JP2001258409A - Water-supply controlling system for paddy field - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-supply controlling system for paddy fields that can achieve easy control of the water feed and drainage in the irrigation of paddy fields and can maintain the water level of the paddy fields at a certain value automatically. SOLUTION: This is a water-supply controlling system for paddy fields divided into a plurality of sections 42 in which at least a water-supply pipe 6A and a water-level-adjusting pipe 6B or the water-supply pipe 6A and a water- draining pipe 6C and buried in the vicinity of the one side face of the divided cultivation section 42. Further, a valve 7A for supplying water to individual sections is arranged to the water-supply pipe 6A, a water level-setting apparatus 7B for maintaining the water level at a constant level is arranged to the water level-adjusting pipe Band a drain valve 7C for draining excessive water in individual sections is arranged to the water-draining pipe 6C so that these devices may come into vicinity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a water management system for automatically managing the supply and discharge of irrigation water to a paddy field. More specifically, by supplying the minimum required water to each cultivation, the water can be supplied evenly over the entire paddy field, the water level of each cultivation area can be constantly maintained, and each device is operated. In particular, the present invention relates to a water management system for paddy fields in which piping and devices are arranged by devising the moving distance as short as possible.

[0002]

2. Description of the Related Art FIG. 11 is a schematic plan view showing a conventional paddy field structure. Water flowing through a river 1 is guided from a channel 2 to an upstream main water supply channel 3 and supplied to a paddy field 4. ing. The paddy field 4 is divided into a plurality of cultivation areas 42 by ridges 41, and on the side of the farm road 40 extending in the longitudinal direction,
An open water supply channel 31 is provided along each cultivation area 42. An upstream side of the water supply channel 31 is connected to the main water supply channel 3, and a water supply port 311 is provided on a side wall of the water supply channel 31 facing each cultivated area 42. As shown in FIG. 12, the water is supplied from each water supply port 311 to each cultivation area 42.

An open drainage channel 32 is provided between the paddy fields 4 and 4 located on the opposite side of the water supply channel 31. A water level setting device 43 is provided at a drain outlet of the drainage channel 32 facing each cultivation area 42, and by adjusting the height of the setting device 43, the surface water level of each cultivation area 42 is set to a certain height. It can be maintained. The downstream side of the drainage channel 32 is connected to the main drainage channel 33, and excess water discharged into the drainage channel 32 is returned to the river 1 from the water channel 34.

[0004]

By the way, in this paddy field structure, the water flowing through the water supply channel 31 flows into the cultivation area 42 from the supply port 311 located on the upstream side of the water supply channel 31.
Then, the water supplied to the cultivation area 42 is supplied to the water level setting device 43.
As a result, the water level is maintained at a constant level, and excess water is discharged to the drainage channel 32. In this way, since the water is supplied sequentially from the upstream side to the cultivation area 42 on the downstream side, the supply of the water tends to be short in the cultivation area 42 on the downstream side. In particular, during the drought period when sunshine continues, almost no water is supplied to the cultivation area 42 on the downstream side, and the harvest may decrease due to poor rice growth.

In the conventional paddy field structure in which each water channel is open, the space of the cultivation area 42 and the farm road 40 is narrowed by the width occupied by the water supply channel 31 and the drain channel 32, so that farmland cannot be effectively used. There was also. Furthermore, since sediment or the like easily falls and accumulates in each of the water channels opened upward, there is a problem that the operation of discharging the soil and the like must be performed frequently and the water channel management is troublesome.

