A biological retention pond

Abstract

The present invention relates to the technical field of urban construction, and in particular to a biological retention pond, comprising a retention pond body and a water retention well, wherein a partition wall is provided in the middle of the water retention well, the partition wall dividing the water retention well into a first water retention chamber and a second water retention chamber, the first water retention chamber being connected to a water outlet of the retention pond body, and the bottom of the second water retention chamber being connected to a municipal pipe network; a first drainage hole connecting the first water retention chamber and the second water retention chamber is provided at the lower part of the partition wall, a second drainage hole connecting the first water retention chamber and the second water retention chamber is provided at the middle part of the partition wall, and a gate body is connected to a side of the partition wall that slides up and down toward the second water retention chamber; the gate body floats up, so that the gate body blocks the first drainage hole and the gate body releases the second drainage hole, thereby reducing the drainage flow and improving the water retention effect; after the rainwater runoff decreases, the gate body blocks the second drainage hole and the gate body releases the first drainage hole, so that the accumulated water in the first retention chamber flows into the second retention chamber through the first drainage hole, thereby avoiding the accumulation of rainwater in the first retention chamber.

Description

Technical Field

[0001] The present invention relates to the technical field of urban construction, in particular to a biological retention pond. Background Art

[0002] In recent decades, my country's urbanization process has been accelerating. Changes in land use types have led to an increase in the proportion of impervious ground year by year, an increase in rainwater runoff, a significant shortening of confluence time, and an advancement of flood peaks. From the perspective of urban hydrology, this has put tremendous pressure on urban drainage networks, leading to frequent urban flooding. On the other hand, rainwater runoff washes away pollutants accumulated on the surface and discharges them into receiving water bodies, causing adverse effects on my country's water ecology and water environment.

[0003] my country has achieved some success in water pollution control, with point source pollution effectively under control. However, non-point source pollution is showing a growing trend. Primary rainwater is the primary source of urban non-point source water pollution. It is generally considered that the first 20% of runoff is primary rainwater, accounting for 50-70% of total pollution. This primary rainwater is characterized by high load, large volume, and rapid flow. Primary rainwater accumulates pollutants primarily by washing the atmosphere and washing away underlying surfaces such as urban roads and building roofs. This runoff carries various pollutants, resulting in a much higher pollution level than secondary and later rainwater.

[0004] Increased stormwater runoff also leads to a higher frequency of combined sewer overflows. Currently, most older urban areas in my country use a combined stormwater and sewage system. Excessive stormwater runoff can cause excess rainwater to mix with municipal and industrial wastewater in the drainage network, polluting water bodies. Combined sewer overflows carry a higher pollution load than municipal sewage and are a major source of pollution in urban water bodies.

[0005] my country's "sponge city" concept is a key approach to addressing non-point source pollution, such as urban waterlogging, initial stormwater pollution, and combined sewer overflows, while also protecting urban aquatic ecosystems. Bioretention ponds, a type of public facility that uses plants, microorganisms, and growth media to intercept, purify, and store runoff, are among the most suitable sponge city facilities for addressing these runoff issues. In terms of urban hydrology, bioretention ponds can reduce runoff volume, delay flood peaks, and effectively improve water quality.

[0006] Bioretention ponds can not only remove heavy metals, organic pollutants, and suspended solids from water flows, but also remove and decompose nitrate nitrogen and phosphorus pollution. In order to improve the nitrogen and phosphorus degradation effect of rainwater, it is necessary to ensure that rainwater has a longer hydraulic retention time in the bioretention pond, and the water retention capacity of the bioretention pond needs to be improved. When the rainwater runoff is large, the water flow rate is fast, and the discharge outlet set at the bottom of the bioretention pond increases rapidly under the action of water pressure, which will cause the water flow to be retained in the bioretention pond for a shorter time, reducing the purification effect of the bioretention pond. In order to ensure the water retention capacity of the bioretention pond when the rainwater runoff is large, existing bioretention ponds often create a flooded area in the bioretention pond by raising the outlet. Although this practice increases the hydraulic retention time of the bioretention pond, the water accumulates in the flooded area for too long, which easily breeds mosquitoes in the bioretention pond, causing damage to the ecological environment in the bioretention pond. Summary of the Invention

[0007] The technical problem to be solved by the present invention is that the existing biological retention pond ensures the water retention capacity of the biological retention pond when the rainwater runoff is large by raising the water outlet to form a flooded area. The accumulated water in the flooded area will accumulate in the biological retention pond for a long time, causing damage to the ecological environment in the biological retention pond.

