Multifunctional rainwater garden system for urban inland inundation treatment

Abstract

A multifunctional rainwater garden system for urban inland inundation treatment comprises a rainwater garden, an ecological pool and an underground water storage tank. The rainwater garden is arranged along the hardened ground, the ecological pool is arranged at the low-lying position of the inner side of the rainwater garden, a clear water tank of the underground water storage tank is connected with the ecological pool through a perforated pipe at the bottom, filtered rainwater is collected through the perforated pipe, and a rainwater tank of the underground water storage tank is connected with the ecological pool through an overflow grating and a pipeline on the bank. Overflowed rainwater is collected through the overflow pipe. According to the system, the rainwater infiltration speed and infiltration amount can be increased, the rainwater quality is preliminarily purified, the purified rainwater is collected for simple life use and flower and tree irrigation, the rainwater utilization rate is increased, rainfall flood regulation and storage and rainwater drainage are integrated, the drainage pressure of urban pipelines is relieved, and the risk and probability of urban inland inundation are reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of urban waterlogging control and comprehensive utilization, and specifically relates to a multifunctional rainwater garden system with integrated functions of rainwater infiltration, purification, storage, reuse and discharge. Background Art

[0002] Urban waterlogging has long been a problem that has puzzled urban managers. Western developed countries have proposed a variety of "stormwater management" theories to turn urban floods into water resources. The main modern "stormwater management" theories include: "Low Impact Development (LID)" proposed by the US Environmental Protection Agency (EPA) in the early 1990s, "Water Sensitive Urban Design (WSUD)" proposed by Australia in the mid-1990s, "Sustainable Drainage System (SUDS)" proposed by the United Kingdom in the late 1990s, and "ABC Water Plan" proposed by Singapore in 2006. These theories basically use a variety of measures to strengthen rainwater infiltration, reduce surface runoff, and reduce the risk and probability of urban waterlogging.

[0003] As the problem of urban waterlogging in China becomes increasingly serious and the theory of "urban stormwater management" has been introduced into China, the industry has proposed the "sponge city" theory with the concept of low-impact development as the core, and has carried out pilot studies in major cities in China. Sponge city construction mainly uses green roofs, permeable pavement, rainwater gardens and other measures to strengthen the infiltration, retention, storage, purification and utilization of rainwater, thereby reducing the discharge of rainwater and reducing the load of the drainage network to reduce the risk of urban waterlogging.

[0004] In recent decades, countries such as Germany and Singapore have conducted extensive research on the management and utilization of rainwater on hardened ground and roofs, and have achieved remarkable results. Among them, Germany widely uses rainwater collection systems in commercial and residential areas to promote the reuse of rainwater, and has established a rainwater fee system to encourage the public and enterprises to use rainwater; Singapore widely uses rainwater gardens and permeable pavements in the utilization of rainwater on hardened ground and roofs, and uses the collected rainwater for irrigation and landscape water bodies. Domestically, some cases have also been proposed in terms of rainwater management and utilization. Among them, CN110012770A discloses a rainwater garden that efficiently reduces runoff flow rate and pollutants. The rainwater garden in this scheme is circular. The entire rainwater garden includes a pre-treatment unit, a garden unit for planting terrestrial plants, and a reservoir from the outside to the inside. In the process of rainwater flowing from the surrounding pre-treatment units and garden units into the reservoir, a large amount of pollutants are adsorbed and intercepted by plants, achieving the purpose of reducing pollutants and flow rate, but its rainwater infiltration capacity is limited and the problem of rainwater reuse is not considered. CN107893469A discloses an integrated rainwater infiltration and drainage system based on sponge cities. The invention mainly includes ecological grass-planted ditches, sunken green spaces and rainwater gardens. The invention increases the rate of rainwater infiltration and uses rainwater wells to collect rainwater for reuse. However, the sunken green space occupies a large area and the terrain is low, so rainwater cannot be discharged normally into the drainage system. Liu Wanhe et al. talked about the structural design of rainwater gardens, the purification effect of rainwater runoff, and the design of rainwater gardens in island areas in "Design and Application of Rainwater Gardens in Island Areas" (China Rural Water Conservancy and Hydropower, 2021, 30), but they are all limited to the effect evaluation and landscape design of rainwater gardens. However, none of the prior art involves a multifunctional rainwater garden system that integrates hardened ground rainwater infiltration, purification, storage, reuse and discharge. Summary of the invention