[0006]

SUMMARY OF THE INVENTION The present invention aims to provide a water management system for paddy fields which solves the above-mentioned problems. The gist of the present invention is (1) a water management system for paddy fields divided into a plurality of cultivation areas. At least a water supply pipe and a water level adjustment pipe are buried adjacent to one side of the cultivation area, the water supply pipe is provided with a water supply valve for supplying water to each cultivation area, and the water level adjustment pipe is provided for each cultivation area. A water management system for a paddy field, comprising: a water level setting period for maintaining a constant water level on a rice field; and a water supply valve and a water level setting period arranged close to each other. (2) A water management system for a paddy field divided into a plurality of cultivation areas, wherein at least a water supply pipe and a drainage pipe are buried adjacent to one side of the cultivation area, and a water supply pipe supplies water to each cultivation area. Water supply management for paddy fields, comprising a water supply valve for supplying water, a drainage pipe for discharging excess water from each cultivation area, and the water supply valve and the drainage valve being arranged close to each other. System. (3) The water supply valve is composed of an outer cylinder that rises vertically, and an inner cylinder that is vertically movably suspended inside the outer cylinder and that has a lower end connected to a water supply pipe, and an upper end of the inner cylinder. (1) The water management system for paddy fields according to the above (1) to (2), wherein the overflowed water is supplied to each of the cultivated areas from a branch provided protruding in the middle of the outer cylinder. (4) The water level setting device is composed of an outer cylinder that rises vertically, and an inner cylinder that is vertically movably suspended inside the outer cylinder and whose lower end is connected to the water level adjustment pipe on the downstream side. A water level setting pipe on the upstream side and a water supply pipe communicating with each cultivation area are connected to a branch portion protrudingly provided at an intermediate position of the outer cylinder, and water flowing into the outer cylinder from the branch portion is supplied to the inner cylinder. The water management system for paddy fields according to the above (1), wherein the water overflows from the upper end to flow into the cylinder and is discharged to the water level setting pipe on the downstream side. (5) The drain valve comprises a vertically rising outer cylinder, and an inner cylinder vertically movably suspended inside the outer cylinder and having a lower end connected to a drain pipe. The above (2), wherein the water that has flowed into the outer cylinder from the branch portion projecting from the position overflows from the upper end of the inner cylinder, flows into the cylinder, and is discharged to the drain pipe. Is a water management system for paddy fields.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic plan view showing an example of an embodiment of a water management system for paddy fields according to the present invention, and FIG. 2 is a schematic diagram of a water supply valve, a water level setting device, and a drain valve used for water management of one section. is there. The inside of the paddy field 4 is divided into a plurality of cultivated areas 42 by ridges 41 extending in the lateral direction. Each cultivation area 42 has, for example, a long side of 100 to 2
It is divided into rectangles of about 00 m and short sides of about 30 to 100 m, and is almost leveled.

On the side of the paddy field 4, an agricultural road 5 is provided along the longitudinal direction. The upper surface of the agricultural road 5 has a central portion formed on a flat surface having substantially the same width as that of the conventional agricultural road, and on one or both sides of the flat surface, an inclined surface 51 having a downward slope toward the paddy field 4 side. Are formed. The inclined surface 51 is a portion where a water channel and a drainage channel provided along a conventional agricultural road are removed and backfilled. For this reason, the farm road 5 is considerably wider than a conventional farm road, and the direction of the farm road 5 can be changed by turning a tractor or the like, and one side of the farm road 5 can be used as a parking space.

On one agricultural road shown on the right side of FIG. 1, three pipes of a water supply pipe 6A, a water level adjusting pipe 6B, and a drainage pipe 6C are buried adjacently below a slope 51 thereof. . In addition, at each position corresponding to each cultivation area 42, a water supply valve 7A, a water level setting device 7B, and a drain valve 7
C is arranged in close proximity. And each water supply valve 7A
Is connected to a water supply pipe 6A, each water level setting device 7B is connected to a water level adjusting pipe 6B, and each drain valve 7C is connected to a drain pipe 6C.

The farm road 5 shown on the left side of FIG.
4 has a water supply pipe 6A at the center.
And a drainage pipe 6C are buried one by one, and water level adjusting pipes 6B are buried on both sides thereof. A water supply valve 7 is provided on the side edge of each cultivation area 42 located on both sides of the farm road 5.
A, the water level setting device 7B, and the drain valve 7C are arranged close to each other. And each water supply valve 7A is provided with a water supply pipe 6A.
And each drain valve 7C is connected to a drain pipe 6C, and each water level setting device 7B is connected to the nearest water level adjusting pipe 6B.
Is connected to

The upstream side of each water supply pipe 6A is connected to the main water supply channel 3
a, and the downstream side is connected to the main drainage channel 3b. The upstream side of each water level adjusting pipe 6B and each drain pipe 6C is connected to a water level setting device 7B and a drain valve 7C installed in the most cultivated area 42,
The downstream side of each pipe 6B, 6C is a main drainage channel 3b.
Is connected to Although not shown, a water channel for drawing water from the river is connected to the main water supply channel 3a, and the water and rainwater discharged to the main water channel 3b are returned to the river. I have.

