Rainwater harvesting structures and networks

Abstract

To provide rainwater storage structure and a rainwater storage network capable of distributing load of processing localized rainfall.SOLUTION: A rainwater storage structure 1 provided in an area 2 having a plurality of localities 21 comprises: a plurality of rainwater storage tanks 11 each provided with a water collection port 112 provided in each locality 21 for collecting rainwater that has rained in the locality 21, and a drainage mechanism 115 capable of draining the collected rainwater; a pair of tubular rising parts 13, 13 that are provided inside adjacent rainwater storage tanks 11, 11, have an open end 132 that is arranged near an inner bottom 113 of the rainwater storage tank 11 and opens downward, and extend upward from the open end 132; a tubular connecting part 14 that connects upper ends 131, 131 of the pair of rising parts 13, 13; and connecting piping 12 that can keep a pipe filled with water, wherein the adjacent rainwater storage tanks 11, 11 have a difference H1 of elevation.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a rainwater harvesting structure and a rainwater harvesting network. [Background technology]

[0002] Conventionally, systems and facilities have been proposed that collect rainwater that falls on a certain area, such as a residential area or land, temporarily store it, and then treat the rainwater after a certain period of time has passed since the rainfall. For example, as shown in Patent Document 1, a method has been proposed in which multiple rainwater tanks are installed around a building, adjacent rainwater tanks are connected to each other with piping with an egg-shaped cross section, and the connected tanks are connected to a public rainwater drain, thereby temporarily storing the collected rainwater and discharging the rainwater after a certain period of time has passed since the rainfall. Also, as shown in Patent Document 2, a method has been proposed in which rainwater is collected in multiple underground storage tanks, and a pump connected to a connecting pipe that connects suction pipes installed in each storage tank is driven, and the rainwater in each storage tank is discharged from each suction pipe by the siphon effect. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4302506 [Patent Document 2] Patent No. 3002436 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in recent years, there have been frequent occurrences of localized heavy rainfall that occurs suddenly over a short period of time, and in areas with large areas such as cities, it is difficult to ensure treatment facilities and resilience against rainfall that can instantaneously exceed the area's rainwater treatment capacity. For example, it would be extremely financially difficult to develop sewerage facilities in all parts of a city that can withstand sudden rainfall with a rainfall intensity of 100 mm / h or more.

[0005] Therefore, an object of the present invention is to provide a rainwater storage structure and a rainwater storage network that can distribute the load of processing localized rainfall. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the rainwater storage structure of the present invention is a rainwater storage structure provided in an area having a plurality of local areas, and includes a plurality of rainwater storage tanks provided in the local areas, each having a water collection outlet for collecting rainwater that has fallen in the local area and a drainage mechanism for freely draining the collected rainwater, and connecting pipes provided inside adjacent rainwater storage tanks, each of which has an opening end that opens downward and is located near the inner bottom of the rainwater storage tank, and which has a pair of tubular rising sections extending upward from the opening end, and a tubular connecting section that connects the upper ends of the pair of rising sections, and which are capable of keeping the inside of the pipe full of water, and adjacent rainwater storage tanks have a difference in elevation.

[0007] With the above configuration, the rainwater storage structure collects rainwater that falls in a certain area in a rainwater storage tank close to the rainfall location, and then transfers the collected rainwater to an adjacent rainwater storage tank via the siphon effect of the connecting pipes. This allows the collected rainwater to be dispersed and stored in multiple rainwater storage tanks, increasing the amount of rainwater that can be stored in response to localized rainfall. The rainwater storage structure can prevent flooding or inundation due to exceeding the treatment capacity of a single rainwater storage tank, even in the event of rainfall that exceeds the storage capacity of a single rainwater storage tank, such as in the case of a localized, short-term heavy downpour.

[0008] In the rainwater storage structure according to the present invention, the connecting pipe may include a water injection section having a valve mechanism that can be opened and closed.