[0005] In order to solve the problems of slow infiltration rate of rainwater discharged from the hardened ground and roof to the hardened ground, rainwater pollution, inability to reuse rainwater discharged directly, and large amount of rainwater directly flowing into the drainage network to increase the drainage load, leading to increased risk of urban waterlogging, etc., the present invention proposes a multifunctional rainwater garden system, which is suitable for the integration of rainwater infiltration, purification, storage, reuse and discharge on urban hardened ground. Its purpose is to accelerate the infiltration of rainwater and surface water through rainwater gardens, reduce pollutants in surface runoff, store the clean water obtained after treatment, reuse rainwater to improve the utilization rate of rainwater resources, and regulate and store rainwater according to the drainage load of the drainage network, so as to alleviate drainage pressure and reduce the risk and probability of urban waterlogging.

[0006] The present invention is achieved through the following technical solutions.

[0007] The multifunctional rain garden system for urban waterlogging control described in the present invention comprises a rain garden, an ecological pool and an underground water storage tank.

[0008] The rain garden comprises a planting soil layer, a sand and stone layer, a gravel layer, a waterproof layer, a permeable pipe, an artificial filling layer, a covering layer, and a combination of terrestrial plants such as Cyperus rotundus and Pampas grass.

[0009] The structure of the rain garden from top to bottom consists of a combination of terrestrial plants such as Cyperus rotundus and Pampas grass, a covering layer, a planting soil layer, an artificial filler layer, a sand and gravel layer, a gravel layer and an infiltration pipe.

[0010] The rain garden has a circular structure, divided into an inner and outer layer and connected in a stepped manner. The outermost rain garden is directly connected to the hardened ground, and the inner rain garden is connected to the central ecological pool.

[0011] The ecological pool comprises an overflow grid and a pipeline, a combination of aquatic plants such as water lilies, calamus, water plantain and water grass, a perforated pipe, a planting soil layer, a sand and stone layer, a gravel layer and a waterproof layer.

[0012] The structure of the ecological pool is composed of a combination of aquatic plants such as water lilies, calamus, water plantain and water grass, a planting soil layer, a sand and gravel layer, a gravel layer, and a waterproof layer from top to bottom. There are perforated pipes at the bottom. The entire ecological pool is circular or elliptical, which is adapted to the annular structure of the rain garden. The overflow grille, pipes and perforated pipes are respectively connected to the rainwater tank and the clean water tank of the underground water storage tank.

[0013] The underground water storage tank comprises a reuse water spray pipe, an external drainage pipe, a three-way valve, a submersible centrifugal pump I, a submersible centrifugal pump II, an external rainwater reuse pipe, a clean water tank and a rainwater tank.

[0014] The underground water storage tank, the clean water tank and the rainwater tank are not connected to each other. The clean water tank and the rainwater tank are respectively connected to the perforated pipes, overflow grilles and pipes of the ecological pool. A submersible centrifugal pump I and an external rainwater recycling pipe are installed on the bottom side of the clean water tank. A submersible centrifugal pump II and a three-way valve are installed on the bottom side of the rainwater tank. The three-way valve is connected to the recycling spray pipe and the external drainage pipe respectively.

[0015] After collecting rainwater, the present invention purifies rainwater through sedimentation, infiltration, filtration and plant adsorption, and plays the role of rainwater reuse and storage through ecological pools, clean water tanks and rainwater tanks. Excess rainwater will be temporarily stored in the rainwater tank and discharged outward when the load of the drainage system is small.

[0016] The rain garden of the present invention is elliptical in shape as a whole in a plane. The outermost part is a rain garden planted with waterlogging and drought-resistant terrestrial plants for filtering, purifying and accelerating the infiltration of rainwater; the middle part is a smaller rain garden for further adsorbing pollutants and suspended matter; the innermost part is an ecological pool planted with aquatic plants for rainwater purification and infiltration, and below the water pool are a clean water tank and a rainwater tank for storing filtered clean water and overflow rainwater in heavy rain.

[0017] The present invention has multiple functions of infiltration, purification, storage, reuse and discharge of rainwater on hardened ground. The clean water tank collects the infiltrated clean water into the clean water tank through a pipe buried under the ecological water pool. A water pump is provided at the bottom of the clean water tank to facilitate pumping out the filtered rainwater for simple domestic water supply for surrounding residents.

