CN103015487A - System using green land rainwater for compensating urban groundwater - Google Patents

Abstract

The invention provides a system using green land rainwater for compensating urban groundwater. A green land is a concave green land, the center of the concave green land is the lowest, the ground of the concave green land is in a steep and gentle combination shape, a rainwater collection unit and an infiltration compensating unit are arranged on the concave green land, the infiltration compensating unit comprises a grit layer A, a gravel layer, a thinnest medical stone layer, a thickest large gravel layer and a grit layer B sequentially from top to bottom, the thickness of the medical stone layer is 50-100cm, the thickness of the large gravel layer is 100-1000cm, the infiltration compensating unit is buried in the concave green land, a top infiltration port is positioned at the center of the concave green land, rainwater enters the infiltration compensating unit through the infiltration port, rest portions on the concave green land belong to the rainwater collection unit, and porous frameworks and broken stones are laid below the soil layer of the rainwater collection unit. The system overcomes the shortcomings of the prior art, is simple in construction and operation and has good water quality treatment effect.

Description

Compensation of urban groundwater system with rainwater from green land

technical field

The invention provides a system for compensating urban groundwater by using rainwater in green spaces, in particular a system capable of efficiently utilizing rainwater in green spaces, improving the infiltration capacity of rainwater in green spaces and compensating for urban groundwater.

Background technique

With the acceleration of urbanization, the water consumption is increasing, and modern life and production produce a large amount of sewage, which makes the urban water resource crisis more and more serious. In order to meet the needs of urban water resources, people have increased the exploitation of groundwater, resulting in serious overexploitation, a sharp decrease in urban underground water storage, a continuous decline in groundwater levels, a corresponding expansion of the area of the underground funnel, and ground subsidence, subsidence, and cracking. and other geological disasters. At the same time, due to the overexploitation of groundwater in coastal areas, the dynamic balance of groundwater is destroyed, causing seawater to intrude into groundwater, resulting in soil salinization and the reduction of cultivated land. At the same time, as an important water source, urban rainwater is discharged in large quantities, which is seriously wasted and has not been utilized as a resource. It even causes urban waterlogging during heavy rain seasons, causing urban rain and flood disasters. In the summer of 2011 alone, six inland cities—Wuhan, Beijing, Changsha, Chengdu, Yangzhou, and Nanjing—were hit by heavy rains. Large areas of urban areas were flooded, traffic was basically paralyzed, communication facilities failed, and serious economic losses were caused. Rainfall is an important part of the hydrological cycle, which can replenish water resources after exploitation and utilization, which is regenerative. Compared with other water sources, rainwater is less polluted, especially rainwater in green areas. Compared with ordinary rainwater, rainwater in green areas has the ability to purify rainwater, combined with the water storage capacity of soil aquifers, and recharges groundwater through recharge. It is an important way for rainwater to be utilized as a resource, effectively solving groundwater overexploitation and urban rain and flood disasters. However, due to the limited infiltration capacity of green land soil, how to speed up green land rainwater infiltration and recharge to compensate urban groundwater has become an urgent problem to be solved.

In recent years, many schemes and devices have emerged in the use of rainwater to compensate urban groundwater. Most of them use roof rainwater or ground rainwater, often ignoring the green space, a natural infiltration channel. Other channels require a lot of cost for rainwater recharge. , and need to invest more in rainwater quality treatment. If the rainwater quality treatment is not up to standard, it will cause great pollution and impact on the entire underground water circle.

Contents of the invention

The invention provides a system for compensating urban groundwater by using rainwater from green land, which solves the above-mentioned deficiencies in the background technology. The construction operation of the invention is simple and has a better treatment effect on water quality.

The technical scheme adopted to realize the above-mentioned purpose of the present invention is:

A system for compensating urban groundwater by using rainwater in green spaces. The green space is a sunken green space, the center of which is the lowest point, and the ground of the sunken green space is steep and gentle. The sunken green space is equipped with rainwater collection units and infiltration compensation The infiltration compensation unit is divided into five layers from top to bottom, which are coarse sand layer A, gravel layer, the thinnest medical stone layer, the thickest large gravel layer, and coarse sand layer B. The thickness of the rice stone layer is 50-100cm, and the thickness of the large gravel layer is 100-1000cm. The infiltration compensation unit is buried in the concave green space, and the top infiltration outlet is located in the center of the concave green space. The infiltration outlet enters the infiltration compensation unit; the rest of the sunken green space is a rainwater collection unit, and the soil layer of the rainwater collection unit is paved with a porous skeleton and gravel under the porous skeleton.

