Rooftop greening rainwater temporary storage system

Abstract

To provide a rooftop greening rainwater temporary storage device that, by temporarily storing rainwater poured on a rooftop of a building in the case where concentrated torrential rainfall occurs for example, can delay drainage onto the ground, eventually flowing into a river, and can suppress river flooding or flood disaster.SOLUTION: A rooftop greening rainwater temporary storage device that is constructed on a rooftop of a building structure of a water-resistant layer of a roof, and arranged in a greening region including soil has: a filter layer which is arranged below a gravity direction of the greening region, and restricts passing of soil but allows permeation of water; a water passage part which is arranged below a gravity direction of the filter layer; a storage part which is arranged in a horizontal direction for the greening region with a sidewall laid between them, and stores water which has permeated through the filter layer and entered via the water passage part; and a drainage port which discharges water from the storage part.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a rooftop greening rainwater temporary storage device.

Background Art

[0002] In recent years, especially in summer, heavy concentrated rainfall, also known as guerrilla heavy rain, has occurred frequently. In urban areas, there are few green areas, and most of the ground is covered with concrete or asphalt. Therefore, when heavy concentrated rainfall occurs, a large amount of rainwater pouring down is rarely stored on the ground, and quickly concentrates and flows into rivers, causing floods and the like, which may cause significant inundation damage.

[0003] In contrast, in urban areas as well, as shown in Patent Document 1, for example, greening the rooftops of buildings has already been carried out. Therefore, storing rainwater in the soil of the greening part that can be placed on the rooftop when heavy concentrated rainfall occurs is also one idea.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, generally, since the amount of soil in the greening part that can be placed on the rooftop is limited, the amount of moisture stored in the soil is also restricted. Therefore, there is a problem that the conventional greening part installed on the rooftop of a building cannot prevent rainwater from concentrating in rivers when heavy concentrated rainfall occurs.

[0006] In view of the above problems, the present invention aims to provide a temporary rainwater storage device for rooftop greening that can temporarily store rainwater that falls on the roof of a building, for example, when heavy rainfall occurs, thereby delaying drainage to the ground and subsequent inflow into rivers, and suppressing river flooding and inundation damage. [Means for solving the problem]

[0007] To achieve the above objective, one representative rooftop greening rainwater temporary storage device of the present invention is: A water storage device for greening, constructed on the rooftop or waterproof layer of a building and placed within a greening area including soil, A filter layer is positioned below the direction of gravity in the aforementioned greening area, which restricts the passage of soil but allows water to pass through. A water passage section located below the filter layer in the direction of gravity, A storage section is arranged horizontally with respect to the greening area, separated by a side wall, and stores water that has passed through the filter layer and entered through the water passage section, The storage section has a drain outlet for discharging water. death, The side wall has a first wall portion and a second wall portion that extend along the direction of gravity and face each other, a third wall portion that connects one side edge of the first wall portion and the second wall portion, and a fourth wall portion that connects the other side edge of the first wall portion and the second wall portion. The fourth wall portion has the drainage opening, and can be installed adjacent to the rising portion of the trim member that separates the inside and outside of the greening area, so as to expose the drainage opening. This is achieved by doing so. Furthermore, one of the representative rooftop greening rainwater temporary storage devices of the present invention is: A water storage device for greening, constructed on the rooftop or waterproof layer of a building and placed within a greening area including soil, A filter layer is positioned below the direction of gravity in the aforementioned greening area, which restricts the passage of soil but allows water to pass through. A water passage section located below the filter layer in the direction of gravity, A storage section is arranged horizontally with respect to the greening area, separated by a side wall, and stores water that has passed through the filter layer and entered through the water passage section, It has a drain port for discharging water from the storage section, This is achieved by having a drain member through which water passing through the drain outlet flows, having a drainage limiting section, and by replacing the drain member, the amount of drainage can be adjusted. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a rooftop greening rainwater temporary storage device that can temporarily store rainwater that falls on the roof of a building, for example, in the event of torrential rain, thereby delaying drainage to the ground and subsequent inflow into rivers, and suppressing river flooding and inundation damage. Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