[0018] The rainwater tank described in the present invention is connected to the ecological water pool through an overflow grille and a pipe. The overflow pipe on the shore collects the overflowing rainwater into the rainwater tank. A submersible pump is provided at the bottom of the rainwater tank to facilitate the extraction of rainwater from the rainwater tank for watering the plants and other flowers and trees in the garden. When the water level in the rainwater tank is too high, the submersible pump will force the rainwater to the nearest drainage pipe. The rainwater tank can temporarily store rainwater when the drainage pipe is heavily loaded, and then discharge it to the drainage pipe when the water level in the drainage pipe drops, thereby playing the role of storage and rainwater reuse.

[0019] The working principle of the invention is as follows: the rainwater from the roof is drained to the hardened ground and then merged with the rainwater from the hardened ground, and then flows to the rain garden with lower terrain. The outer rain garden is 400 mm lower than the surrounding hardened ground. The rainfall runoff flows into the outermost rain garden, and a large amount of pollutants are intercepted and adsorbed by plants and infiltrated and purified to replenish groundwater. When the rainfall is large, the water accumulation in the outermost rain garden exceeds 200 mm. mm, rainwater will overflow to the second-level rainwater garden with smaller size in the middle, further intercepting, adsorbing, infiltrating and purifying rainwater, and finally flowing into the ecological pool in the middle for landscape use. Some rainwater infiltrates and is purified in the ecological pool and then collected into the clean water tank through perforated pipes. When heavy rain occurs and the water level of the ecological pool is too high, the overflow grilles and pipes along the ecological pool will drain the rainwater into the rainwater tank for temporary storage. When the water level in the rainwater tank is high and the water level in the nearest drainage pipe rainwater well is low, the submersible pump in the rainwater tank will start to drain water outward. The clean water in the clean water tank can be pumped out by a water pump for simple domestic water use, and the rainwater in the rainwater tank can be pumped out by a water pump for irrigation of flowers, plants and trees.

[0020] The present invention improves the speed and amount of rainwater infiltration, preliminarily purifies the rainwater quality, collects the purified rainwater for simple daily use and irrigation of flowers, plants and trees, improves the utilization rate of rainwater, and integrates rainwater storage and rainwater discharge, relieves the drainage pressure of urban pipes, and reduces the risk and probability of urban waterlogging. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structural cross-section of the rain garden system of the present invention.

[0022] Figure 2 It is a plan view of the rain garden system of the present invention.

[0023] Figure 3 It is a structural schematic diagram of the rain garden in the present invention.

[0024] In the figure: 1-hardened ground; 2-reuse sprinkler pipe; 3-rainwater garden; 4-external drainage pipe; 5-three-way valve; 6-submersible centrifugal pump; 7-external rainwater reuse pipe; 8-clean water tank; 9-rainwater tank; 10-ecological pool; 11-overflow grille and pipe; 12-aquatic plants such as water lilies, calamus, water plantain and water grass; 13-perforated pipe; 14-planting soil layer; 15-sand and gravel layer; 16-gravel layer; 17-waterproof layer; 18-infiltration pipe; 19-artificial filler layer; 20-covering layer; 21-terrestrial plants such as Cyperus rotundus and Cattail reed; 22-underground water storage tank; 23-rainwater well of drainage system. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0026] Reference Figure 1 , Figure 2 and Figure 3 As shown, a multifunctional rain garden system for urban waterlogging control described in this embodiment includes a rain garden 3, an ecological pool 10 and an underground water storage tank 22.

[0027] The rain garden 3 comprises a planting soil layer 14, a sand and stone layer 15, a gravel layer 16, a waterproof layer 17, a permeable pipe 18, an artificial filler layer 19, a covering layer 20, and a combination of terrestrial plants 21 such as Cyperus rotundus and Pampas grass.

[0028] The structure of the rain garden 3 is, from top to bottom, a combination of terrestrial plants 21 such as Cyperus rotundus and Pampas grass, a covering layer 20, a planting soil layer 14, an artificial filling layer 19, a sand and gravel layer 15, a gravel layer 16 and an infiltration pipe 18.

[0029] The rain garden 3 is annular in structure, divided into inner and outer layers and connected in a stepped manner, the outermost rain garden 3 is directly connected to the hardened ground 1, and the inner rain garden 3 is connected to the central ecological pool 10.

