embodiment can be realized by laying a resistance wire paired with the conductive wire and further laying another resistance wire paired with the conductive wire above the second impermeable sheet. And therefore the same effect can be obtained. Also, the resistance wire 24
For example, by connecting a series circuit of, for example, a power supply and an ammeter between the end 68 of the conductive wire 30 and the end 62 of the covered conductive wire 30 as required, it is also possible to perform a disconnection test of the resistance wire. That is, if the resistance wire 24 is normal, a current flows through the resistance wire 24 and the coated conductive wire 30, and the ammeter indicates that a certain amount of current is flowing.
Can be determined to be normal. On the other hand, when the current value indicated by the ammeter is zero, the disconnection of the resistance wire 24 is suspected. Further, in the above-described embodiment, the water-impervious sheet is duplexed. However, the present invention is of course also effective when the water-impervious sheet is not duplexed, and the first and second conductive wires 26 and 2 are used.
A similar system can be configured by eliminating one of the components 8 and the related current source and ammeter.

[0026]

As described above, in the water leakage detection system for a waste disposal site according to the present invention, when the water impermeable sheet is damaged and water leaks, the resistance wire and the conductive wire are electrically connected at that location. Becomes As a result, a current flows through the resistance wire and a voltage drop occurs in the resistance wire, so that the voltage measurement result by the voltage measurement means is not zero. As a result, first, it can be determined in which vicinity of the resistance wire the water leakage is occurring. If the voltage measured by the voltage measuring means is V and the current supplied by the current source is I, the resistance between the location of the resistance wire near the water leakage location and the end of the resistance wire is V / I. If the resistance value per unit length of the resistance wire is r, the distance from the end of the resistance wire to the leak location is V / (Ir). As described above, in the water leakage detection system for a waste disposal site according to the present invention, the presence or absence of water leakage can be detected based on whether or not an electric current flows through the resistance wire, and the first or second waterproof sheet can be detected from the end of the resistance wire The distance to the leak point of the current, the value of the current supplied by the constant current source,
It can be easily calculated from the measurement result of the voltage measuring means by a simple calculation formula. In the leak detection system at this waste disposal site, although the accuracy of specifying the location of the leak in the arrangement direction of the resistance wires is limited by the spacing between the resistance wires,
There is no such restriction on the accuracy in the direction in which the resistance wire extends, and the position of the water leakage point can be specified very accurately. Furthermore, the resistance wires and the conductive wires do not need to cross each other, but may simply extend in the same direction. Furthermore, when one point-like, planar or linear conductor is used instead of the conductive wire, the position of the conductor does not need to be selected. Therefore, it is easy to construct the system, and it is possible to reduce the working time and the number of workers.

[Brief description of the drawings]

FIG. 1 is a principle diagram for explaining a principle of specifying a leak location in a water leak detection system according to an embodiment.

FIG. 2 is a cross-sectional side view illustrating a main part of an example of a water leakage detection system according to an embodiment.

FIG. 3 is a plan view illustrating a main part of an example of a water leakage detection system according to the embodiment.

FIG. 4 is a circuit diagram of a water leakage detection system according to an embodiment.

FIG. 5 is a sectional side view showing a waste disposal site provided with the water leakage detection system according to the embodiment.

[Explanation of symbols]

 4 1st impermeable sheet 6 2nd impermeable sheet 10 waste disposal site 14 1st felt layer 16 2nd felt layer 18 3rd felt layer 20 covering layer 22 water leakage detection system 24 resistance wire 26 first Conductive wire 28 second conductive wire 30 coated conductive wire 34 first constant current source 36 second constant current source 38 first ammeter 40 second ammeter 42 voltmeter 44 switch

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yuzo Fukushima 4-6-115 Sendagaya, Shibuya-ku, Tokyo Inside Fujita Co., Ltd. (72) Takeshi Nakazawa 4-6-1-15 Sendagaya, Shibuya-ku, Tokyo Stock Company (72) Inventor Hideo Tsukada 4-6-15 Sendagaya, Shibuya-ku, Tokyo Stock Company (72) Inventor Toshio Nakabushi 4-6-115 Sendagaya, Shibuya-ku, Tokyo Stock Company Inside Fujita (72) Inventor: Tamotsu Kobori 2-3-1, Iwatacho, Higashiosaka-shi, Osaka Tatsuta Electric Wire Co., Ltd. (72) Shinichi Ono 2-3-1, Iwatacho, Higashiosaka-shi, Osaka Ivy Wire Co., Ltd.