In the above embodiment, three water supply pipes 6A, water level adjustment pipes 6B, and drainage pipes 6C are buried adjacent to one side of each cultivation area 42. Not limited to this example, among the three pipes, at least the water supply pipe 6A and the water level adjustment pipe 6B
The main function of the water management system of the present invention is sufficiently achieved even if the two pipes are buried adjacent to each other, or two adjacent pipes of the water supply pipe 6A and the drainage pipe 6C are buried. Is done.

FIG. 3 is a cross-sectional view of the water supply valve.
Has a vertical cylindrical outer cylinder 71.
A branch portion 72 projecting in the horizontal direction is provided at an intermediate position of the side wall of the outer cylinder 71.
2 is supplied with service water.

Further, as shown in FIG. 4, at the intermediate position on the side surface of the outer cylinder 71, the height of the outer branch 71 is substantially the same as that of the former branch portion 72.
A branch portion 72a is provided at a position shifted by 0 degrees so as to protrude in the horizontal direction. An adjacent water level setting device 7B is connected to the branch portion 72a of the water supply valve 7A via a pipe 79 (see FIGS. 2 and 7).

A joint 73 is integrally connected to the lower end of the outer cylinder 71. The joint portion 73 is formed on a truncated cone whose diameter is gradually reduced toward the lower side, and the lower end portion of the support tube 74 is fitted and supported concentrically. The support cylinder 74 is fixed to the joint portion 73 and rises upward, and its upper end is set at substantially the same height as the branch portions 72 and 72a.

A connecting tube 75 is fitted into the support cylinder 74 and is supported concentrically. The lower end of the connecting pipe portion 75 extends downward from the support tube 74,
A curved pipe joint 61 is connected to the lower end. Further, the curved pipe joint 61 is bent in a substantially S-shape, and the other end is provided with the water supply pipe 6.
Connected to A.

FIG. 5 is an enlarged sectional view of a portion S in FIG. 3, and a ring-shaped sealing member 7 is provided at the upper end of the support cylinder 74.
6 are fitted. The sealing member 76 is
4 is fixed to the upper end of the support tube 74 in a state where the upper end surface of the support tube 4 is covered. A flange-like flange 76a is provided on the outer periphery of the seal member 76, and a seal ring 76b is mounted on the flange 76a. The seal ring 76b is tightly and tightly fitted to the inner peripheral surface of the outer cylinder 71 to seal the space between the outer cylinder 71 and the support cylinder 74 in a watertight manner.

The upper end of the connecting tube portion 75 inserted into the support tube 74 is located near the upper end of the support tube 74, and an O-ring 75b is mounted in an annular groove provided on the outer peripheral surface thereof. ing. The O-ring 75b is tightly and tightly fitted to the inner peripheral surface of the support cylinder 74 to seal the space between the support cylinder 74 and the connection pipe 75 in a watertight manner.

An inner cylinder 77 is supported concentrically and vertically slidably on the inner periphery of a seal member 76 fixed to the upper end of the support cylinder 74. The upper end and the lower end of the inner cylinder 77 are open, respectively, and the outer peripheral surface thereof is hermetically sealed by a seal member 76.

The lower end of the operating rod 78 is attached to the inner surface of the inner cylinder 77 in a vertical state. An upper portion of the operation rod 78 rising upward from the inner cylinder 77 is supported by projecting from an upper portion of the outer cylinder 71, and a handle is provided at an upper end thereof.