[0008] In order to solve the above technical problems, the present invention aims to provide a biological retention pond, comprising a retention pond body and a retention well, wherein a partition wall is provided in the middle of the retention well, the partition wall dividing the retention well into a first retention chamber and a second retention chamber spaced apart on the left and right sides, the first retention chamber being connected to the water outlet of the retention pond body, and the bottom of the second retention chamber being connected to a municipal pipe network;

[0009] A first drainage hole is provided at the lower portion of the partition wall, communicating with the first water retention chamber and the second water retention chamber; a second drainage hole is provided at the middle portion of the partition wall, communicating with the first water retention chamber and the second water retention chamber; a gate body is connected to a side of the partition wall that slides upward and downward toward the second water retention chamber;

[0010] When the water level in the second water retention chamber rises to a level higher than a set height, the gate body floats up, so that the gate body blocks the first leakage hole and the gate body releases the second leakage hole; when the water level in the second water retention chamber drops to a level lower than the set height, the gate body sinks, so that the gate body blocks the second leakage hole and the gate body releases the first leakage hole.

[0011] As a preferred solution, the gate body includes a first blocking portion, a first discharge portion, a second discharge portion, and a second blocking portion, which are arranged in sequence from top to bottom. The water level in the second water retention chamber rises to be higher than the set height. The first discharge portion is arranged opposite to the second discharge hole, and the second blocking portion is arranged opposite to the first discharge hole.

[0012] The water level in the second water retention chamber drops below the set height, the first blocking portion is arranged opposite to the second leakage hole, and the second leakage portion is arranged opposite to the first leakage hole.

[0013] As a preferred solution, the gate body includes an upper gate plate, a connecting structure and a lower gate plate arranged in sequence from top to bottom, the upper gate plate and the lower gate plate are both in contact with the side of the partition wall facing the second water retention chamber, and the connecting structure is spaced apart from the side of the partition wall facing the second water retention chamber; the upper part of the connecting structure forms the first discharge part, and the lower part of the connecting structure forms the second discharge part.

[0014] As a preferred solution, a first stopper and a second stopper are provided on a side of the partition wall facing the second water retention chamber, the first stopper is located below the gate body, and the second stopper is located above the gate body;

[0015] When the gate body blocks the first leakage hole and releases the second leakage hole, the upper end of the gate body abuts against the second stopper; when the gate body blocks the second leakage hole and releases the first leakage hole, the lower end of the gate body abuts against the first stopper.

[0016] As a preferred solution, the bottom of the second water retention chamber is connected to the municipal pipe network through a drainage mechanism, and the drainage flow of the drainage mechanism is adjustable.

[0017] As a preferred solution, the drainage mechanism is a back pressure device, and the water outlet of the back pressure device is connected to the municipal pipe network.

[0018] As a preferred embodiment, the retention pond includes a soil layer planted with plants and a gravel layer arranged under the soil layer. A transversely arranged water collecting pipe is provided in the gravel layer, and a water collecting hole is provided on the side wall of the water collecting pipe. The water outlet end of the water collecting pipe is connected to the first water retention chamber.

[0019] As a preferred solution, the outer side of the water collecting pipe is covered with a first permeable geotextile.

[0020] As a preferred solution, a second permeable geotextile is laid between the soil layer and the gravel layer.

