Rainwater Infiltration System

The process of rainwater infiltration system is generally simple, including sewage interception or pretreatment measures, infiltration facilities and overflow facilities. Rainwater infiltration facilities can be one or more combinations. The selection and scale of rainwater infiltration schemes are determined mainly according to the specific requirements and site conditions of the project.
 

According to the different purposes of rainwater infiltration, it can be roughly divided into three situations:
 

First, the main purpose is to control the initial runoff pollution.
 

Second, in order to reduce the loss of rainwater, reduce the runoff coefficient and increase the infiltration of rainwater, there is no strict requirement for regulating and utilizing rainwater and controlling peak discharge.
 

Third, the main objective is to regulate and utilize (supplement groundwater) or control peak flow, which requires to meet certain design standards.
 

The design of rainwater infiltration system in these three cases will be very different. For the first case, we mainly use the vegetation near the catchment surface or water body to design shallow vegetation ditches, vegetation buffer belts or low-potential green spaces, absorb and purify pollutants in rainwater runoff, ensure the smooth flow of overflow and drainage, generally do not need special hydraulic and storage calculation, and have lower requirements for soil quality; for the second case, some similar cases, we also use green space or Multi-Harvesting as far as possible. The permeability of soil rainwater is required by using permeable surface, but there is no strict requirement for the scale of rainwater infiltration facilities, or proper regulation and storage and hydraulic calculation to ensure the smooth flow of overflow and drainage. The third case is different. Firstly, according to the design standard of rainstorm, the runoff to be regulated or the peak discharge to be reduced is determined, and the permeability coefficient of local soil is determined. According to the design requirements, one or more suitable rainwater infiltration facilities should be selected according to the site conditions, and the size of the rainwater infiltration facilities (infiltration area, length, storage capacity, etc.) should be determined by hydraulic calculation to achieve the goal of regulating, utilizing and restraining peak discharge. The overflow discharge of rainwater runoff beyond the design standard should also be considered.
 

In urban residential areas, parks and other areas, the design of rainwater infiltration system generally adopts a combination of various rainwater infiltration facilities.