[0009] With the above configuration, the rainwater storage structure can instantly fill the connecting pipe with water by driving the water injection unit. Therefore, the rainwater storage structure can reliably exert a siphon effect via the connecting pipe and move the collected rainwater.

[0010] In the rainwater storage structure according to the present invention, the rainwater storage tank may include a water level detection mechanism that detects the level of the rainwater stored therein.

[0011] With the above configuration, the rainwater storage structure can keep the open end of the connecting pipe constantly submerged by managing the water level of the stored water, making it easy to maintain the siphon effect of the connecting pipe.

[0012] In the rainwater retention network according to the present invention, the connecting pipe may be provided with an air vent mechanism for discharging air from inside the pipe.

[0013] With the above configuration, the rainwater storage structure can prevent air bubbles and other particles that disrupt the flow of stored water from entering the stored water flowing through the connecting pipe by expelling air from the connecting pipe.

[0014] In order to achieve the above-mentioned object, the rainwater storage network of the present invention is provided in an area having a plurality of adjacent local areas each equipped with the above-mentioned rainwater storage structure, and is characterized in that rainwater that falls in the area is stored in the rainwater storage tank whose collection range is the place where the rain fell, and a portion of the stored rainwater is transferred via the connecting pipe to the rainwater storage tank provided within the area so that the water levels of the rainwater storage tanks located within the area are approximately the same.

[0015] With the above configuration, the stormwater retention network spreads the network of stormwater retention structures throughout the entire area, making it possible to widely distribute the load on the stormwater retention tanks, which are part of the sewerage infrastructure within the area, caused by localized heavy rain at the zonal or local level. As a result, the stormwater retention network can quickly treat stormwater stored during localized heavy rain, improving resilience to zonal and localized rainfall. By forming the above-mentioned rainwater storage network in urban areas, it is possible to avoid replacing sewerage infrastructure that may be over-specified during normal rainfall, thereby reducing the financial burden required to develop sewerage infrastructure in the area. The rainwater storage network distributes the stored rainwater approximately evenly among the rainwater storage tanks within the network, making it possible to use the stored rainwater at each local area as a water resource. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a rainwater storage structure and a rainwater storage network that can distribute the load of processing localized rainfall. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is an explanatory diagram showing an example of a rainwater storage network to which a rainwater storage structure according to an embodiment of the present invention is applied. [Figure 2] 1 is an explanatory diagram showing an example of a rainwater storage structure according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, a rainwater storage structure and a rainwater storage network according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, a plurality of rainwater storage structures 1 according to this embodiment are provided within an area 2 to form a rainwater storage network 3. The area 2 is made up of a plurality of local areas 21. The area 2 is, for example, a city. A local area 21 is, for example, one block that makes up the city. Hereinafter, the area 2 will be referred to as the city 2, and the local area 21 will be referred to as the block 21. In the city 2, rainfall occurs with random conditions such as rainfall range, rainfall duration, and rainfall intensity. For example, localized heavy rain of up to approximately 100 mm / h suddenly occurs in a plurality of blocks 21.

[0019] The rainwater storage structure 1 comprises rainwater storage tanks 11, 11 provided in adjacent blocks 21, 21, respectively, and a connecting pipe 12 connecting the rainwater storage tanks 11, 11. All of the rainwater storage structures 1 provided within the city 2 are connected to each other via multiple connecting pipes 12 to form a rainwater storage network 3.

[0020] The rainwater storage network 3 is configured to collect and store rainwater that falls due to localized heavy rainfall that occurs within the city 2. In this embodiment, each rainwater storage tank 11 provided in the rainwater storage network 3 is arranged one per block 21.

[0021] The rainwater storage tanks 11 are buried underground and installed one per block 21. Adjacent rainwater storage tanks 11, 11 are installed at different elevations. The rainwater storage tanks 11 have a cylindrical tank shape, with the central axis of the cylinder approximately aligned vertically.

