A lid type rainwater ditch and its design calculation method

Abstract

The invention discloses an LID (low impact development) type rainwater ditch and a design and calculation method for the same, and is applicable to various rainwater drainage ditches such as drainage ditches, farmland drainage ditches and floodwater drainage ditches on two sides of a slope and two sides of a road. The rainwater ditch comprises a ditch, storage dams, overflow ports, a rubble layer, a sandy soil layer, ecological slopes and the like. The sandy soil layer is laid on a bed of the ditch, the rubble layer is laid on the upper side of the sandy soil layer, and the storage dams are longitudinally continuously arranged along the ditch and are separated from one another by a certain distance, so that a series of reservoirs which are continuously distributed are formed along the ditch. The design and calculation method includes designing and calculating layout spacing of the water storage dams and the sizes of the overflow ports. The LID type rainwater ditch and the design and calculation method have the advantages that the LID type rainwater ditch has multiple functions of 'drainage, water storage, infiltration and decontamination', and is incomparable to a hard rainwater ditch only with a drainage function; the LID type rainwater ditch is high in water storage capacity and drainage speed which are deficient in a wetland bed type rainwater ditch; the rainfall flood runoff volume can be obviously reduced, the groundwater recharge can be improved, non-point surface pollutants of rainwater can be reduced, and environments can be beautified.

Description

technical field [0001] The invention belongs to the technical field of water conservancy engineering and municipal engineering, and specifically relates to a LID-type rainwater ditch and a design calculation method thereof. Background technique [0002] The purpose of the traditional hardened rainwater ditch is only to quickly discharge the surrounding rainwater runoff into the receiving water body, and its single function only has the function of "drainage". This single function, while exerting the advantages of drainage, also brings the following problems: it aggravates the flood pressure of the receiving water body and the occurrence of flood disasters in the rainy season, and it is difficult for rainwater to infiltrate through the ditch bed to replenish groundwater, which makes the river easy to dry up in the dry season. , in addition to exacerbating the problem of rainwater non-point source pollution. In particular, most of the rivers serving as drinking water sources ...

AI Technical Summary

Problems solved by technology

[0002] The traditional hardened stormwater ditches are only built to quickly discharge the surrounding rainwater runoff into the receiving water body, and their single function is only "drainage"

This single function not only gives full play to the advantages of drainage, but also brings the following problems: it intensifies the flood pressure of the receiving water body in the rainy season and the occurrence of flood disasters, and it is difficult for rainwater to infiltrate and recharge groundwater through the ditch bed, which makes the river prone to dry up in the dry season , in addition to exacerbating the problem of non-point source pollution of rainwater

This patent builds ditches into wetlands to reduce rainwater non-point source pollutants. Its main disadvantages are: 1) It is not suitable for drainage ditches with large drainage and fast drainage speed. It is easy to be washed away, and secondly, the water flow shuttles among the wetland plants, which suffers from great resistance and is difficult to drain smoothly, which may easily cause backwater to overflow the wetland bed; 2) The water storage function is not strong. In order to ensure the growth of wetland plants, water storage Generally, the design is low to avoid flooding the wetland plants and causing them to die, so the water storage space is very limited

The patent application also builds the drainage ditch into a wetland to reduce rainwater surface source pollutants, although the patent application covers a layer of gravel on the sand layer to increase the erosion resistance of the wetland to water flow, and will be placed under the wetland. The water collection pipe has been changed to a water collection tank, but it still cannot overcome the above two main shortcomings, because the water flow also needs to shuttle between the wetland plants during drainage, which encounters high resistance and makes it difficult to drain smoothly, and the water storage level also needs to be designed relatively low. Low to avoid flooding wetland plants and causing their death

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