Eco-cities drain 40% more rainfall than ordinary cities to "feed" green plants

The heavy rain in recent days has caused a large amount of water in some cities in China. However, despite the low-lying terrain of the eco-city, the high-level planning and scientific design at the beginning of construction make the city easily withstand the test of heavy rainfall. The city has never been waterlogged in the past five years. The "Rainwater Special Plan" was formulated at the beginning of the construction of the "magic weapon" eco-city. According to the relevant planning, the eco-city will set up side drainage holes at the bottom of the "road junctions" along the road at an average interval of 30 meters to collect the water from the motorway.

In non-motorized lanes and parking lots, a large number of sand-based permeable tiles are used, which can contain part of the rainwater. When it rains, the rainwater flows first into the isolated green belt of the road from the side drainage holes and the gravel layer under the permeable brick, and then flows into the underground rainwater pipe network after ensuring that the green plants are "drunk". Due to the characteristics of the eco-city's high greening rate and water-bearing road surface, half of each rainfall is absorbed as soon as it falls. In addition, for rainwater that cannot be absorbed by the surface, the eco-city also plans a path for rainwater to be collected underground. At the beginning of the planning, the construction standard of the underground stormwater network was adjusted to meet the drainage demand of three to five years of rain (95.1mm/24 hours), which is 40% higher than the drainage demand of the current stormwater network of most cities in the country to meet the drainage demand of one year of rain (67.7mm/24 hours). "The rainwater pipe network in the planned area shall be designed in accordance with the planned final flow, and the rain and pollution diversion drainage system shall be implemented." According to the staff, the eco-city will build five rainwater pumping stations in the early stage to purify and treat the early and late rainwater. There are two ways to discharge the initial rainwater. One is to set up constructed wetland at the outlet of the pumping station, store and purify the constructed wetland before entering the ecological city water system. The second is to set up special pipes for initial rainwater, access the nearby sewage system, and enter the eco-city water system after treatment by the sewage treatment plant. In the later stage, the water quality of rainwater is relatively stable, and it is directly discharged into the water system through special pipes, and the water quality is purified by the self-purification capacity of the eco-city water system.