[0022] The rainwater storage tank 11 has a water collection port 112 on its top surface 111 for collecting rainwater that falls on the block 21, and its inner bottom 113 is closed. The rainwater storage tank 11 has a desired strength against the surrounding ground and a desired water resistance to prevent leakage of the stored water. The rainwater storage tank 11 is, for example, a well-known underground concrete storage tank.

[0023] The water collection outlet 112 is an opening that connects the rainwater storage tank 11 to a surface water collection facility 211, such as a culvert or open channel, provided on the ground surface of the block 21. The water collection outlet 112 may be a pipe drilled between the upper surface 111 and the surface water collection facility 211, or may be a water collection box with a lattice-shaped box cover that collects water directly from the surface water collection facility 211.

[0024] Rainwater that falls on the block 21 and is collected from each surface water collection facility 211 is collected and stored in the rainwater storage tank 11 through the water collection outlet 112. The rainwater stored in the rainwater storage tank 11 is referred to as stored water 114. The rainwater storage tank 11 has a storage volume corresponding to the required storage amount, taking into account normal rainfall in the block 21 where the rainwater storage tank 11 is installed.

[0025] In the case where the distance between the water collection outlet 112 and the surface water collection equipment 211 of the rainwater storage structure 1 is large and it is difficult to connect them directly, a connecting mechanism such as a connecting pipe may be provided to connect the water collection outlet 112 and the surface water collection equipment 211 and move the collected rainwater to the rainwater storage tank 11.

[0026] The rainwater storage tank 11 is equipped with a drainage mechanism 115 that drains stored water 114 that has reached a certain level. In this embodiment, the drainage mechanism 115 includes a drainage pipe 115a that transfers the stored water 114 to a wastewater treatment facility (not shown) installed above ground, and a drainage pump 115b that is connected to the drainage pipe 115a and is driven to pump up the stored water 114 when the water level of the stored water 114 reaches a certain level or higher.

[0027] The rainwater storage tank 11 is provided with a water level detection mechanism 116 that detects the water level of the stored water 114 in the rainwater storage tank 11. In this embodiment, the water level detection mechanism 116 is provided on a part of a side wall 117 of the rainwater storage tank 11 and is provided as a sensor that measures the water level of the stored water 114.

[0028] The connecting pipe 12 is provided with an air vent mechanism 118 that can freely discharge air inside the connecting pipe 12 to the outside of the pipe. The air vent mechanism 118 is provided as an air vent mechanism that discharges air bubbles and the like that have become mixed in the stored water 114 inside the connecting pipe 12 to the outside of the pipe, for example.

[0029] The configuration of the rainwater storage structure 1 will be described below based on the rainwater storage structure 1a shown in FIG. 2, which includes rainwater storage tanks 11a and 11b and a connecting pipe 12a. As shown in Figure 2, rainwater storage tanks 11a and 11b are connected via connecting pipe 12a. Rainwater storage tanks 11a and 11b are installed with a height difference H1. Rainwater storage tank 11a is connected to two rainwater storage tanks, rainwater storage tank 11b and adjacent rainwater storage tank 11c, via connecting pipes 12a and 12b, respectively. Rainwater storage tank 11b is connected to two rainwater storage tanks (not shown) adjacent to rainwater storage tank 11a via connecting pipes 12a and 12c, respectively. Rainwater storage tanks 11a and 11b collect rainwater from water collection ports 112a and 112b, respectively.

[0030] The connecting pipe 12a has a pair of rising portions 13a, 13b, a connecting portion 14, and a water injection portion 15. The connecting pipe 12a is a cylindrical steel pipe that is arranged between the adjacent rainwater storage tanks 11a, 11b to connect them, and has an interior through which water can flow.

