SECONDARY DRAINAGE METHOD AT TIME OF FLOODING

Abstract

The present application provides a secondary drainage method for use at the time of flooding. A rainwater storage tank is provided, drainage pipes are installed between positions in which flooding of land or of property occurs and the rainwater storage tank, and inflow switching valves are installed in portions where water flows in from the drainage pipes to the rainwater storage tank. As a general rule, the flow of water into the rainwater storage tank is prevented by switching the inflow switching valves during the initial stages of a localized severe rain storm or of river flooding. After the wide-area flooding of land has receded, the inflow switching valves are opened, guiding the water in the locally remaining zones of flooded land or of flooded property into the rainwater storage tank, and allowing the localized flooding of land or of property to be eliminated at an early stage.

Claims

1. A secondary drainage method for use at the time of flooding, the method making use of a secondary drainage system that is for use at the time of flooding and comprises a rainwater storage tank having inflow switching valves installed in water flowing-in portions to temporarily prevent water from flowing in from said water flowing-in portions, a water guiding means for guiding, into said rainwater storage tank, the water in the locally remaining zones of flooded land or of flooded property even after wide-area flooding of land due to a localized severe rain storm or river flooding has receded, and a water drainage means for draining the water stored in said rainwater storage tank, wherein the flow of water into said rainwater storage tank is prevented by closing said inflow switching valves during the initial stages of the river flooding or of localized severe rain storm that occurs in a target region, and wherein after the wide-area flooding of land due to the river flooding or localized severe rain storm has receded, said inflow switching valves are opened, guiding the water in the locally remaining zones of flooded land or of flooded property into said rainwater storage tank, followed by draining the water stored in said rainwater storage tank by the drainage means.

2. A secondary drainage method for use at the time of flooding, the method making use of a secondary drainage system that is for use at the time of flooding and comprises a rainwater storage tank having inflow switching valves installed in water flowing-in portions to temporarily prevent water from flowing in from said water flowing-in portions, a water guiding means for guiding, into said rain water storage tank, the water in the locally remaining zones of flooded land or of flooded property even after the wide-area flooding of land due to river flooding or a localized severe rain storm has receded, and a drainage means for draining the water stored in said rainwater storage tank, wherein the flow of water into said rainwater storage tank is partly permitted, while being suppressed by switching said inflow switching valves during the initial stages of the river flooding or of localized severe rain storm that occurs in a target region, and wherein after the wide-area flooding of land due to the river flooding or localized severe rain storm has receded, said inflow switching valves are opened, guiding the water in the locally remaining zones of flooded land or of flooded property into said rainwater storage tank, followed by draining the water stored in said rainwater storage tank by the drainage means.

3. The secondary drainage method for use at the time of flooding according to claim 1, wherein said rainwater storage tank is provided in the ground.

4. The secondary drainage method for use at the time of flooding according to claim 1, wherein said water guiding means or said rainwater storage tank is provided with a filter means for removing a soil component.

5. The secondary drainage method for use at the time of flooding according to claim 1, wherein said water guiding means includes a drainage pipe for interconnecting said rainwater storage tank and said locally remaining zones of flooded land or of flooded property.

6. The secondary drainage method for use at the time of flooding according to claim 1, wherein said water guiding means has a water suction means for sucking the water in said locally remaining zones of flooded land or of flooded property from a ground surface side, and a connection means for interconnecting said water suction means and said rainwater storage tank.

7. The secondary drainage method for use at the time of flooding according to claim 1, wherein said drainage means includes a drainage channel connected to a river or to a sewerage.

8. The secondary drainage method for use at the time of flooding according to claim 1, wherein said drainage means includes a drainage pump connected to a river or to a sewerage.

9. The secondary drainage method for use at the time of flooding according to claim 2, wherein said rainwater storage tank is provided in the ground.

10. The secondary drainage method for use at the time of flooding according to claim 2, wherein said water guiding means or said rainwater storage tank is provided with a filter means for removing a soil component.