[0030] The ecological pool 10 includes an overflow grid and a pipe 11 , a combination of aquatic plants 12 such as water lilies, calamus, water plantain and water grass, a perforated pipe 13 , a planting soil layer 14 , a sand and stone layer 15 , a gravel layer 16 , and a waterproof layer 17 .

[0031] The structure of the ecological pool 10 is, from top to bottom, a combination of aquatic plants 12 such as water lilies, calamus, water plantain and water grass, a planting soil layer 14, a sand and gravel layer 15, a gravel layer 16, and a waterproof layer 17. A perforated pipe 13 is provided at the bottom. The entire ecological pool is circular or elliptical, which is adapted to the annular structure of the rain garden 3. The overflow grille and pipe 11 and the perforated pipe 13 are respectively connected to the rainwater tank 9 and the clean water tank 8 of the underground water storage tank 22.

[0032] The underground water storage tank 22 includes a reuse water spray pipe 2, an external drainage pipe 4, a three-way valve 5, a submersible centrifugal pump I6, a submersible centrifugal pump II61, an external rainwater reuse pipe 7, a clean water tank 8 and a rainwater tank 9.

[0033] The underground water storage tank 22, the clean water tank 8 and the rainwater tank 9 are not connected to each other. The clean water tank 8 and the rainwater tank 9 are respectively connected to the perforated pipe 13, the overflow grille and the pipeline 11 of the ecological pool 10. A submersible centrifugal pump I6 and an external rainwater recycling pipe 7 are provided on the bottom side of the clean water tank 8. A submersible centrifugal pump II61 and a three-way valve 5 are provided on the bottom side of the rainwater tank 9. The three-way valve 5 is connected to the recycling spray pipe 2 and the external drainage pipe 4 respectively.

[0034] After collecting rainwater, the present invention purifies the rainwater through sedimentation, infiltration, filtration and plant adsorption, and plays the role of rainwater reuse and storage through the ecological pool 10, the clean water tank 8 and the rainwater tank 9. Excess rainwater will be temporarily stored in the rainwater tank 9 and discharged outward when the load of the drainage system is small.

[0035] The outermost rain garden of the rain garden 3 is 400 mm lower than the surrounding hardened ground 1. After the rainwater from the roof is discharged to the hardened ground 1 and the rainwater from the hardened ground 1 is collected, the rainwater will flow to the outermost rain garden with a lower terrain. The rainwater retained in the outermost rain garden will seep downward from the ground and pass through the covering layer 20, the planting soil layer 14, the artificial filling layer 19, the sand layer 15, the gravel layer 16 and the infiltration pipe 18 in sequence to replenish the groundwater. When the water depth of the outermost rain garden exceeds 200 mm, it will overflow to the next level rain garden.

[0036] The rainwater overflowing from the rain garden 3 will be stored in the ecological pool 10, which has a depth of 2.5 m and is provided with a planting soil layer 14, a sand layer 15, a gravel layer 16, a waterproof layer 17 and a perforated pipe 13 from top to bottom.

[0037] The clean water collected in the clean water tank 8 can be pumped out through the submersible centrifugal pump Ⅰ 6 arranged at the bottom side thereof to facilitate the filtered rainwater to be provided for simple domestic water use by the surrounding residents.

[0038] The rainwater temporarily stored in the rainwater tank 9 can also be pumped out to irrigate the plants and other flowers and trees in the garden by utilizing the submersible centrifugal pump II 61 located at its bottom side.

[0039] The thickness of the covering layer 20 in the rain garden 3 is 75 mm. A combination of terrestrial plants 21 such as Cyperus rotundus and Cattail reed can be appropriately planted on the covering layer 20 to play a role in covering and retaining water; the thickness of the planting soil layer 14 is 300 mm. The planting soil layer 14 is mainly composed of sand mixed with peat soil with good permeability, and the ratio of the sand mixed with peat soil is 2:1; the thickness of the artificial filler layer 19 is 500 mm. The artificial filler layer 19 uses biochar, which can better absorb heavy metals and organic matter; the thickness of the sand layer 15 is 200 mm, which plays a certain filtering and purification role; the thickness of the gravel layer 16 is 300 mm, and the gravel diameter is ≤50 mm; the infiltration pipe 18 is located below the gravel layer 16, the diameter of the infiltration pipe is 200 mm, the height is 1000 mm, and the pipe body is covered with holes with an aperture of 25 mm, which can better infiltrate rainwater into the ground to replenish groundwater.