[0031] The rising portion 13a is provided inside the rainwater storage tank 11a close to the side wall portion 117a of the rainwater storage tank 11a, and is disposed so that its central axis is substantially aligned with the vertical direction. An upper end portion 131a of the rising portion 13a penetrates the upper surface 111a and connects to the connecting portion 14 (hereinafter, the "upper end portion 131a" will be referred to as the "connecting portion 131a"). A lower end portion 132a of the rising portion 13a is close to the inner bottom portion 113a and opens downward (hereinafter, the "lower end portion 132a" will be referred to as the "opening end portion 132a"). The rising portion 13a extends from the opening end portion 132a toward the connecting portion 131a, and is provided as a rising pipe whose opening end portion 132a opens downward. The rising portion 13a is provided in the rainwater storage tank 11a so that the water level H3a of the stored water 114 is higher than the placement height H2a of the open end 132a, and the water level at which the open end 132a is submerged is maintained.

[0032] The rising portion 13b has the same configuration as the rising portion 13a. That is, the rising portion 13b is provided inside the rainwater storage tank 11b close to the side wall portion 117b, and is disposed so that its central axis is substantially aligned with the vertical direction. The upper end portion 131b penetrates the upper surface 111b and is connected to the connecting portion 14 (hereinafter, the "upper end portion 131b" will be referred to as the "connecting portion 131b"). The lower end portion 132b is close to the inner bottom portion 113b and opens downward (hereinafter, the "lower end portion 132b" will be referred to as the "opening end portion 132b"). The rising portion 13b extends from the opening end portion 132b toward the connecting portion 131b, and is provided as a rising pipe whose opening end portion 132b opens downward. The rising portion 13b is provided in the rainwater storage tank 11b so that the water level H3b of the stored water 114 is higher than the placement height H2b of the open end 132b, and the water level at which the open end 132b is submerged is maintained.

[0033] The water levels H3a and H3b of the stored water 114 are managed by water level detection mechanisms 116 provided in the rainwater storage tanks 11a and 11b, respectively, and the open ends 132a and 132b are kept submerged in water.

[0034] The connecting portion 14 comprises an underground portion 141 buried in the ground and connected to the rising portion 13a, an underground portion 142 buried in the ground and connected to the rising portion 13b, a rising portion 143 connected to the underground portion 141 and extending vertically upward, a rising portion 144 connected to the underground portion 142 and extending vertically upward, and an above-ground portion 145 connected to the rising portion 143 and the rising portion 144 and placed on the ground.

[0035] The connecting pipe 12a has a convex outer shape in a front view, which is formed so that the vertical lengths of the rising portion 13a and the rising portion 13b are approximately the same. Also, for example, the connecting pipe 12a may be formed so that the rising portion 13b arranged in the rainwater storage tank 11b at a low altitude is longer than the rising portion 13a arranged in the rainwater storage tank 11a at a high altitude, and the installation heights of the underground portion 141 and the underground portion 142 are approximately the same.

[0036] The underground portion 141 is connected at one side end 141a to the connecting portion 131a of the rising portion 13a that penetrates the upper surface 111a. The periphery of the penetration point in the upper surface 111a is closed off from the ground.

[0037] The underground portion 142 is connected at one side end 142a to the connecting portion 131b of the rising portion 13b that penetrates the adjacent upper surface 111b in the same manner as above. The periphery of the penetration point in the upper surface 111b is closed off from the ground.

[0038] The rising portion 143 is connected to the other end 141b of the underground portion 141, extends vertically upward through the ground to the ground, and is connected to one end 145a of the above-ground portion 145 at its upper end 143a.

[0039] The rising portion 144 is connected to the other end 142b of the underground portion 142 in the same manner as above, extends vertically upward through the ground to the ground, and connects to the other end 145b of the above-ground portion 145 at its upper end 144a.

[0040] The above-ground portion 145 is connected at one end 145a to the rising portion 143 and at the other end 145b to the rising portion 144. The above-ground portion 145 corresponds to the top of the connecting pipe 12.