The sunken green space is adjacent to the urban road, and the part of the sunken green space close to the road is the abandoned flow green space. The abandoned flow green space is a slope, and its height gradually decreases towards the direction of the road. The abandoned flow unit includes a drainage ditch and a seepage pipe. The drainage ditch is located at the junction of the abandoned flow green space and the road. The seepage pipe is laid under the soil layer of the abandoned flow green space and slopes towards the road, and its water outlet is located on the drainage ditch.

The rainwater waste flow unit is provided with a retaining screen, and the soil retaining screen is located at the junction of the waste flow green space and the road to prevent soil loss in the green space.

A water pump is arranged in the large gravel layer, and a water outlet pipe leading to the surface of the green space is arranged on the water pump, and a nozzle is connected to the water outlet of the water outlet pipe.

The cross-sectional areas of the coarse sand layer A, the gravel layer, the medical stone layer, the large gravel layer and the coarse sand layer B increase sequentially.

The system for compensating urban groundwater with greenfield rainwater provided by the present invention has the following advantages: one is to bring greenfield rainwater into the category of compensating urban groundwater, and to improve the water quality of compensating urban groundwater by utilizing the infiltration capacity and purification ability of greenfield itself; The solid pollutants in the rainwater are filtered by plants and soil, and are intercepted and deposited in the green space. The organic pollutants in the rainwater are transformed into nutrients for plants under the action of soil microorganisms, which increases the fertility of the green space soil. The third is that the cost is relatively low. Low, small engineering volume, low requirements for construction conditions, and wide applicability. It provides new thinking on rainwater utilization and can improve the utilization rate of rainwater.

Description of drawings

Fig. 1 is the overall structure schematic diagram of utilizing green space rainwater to compensate urban groundwater system provided by the present invention;

In the figure: 1-road, 2-drainage ditch, 3-soil retaining fence, 4-discarded flow green space, 5-seepage pipe, 6-sunken green space, 7-porous skeleton, 8-gravel, 9-coarse sand layer A, 10-gravel layer, 11-medicine stone layer, 12-large gravel layer, 13-coarse sand layer B, 14-water pump, 15-outlet pipe, 16-nozzle.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings.

The overall structure of the urban groundwater compensation system utilizing rainwater in the green space provided by the present invention is as shown in Figure 1, the green space is a concave green space 6, and the center of the concave green space 6 is the lowest point, and the depth of depression of the concave green space 6 is 150mm. It can not only ensure that the rainwater can fully flow into the sunken green space, but also prevent the vegetation in the green space from being necrotic due to excessive rain. The ground of the sunken green land 6 is steep and gentle. The steep and gentle slope can effectively prolong the confluence time of rainwater, increase the amount of rainwater infiltration, reduce the load of the compensation system after that, and increase the infiltration rate of the green land itself. The concave green space 6 is adjacent to the urban road 1, and the part of the concave green space 6 close to the road 1 is the abandoned flow green space 4, and the abandoned flow green space 4 is a slope, and its height gradually decreases towards the road direction.

The infiltration compensation unit is buried in the concave green space 6, and the top seepage opening is located at the center of the concave green space 6, and the rainwater enters the infiltration compensation unit from the infiltration opening. It is divided into 5 layers from the bottom, which are coarse sand layer A9, gravel layer 10, medical stone layer 11 with the thinnest thickness, large gravel layer 12 with the thickest thickness, and coarse sand layer B13, wherein the thickness of medical stone layer 11 is The thickness of the large gravel layer 12 is 100-1000cm; the medical stone can absorb and decompose free chlorine, impurities, organic matter, and miscellaneous bacteria in the water, and supply the water with minerals to purify the water quality. The large gravel layer 12 is below the medical stone layer 11, and when the rainfall rate is too fast and the rainwater cannot infiltrate in time, it can prevent the rainwater from forming runoff and flowing away; at the same time, the large gravel layer 12 has the function of holding water and can form a water-holding layer . The cross-sectional areas of the coarse sand layer A9, the gravel layer 10, the medical stone layer 11, the large gravel layer 12 and the coarse sand layer B13 increase sequentially, so the infiltration compensation unit is in the shape of an inverted bowl.

The remaining parts on the sunken green space 6 are rainwater collection units, and the soil layer of the rainwater collection unit is provided with a porous framework 7 and gravel 8, wherein the gravel 8 is located under the porous framework 7, which can improve the infiltration capacity of the green space. While enhancing the water storage capacity of the green space.