Brief Description of the Drawings

[0009] [Figure 1] FIG. 1 is a cross-sectional view showing a state where a rooftop greening rainwater temporary storage device according to a first embodiment is installed in a greening section and cut along a vertical plane, where the vertical direction in the figure is the direction of gravity. [Figure 2] FIG. 2 is a perspective view showing a state where the installed rooftop greening rainwater temporary storage device is visually recognized from the outside together with a partition member, but the configuration of the greening section is omitted. [Figure 3] FIG. 3 is a perspective view showing the water storage tank disassembled and is a view showing it together with a part of the partition member. [Figure 4] FIG. 4 is a perspective view showing a part of a permeable filter and a water retention, drainage, and ventilation structure. [Figure 5] FIG. 5 is a perspective view showing a state where the water storage tank is visually recognized from the outside together with a partition member according to a first modification. [Figure 6] FIG. 6 is a perspective view showing a state where the water storage tank is visually recognized from the outside together with a partition member according to a second modification. [Figure 7] FIG. 7 is a perspective view showing the water storage tank according to a second embodiment disassembled and is a view showing it together with a part of the partition member. [Figure 8] FIG. 8 is a perspective view showing a modification of the first embodiment.

Modes for Carrying Out the Invention

[0010] Modes for carrying out the present invention will be described.

[0011] (First Embodiment) FIG. 1 is a cross-sectional view showing a state where a rooftop greening rainwater temporary storage device according to a first embodiment is installed in a greening section and cut along a vertical plane, where the vertical direction in the figure is the direction of gravity. FIG. 2 is a perspective view showing a state where the installed rooftop greening rainwater temporary storage device is visually recognized from the outside together with a partition member, but the configuration of the greening section is omitted.

[0012] The water storage tank 10 is installed on the installation surface FL of a building, such as on the roof, roof, or balcony. The area inside the trim member 1 becomes a green area (green zone), and the area outside becomes a non-green area. In this embodiment, as shown in Figure 2, water storage tanks 10 adjacent to the green area on the installation surface FL, separated by a side wall, are arranged to fill the gaps in the trim member 1.

[0013] For example, the trim member 1, which is made of aluminum, consists of a horizontal plate 1a installed on the greening side of the installation surface FL, a vertical plate (rising portion) 1b connected to the outer edge of the horizontal plate 1a, a soffit plate 1c connected to the upper edge of the vertical plate 1b and extending parallel to the horizontal plate 1a in the same direction, and an edge plate 1d extending downward from the tip of the soffit plate 1c, all connected in series.

[0014] The green area inside the trim member 1 is a planting area where plants 2 are planted, as shown in Figure 1. From top to bottom, along the direction of gravity, a wind-shatter prevention net 3, a soil scattering prevention layer 4, a soil layer 5, a water-permeable filter (filter layer) 6, and a water-retaining, drainage, and ventilation structure 7 (water passage section) are arranged. Below the water-retaining, drainage, and ventilation structure 7, a waterproof sheet 8 is attached to the installation surface FL. A root-resistant sheet may also be attached to the upper surface of the waterproof sheet 8. The waterproof layer is formed by the waterproof sheet 8 alone, or by a combination of the waterproof sheet 8 and the root-resistant sheet. A water storage tank (storage section) 10 is placed adjacent to the green area. The water-permeable filter 6, the water-retaining, drainage, and ventilation structure 7, and the water storage tank 10 constitute a temporary rainwater storage device for rooftop greening.

[0015] Figure 3 is a perspective view showing the water storage tank 10 in an exploded state, along with a part of the trim member 1. In Figure 3, the water storage tank 10, for example, which is made of stainless steel, has a rectangular tubular structure with four side walls: a left wall 10a (first wall) and a right wall 10b (second wall) that extend along the direction of gravity and face each other, a rear wall 10c (third wall) that connects the rear edges of the left wall 10a and the right wall 10b, and a front wall 10d (fourth wall) that connects the front edges of the left wall 10a and the right wall 10b. It does not have a bottom wall or a top wall. A flat plate-shaped lid (cover) 11 is provided so as to be able to abut against the left wall 10a, the right wall 10b, the rear wall 10c, and the front wall 10d, and is provided so as to be able to shield the upper part of the water storage tank 10.

[0016] A scale SC (Figure 1) indicating the height from the bottom end may be formed on the inner surface of any of the left wall 10a, right wall 10b, rear wall 10c, and front wall 10d.