[0021] As a preferred solution, the material used for the water collecting pipe is PE or PVC.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The biological retention pond of the present invention comprises a retention pond body and a retention well, wherein a partition wall is provided in the middle of the retention well, and the partition wall divides the retention well into a first retention chamber and a second retention chamber arranged at intervals on the left and right, the first retention chamber is connected to the water outlet of the retention pond body, and the bottom of the second retention chamber is connected to the municipal pipe network; a first drainage hole connecting the first retention chamber and the second retention chamber is provided at the lower part of the partition wall, and a second drainage hole connecting the first retention chamber and the second retention chamber is provided in the middle part of the partition wall, and a gate body is connected to the partition wall by sliding up and down toward one side of the second retention chamber; when the rainwater runoff is large, the water level in the second retention chamber rises to above the set height, and the gate body floats up, so that the gate body blocks the first retention chamber and the second retention chamber. The gate body releases the first leakage hole, and the water flows from the higher second leakage hole into the second retention chamber. The water pressure at the second leakage hole is lower than that at the first leakage hole, thereby reducing the leakage flow and improving the water retention effect. After the rainwater runoff decreases, the water level in the second water retention chamber drops below the set height, and the gate body sinks, so that the gate body blocks the second leakage hole and the gate body releases the first leakage hole, thereby allowing the accumulated water in the first retention chamber to flow into the second retention chamber through the first leakage hole, avoiding the accumulation of rainwater in the first retention chamber. Therefore, the biological retention tank of the present invention can not only ensure the water retention capacity of the biological retention tank, but also avoid the accumulation of accumulated water in the retention tank body for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic structural diagram of the biological retention pond of the present invention;

[0025] Figure 2 This is a schematic diagram of the structure of the water well when there is no rain;

[0026] Figure 3 This is a schematic diagram of the structure of the delay well when the rainwater runoff is large;

[0027] Figure 4 This is a schematic diagram of the structure of the water retention well after the rain has ended;

[0028] In the figure, 1. retention pond body; 11. soil layer; 12. gravel layer; 121. fine gravel layer; 122. coarse gravel layer; 2. water retention well; 21. first water retention chamber; 22. second water retention chamber; 23. partition wall; 231. first spillway; 232. second spillway; 233. first stopper; 234. second stopper; 3. gate body; 31. upper gate plate; 32. connecting structure; 33. lower gate plate; 4. water collecting pipe; 5. back pressure device. DETAILED DESCRIPTION

[0029] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0030] In the description of the present invention, it should be understood that the terms "upper", "lower", "left", "right", "top", "bottom", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. It should be understood that the terms "first", "second", etc. are used in the present invention to describe various information, but such information should not be limited to these terms, which are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present invention, "first" information may also be referred to as "second" information, and similarly, "second" information may also be referred to as "first" information.

[0031] like Figures 1 to 4 As shown, a preferred embodiment of the biological retention pond of the present invention includes a retention pond body 1 and a retention well 2, a partition wall 23 arranged up and down is provided in the middle of the retention well 2, the partition wall 23 divides the retention well 2 into a first retention chamber 21 and a second retention chamber 22 arranged at intervals on the left and right, the first retention chamber 21 is connected to the water outlet of the retention pond body 1, and the bottom of the second retention chamber 22 is connected to the municipal pipe network; a first drainage hole 231 connecting the first retention chamber 21 and the second retention chamber 22 is provided at the lower part of the partition wall 23, and a second drainage hole 232 connecting the first retention chamber 21 and the second retention chamber 22 is provided in the middle part of the partition wall 23, and the partition wall 23 slides up and down toward one side of the second retention chamber 232 and is connected to a gate body 3; when the rainwater runoff is large, the water level in the second retention chamber 22 rises to a high At the set height, the gate body 3 floats up, so that the gate body 3 blocks the first leakage hole 231 and the gate body 3 releases the second leakage hole 232; the water flows into the second retention chamber from the higher second leakage hole, and the water pressure at the second leakage hole is lower than that at the first leakage hole, thereby reducing the discharge flow and improving the water retention effect; after the rainwater runoff decreases, the water level in the second water retention chamber 22 drops to below the set height, and the gate body 3 sinks, so that the gate body 3 blocks the second leakage hole 232 and the gate body 3 releases the first leakage hole 231, thereby allowing the accumulated water in the first retention chamber to flow into the second retention chamber through the first leakage hole, avoiding the accumulation of rainwater in the first retention chamber. Therefore, the biological retention tank of the present invention can not only ensure the water retention capacity of the biological retention tank, but also avoid the accumulation of accumulated water in the retention tank body for a long time.

