Rain garden

Abstract

To provide a rain garden in which a water environment of planting soil provided for an upper part of a rain garden can be maintained in an appropriate state for each place, and various planting can be performed.SOLUTION: In a rain garden 1, a plurality of planting zones 10A, 20, 10B are arranged in an array from an upstream side to a downstream side, wherein the planting zones 10A, 20, 10B comprise: groove-like recesses 11, 21 which are provided deeper than a ground surface GL; and planting soil layers 13, 23 which are provided with planting soil. The planting zones 10A, 20, 10B further comprise: a subsurface drain layer 40 which are arranged below the planting soil layers 13, 23, and communicates from an upstream side to a downstream side without being partitioned by the partition plate 30; a water storage tank 50 which is communicated with the subsurface drain layer 40; a pump 52 which pumps up water stored in the water storage tank 50; and a piping 60 through which water pumped up by the pump 52 flows, wherein the piping 60 comprises valves 71, 72, 73 which selectively perform irrigation to the planting zones 10A, 20, 10B.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a rain garden.

Background Art

[0002] Green infrastructure is a concept that refers to the promotion of land use and the like that utilizes various functions of the natural environment. Among these, in order to suppress urban floods such as inland water inundation, a structure called a rain garden has been proposed as a green space with high rainwater infiltration and storage performance (for example, Patent Document 1).

[0003] A rain garden has a function of suppressing urban floods by temporarily storing surrounding water generated by heavy rain or the like and gradually infiltrating it into the soil.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, since a rain garden infiltrates water into the soil for drainage, the planting soil provided on the upper part of the rain garden tends to be in a dry state. On the other hand, when drainage does not work well due to rainfall exceeding the allowable amount, waterlogging may occur.

[0006] Therefore, it has been difficult to maintain the moisture of the planting soil in a rain garden in a state suitable for plants. In addition, in large-scale and extensive rain gardens that have existed in the past, since the same soil is used over the entire area, the soil environment and water environment are substantially the same. For this reason, the types of plants suitable for cultivation at that location are limited, resulting in a lack of variation in the landscape. Also, if the plant selection is incorrect, there is a risk of poor growth and withering across all the plants in the entire rain garden.

[0007] The problem of the present disclosure is to change the water environment of the planting soil provided on the upper layer of the base of the rain garden for each location, design and maintain an environment optimized for the planting at that location, have a richly changing landscape, and eliminate the risk of poor growth and withering of all plants in the entire rain garden.

Means for Solving the Problem

[0008] The present disclosure solves the above problems by the following means. For ease of understanding, reference numerals corresponding to the embodiments of the present disclosure are used for explanation, but it is not limited thereto.

[0009] The first disclosure is, for example, a rain garden (1) continuous from the upstream side to the downstream side as shown in FIGS. 1, 2, 4, etc., in which a plurality of planting sections (10A, 20, 10B) partitioned from the regions adjacent to the upstream side or the downstream side by partition plates (30) are arranged side by side from the upstream side to the downstream side. The planting sections (10A, 20, 10B) include groove-shaped recesses (11, 21) provided deeper than the ground surface (GL), and planting soil layers (13, 23) in which planting soil is provided in the groove-shaped recesses (11, 21). An underdrain layer (40) disposed below the planting soil layer (13, 23) and communicating from the upstream side to the downstream side without being partitioned by the partition plate (30), a water storage tank (50) communicating with the underdrain layer (40), a pump (52) for pumping up the water stored in the water storage tank (50), and a pipe (60) through which the water pumped up by the pump (52) flows. The pipe (60) is a rain garden (1) including valves (71, 72, 73) capable of selectively irrigating the planting sections (10A, 20, 10B).

[0010] The second disclosure is the rain garden (1) according to the first disclosure, wherein the planting sections (10A, 20, 10B) have a planting section overflow part (54) for draining water with a water level above a certain level to the water storage tank (50).

[0011] The third disclosure is a rain garden (1) described in the first disclosure or the second disclosure. For example, as shown in FIG. 4, the water storage tank (50) has a water storage tank overflow portion (53) that drains water at a water level above a certain level to an external drainage channel (200). The rain garden (1) is characterized by this.