[0017] Water inlets 10e (or notches) are formed at the lower ends of the left wall 10a, the right wall 10b, and the rear wall 10c. However, it is sufficient if the water inlets 10e are formed in any of the left wall 10a, the right wall 10b, or the rear wall 10c. On the other hand, as shown in Figure 2, a drain outlet 10f (or notch) is formed at the lower end of the front wall 10d, and an overflow opening 10g is formed at a predetermined height from the lower end of the front wall 10d. The opening area of ​​the overflow opening 10g is larger than the opening area of ​​the drain outlet 10f.

[0018] In Figure 3, a U-shaped bottom vane plate 10h is formed so as to be connected to the lower ends of the left wall 10a, the right wall 10b, and the rear wall 10c. Furthermore, a rectangular left vane plate 10i is connected to the front edge of the left wall 10a and extends opposite to the front wall 10d, and a rectangular right vane plate 10j is connected to the front edge of the right wall 10b and extends opposite to the front wall 10d. The lower ends of the left vane plate 10i and the right vane plate 10j are connected to the ends of the bottom vane plate 10h.

[0019] With the lid 11 in place, the water storage tank 10 has its bottom vane plate 10h installed on the waterproof sheet 8 (Figure 1) (or root-resistant sheet), the left vane plate 10i and the right vane plate 10j are inserted between the vertical plate 1b and the edge plate 1d of the trim member 1, and the front wall 10d is positioned so that it is exposed from between the trim members 1. In this case, even if there is a gap between the trim member 1 and the left wall 10a and the right wall 10b, the left vane plate 10i and the right vane plate 10j can prevent soil from falling out or water from leaking through such a gap. It is preferable from an aesthetic standpoint if the outer surface of the front wall 10d is aligned with the outer surface of the adjacent trim member 1.

[0020] Furthermore, waterproof tape is applied to the bottom vane plates 10h that are in contact with each other and to the installation surface FL (or waterproof sheet 8 or root-resistant sheet), and waterproof tape is also applied between the left vane plate 10i and the right vane plate 10j that are in contact with each other and the vertical plate 1b.

[0021] In Figure 1, the wind-preventing net 3, positioned in the green area adjacent to the water storage tank 10, is installed so as to completely cover the soil dust prevention layer 4 and is a wind-preventing component that prevents the plants 2, soil dust prevention layer 4, and soil layer 5 from being blown away by the wind. The wind-preventing net 3 can be made of, for example, a polyethylene net.

[0022] The soil scattering prevention layer 4 covers the surface of the soil layer 5 and prevents soil scattering. Furthermore, the soil scattering prevention layer 4 can also enhance the aesthetic appearance. The soil scattering prevention layer 4 can be made of mulching material such as volcanic gravel, for example.

[0023] Soil layer 5 is the layer that will become the soil for planting 2. For example, soil can be used for soil layer 5.

[0024] The permeable filter 6 prevents the outflow of topsoil from the soil layer 5 and allows water from the soil layer 5 to pass through and be discharged into the water-retaining, draining, and aeration structure 7. The water-retaining, draining, and aeration structure 7 is a layer that drains water from the soil layer 5 and also promotes aeration.

[0025] Figure 4 is a perspective view showing a part of the permeable filter 6 and the water retention, drainage, and ventilation structure 7. The permeable filter 6 is made of a nonwoven fabric or the like. Because the permeable filter 6 is made of a flexible material, as shown in Figure 1, it can be bent from a horizontal to a vertical position and stretched across the left wall 10a, right wall 10b, and rear wall 10c of the water storage tank 10. It is preferable to fix the permeable filter 6 to the water storage tank 10 using masking tape.

[0026] The water-retaining, draining, and ventilating structure 7 comprises a flat substrate 7a, a plurality of recesses 7b arranged in a matrix pattern at intervals on the substrate 7a, and protrusions (support portions) 7c arranged between the recesses 7b on the substrate 7a. The protrusions 7c have a cross-shaped notch 7d and a through hole 7e on their top surface. The water-retaining, draining, and ventilating structure 7 has a plurality of protrusions 7f that project downward in a truncated pyramidal shape due to the formation of the recesses 7b. The protrusions 7f are formed spaced apart on the lower surface of the substrate 7a and abut against the upper surface of the waterproof sheet 8 (or root-resistant sheet). This allows the water-retaining, draining, and ventilating structure 7 to be held on the waterproof sheet 8 (or root-resistant sheet).