[0032] The density of the gate body 3 is less than that of water, and the gate body 3 can adopt a hollow box structure. In this embodiment, the gate body 3 includes a first blocking portion, a first drainage portion, a second drainage portion, and a second blocking portion, arranged sequentially from top to bottom. When the water level in the second stagnant water chamber 22 rises to a level higher than a set height, the first drainage portion is arranged opposite the second drainage hole 232, and the second blocking portion is arranged opposite the first drainage hole 231. When the water level in the second stagnant water chamber 22 drops to a level lower than a set height, the first blocking portion is arranged opposite the second drainage hole 232, and the second drainage portion is arranged opposite the first drainage hole 231. Specifically, the first blocking portion and the second blocking portion can be plate-like structures that are attached to the side of the partition wall 23 facing the second stagnant water chamber 22, and the first drainage portion and the second drainage portion can be through holes provided on the plate-like structure.

[0033] In this embodiment, the gate body 3 includes an upper gate plate 31, a connecting structure 32 and a lower gate plate 33 arranged in sequence from top to bottom. The upper gate plate 31 and the lower gate plate 33 are both in contact with the side of the partition wall 23 facing the second water retention chamber 22, and the connecting structure 32 is spaced apart from the side of the partition wall 23 facing the second water retention chamber 22; the upper part of the connecting structure 32 forms a first discharge portion, and the lower part of the connecting structure 32 forms a second discharge portion.

[0034] Specifically, the water level in the second water retention chamber rises to above the set height, the upper part of the connecting structure is arranged opposite to the second leakage hole and the lower gate plate is arranged opposite to the first leakage hole; the water level in the second water retention chamber drops to below the set height, the upper gate plate is arranged opposite to the second leakage hole and the lower part of the connecting structure is arranged opposite to the first leakage hole.

[0035] In this embodiment, a first stopper 233 and a second stopper 234 are provided on the side of the partition wall 23 facing the second water retention chamber 22. The first stopper 233 is located below the gate body 3, and the second stopper 234 is located above the gate body 3. When the gate body 3 blocks the first leakage hole 231 and releases the second leakage hole 232, the upper end of the gate body 3 abuts the second stopper 234. When the gate body 3 blocks the second leakage hole 232 and releases the first leakage hole 231, the lower end of the gate body 3 abuts the first stopper 233. Specifically, the first stopper 233 and the second stopper 234 are both protruding structures that protrude into the second water retention chamber 22.

[0036] In this embodiment, the bottom of the second water retention chamber 22 is connected to the municipal pipeline network through a drainage mechanism. The drainage flow of the drainage mechanism is adjustable. By adjusting the drainage flow of the drainage mechanism, the specific position of the set height can be adjusted to achieve adjustment of the water retention time.

[0037] Among them, the drainage mechanism can be a flow regulating valve. In this embodiment, in order to ensure the stability of the drainage mechanism, the drainage mechanism is a back pressure device 5. The water outlet of the back pressure device is connected to the municipal pipe network. By adjusting the spring parameters of the back pressure device 5, the set height and drainage flow can be adjusted. In this embodiment, the bottom wall of the second water retention chamber 22 is lower than the bottom wall of the first water retention chamber 21. By adjusting the spring parameters of the back pressure device 5, when the water level in the second water retention chamber 22 reaches the first leakage hole 231, the gate body 3 floats and the back pressure device 5 is opened; due to the large rainwater runoff and the floating of the gate body 3, the first leakage hole 231 is opened. 31 opening is reduced, the flow rate of rainwater flowing out of the first drainage hole 231 is reduced, and the water retention performance is improved; the flow rate of rainwater flowing into the first water retention chamber 21 is much greater than the amount of water discharged from the second water retention chamber 22, and the rainwater will accumulate in the first water retention chamber 21. When the water level in the first water retention chamber 21 reaches the second drainage hole 232, the rainwater will flow into the second water retention chamber 22 from the second drainage hole 232. Since the height of the second drainage hole 232 is higher than the first drainage hole 231, the water pressure at the second drainage hole 232 is lower than that at the first drainage hole 231, thereby reducing the drainage speed and further improving the water retention performance; after the rain stops, Figure 4 As shown, the water level in the first water retention chamber 21 gradually decreases to below the second leakage hole 232. At this time, the gate body 3 repeatedly moves up and down in the second water retention chamber 22, reducing the average flow rate outflowing from the first leakage hole 231, and further achieving water retention; until the water in the first water retention chamber 21 decreases to below the first leakage hole 231, the first leakage hole 231 is located at the bottom of the pool body 1, thereby avoiding water accumulation in the pool body.