[0041] The water injection section 15 includes a water injection pipe 151 connected to one of the rainwater storage tanks 11 and the above-ground section 145, a water injection valve 152 connected to the above-ground section 145 and allowing the water injection pipe 151 to be opened and closed, and a water injection pump 153 positioned in the middle of the water injection pipe 151 and injecting water into the connecting pipe 12 via the water injection pipe 151 and the water injection valve 152.

[0042] When localized heavy rain falls, the water injection unit 15 drives the water injection pump 153, opens the water injection valve 152, and pumps a portion of the stored water 114 into the water injection pipe 151, which then injects the water into the connecting pipe 12. When the connecting pipe 12 becomes full of water, the water injection unit 15 stops pumping the stored water 114. The water injection unit 15 is equipped with a mechanism that detects that the connecting pipe 12 is full of water. For example, the water injection valve 152 may be an electromagnetic valve, or the water injection unit 15 may be equipped with a mechanism that automatically controls the operation of the water injection pump 153 according to the water flow conditions in the connecting pipe 12.

[0043] The water injection unit 15 is not limited to the above configuration as long as it can fill the connecting pipe 12 with water by injecting water, and may be configured to be connected to a water source separate from the rainwater storage network 3 and pump up water to be injected into the connecting pipe 12. For example, the water injection unit 15 may be configured to connect the water injection pipe 151 to a lake or river near the rainwater storage structure 1, or to connect the water injection pipe 151 to a mobile water supply source such as a well-known water tanker. With the above configuration, even if all of the rainwater storage tanks 11 that make up the rainwater storage network 3 are in a drought or near-drought state and the connecting pipe 12 is broken to release the full water state, the rainwater storage structure 1 can easily secure water to inject into the connecting pipe 12 and maintain the full water state of the connecting pipe 12.

[0044] In rainwater storage tank 11a, the water intake position of drain pipe 115a of drainage mechanism 115 is located above open end 132a. The water intake position of water injection pipe 151 of water injection unit 15 is located above open end 132a. As with rainwater storage tank 11b, the water intake position of drain pipe 115a and the water intake position of water injection pipe 151 provided in connecting pipe 12c are located above open end 132b. With the above configuration, open ends 132a, 132b can remain submerged even when stored water 114 is taken in by drainage mechanism 115 and water injection unit 15 and the water level of stored water 114 drops.

[0045] With the above configuration, the rainwater storage structure 1a is formed by connecting adjacent rainwater storage tanks 11a and 11b via a connecting pipe 12a consisting of a pair of rising portions 13a and 13b and a connecting portion 14. All rainwater storage structures 1 placed within the city 2 have the same configuration as the above rainwater storage structure 1a.

[0046] The rainwater storage network 3 is formed by connecting all the rainwater storage structures 1 placed within the city 2 via connecting pipes 12.

[0047] Next, the operation and effect of the rainwater storage structure and the rainwater storage network according to the embodiment of the present invention described above will be described with reference to the drawings.

[0048] As shown in Figures 1 and 2, the rainwater storage structure 1 of this embodiment is provided in adjacent blocks 21, 21, and comprises rainwater storage tanks 11, 11 having a height difference H1, and a connecting pipe 12 connecting the rainwater storage tanks 11, 11, and the connecting pipe 12 is kept full of water. With the above configuration, the rainwater storage structure 1 creates a siphon effect by filling the connecting pipe 12 with water, whereby a portion of the stored water 114 moves from the higher-level rainwater storage tank 11 to the lower-level rainwater storage tank 11 in adjacent rainwater storage tanks 11. Due to the siphon effect, the water levels of the stored water 114 in adjacent rainwater storage tanks 11 are approximately the same. Therefore, the rainwater storage structure 1 can distribute and store the stored water 114 collected from rainfall within a block 21 among multiple rainwater storage tanks 11, thereby increasing the amount of rainwater that can be stored in response to localized rainfall. For example, when heavy rainfall occurs in one block 21 for a short period of time, the rainwater storage structure 1 can increase the amount of rainwater that can be stored by transferring a portion of the stored water 114 to an adjacent rainwater storage tank 11, thereby preventing flooding or inundation caused by exceeding the treatment capacity of each rainwater storage tank 11. The stored water 114 distributed among the multiple rainwater storage tanks 11 is partially drained to a drainage facility via a drainage mechanism 115, making it possible to respond to the next localized heavy rain using a mechanism similar to that described above.