[0027] When the water-retaining, draining, and ventilation structure 7 is placed on top of the water-permeable filter 6, the protrusion 7c has the function of contacting and supporting the lower surface of the water-permeable filter 6. At this time, because of the notch 7d, even when the water-permeable filter 6 is in close contact with the substrate 7a, the ventilation of the water-retaining, draining, and ventilation structure 7 can be ensured.

[0028] In Figure 1, the waterproof sheet 8 is a tape or sheet that is waterproof and has adhesive on at least one side, and has the function of preventing water from seeping from the greened area to the surrounding area. When a root-resistant sheet is installed on the waterproof sheet 8, the root-resistant sheet functions as an adhesive layer that prevents the roots of growing plants from penetrating the waterproof sheet 8. Between the water-retaining, draining, and ventilating structure 7 and the waterproof sheet 8 (or root-resistant sheet), the space between adjacent protruding parts 7f constitutes a flow channel that communicates with the water inlet 10e provided at the bottom of the water storage tank 10.

[0029] Referring to Figure 1, the operation of this embodiment will be explained. Water that falls on the plants 2 due to rainwater or sprinkling passes through the wind-preventing net 3 and the soil-preventing layer 4 to the soil layer 5. The moisture stored in the soil layer 5 is used for the growth of the plants 2, but water other than the moisture stored in the soil layer 5 is filtered and purified by passing through the water-permeable filter 6, and after impurities such as dead leaves are removed, it reaches the water-retaining, draining, and aeration structure 7. Some of the water that reaches the water-retaining, draining, and aeration structure 7 is stored in the recess 7b, and another part flows through the through hole 7e to the bottom of the water-retaining, draining, and aeration structure 7. As a result, no deposits that obstruct water flow are formed below the water-retaining, draining, and aeration structure 7.

[0030] Water flowing below the water retention, drainage, and ventilation structure 7 travels along the upper surface of the waterproof sheet 8 (or root-resistant sheet) to the water storage tank 10, enters the tank through the water inlet 10e, and is stored there. However, water may also enter the tank 10 by passing between the lower ends of the left wall 10a, right wall 10b, and rear wall 10c and the waterproof sheet 8 (or root-resistant sheet). The drain outlet 10f of the water storage tank 10 has an opening area suitable for drainage over a certain period of time (e.g., 24 hours), so the amount of water discharged to the outside of the trim member 1 through the drain outlet 10f is limited. Therefore, a predetermined amount of water is always stored inside the water storage tank 10. In other words, with the rooftop greening rainwater temporary storage device of this embodiment, the entire area enclosed by the trim member 1 can be used as a water storage area, so a large amount of rainwater can be temporarily stored. Furthermore, it has a simple configuration and does not require a power source, yet it can naturally adjust the amount of moisture contained in the soil. Furthermore, by providing a shutter or throttling mechanism at the drain port 10f to make the opening area variable, the amount of drainage can be adjusted as needed.

[0031] The manager of the greening department can open the lid 11 and visually inspect the inside of the water storage tank 10 to determine the remaining amount of water stored, and can also check for any blockages in the drainage system. If a scale SC is formed on the inner surface of the water storage tank 10, the remaining amount of water can be accurately determined by comparing the scale SC with the water level.

[0032] On the other hand, if a large amount of rainwater falls on the green area in a short period of time due to heavy rain (for example, 50 mm / h), a large amount of water will enter the water storage tank 10 through the gap between the water retention / drainage / ventilation structure 7 and the waterproof sheet 8 (or root-resistant sheet). According to the temporary rainwater storage device for rooftop greening of this embodiment, in the event of a torrential downpour, rainwater that falls on the roof of the building can be temporarily stored, delaying drainage to the ground and, consequently, inflow into rivers, thereby suppressing river flooding and inundation damage. Since the amount of drainage from the drain outlet 10f is limited, the amount of water stored in the water storage tank 10 will increase in proportion to the amount of water entering. However, when the amount of water stored in the water storage tank 10 exceeds the limit, excess water is discharged to the outside of the trim member 1 through the overflow opening 10g. This prevents the green area from being overflowed with a large amount of water.

[0033] (Variation 1) Figure 5 is a perspective view showing the water tank 10 as seen from the outside, together with the trim member 1A according to the first modified example, but the configuration of the greening section is omitted. The trim member 1A of this modified example has a large opening 1Ae formed in the vertical plate 1Ab, extending upward from the lower end. The other configurations (including the water tank 10) are the same as those of the embodiment described above, so their explanation is omitted.