[0038] In this embodiment, the retention pond body 1 includes a soil layer 11 planted with plants and a gravel layer 12 arranged under the soil layer 11. A horizontally arranged water collecting pipe 4 is provided in the gravel layer 12. The side wall of the water collecting pipe 4 is provided with a water collecting hole, and the water outlet end of the water collecting pipe 4 is connected to the first water retention chamber 21.

[0039] Specifically, the outer side of the water collecting pipe 4 is covered with a first permeable geotextile. A second permeable geotextile is laid between the soil layer 11 and the gravel layer 12. In this embodiment, the gravel layer 12 includes a fine gravel layer 121 and a coarse gravel layer 122. The soil layer 11, the fine gravel layer 121 and the coarse gravel layer 122 are arranged in sequence from top to bottom. A second permeable geotextile is laid between the soil layer 11 and the fine gravel layer 121, and a third permeable geotextile is laid between the fine gravel layer 121 and the coarse gravel layer 122. Water collecting pipes 4 are provided in both the fine gravel layer 121 and the coarse gravel layer 122. The planting layer 11 is a mixture of fine sand and planting soil or local sandy loam, wherein the mass ratio of fine sand to soil is 3:2 to 4:1. The main function of the planting layer 11 is to provide growth for plants, store water, and adsorb some pollutants. The coarse gravel layer 122 is composed of gravel with a particle size larger than the water collection hole diameter. The gravel diameter should preferably not exceed 20 mm, and the thickness of the coarse gravel layer 122 should preferably be 15-20 cm. The water collection pipe 4 is designed based on local rainfall, with a hole diameter generally between 6-12 mm and a diameter of 50-110 mm. The fine gravel layer 121 has a particle size between the soil layer 11 and the coarse gravel layer 122, and the thickness of the fine gravel layer 121 should preferably be 10-20 cm. Plants planted in the soil layer 11 are flood-tolerant, drought-tolerant, easy-to-grow, and locally unique and universal plants, such as calamus, reed, canna, and iris. These plants have good coupling with the preferred filler and are locally unique. The water collection pipe 4 is made of PE or PVC. This material is corrosion-resistant and rust-resistant, extending the service life of the water collection pipe 4. The bottom of the retention well 1 is cast with fine stone concrete, and the partition wall 23 is cast with reinforced concrete. The heights of the first drainage hole 231 and the second drainage hole 232 are determined according to the designed water storage level and dead water level of the biological retention tank, and the apertures of the first drainage hole 231 and the second drainage hole 232 are determined by the designed water flow rate.

[0040] In summary, the biological retention pond of the present invention includes a retention pond body 1 and a retention well 2, and a partition wall 23 arranged up and down is provided in the middle of the retention well 2, and the partition wall 23 divides the retention well 2 into a first retention chamber 21 and a second retention chamber 22, the first retention chamber 21 is connected to the water outlet of the retention pond body 1, and the bottom of the second retention chamber 22 is connected to the municipal pipe network; a first drainage hole 231 connecting the first retention chamber 21 and the second retention chamber 22 is provided at the lower part of the partition wall 23, and a second drainage hole 232 connecting the first retention chamber 21 and the second retention chamber 22 is provided in the middle part of the partition wall 23, and the partition wall 23 slides up and down toward one side of the second retention chamber 232 and is connected to a gate body 3; when the rainwater runoff is large, the water level in the second retention chamber 22 rises to above the set height, and the gate The body 3 floats up, so that the gate body 3 blocks the first leakage hole 231 and the gate body 3 releases the second leakage hole 232; the water flows into the second retention chamber from the higher second leakage hole, and the water pressure at the second leakage hole is lower than that at the first leakage hole, thereby reducing the leakage flow and improving the water retention effect; after the rainwater runoff decreases, the water level in the second water retention chamber 22 drops to below the set height, and the gate body 3 sinks, so that the gate body 3 blocks the second leakage hole 232 and the gate body 3 releases the first leakage hole 231, thereby allowing the accumulated water in the first retention chamber to flow into the second retention chamber through the first leakage hole, avoiding the accumulation of rainwater in the first retention chamber. Therefore, the biological retention tank of the present invention can not only ensure the water retention capacity of the biological retention tank, but also avoid the accumulation of accumulated water in the retention tank body for a long time. Moreover, by adjusting the aperture and position of the first leakage hole 231 and the aperture and position of the second leakage hole 232, the water retention capacity of the first water retention chamber can be adjusted; by the drainage flow of the second retention chamber, the water retention capacity of the second water retention chamber can be adjusted.