An opening is provided on one upper side of the outer cylinder 71. The opening allows the inside of the outer cylinder 71 to be seen through, so that the farmer can visually check the state in which the overflowed water is supplied to the cultivation area 42 from the upper end of the inner cylinder 77.

The curved pipe joint 61 connecting the water supply pipe 6A and the water supply valve 7A is provided with a gate valve 8. A wedge-shaped gate 81 is slidably arranged in a vertical direction within a housing 83 constituting the gate valve 8. The shaft 8 which stands up at the gate 81
2 are connected to each other, and the shaft 82 is connected to the cylindrical body 8.
4 protected.

The gate valve 8 can be operated from the ground. When the shaft 82 is lowered and the passage of the curved pipe joint 61 is cut off at the gate 81, the passage of water from the water supply pipe 6A to the water supply valve 7A is cut off. Is done. When the gate 81 is pulled up to open the passage of the curved pipe joint 61, the water supply pipe 6A
From the water supply valve 7A, and the water is supplied to each cultivation area 42.

The water supply valve 7A and the gate valve 8 having such a configuration are buried in a vertical state on the inclined surface 51 of the farm road 5 facing each cultivation area 42. Similarly, a water level setting device 7B and a drain valve 7C are buried close to each other on the inclined surface 51 of the farm road in a vertical state.

FIG. 6 is a sectional view of the water level setting device 7B.
It has substantially the same configuration as the above-described water supply valve 7A.
Since the same reference numerals in the drawings have the same meaning, description thereof will be omitted. Explaining only the differences from the water supply valve 7A, the outer cylinder 7
A branch portion 72b is provided protrudingly at an intermediate position of the side wall of the first side, and the upstream side of the water level adjusting pipe 6B and the water supply valve 7A are connected to the branch portion 72b.

As shown in FIGS. 2 and 7, the water level setting device 7
The branching portion 72b of B is connected to the upstream side of the water level adjusting pipe 6B via the pipe 63, and is connected to the water supply valve 7A via the pipe 79. Further, a lower end of the connecting pipe 75 protruding from a lower end of the outer cylinder 71 is connected to a downstream side of the water level adjusting pipe 6B via the joint 62.

One side of the upper part of the outer cylinder 71 of the water level setting device 7B is
It is cut out in a semi-cylindrical shape, and the inside of the outer cylinder 71 can be seen through the cut-out portion. A scale 711 is provided in the upper part on the inner side of the outer cylinder 71, and a pointer 781 is attached to an appropriate position of the operation rod 78 corresponding to the scale 711. The farm worker moves the operation rod 78 up and down to set the pointer 781 on the scale 711.
, The height of the upper end surface of the inner cylinder 77 is set at the height position indicated by the scale 711.

FIG. 8 is a sectional view of the drain valve 7C. The drain valve 7C is buried vertically in the inclined surface 51 of the agricultural road 5. The drain valve 7C has substantially the same configuration as the above-described water level setting device 7B, and the same reference numerals in the drawing have the same meanings, and therefore description thereof will be omitted. In the case of the drain valve 7C, a branch portion 72c is provided to protrude at an intermediate position of the side wall of the outer cylinder 71. The surplus water supplied to the cultivation area 42 is returned to the branch part 72c of the drain valve 7C, and the lower end of the connecting pipe part 75 is connected to the drain pipe 6C via the joint 64.

Also in the case of the drain valve 7C, a scale 711 is provided in the upper part on the inner side of the outer cylinder 71, and a pointer 781 is attached to an appropriate position of the operation rod 78 corresponding to the scale 711. I have. The farm worker moves the operation rod 78 up and down to set the pointer 781 on the scale 711.
, The height of the upper end surface of the inner cylinder 77 is set at the height position indicated by the scale 711.

The water supply valve 7A, the water level setting device 7B, and the drain valve 7C having the above-described configuration are installed in each cultivation area close to each other, and the paddy water level is set for each cultivation area 42. Usually, the paddy fields 4 of one section are leveled flat so that the cultivated areas 42 have the same height, but a slight difference in elevation may occur between the cultivated areas 42 depending on the topography. Therefore, the operating rod 78 of the water level setting device 7B installed in each cultivation area 42 is moved up and down, and the height position of the upper end surface of the inner cylinder 77 is adjusted so as to be constant for each cultivation area 42. .