[0034] The water storage tank 10 is positioned such that the front wall 10d, and parts of the left wall 10a and right wall 10b (not shown in Figure 5) rest on the horizontal plate 1Aa of the trim member 1A, and the front wall 10d is in contact with the inner surface of the vertical plate 1Ab of the trim member 1A. At this time, the drain port 10f and the overflow opening 10g are positioned to be exposed from the large opening 1Ae. As a result, a limited amount of water is discharged from the water storage tank 10 through the drain port 10f, and when the water storage tank 10 overflows, excess water is discharged through the overflow opening 10g.

[0035] According to this modified version, since it is not necessary to separate the trim member in order to install the water storage tank 10, leakage of soil, plants, fallen leaves, etc. from the green area between the water storage tank 10 and the trim member is suppressed. Furthermore, it is not necessary to provide the left vane 10i and the right vane 10j on the water storage tank 10.

[0036] (Modification 2) Figure 6 is a perspective view showing the water tank 10 as seen from the outside, together with the trim member 1B according to the second modified example, but the configuration of the green area is omitted. The trim member 1B in this modified example is made by stacking bricks or blocks. The other configurations (including the water tank 10) are the same as in the embodiment described above, so their explanation is omitted.

[0037] The water storage tank 10 is positioned such that the inner surfaces of the left vane 10i and the right vane 10j are in contact with the outer surface of the trim member 1B. At this time, a portion of the bottom vane 10h (not shown in Figure 6) is located below the heavy trim member 1B, thus holding the water storage tank 10 in a stable state.

[0038] (Second embodiment) Figure 7 is a perspective view of a water storage tank 10C according to the second embodiment, shown disassembled, along with a part of the trim member 1C. In Figure 7, the water storage tank 10C, for example, made of stainless steel, has a structure with three side walls: a left wall 10Ca (first wall) and a right wall 10Cb (second wall) that extend along the direction of gravity and face each other, and a rear wall 10Cc (third wall) that connects the rear edges of the left wall 10a and the right wall 10b. It does not have a front wall, bottom wall, or top wall. A lid (cover) 11C is provided so as to be able to abut against the left wall 10Ca, the right wall 10Cb, and the rear wall 10Cc, and is able to shield the upper part of the water storage tank 10C.

[0039] A U-shaped intermediate vane plate 10Ck is formed at a predetermined distance above the lower ends of the left wall 10Ca, the right wall 10Cb, and the rear wall 10Cc, and is horizontally connected to the outer surfaces of the left wall 10Ca, the right wall 10Cb, and the rear wall 10Cc. The intermediate vane plate 10Ck can be used, for example, to support the substrate 7a (Figure 4) of the water retention, drainage, and ventilation structure 7. However, the intermediate vane plate 10Ck is not necessarily required and can be selected or omitted depending on the specifications.

[0040] An inlet 10Ce (or notch) is formed below the left wall 10Ca, the right wall 10Cb, and the rear wall 10Cc. However, it is sufficient if the inlet 10Ce is formed in any of the left wall 10Ca, the right wall 10Cb, or the rear wall 10Cc.

[0041] In Figure 7, a U-shaped bottom vane plate 10Ch is formed so as to be connected to the lower ends of the left wall 10Ca, the right wall 10Cb, and the rear wall 10Cc. Furthermore, the left vane plate 10Ci is connected to the front edge of the left wall 10Ca, and the right vane plate 10Cj is connected to the front edge of the right wall 10Cb, with the left vane plate 10Ci and the right vane plate 10Cj extending opposite each other. The lower ends of the left vane plate 10Ci and the right vane plate 10Cj are connected to the ends of the bottom vane plate 10Ch.

[0042] The trim member 1C is made up of a horizontal plate 1Ca, a vertical plate (rising portion) 1Cb connected to the outer edge of the horizontal plate 1Ca, a soffit plate 1Cc connected to the upper edge of the vertical plate 1Cb and extending parallel to the horizontal plate 1Ca in the same direction, and an edge plate 1Cd extending downward from the tip of the soffit plate 1Cc, all connected in series. In this embodiment, the height from the horizontal plate 1Ca to the lower end of the edge plate 1Cd is higher than the height of the water tank 10C covered with the lid 11C. In this embodiment, the water tank 10C and the trim member 1C constitute the storage section.