Effect of the Invention

[0012] According to the present disclosure, it is possible to maintain the water environment of the planting soil provided on the upper part of the rain garden in an appropriate state for each location, and it is possible to provide a rain garden that enables diverse planting.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0014] Hereinafter, an embodiment for carrying out the present disclosure will be described with reference to the drawings and the like.

[0015] (First Embodiment) FIG. 1 is a schematic view of the rain garden 1 of the present embodiment and a building 100 nearby as viewed from above. Including FIG. 1, each of the following figures is a schematically shown figure, and the size and shape of each part are exaggerated or omitted as appropriate for easy understanding. Also, in the following description, specific numerical values, shapes, materials, etc. are shown for the description, but these can be changed as appropriate.

[0016] The rain garden 1 of the present embodiment may be arranged, for example, near the building 100. The building 100 may be a building for any use. The rainwater collected in the rain gutter 101 of the building 100 is arranged to flow into the planting section 10A of the rain garden 1 through the supply pipe 102.

[0017] The rain garden 1 extends toward the downstream side of the water storage tank 50 with the supply pipe 102 side in FIG. 1 as the upstream side. FIG. 2 is a schematic cross-sectional view of the rain garden 1 cut at the position of arrow A-A in FIG. 1. FIG. 3 is a schematic cross-sectional view of the rain garden 1 cut at the position of arrow B-B in FIG. 1. FIG. 4 is a schematic cross-sectional view of the rain garden 1 cut at the position of arrow C-C in FIG. 1. In FIG. 4, in order to explain the communication path 51 and the planting section overflow part 54, these two parts described in different positions in FIG. 1 are shown together.

[0018] The rain garden 1 includes planting sections 10A, 20, 10B, an underground culvert layer 40, a water storage tank 50, a pump 52, a pipe 60, and valves 71, 72, 73.

[0019] The planting sections 10A, 20, 10B constitute the main part of the rain garden 1. In the present embodiment, the planting sections 10A, 20, 10B are arranged side by side in the order of the planting section 10A, the planting section 20, and the planting section 10B from the upstream side. Here, for the sake of simplicity, the description is made with a configuration in which three planting sections are arranged side by side. However, for example, a configuration in which more planting sections are arranged side by side, such as in 10 sections or the like where the types of planting in the planting intervals are arranged randomly in a row, may also be used. Also, in the top view shown in FIG. 1, the planting sections 10A, 20, 10B are all shown as being arranged in a straight line in a rectangular shape. However, the present invention is not limited to this, and the planting section may have a curved form in the top view, and the specific shape can be changed as appropriate.

[0020] The planting area 10A has a groove-shaped recess 11 provided deeper than the ground surface GL as shown in FIG. 2. In FIG. 2 and FIG. 3 described later, hatching is applied only to the cross-sectional part of the rain garden 1, and the cross-sectional part of the surrounding soil part is omitted from hatching. Since the groove-shaped recess 11 of the present embodiment is formed such that the upper width is wider than the lower width, the groove-shaped recess is less likely to collapse at the stage before providing the planting soil layer and the like described later, and the workability is good. A storage layer 12 and a planting soil layer 13 are provided in the groove-shaped recess 11.

[0021] The storage layer 12 has a function of temporarily storing rainwater flowing into the rain garden 1 from the surroundings and the supply pipe 102. The storage layer 12 also has a function as a bottom surface that supports the planting soil layer 13. Therefore, the storage layer 12 needs to have a gap (space) for storing rainwater and a strength capable of supporting the weight of the planting soil layer 13. A structure for exerting the above functions is arranged in the storage layer 12. For example, rocks, crushed stones, etc. can be arranged in the storage layer 12. Further, in order to prevent the soil of the planting soil layer 13 from invading into the storage layer 12, it is desirable to arrange a water-permeable member that is impermeable to soil and permeable to water between the storage layer 12 and the planting soil layer 13. As the water-permeable member, for example, a fine mesh, a non-woven fabric, a water-permeable sheet, etc. can be used.