[0040] The planting soil layer 14 in the ecological pool 10 is 300 mm thick. The planting soil layer 14 is mainly composed of sand with good permeability mixed with peat soil. The ratio of the sand and peat soil is 2:1, which is used to plant aquatic plants that purify water bodies; the sand layer 15 is 100 mm thick and plays a certain filtering and purification role; the gravel layer 16 is 200 mm thick, and the gravel size is less than 50 mm; the waterproof layer 17 is located below the gravel layer, and an impermeable waterproof cloth is laid below the gravel layer; the perforated pipe 13 is located in the gravel layer, and is used to collect water that penetrates into the gravel layer into the clean water tank 8.

[0041] In the above-mentioned multifunctional rain garden system for urban waterlogging control, the outermost rain garden facility is located next to roads and green spaces in urban communities. The outermost side of the rain garden is about 200 mm higher than the inner side, and its structure from top to bottom is respectively arranged as a covering layer, a planting soil layer, an artificial filling layer, a sand layer, a gravel layer and an infiltration pipe.

[0042] In the above-mentioned multifunctional rain garden system for urban waterlogging control, the smaller middle rain garden is connected to the outermost rain garden in a stepped shape. When the water storage in the outermost rain garden exceeds 200 mm, the rainwater will overflow to the two smaller rain gardens in the middle to further absorb pollutants and suspended matter in the rainwater. The structure is respectively arranged as a covering layer, a planting soil layer, an artificial filling layer, a sand layer, and a gravel layer from top to bottom.

[0043] In the above-mentioned multifunctional rainwater garden system for urban waterlogging control, the ecological pool is located in the center. After the rainwater flows through the outermost and middle rainwater gardens, it gathers in the ecological pool, and its structure is respectively arranged as a planting soil layer, a sand layer, a gravel layer, a perforated pipe and a waterproof layer from top to bottom.

Claims

1. A multifunctional rain garden system for urban waterlogging control, characterized by Includes rain gardens, bio-ponds and underground water storage tanks; The rain garden comprises a planting soil layer, a sand and stone layer, a gravel layer, a waterproof layer, a permeable pipe, an artificial filler layer, a covering layer, and a combination of terrestrial plants such as Cyperus rotundus and Pampas grass; The structure of the rain garden from top to bottom consists of a combination of terrestrial plants such as Cyperus rotundus and Pampas grass, a covering layer, a planting soil layer, an artificial filler layer, a sand and gravel layer, a gravel layer and an infiltration pipe. The rain garden is a ring-shaped structure, divided into inner and outer layers and connected in a stepped manner. The outermost rain garden is directly connected to the hardened ground, and the inner rain garden is connected to the ecological pool in the middle. The ecological pool includes overflow grilles and pipes, a combination of aquatic plants such as water lilies, calamus, water plantains and water grasses, perforated pipes, planting soil layers, sand and stone layers, gravel layers, and waterproof layers; The structure of the ecological pool is composed of aquatic plants such as water lilies, calamus, water plantain and water grass, a planting soil layer, a sand and stone layer, a gravel layer, and a waterproof layer from top to bottom. The bottom is equipped with a perforated pipe. The entire ecological pool is circular or elliptical, which is compatible with the annular structure of the rain garden. The overflow grid, pipes and perforated pipes are respectively connected to the rainwater tank and the clean water tank of the underground water storage tank; The underground water storage tank includes a reuse water spray pipe, an external drainage pipe, a three-way valve, a submersible centrifugal pump I, a submersible centrifugal pump II, an external rainwater reuse pipe, a clean water tank and a rainwater tank; The underground water storage tank, the clean water tank and the rainwater tank are not connected to each other. The clean water tank and the rainwater tank are respectively connected to the perforated pipes, overflow grilles and pipes of the ecological pool. A submersible centrifugal pump I and an external rainwater recycling pipe are installed on the bottom side of the clean water tank. A submersible centrifugal pump II and a three-way valve are installed on the bottom side of the rainwater tank. The three-way valve is connected to the recycling spray pipe and the external drainage pipe respectively.

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