[0043] The vertical plate 1Cb has a rectangular drain opening 1Ce located in close proximity to the horizontal plate 1Ca. A gutter member 12C is attached to the drain opening 1Ce.

[0044] The gutter member 12C has a stopper plate 12Ca and a rectangular tubular water conduit 12Cb extending in a direction intersecting the stopper plate 12Ca. The stopper plate 12Ca has a rectangular opening 12Cc, and one end 12Cd of the water conduit 12Cb is connected to the rectangular opening 12Cc. The cross-section of the one end 12Cd of the water conduit 12Cb is approximately equal to that of the rectangular drain opening 1Ce. On the other hand, the other end 12Ce of the water conduit 12Cb is formed with a smaller cross-section than the one end 12Cd. That is, the other end 12Ce of the water conduit 12Cb constitutes a drainage limiting section.

[0045] During assembly, the water guide pipe 12Cb is inserted through the drain opening 1Ce, and the outer surface of the abutment plate 12Ca is brought into contact with the inner surface of the trim member 1C, thereby attaching the gutter member 12C to the trim member 1C so that it covers the drain opening 1Ce and the other end 12Ce protrudes from the trim member 1C.

[0046] Furthermore, with the lid 11C placed over the water tank 10C, the bottom vane plate 10Ch is installed on the waterproof sheet 8 (Figure 1) (or root-resistant sheet), the left vane plate 10Ci and the right vane plate 10Cj are inserted between the vertical plate 1Cb and the edge plate 1Cd of the trim member 1C, and the rear wall 10Cc is positioned to face the drain port 1Ce of the trim member 1C. The left wall 10Ca and the right wall 10Cb are preferably in contact with the inner surface of the trim member 1C, but they may also be arranged with a gap between them.

[0047] Furthermore, waterproof tape is applied to the bottom vane plates 10Ch that are in contact with each other and to the installation surface FL (or waterproof sheet 8 or root-resistant sheet), and waterproof tape is also applied between the left vane plate 10Ci and the right vane plate 10Cj that are in contact with each other and the vertical plate 1Cb.

[0048] In this embodiment as well, water that enters the water storage tank 10C through the water inlet 10Ce is stored inside the water storage tank 10C and discharged through the water guide pipe 12Cb of the gutter member 12C located at the drain outlet 1Ce. At this time, since the other end 12Ce of the water guide pipe 12Cb is spaced apart from the outer surface of the trim member 1C, contamination of the trim member 1C with muddy water is suppressed, which is preferable for maintaining aesthetics. Furthermore, the amount of wastewater passing through the water guide pipe 12Cb can be easily changed by replacing the gutter member 12C with one that has a different cross-sectional area at the other end 12Ce. Also, as in the embodiment described above, since the overflow opening 1Cf is formed above the drain outlet 1Ce of the trim member 1C, excess water can be discharged.

[0049] (Variation 3) Figure 8 is a perspective view showing a modified example of the first embodiment. This modified example differs from the embodiment in Figure 2 in that a gutter member 12D is attached to the housing 10. The other components are the same as in the first embodiment, so the same reference numerals are used and redundant explanations are omitted.

[0050] The gutter member 12D has a rectangular tubular water conduit 12Db that is attached to the front wall 10d of the housing 10. One end 12Dd of the water conduit 12Db has the same cross-sectional shape as the drain port 10f of the front wall 10d and is detachably attached to the front wall 10d so as to connect to the drain port 10f. Similar to the second embodiment, a stopper plate may be provided on the gutter member 12D and the water conduit 12Db may be attached by inserting it into the drain port 10f from the inside of the front wall 10d. On the other hand, the other end (tip) 12De of the water conduit 12Db is formed with a smaller cross-sectional area than the one end 12Dd, i.e., the drain port 10f. That is, the other end 12De of the water conduit 12Db constitutes a drainage limiting portion.

[0051] In this modified example as well, the water that enters the water storage tank 10 through the water inlet 10e is stored inside the water storage tank 10 and then drains through the drain outlet 10f (Figure 2) and through the water guide pipe 12Db of the trough member 12D arranged around it, to a position away from the front wall 10d.