The water supply valve 7A installed in each cultivation area 42 has its upper end surface set at a position higher than the upper end surface of the inner tube 77 of the water level setting device 7B.
The upper end surface of the inner cylinder 77 is set at a position slightly higher than the upper end surface of the inner cylinder 77 of the water level setting device 7B.

Next, a description will be given of a mode in which water flows through the apparatus of the present system and is managed when three pipes of a water supply pipe 6A, a water level adjusting pipe 6B, and a drainage pipe 6C are buried adjacent to each other. I do. First, the water flowing into the water supply valve 7A from the water supply pipe 6A overflows the upper end of the inner cylinder 77 of the water supply valve 7A and is supplied from the branch pipe 72 to the cultivation area 42. Further, since the water supply valve 7A and the water level setting device 7B communicate with each other via the pipe 79, the water flowing into the water level setting device 7B from the upstream water level adjustment pipe 6B flows into the cultivation zone from the branch portion 72 of the water supply valve 7A. 42. The supply of irrigation water to the cultivation area 42 increases the water level of the rice field and
The process is continuously performed until the height reaches the same height as the upper end surface of the inner cylinder 77 of B.

When the water level on the paddy field becomes higher than the upper end face of the inner cylinder 77 of the water level setting device 7B, excess water flows into the cylinder from the inner cylinder 77 of the water level setting device 7B, and the downstream water level adjusting pipe 6B
, The water level of the cultivated area 42 is maintained at a constant level. When the surface water level of the cultivation zone 42 on the upstream side is maintained constant, surplus water is supplied to the cultivation zone 42 on the downstream side,
Similarly, the surface water level is maintained constant. At this time, since the upper end surface of the inner cylinder 77 of the drain valve 7C is at a position higher than the rice field water level, the water is not discharged from the drain valve 7C.

When such water management is performed, each cultivation zone 42
Cultivation zone 4 on the upstream side because the supply of water to
Water can be supplied uniformly from 2 to the cultivation area 42 on the downstream side, and water shortage does not occur in the cultivation area 42 on the downstream side. In addition, since the amount of the pesticides, fertilizers, and the like applied to each cultivation area 42 flowing out together with the water is reduced, there is no possibility of causing a problem of environmental destruction.

In the present invention, since the amount of water flowing through the water supply pipe 6A and the water level setting pipe 6B is small, a small-diameter pipe can be used. Further, since a certain flow velocity can be secured without giving a large gradient to each of the pipes 6A, 6B, 6C, the pipe laying work is simple and easy, and the construction cost can be greatly reduced. In addition, in the conventional flat land irrigation, a pump for pumping service water was necessary, but in the present invention, it is not necessary, and the service water can be sent at an extremely low pressure.

When the surface water level of each cultivation area 42 rises due to prolonged rain or torrential rain, the branch portion 72c of each drain valve 7C
Rainwater overflows from the upper end of the inner cylinder 77, flows into the cylinder, and is quickly discharged from the drain pipe 5C. Therefore, the surface water level is always kept constant.

When draining the water stored in some of the cultivation areas 42, the gate valve 8 and the valve 79V are closed to shut off the supply of the water to the cultivation areas 42.
Then, the water can be discharged by lowering the inner cylinder 77 of the drain valve 7C to the lowest position.

The water supply pipe 6A and the water level adjustment pipe 6B may be infiltrated with water and rainwater and may be accumulated. In this case, as shown in FIG.
A, a valve 91V provided on a pipe 91 connecting the drain pipe 6C and a water level adjusting pipe 6B and a drain pipe 6C.
By opening the valve 92V provided on the pipe 92 connecting the pipes, the soil and the like accumulated in the pipes 6A and 6B can be discharged to the drain pipe 6C.