[0041] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A bioretention pond, characterized in that: The invention comprises a detention pond body (1) and a detention well (2), wherein a partition wall (23) is provided in the middle of the detention well (2), and the partition wall (23) divides the detention well (2) into a first detention chamber (21) and a second detention chamber (22) arranged at intervals on the left and right, wherein the first detention chamber (21) is connected to the water outlet of the detention pond body (1), and the bottom of the second detention chamber (22) is connected to the municipal pipe network; A first drainage hole (231) communicating with the first stagnant water chamber (21) and the second stagnant water chamber (22) is provided at the lower portion of the partition wall (23); a second drainage hole (232) communicating with the first stagnant water chamber (21) and the second stagnant water chamber (22) is provided at the middle portion of the partition wall (23); and a gate body (3) is connected to the partition wall (23) on one side thereof that slides upward and downward toward the second stagnant water chamber (22); The water level in the second water retention chamber (22) rises to a level higher than the set height, and the gate body (3) floats up, so that the gate body (3) blocks the first leakage hole (231) and the gate body (3) releases the second leakage hole (232); the water level in the second water retention chamber (22) drops to a level lower than the set height, and the gate body (3) sinks, so that the gate body (3) blocks the second leakage hole (232) and the gate body (3) releases the first leakage hole (231); the gate body (3) comprises a first blocking portion, a first leakage portion, a second leakage portion, and a second blocking portion, which are sequentially arranged from top to bottom; the water level in the second water retention chamber (22) rises to a level higher than the set height, the first leakage portion and the second leakage hole (232) are arranged opposite to each other, and the second blocking portion and the first leakage hole (231) are arranged opposite to each other; The water level in the second water retention chamber (22) drops below the set height, the first blocking portion and the second leakage hole (232) are arranged opposite to each other, and the second leakage portion and the first leakage hole (231) are arranged opposite to each other; The gate body (3) comprises an upper gate plate (31), a connecting structure (32) and a lower gate plate (33) arranged in sequence from top to bottom. The upper gate plate (31) and the lower gate plate (33) are both in contact with the side of the partition wall (23) facing the second water retention chamber (22). The connecting structure (32) is spaced apart from the side of the partition wall (23) facing the second water retention chamber (22). The upper part of the connecting structure (32) forms the first discharge portion, and the lower part of the connecting structure (32) forms the second discharge portion.

2. The bioretention pond according to claim 1, characterized in that A first stopper (233) and a second stopper (234) are provided on one side of the partition wall (23) facing the second water retention chamber (22), wherein the first stopper (233) is located below the gate body (3), and the second stopper (234) is located above the gate body (3); When the gate body (3) blocks the first leakage hole (231) and the gate body (3) releases the second leakage hole (232), the upper end of the gate body (3) abuts against the second stopper (234); when the gate body (3) blocks the second leakage hole (232) and the gate body (3) releases the first leakage hole (231), the lower end of the gate body (3) abuts against the first stopper (233).

3. The bioretention pond according to claim 1, characterized in that The bottom of the second water retention chamber (22) is connected to the municipal pipe network through a drainage mechanism, and the drainage flow of the drainage mechanism is adjustable.

4. The bioretention pond according to claim 3, characterized in that The drainage mechanism is a back pressure device (5), and the water outlet of the back pressure device is connected to the municipal pipe network.

5. The bioretention pond according to any one of claims 1 to 4, characterized in that: The retention pond body (1) comprises a soil layer (11) planted with plants and a gravel layer (12) arranged below the soil layer (11); a transversely arranged water collecting pipe (4) is provided in the gravel layer (12); a water collecting hole is provided on the side wall of the water collecting pipe (4); and a water outlet end of the water collecting pipe (4) is in communication with the first water retention chamber (21).

6. The bioretention pond according to claim 5, characterized in that The outer side of the water collecting pipe (4) is covered with a first permeable geotextile.

7. The bioretention pond according to claim 5, characterized in that A second permeable geotextile is laid between the soil layer (11) and the gravel layer (12).

8. The bioretention pond according to claim 5, characterized in that The material used for the water collecting pipe (4) is PE or PVC.

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