The rainwater abandonment flow unit is arranged at the waste flow green space 4, including the drainage ditch 2 and the seepage pipe 5. The seepage pipe 5 is laid under the soil layer of the waste flow green space 4 and slopes towards the road 1, and its water outlet is located on the drainage ditch 2. The rainwater on road 1 has a high content of heavy metals such as lead and chromium, and the pollution is serious, and it flows directly into the drainage ditch 2; at the same time, due to the impact of road vehicles, the rainwater on the abandoned green land 4 is polluted and needs to pass through The seepage pipe 5 is discharged into the gutter 2. The rainwater waste flow unit is also provided with a retaining wall 3, and the soil retaining wall 3 is located at the junction of the waste flow green space 4 and the road 1 to prevent soil loss in the green space.

When there is rainfall, the rainwater is purified and infiltrated through the sunken green space, gravel layer A, coarse sand layer, gravel layer, medical stone layer, etc. During the infiltration process, a water pump is designed at the large gravel layer 12 14. The water pump 14 is provided with a water outlet pipe 15 leading to the surface of the green space, and a nozzle 16 is connected to the water outlet of the water outlet pipe 15 . When there is no rainfall for a short period of time, the water drawn from the pump can be used to irrigate the green areas.

In the present invention, the infiltration capacity of the green land itself is fully utilized. At the same time, the green land soil layer can purify the rainwater during the rainwater infiltration process, so that the rainwater can supplement the groundwater through the natural infiltration mode, which has a significant effect on improving the water quality of the recharge water. effect. Moreover, the sunken green space can effectively cut off the way of non-point source pollution by reducing the runoff of rainwater, and the initial rainwater and most of the rainwater will not be discharged, and can greatly reduce the non-point source pollution load of water bodies. The urban sunken green space in the present invention is equivalent to a grit chamber and a sewage land treatment system. While the rainwater is flowing and infiltrating, the solid pollutants in the rainwater are filtered by plants and soil, and are trapped and deposited in the green space. Organic pollutants in rainwater are converted into nutrients for plants by soil microorganisms, which not only increases the fertility of green land soil, but also purifies the water quality of rainwater runoff. In this way, the dynamic balance of groundwater can be effectively maintained, and problems such as seawater intrusion into groundwater, soil salinization, and reduction of cultivated land will be greatly alleviated, which is of great significance to people's production and life.

Claims (5)

1. A system for compensating urban groundwater by rainwater in green spaces, characterized in that: the green spaces are sunken green lands, the center of the sunken green lands is the lowest point, the ground of the sunken green lands is steep and gentle, and rainwater is provided on the sunken green lands The collection unit and the infiltration compensation unit, in which the infiltration compensation unit is divided into five layers from top to bottom, which are coarse sand layer A, gravel layer, the thinnest medical stone layer, the thickest large gravel layer and coarse Sand layer B, in which the thickness of the medical stone layer is 50-100cm, the thickness of the large gravel layer is 100-1000cm, the infiltration compensation unit is buried in the sunken green space, and the top infiltration outlet is located in the sunken green space At the center of the center, rainwater enters the infiltration compensation unit from the infiltration opening; the rest of the sunken green space is a rainwater collection unit, and the soil layer of the rainwater collection unit is paved with a porous framework and gravel under the porous framework. 2. The urban groundwater compensation system utilizing rainwater in green spaces according to claim 1, characterized in that: the concave green space is adjacent to the urban road, and the part of the concave green space close to the road is a waste flow green space, and the waste flow green space is a slope , its height gradually decreases toward the direction of the road. A rainwater abandonment unit is installed at the abandoned flow green space. The rainwater abandoned flow unit includes a drainage ditch and a seepage pipe. The drainage ditch is located at the junction of the abandoned flow green space and the road, and the seepage pipe is laid on the abandoned flow green space. It is below the soil layer and slopes towards the road, and its outlet is located on the drainage ditch. 3. The urban groundwater compensation system utilizing green space rainwater according to claim 1, characterized in that: the rainwater abandonment flow unit is provided with a soil retaining barrier, and the soil retaining barrier is located at the junction of the waste flow green space and the road to prevent the soil of the green space from drain. 4. The urban groundwater compensation system utilizing rainwater in green land according to claim 1, characterized in that: a water pump is arranged in the large gravel layer, a water outlet pipe leading to the surface of the green land is arranged on the water pump, and a nozzle is connected to the water outlet of the water outlet pipe . 5. The urban groundwater system utilizing green land rainwater compensation according to claim 1 is characterized in that: the cross-sectional areas of the coarse sand layer A, the gravel layer, the medical stone layer, the large gravel layer and the coarse sand layer B are successively increase.