On the other hand, when the paddy field requires a large amount of water, the inner cylinder 77 of the water supply valve 7A is pushed down below the normal state. Thus, the water supplied from the water supply pipe 6A vigorously overflows the upper end of the inner cylinder 77, is supplied to the cultivation area 42, and reaches a predetermined water level. By repeating this operation, water can be sequentially supplied from the cultivation area 42 on the upstream side to the cultivation area 42 on the downstream side.

FIG. 1 showing an embodiment of the present invention shows a water supply valve 7A, a water level setting device 7B, and a discharge valve 7C on opposite sides of each cultivation area 42 extending along the longitudinal direction of the paddy field 4. Although the example in which is installed is illustrated, the present invention is not limited to this embodiment. When the water supply valve 7A, the water level setting device 7B, and the discharge valve 7C are installed on both sides of the cultivation area 42, there is an advantage that fine water management can be performed over the entire cultivation area 42. If the area is not so large, the water supply valve 7A water level setting device 7
Even by installing B and the drain valve 7C, sufficient water management is possible.

Further, in the above-described embodiment, an example is shown in which the branch portion 72a of the water supply valve 7A and the water level setting device 7B are connected by a pipe 79. However, as shown in FIG. The branch 79a may be eliminated by connecting the pipe 79. In some cases, as shown in FIG.
In addition to closing the end of the branch portion 72A, the branch portion 72 of the water supply valve 7A and the branch portion 72c of the drain valve 7C are connected to a pipe 93.
May be connected.

Further, a gate valve 8 provided on the curved pipe joint 61, a valve 79V provided on a pipe 79 connecting the water supply valve 7A and the water level setting device 7B, a bypass pipe 91 for discharging earth and sand, etc. Valve 9 provided at 92
1V, 92V, etc. may be automatically controlled using a computer or the like.

As another embodiment of the present invention, two pipes of the water supply pipe 6A and the water level setting pipe 6B or two pipes of the water supply pipe 6A and the drainage pipe 6C are provided on one side of the cultivation area 42. The case of burying adjacently will be described. First, in the former example, as shown in FIGS. 2 and 9, the water that has flowed into the water supply valve 7A from the water supply pipe 6A is supplied to the cultivation area 42 from the branch portion 72 of the water supply valve 7A. Then, when the paddy water level rises and becomes higher than the upper surface of the inner cylinder 77 of the water level setting device 7B, surplus water flows into the cylinder from the inner cylinder 77 of the water level setting device 7B via the pipe 79, and adjusts the water level on the downstream side. Since the water is supplied to the pipe 6B, the surface water level of the cultivated area 42 is kept constant.

In the latter example, as shown in FIG. 10, for example, the water flowing into the water supply valve 7A from the water supply pipe 6A is cultivated from the branch 72 of the water supply valve 7A to the branch 72c of the drain valve 7C. It is supplied to the ward 42. Then, when the water level of the rice field rises and becomes higher than the upper surface of the inner cylinder 77 of the drain valve 7C, the surplus water flows into the cylinder from the inner cylinder 77 of the drain valve 7C and is sent to the drain pipe 6C. Field water level is kept constant.

[0045]

According to the paddy field management system of the present invention, a water supply pipe, a drain pipe, and a drain pipe are buried adjacent to a farm road provided along the periphery of the paddy field. Can be expanded, and farmland can be used effectively.

Each cultivation area has a supply valve for supplying irrigation water from a water supply pipe, a water level setting device for maintaining the water level of each cultivation area constant, and an excess water or rainwater supplied to each cultivation area. Since a drain valve for discharging to the drain pipe is installed,
Efficient water management can be performed by maintaining the surface water level constant in each cultivation zone.

According to the present invention, water management can be performed so as to minimize discharge of water supplied to each cultivated area as surplus water. Therefore, pesticides, fertilizers, and the like applied to each cultivated area can be controlled. It does not flow out with water and cause environmental damage.

Further, when operating each equipment in order to set the paddy field management system of the present invention to optimal conditions, a water supply pipe and a water level adjustment pipe or a water supply pipe and a drainage pipe are adjacent to one side of a cultivated area. Since the water supply valve, water level setting device, and drain valve attached to these pipes are arranged close to each other, the moving distance is extremely short, and the centralized operation can be performed.