[0049] The rainwater storage structure 1 includes a water injection section 15 that includes a water injection pipe 151, a water injection valve 152, and a water injection pump 153, and is connected to one of the rainwater storage tanks 11 and the above-ground section 145 via the water injection pipe 151. With the above configuration, when a localized heavy rain occurs, the rainwater storage structure 1 can instantly fill the connecting pipe 12 with water by driving the water injection unit 15. Therefore, the rainwater storage structure 1 can reliably exert a siphon effect via the connecting pipe 12 and move the stored water 114.

[0050] In the rainwater storage structure 1, the rainwater storage tank 11 is always filled with water 114 to the extent that the open end 132 is submerged, and the connecting pipe 12 can be filled with water in advance before the occurrence of localized heavy rain through the water injection section 15. Therefore, the siphon effect of the connecting pipe 12 can be exerted as soon as rainwater starts to be stored in the rainwater storage tank 11.

[0051] The rainwater storage structure 1 includes a water level detection mechanism 116 that detects the water level of the stored water 114 in the rainwater storage tank 11. With the above configuration, the rainwater storage structure 1 can easily submerge the open end 132 of the connecting pipe 12 by managing the water level of the stored water 114 in the rainwater storage tank 11. Therefore, the rainwater storage structure 1 can maintain the siphon effect of the connecting pipe 12 without being affected by fluctuations in the water level of the stored water 114.

[0052] The rainwater storage structure 1 is provided with an air vent mechanism 118 in the connecting pipe 12 that can freely discharge air inside the connecting pipe 12 to the outside of the pipe. With the above configuration, the rainwater storage structure 1 can prevent air bubbles and the like that disrupt the flow of the stored water 114 from being mixed into the stored water 114 flowing through the connecting pipe 12 by expelling air from the connecting pipe 12.

[0053] The rainwater storage network 3 is formed by connecting a plurality of rainwater storage structures 1 arranged within the city 2 via connecting pipes 12. The rainwater storage network 3 stores rainwater that falls within the city 2 in rainwater storage tanks 11 whose collection range is the location where the rain fell, and moves a portion of the stored water 114 by the siphon effect via the connecting pipes 12 so that the water levels of the rainwater storage tanks 11 that make up the rainwater storage network 3 are approximately the same. With the above configuration, the rainwater storage network 3 is formed, and the network of rainwater storage structures 1 is expanded throughout the entire city 2. As a result, the load on the sewerage infrastructure within city 2 caused by localized heavy rain at the block 21 level and city 2 level can be widely distributed. As a result, the rainwater storage network 3 can quickly treat rainwater stored due to localized heavy rain, and the resilience of city 2 and block 21 to rainfall can be improved.

[0054] The stormwater storage network 3 can avoid replacing sewerage infrastructure that may be over-specified during normal rainfall, thereby reducing the financial burden required to develop sewerage infrastructure in city 2.

[0055] The rainwater storage network 3 distributes the stored rainwater almost evenly, so that it can also be used as a water resource in each block 21.

[0056] The above describes embodiments of the rainwater storage structure and rainwater storage network according to the present invention, but the present invention is not limited to the above embodiments and can be modified as appropriate within the scope of the spirit thereof. For example, in the above embodiment, one rainwater storage tank 11 is connected to two rainwater storage tanks 11 that constitute the rainwater storage structure 1 and the adjacent rainwater storage tank 11 that constitutes the adjacent rainwater storage structure 1, but it may also be connected to three or more adjacent rainwater storage tanks 11 via connecting pipes 12.

