What is a sponge city?

Vandu era sponge city refers to the traditional construction of towns and cities, mainly based on hardened road surface, supplemented by reasonable urban planning and appropriate greening to create a beautiful and clean urban environment.

But the hardening of the urban road system everywhere on the local drainage system requirements will be very high, with the accelerated process of urbanization, the population growth of the cities, life and production of water has increased dramatically, mainly relying on the pipeline, pumping stations, and other "grey" facilities to drainage of the traditional big cities, it is stretched to the limit, and then meet the rainy season, almost every rain. If the rainy season, it is almost always flooded.

The concept of "sponge city" requires that urban construction will emphasize the priority use of grass ditches, soakaway bricks, rain gardens, sunken green space and other "green" measures to organize drainage, with "slow drainage and slow release

Construction of a new building will emphasize the use of grass-planted ditches, soakaway tiles, rain gardens, sunken green spaces and other "green" measures to organize drainage, with "slow drainage and slow release" and "source dispersion" control as the main planning and design concepts, both to avoid flooding, but also to effectively collect rainwater.

Construction of sponge city, that is, the construction of low-impact development of rainwater system, mainly refers to the "seepage, stagnation, storage, purification, use, discharge" and other technical ways to realize the city's benign hydrological cycle, to improve the infiltration of runoff rainfall, storage, purification, utilization and discharge capacity, to maintain or restore sponge function of the city. Simply put, sponge cities have good flexibility in adapting to environmental changes and coping with natural disasters, absorbing, storing, seeping and purifying water when it rains, and releasing and utilizing the stored water when needed.

Sponge city development in China is still in an immature stage, successively many cities were proposed sponge city concept, but sponge city planning needs to take into account the natural ecological environment of the city, topography, rainfall, geological hazards, urban pipe network capacity and other factors, more complex, there is not yet a unified design standards.