11. The secondary drainage method for use at the time of flooding according to claim 2, wherein said water guiding means includes a drainage pipe for interconnecting said rainwater storage tank and said locally remaining zones of flooded land or of flooded property.

12. The secondary drainage method for use at the time of flooding according to claim 2, wherein said water guiding means has a water suction means for sucking the water in said locally remaining zones of flooded land or of flooded property from a ground surface side, and a connection means for interconnecting said water suction means and said rainwater storage tank.

13. The secondary drainage method for use at the time of flooding according to claim 2, wherein said drainage means includes a drainage channel connected to a river or to a sewerage.

14. The secondary drainage method for use at the time of flooding according to claim 2, wherein said drainage means includes a drainage pump connected to a river or to a sewerage.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG. 1 is a vertical cross-sectional view conceptionally showing one embodiment of a secondary drainage method for use at the time of flooding according to the present invention.

[0038] FIG. 2 is a vertical cross-sectional view conceptionally showing another embodiment of the secondary drainage method for use at the time of flooding according to the present invention.

MODE FOR EMBODYING THE INVENTION

[0039] Hereinafter will be described the present invention with reference to the attached drawings.

[0040] FIG. 1 conceptionally shows one embodiment of a secondary drainage method for use at the time of flooding, wherein in a region where it is known, from experiences or from topography or geological stratum conditions, that flooding of land or of property remains locally even after wide-area flooding of land due to a localized severe rain storm, river flooding or the like has receded, a rainwater storage tank 1 is provided, drainage pipes 2 are installed between positions in which flooding of land or of property occurs and the rainwater storage tank, and inflow switching valves are installed in portions where water flows in from the drainage pipes 2 to the rainwater storage tank 1.

[0041] As a general rule, the flow of water into the rainwater storage tank 1 is prevented by switching the inflow switching valves 3 during the initial stages of a localized severe rain storm or of river flooding that occurs in a target region. In which case, however, depending on the scale of wide-area flooding that is anticipated to occur in surrounding areas of the target region, the flow of water into the rainwater storage tank is partly permitted for contribution to suppression of wide-area flooding as well.

[0042] After the wide-area flooding of land due to the river flooding or localized severe rain storm has receded, the inflow switching valves 3 are opened, guiding the water in the locally remaining zones of flooded land or of flooded property into the rainwater storage tank 1, resulting in that it is possible to eliminate, at an early stage, the localized flooding of land or of property that remains for a long time and has thus caused some difficulties in the daily lives of local residents.

[0043] The rainwater storage tank 1 drains the water toward a sewerage or toward a river or the like using a drainage means passing through a drainage channel 4. In this case, it may be possible also to use a forcible drainage means using a drainage pump 5 or the like.

[0044] FIG. 2 conceptionally shows another embodiment of the secondary drainage method for use at the time of flooding according to the present invention. In this embodiment, similarly to the case of a conventional rainwater storage tank 1, a filter tank 7 serving as a filter means is provided in the front of the rainwater storage tank 1, wherein after a soil component is once settled in the filter tank 7, the water with earth and sand removed therefrom is introduced into the rainwater storage tank 1 through a connection pipe 8.

[0045] However, because of the fact that floodwater remaining even after flooding is in the state of surface water with the soil component settled to a certain degree as compared with muddy water or the like generated immediately after flooding, it is possible to cope with the remaining floodwater by use of a more simplified rainwater storage tank compared with a common type of rainwater storage tank 1.

[0046] Further, in this embodiment, in a portion where it is known that the flooding of land remains, a drain 6 is provided, and the inflow switching valve is installed in the vicinity of the drain. The water stored in the rainwater storage tank 1 is drained toward the sewerage or toward the river through the drainage channels 4, 9.

EXPLANATION OF REFERENCE NUMERALS

[0047] 1 . . . Rainwater storage tank, 2 . . . Drainage pipe, 3 . . . Inflow switching valve, 4 . . . Drainage channel, 5 . . . Drainage pump, 6 . . . Drain, 7 . . . Filter tank, 8 . . . Connection pipe, 9 . . . Drainage channel