[0022] For the planting soil layer 13, soil suitable for the plants to be planted can be appropriately used. For example, as the soil used for the planting soil layer 13, the soil excavated at the construction site may be used as it is, or other soil may be mixed with the excavated soil and used, or completely different soil may be used.

[0023] The underdrain layer 40 is disposed further below the groove-shaped recess 11, that is, below the storage layer 12. The underdrain layer 40 extends in communication from the upstream side to the downstream side without being partitioned not only below the planting section 10A but also with respect to the other planting sections 20 and 10B. The underdrain layer 40 has a function of temporarily storing rainwater flowing into the rain garden 1, similar to the storage layer 12, and also has a function as a bottom surface that supports the storage layer 12 and the planting soil layer 13. Therefore, the underdrain layer 40 can also be regarded as a second storage layer. The underdrain layer 40 of the present embodiment has a substantially rectangular parallelepiped shape and extends from the upstream side to the downstream side, but may have a structure in which the upper width is narrower than the lower width, similar to the storage layer 12. The underdrain layer 40 also needs to have a gap (space) for storing rainwater and a strength capable of supporting the weights of the storage layer 12 and the planting soil layer 13. A structure for exerting the above functions is disposed in the underdrain layer 40. For example, rocks, crushed stones, etc. can be disposed in the underdrain layer 40. Further, it is desirable that a water-permeable delay member (not shown) for delaying the movement of rainwater from the storage layer 12 to the underdrain layer 40 is disposed between the underdrain layer 40 and the storage layer 12. As the water-permeable delay member, a finer mesh, non-woven fabric, water-permeable sheet, etc. than the previous water-permeable member can be used. Also, as the water-permeable delay member, soil with poor water permeability may be disposed in combination with a mesh, non-woven fabric, water-permeable sheet, etc. Note that it is desirable that the bottom surface of the underdrain layer 40 is provided with a gradient such that the height gradually decreases from the upstream side to the downstream side.

[0024] The planting section 20 has a groove-shaped recess 21 provided deeper than the ground surface GL as shown in FIG. 3. The groove-shaped recess 21 of the present embodiment has the same form as the groove-shaped recess 11. A storage layer 12 and a planting soil layer 23 are provided in the groove-shaped recess 11. The storage layer 12 and the underdrain layer 40 are the same as the storage layer 12 and the underdrain layer 40 of the planting section 10A.

[0025] The planting soil layer 23 has a main planting soil 23a and a sub-planting soil 23b. Here, the main and sub of the main planting soil 23a and the sub-planting soil 23b are just terms to distinguish the soil composition. It is natural that the narrow relationship and the volume size relationship between the main planting soil 23a and the sub-planting soil 23b may be reversed due to the planting arrangement and the necessity of soil stratification. The main planting soil 23a is arranged in most of the area of the sub-planting soil 23b above the storage layer 12, excluding the area. The sub-planting soil 23b is arranged in a part above the main planting soil 23a (in this embodiment, approximately in the center in the width direction of the planting section 20). A water-blocking member 24 is arranged at the boundary between the main planting soil 23a and the sub-planting soil 23b. The water-blocking member 24 may be constituted by, for example, a water-blocking sheet, or a member formed in a boat shape using metal, resin, or the like. For the sub-planting soil 23b, for example, soil suitable for aquatic plants that prefer a wet environment can be used. Since the sub-planting soil 23b is arranged on the water-blocking member 24, rainwater does not penetrate downward, and it is easy to maintain a wet environment.

[0026] The planting section 10B has the same configuration as the planting section 10A described above. Partition plates 30 are provided at the boundaries between the planting section 10A and the planting section 20, and between the planting section 20 and the planting section 10B, respectively. By providing the partition plates 30, each of the planting section 10A, the planting section 20, and the planting section 10B can be made into an independent and different vegetation environment. Also, the height of the soil surface of each of the above planting sections is configured to decrease in the order of the planting sections 10A, 20A, and 10B, and the height of the partition plate 30 is also set according to the height of the soil surface. This is a configuration considering the flow of water (from the upstream side to the downstream side) in the rain garden 1.

[0027] Also, a planting section overflow part 54 is provided in the planting section 10B. When a predetermined amount or more of rainwater is stored in the planting sections 10A, 20A, and 10B, the planting section overflow part 54 drains the excess water to the water storage tank 50.