[0052] The gutter member 12D allows for adjustment of the drainage volume by replacing the other end 12De of the water conduit 12Db with one having a different cross-sectional area, thus allowing the amount of water stored in the temporary rainwater storage device for rooftop greening to be changed as needed. The gutter member 12D and the drain outlet 10f are preferably installed near the bottom of the housing 10.

[0053] On the other hand, in the above embodiments and modifications, it is preferable to position the overflow opening 10g below the surface of the soil layer 5 in the rooftop greening area. This is because if the overflow opening 10g is positioned higher than the surface of the soil layer 5, there is a concern that during heavy rainfall, fallen leaves and a large amount of soil flowing from the rooftop greening area may clog the building's drains, thereby causing drainage problems.

[0054] It should be noted that the present invention is not limited to the embodiments described above. Within the scope of the present invention, any component of the embodiments described above can be modified. Furthermore, any component can be added to or omitted in the embodiments described above. [Explanation of Symbols]

[0055] 1,1A,1B,1C Trim material 2. Planting 3. Windproof net 4. Soil scattering prevention layer 5. Soil layer 6. Permeable filter (filter layer) 7. Water retention, drainage, and ventilation structure 7 (water passage section) 8. Waterproof sheet or root barrier sheet 10,10C Water storage tank 11,11C Lid 12C, 12D gutter parts

Claims

1. A water storage device for greening, constructed on the rooftop or waterproof layer of a building and placed within a greening area including soil, A filter layer is positioned below the direction of gravity in the aforementioned greening area, which restricts the passage of soil but allows water to pass through. A water passage section located below the filter layer in the direction of gravity, A storage section is arranged horizontally with respect to the greening area, separated by a side wall, and stores water that has passed through the filter layer and entered through the water passage section, It has a drain port for discharging water from the storage section, The side wall has a first wall portion and a second wall portion that extend along the direction of gravity and face each other, a third wall portion that connects one side edge of the first wall portion and the second wall portion, and a fourth wall portion that connects the other side edge of the first wall portion and the second wall portion. The fourth wall portion has the drainage opening, and can be installed adjacent to the rising portion of the trim member that separates the inside and outside of the greening area, so as to expose the drainage opening. A temporary rainwater storage device for rooftop greenery, characterized by the following features.

2. The outer surface of the fourth wall portion can be installed along substantially the same plane as the outer surface of the rising portion of the trim member. The rooftop greening rainwater temporary storage device according to feature 1.

3. The outer surface of the fourth wall portion abuts against the inner surface of the rising portion of the trim member, and the rising portion has an opening that exposes the drain port when the fourth wall portion abuts against it. The rooftop greening rainwater temporary storage device according to feature 1.

4. The fourth wall portion has an overflow opening that drains water from a source other than the drain outlet when the amount of water stored in the storage portion exceeds a predetermined amount. The temporary rainwater storage device for rooftop greening according to feature 1.

5. The first wall portion and the other side edge of the second wall portion have wing plates that extend in a direction that separates them from each other along the rising portion of the trim member that separates the inside and outside of the greening area, A temporary rainwater storage device for rooftop greening according to any one of claims 1 to 4.

6. At least one of the first wall, the second wall, and the third wall has an inlet for drawing water from the water passage into the storage section. A temporary rainwater storage device for rooftop greening according to any one of claims 1 to 4.

7. The water passage section comprises a support section that supports the filter layer and a flow path section that is positioned below the support section in the direction of gravity and connects to the bottom of the storage section. A temporary rainwater storage device for rooftop greening according to any one of claims 1 to 4.

8. The aforementioned drain outlet is configured to allow adjustment of the amount of drainage. A temporary rainwater storage device for rooftop greening according to any one of claims 1 to 4.

9. A water storage device for greening, constructed on the rooftop or waterproof layer of a building and placed within a greening area including soil, A filter layer is positioned below the direction of gravity in the aforementioned greening area, which restricts the passage of soil but allows water to pass through. A water passage section located below the filter layer in the direction of gravity, A storage section is arranged horizontally with respect to the greening area, separated by a side wall, and stores water that has passed through the filter layer and entered through the water passage section, It has a drain port for discharging water from the storage section, The gutter member through which water passes through the drain outlet has a drainage limiting section, and the amount of drainage can be adjusted by replacing the gutter member. A temporary rainwater storage device for rooftop greenery, characterized by the following features.

10. Having a cover that covers the storage section, A temporary rainwater storage device for rooftop greening according to claim 1 or 9.

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