[0057] For example, in the above embodiment, the water injection unit 15 has the water injection pipe 151 connected to one of the rainwater storage tanks 11, but the water injection pipe 151 may also be connected to both of the adjacent rainwater storage tanks 11. Also, the water injection unit 15 does not need to be provided as long as the rainwater storage structure 1 can obtain the desired siphon effect through the connecting pipe 12.

[0058] For example, in the above embodiment, the water level detection mechanism 116 is provided as a sensor for measuring the water level on the side wall 117 of the rainwater storage tank 11, but a configuration may also be adopted in which a water level measuring scale is provided inside the rainwater storage tank 11 and the water level is measured and managed by monitoring with a camera or the like. Also, the water level detection mechanism 116 does not have to be provided as long as the rainwater storage structure 1 can obtain the desired siphon effect through the connecting pipe 12. Also, in the above embodiment, the water level detection mechanism 116 is provided to maintain the siphon effect, but it may also be used as an indicator for managing the water level of the stored water 114 when the drainage mechanism 115 drains the stored water 114 after localized heavy rainfall.

[0059] For example, in the above embodiment, the de-airing mechanism 118 is provided in the connecting pipe 12, but the de-airing mechanism 118 does not need to be provided as long as the rainwater storage structure 1 can obtain the desired siphon effect through the connecting pipe 12. [Explanation of symbols]

[0060] 1, 1a Rainwater storage structure 2 areas (cities) 3. Rainwater harvesting network 11, 11a, 11b, 11c Rainwater storage tank 12, 12a, 12b, 12c connecting piping 13, 13a, 13b rising part 14 Connection part 15 Water injection section 21 Local area (block) 112, 112a, 112b water intake 113, 113a, 113b inner bottom 115 Drainage mechanism 116 Water level detection mechanism 118 Venting mechanism 131, 131a, 131b connection part (upper end) 132, 132a, 132b Open end (lower end) 152 Water inlet valve H1 Height difference

Claims

1. A rainwater retention structure provided in an area having a plurality of local areas, A plurality of rainwater storage tanks each provided in the local area, each tank having a water collection outlet for collecting rainwater that has fallen in the local area and a drainage mechanism for freely draining the collected rainwater; a connecting pipe provided inside each of the adjacent rainwater storage tanks, the connecting pipe having an open end portion that is located near the inner bottom of the rainwater storage tank and opens downward, the connecting pipe including a pair of tubular rising portions that extend upward from the open end portion, and a tubular connecting portion that connects the upper ends of the pair of rising portions, the connecting pipe being capable of keeping the inside of the pipe filled with water; Equipped with The inner bottoms of adjacent rainwater storage tanks have a height difference. Rainwater harvesting structures.

2. The connecting pipe includes a water injection section having a valve mechanism that can be opened and closed. The rainwater retention structure according to claim 1.

3. The water injection section A water injection pipe connected to the inside of the rainwater storage tank and the connecting portion; a water injection valve connected to the water injection pipe for freely opening and closing the water injection pipe; The rainwater storage structure according to claim 2, further comprising: a water injection pump disposed in the water injection pipe and injecting water into the connecting pipe via the water injection pipe and the water injection valve.

4. The rainwater storage tank is provided with a water level detection mechanism for detecting the water level of the stored rainwater. The rainwater storage structure according to any one of claims 1 to 3.

5. The connecting pipe is provided with an air vent mechanism for discharging air from the pipe. A rainwater storage structure according to any one of claims 1 to 4.

6. The rainwater storage structure according to any one of claims 1 to 5 is provided in the area having a plurality of adjacent local areas, Rainwater that falls in the area is stored in the rainwater storage tank, the collection range of which is the place where the rain fell, A rainwater storage network characterized in that a portion of the stored rainwater is transferred to the rainwater storage tank provided within the area via the connecting pipe so that the water level of the rainwater storage tank located within the area is approximately the same.

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