What Is a Rain Check?

Rainwater channel ^[1] is a pipe system that uses open channels or concealed pipes to discharge rainwater (snow-dissolved water) to natural water bodies or transport them to sewage treatment plants for treatment (generally only first-level sedimentation treatment). Sometimes rainwater systems can also discharge relatively clean industrial wastewater.

Rainwater channel is used

The stormwater channel system consists of stormwater outlets, stormwater pipes, inspection wells, and rainwater outlets. The design of the rainwater channel includes: the alignment of the rainwater pipeline, the determination of the local rainstorm intensity, the delineation of the design pipe section, and the calculation of the design flow in the pipe section, the determination of its pipe diameter, slope, and the elevation and buried depth of the pipe section

There are two types of rainwater channels: indoor rainwater channels and outdoor rainwater channels. The outdoor rainwater channel consists of rainwater outlets, pipes or open channels, inspection wells (rainwater wells), and drainage outlets that discharge rainwater to water bodies. The design flow of the rainwater channel is related to the local design rainfall intensity, catchment area, catchment time and surface runoff coefficient. Generally, it can be calculated and determined according to factors such as the corresponding rainfall formula, local terrain and ground cover conditions. In practice, concrete and reinforced concrete pipes or open channels such as soil and brick, mortar block, concrete are used.

The basic composition of a drainage pumping station includes: a machine room, a pool, a grille, and an auxiliary room. Generally, a substation is also attached ^[3] . The working characteristics of the drainage pumping station are that the pumped water generally contains a large amount of impurities, and the flow of incoming water changes day by day. The pump room and related auxiliary equipment are set in the machine room. The grille and the suction pipe are installed in the sump. The sump can also adjust the unevenness of the incoming water to a certain extent, so that the pump can work more evenly. The grid is used to block coarse solid impurities in the water to prevent the impurities from blocking and damaging the pump. Auxiliary rooms generally include storage rooms, repair rooms, rest rooms and toilets. According to the nature of drainage, drainage pumping stations can be generally divided into sewage pumping stations, rainwater pumping stations, combined pumping stations and sludge pumping stations. Among them, when the water level at the outlet of the rainwater pipeline is high, rainwater cannot drain by itself; or when the highest water level is higher than the ground in the drainage area, a rainwater pump station should be set up in front of the rainwater pipeline outlet ^[1] .