According to the present invention, there is no need for a means of transporting water by a pump, which is required in conventional flatland irrigation, and the flow velocity can be ensured without a large gradient of pipes. It can be performed easily and can greatly reduce construction costs.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a paddy field showing an embodiment of a water management system of the present invention.

FIG. 2 is a piping schematic diagram of a water supply valve, a water level setting device, and a drain valve used for water management in a cultivated area of one section.

FIG. 3 is a sectional view of a water supply valve used in the water management system of the present invention.

FIG. 4 is a partial front view of a water supply valve.

FIG. 5 is an enlarged sectional view of a main part of the water supply valve shown in FIG. 3;

FIG. 6 is a sectional view of a water level setting device used in the water management system of the present invention.

FIG. 7 is a schematic piping diagram of a water level adjusting pipe.

FIG. 8 is a sectional view of a drain valve used in the water management system of the present invention.

FIG. 9 is a schematic piping diagram showing another embodiment of the present invention.

FIG. 10 is a schematic piping diagram showing still another embodiment of the present invention.

FIG. 11 is a schematic plan view showing an example of a conventional paddy field structure.

FIG. 12 is a perspective view of a conventional water supply channel.

[Explanation of symbols]

 4 Paddy field 41 Levees 42 Cultivated area 5 Farm road 51 Slope 6A Water supply pipe 6B Water level adjustment pipe 6C Drainage pipe 7A Water supply valve 7B Water level setting device 7C Drainage valve

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shigehara Shibahara 75 Nojiri, Ritto-cho, Kurita-gun, Shiga Prefecture Inside Sekisui Pipe Materials and Technics Co., Ltd. (72) Inventor Yasunori Hashimoto 5-8 Mitsuyacho, Nagahama-shi, Shiga Prefecture Mitsubishi Plastics Co., Ltd. Inside Nagahama Plant

Claims (5)

[Claims] 1. A water management system for a paddy field divided into a plurality of cultivation areas, wherein at least a water supply pipe and a water level adjustment pipe are buried adjacent to one side of the cultivation area, and each water supply pipe has a cultivation area. The water level adjustment pipe is provided with a water level setting period for maintaining the surface water level of each cultivation area constant, and the water level setting pipe is brought close to the water level setting period. A water management system for paddy fields, which is arranged. 2. A water management system for a paddy field divided into a plurality of cultivation areas, wherein at least a water supply pipe and a drainage pipe are buried adjacent to one side of the cultivation area. A paddy field characterized by having a water supply valve for supplying water, and a drainage pipe having a drainage valve for discharging surplus water in each cultivation area and arranging each water supply valve and the drainage valve close to each other. Irrigation management system. 3. The water supply valve comprises a vertically rising outer cylinder, and an inner cylinder vertically movably suspended inside the outer cylinder and having a lower end connected to a water supply pipe. The water management system for paddy fields according to claim 1, wherein the water overflowing from the upper end of the water supply is supplied to each cultivated area from a branch portion provided in the middle of the outer cylinder. 4. A water level setting device comprising: a vertically rising outer cylinder;
An inner cylinder connected to the water level adjustment pipe on the downstream side, the lower end of which is vertically movably suspended vertically inside the outer cylinder, and is provided at a branch portion protrudingly provided at an intermediate position of the outer cylinder. The water level setting pipe on the upstream side and the water supply pipe communicating with each cultivation area are connected, and the water flowing into the outer cylinder from the branch portion overflows from the upper end of the inner cylinder and flows into the cylinder,
2. The water management system for paddy fields according to claim 1, wherein the water is discharged to a water level setting pipe on the downstream side. 5. A drain valve comprising: a vertically rising outer cylinder; and an inner cylinder vertically movably suspended inside the outer cylinder and having a lower end connected to a drain pipe. The water that has flowed into the outer cylinder from a branch portion protrudingly provided at an intermediate position of the inner cylinder overflows from the upper end of the inner cylinder, flows into the cylinder, and is discharged to a drain pipe. 2. The water management system for paddy fields according to 2.