Claims (8)

[Claims] 1. A system for detecting water leakage of a water-impervious sheet at a waste disposal site where a water-impervious sheet is laid in a concave portion of the ground, and waste is dumped and deposited on the water-impervious sheet. A resistance wire having a known resistance value per unit length laid on the upper or lower side of the water sheet, a conductor laid on the opposite side of the resistance wire across the water-impervious sheet, and the conductor And a constant current source for supplying a constant current between the resistance wires, and voltage measuring means for measuring a voltage at both ends of the resistance wires, wherein a plurality of the resistance wires are provided at intervals. Characterized by a leak detection system at a waste disposal site. 2. A system for detecting water leakage of a water-impervious sheet at a waste disposal site where a water-impervious sheet is laid in a concave portion of the ground, and waste is dumped and deposited on the water-impervious sheet, A resistance wire having a known resistance value per unit length laid on the upper or lower side of the water sheet, a conductor laid on the opposite side of the resistance wire across the water-impervious sheet, and the conductor And a current source that supplies a current between the resistance wires; a current measurement unit that measures a current flowing through the resistance wires; and a voltage measurement unit that measures voltages at both ends of the resistance wires. A leak detection system for a waste disposal site, wherein a plurality of the leak detection systems are provided at intervals. 3. The water-impervious sheet is double, the resistance wire is laid between two sheets of the water-impervious sheet, the upper part of the upper water-impervious sheet and the lower part of the water-impervious sheet. The leak detection system for a waste disposal site according to claim 1 or 2, wherein the conductor is laid on a lower side. 4. A system for detecting water leakage of a water-impervious sheet at a waste disposal site where a water-impervious sheet is laid in a concave portion of the ground, and waste is dumped and deposited on the water-impervious sheet. A resistance wire having a known resistance value per unit length laid on the upper side or the lower side of the water sheet, a conductive line laid on the opposite side of the resistance line with the impermeable sheet interposed therebetween, and the conductive line A constant current source connected between one end of the resistance wire and one end of the resistance wire; and voltage measuring means for measuring a voltage at both ends of the resistance wire. A water leakage detection system for a waste disposal site, wherein a plurality of water leakage detection systems are provided. 5. A system for detecting water leakage of a water-impervious sheet at a waste disposal site where a water-impervious sheet is laid in a concave portion of the ground, and waste is dumped and deposited on the water-impervious sheet. A resistance wire having a known resistance value per unit length laid on the upper side or the lower side of the water sheet, a conductive line laid on the opposite side of the resistance line with the impermeable sheet interposed therebetween, and the conductive line A current source connected between one end of the resistance wire and one end of the resistance wire, current measurement means for measuring a current flowing through the resistance wire, and voltage measurement means for measuring a voltage at both ends of the resistance wire, A plurality of pairs of the resistance wire and the conductive wire are provided at an interval, wherein a water leakage detection system for a waste disposal site is provided. 6. The water-impervious sheet is double, the resistance wire is laid between two sheets of the water-impervious sheet, the upper part of the upper water-impervious sheet and the lower part of the water-impervious sheet. The water leakage detection system for a waste disposal site according to claim 4 or 5, wherein the conductive wire paired with one of the resistance wires is laid on a lower side. 7. The water-impervious sheet is double, and the conductive wire is laid between two sheets of the water-impervious sheet, the upper part of the upper water-impervious sheet and the lower part of the water-impervious sheet. The leak detection system for a waste disposal site according to claim 4, wherein the resistance wire paired with one of the conductive wires is laid on a lower side. 8. A current supply means for supplying a current to the resistance wire, and a current detection means for detecting whether or not a current flows through the resistance wire when the current supply means supplies a current to the resistance wire. 8. The method according to claim 1, further comprising:
Water leak detection system at a waste disposal site as described in the section.