[0028] The storage tank 50 is provided in communication with the storm sewer layer 40 through a communication passage 51. Rainwater flowing into the storm sewer layer 40 flows into the storage tank 50 and is stored therein. Also, a check valve 51a for preventing backflow from the storage tank 50 side is provided in the communication passage 51. Note that the check valve 51a may be omitted. The storage tank 50 is stored with water until it reaches the same level as the level stored in the storm sewer layer 40. Further, an overflow portion 53 of the storage tank 50 is provided above the storage tank 50. When a predetermined amount or more of rainwater is stored, the excess water is drained to the external drainage channel 200.

[0029] The pump 52 pumps up the rainwater stored in the storage tank 50 and flows it into the pipe 60. In FIG. 4, the form in which the pump 52 is arranged in the water (bottom of the storage tank 50) is illustrated, but the main body of the pump 52 may be arranged on the ground.

[0030] The pipe 60 is piped from the storage tank 50 to the planting section 10A so that the water pumped up by the pump 52 can be supplied to each of the planting section 10A, the planting section 20, and the planting section 10B. A discharge pipe 61 for discharging water to the planting section 10A, a discharge pipe 62 for discharging water to the planting section 20, and a discharge pipe 63 for discharging water to the planting section 10B are branched and provided in the pipe 60. Further, valves 71, 72, and 73 are provided in each of the discharge pipes 61, 62, and 63, respectively. Therefore, selective irrigation can be performed for each of the planting section 10A, the planting section 20, and the planting section 10B. With this configuration, not only the rainwater temporarily stored in the rain garden 1 is simply infiltrated into the soil, but it can also be used for plant growth. In particular, since irrigation can be performed separately for each of the plurality of divided planting sections, planned irrigation such as frequently irrigating the planting section 20 where a wet environment is desirable and irrigating the relatively dry planting sections 10A and 10B at intervals longer than that of the planting section 20 becomes possible.

[0031] As described above, according to the rain garden 1 of the present embodiment, it is possible to perform optimal irrigation for each of different plants in each planting section, and it is possible to change the plants to be cultivated depending on the location. Therefore, the water environment of the planting soil provided on the upper part of the rain garden 1 can be maintained in an appropriate state for each location, and diverse planting is possible. Also, it is possible to effectively utilize rainwater.

[0032] Note that the present disclosure is not limited to the embodiments described above.

Explanation of Reference Numerals

[0033] 1 Rain garden 10A, 10B Planting sections 11 Grooved recess 12 Storage layer 13 Planting soil layer 20 Planting section 21 Grooved recess 23 Planting soil layer 23a Main planting soil 23b Sub-planting soil 24 Water-blocking member 30 Partition board 40 Subsurface drainage layer 50 Water storage tank 51 Connecting passage 52 Pump 53 Water storage tank overflow part 54 Planting section overflow part 60 Pipe 61, 62, 63 Discharge pipes 71, 72, 73 Valves 100 Building 101 Rain gutter 102 Supply pipe 200 External drainage channel

Claims

1. A continuous rain garden extending from the upstream side to the downstream side, wherein a plurality of planting sections partitioned by partition plates from the regions adjacent to the upstream side or the downstream side are arranged side by side from the upstream side to the downstream side, the planting section comprising: a groove-shaped recess provided deeper than the ground surface; a planting soil layer provided in the groove-shaped recess with planting soil; and an underdrain layer disposed below the planting soil layer and communicating from the upstream side to the downstream side without being partitioned by the partition plates; a water storage tank communicating with the underdrain layer; a pump for pumping up the water stored in the water storage tank; a pipe through which the water pumped up by the pump flows; and further comprising a rain garden, wherein the pipe is provided with a valve capable of selectively irrigating the planting section.

2. The rain garden according to claim 1, wherein the planting section has a planting section overflow portion for draining water at a certain level or higher to the water storage tank. A rain garden characterized by this.

3. The rain garden according to claim 1 or claim 2, wherein the water storage tank has a water storage tank overflow portion for draining water at a certain level or higher to an external drainage channel. A rain garden characterized by this.

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