The construction of sponge city should follow the principle of ecological priority, combine natural channels with artificial measures, maximize the accumulation, infiltration and purification of rainwater in urban areas, and promote the utilization of rainwater resources and ecological environment protection on the premise of ensuring the safety of urban drainage and waterlogging prevention.
Building a "sponge city" is not a complete transformation to replace the traditional drainage system, but a "burden reduction" and supplement to the traditional drainage system, so as to maximize the role of the city itself. In the process of sponge city construction, it is necessary to coordinate the systematicness of natural precipitation, surface water and groundwater, coordinate all aspects of water supply and drainage, and consider its complexity and long-term nature.
As an important symbol of the transformation of urban development concept and construction mode, the "timetable" of sponge city construction in China has been made clear, "only forward, not backward". More than 130 cities across the country have formulated sponge city construction plans.
The core of the goal is to make 70% of the rainfall absorbed and utilized locally through the construction of sponge city. The timetable for this goal is that by 2020, 20% of urban built-up areas will meet this requirement. If the built-up area of a city is 100 square kilometers, at least 20 square kilometers will meet this requirement in 2020. By 2030, 80% of urban built-up areas will meet this requirement. ?
design concept
To build a sponge city, we must first change our concepts. The traditional urban construction mode is full of hardened roads. When it rains heavily, it mainly relies on "gray" facilities such as pipes, canals and pumping stations to drain water. Taking "quick drainage" and "terminal concentration" control as the main planning and design concepts often leads to waterlogging when it rains, and drought and waterlogging turn sharply.
According to the Technical Guide of Sponge City Construction, green measures such as grass ditch, permeable brick, rain garden and sunken green space will be given priority in urban construction, and the main planning and design concepts of "slow drainage and slow release" and "scattered source" will not only avoid floods, but also effectively collect rainwater.
Building a sponge city, that is, building a low-impact rainwater development system, mainly refers to achieving a benign hydrological cycle of the city through various technical channels such as "infiltration, stagnation, storage, purification, utilization and drainage", improving the ability of infiltration, storage, purification, utilization and discharge of runoff rainwater, and maintaining or restoring the sponge function of the city.
Extended data:
Sponge city has several characteristics:
Try to digest rainwater locally. This is commonly called water storage. There are surface water storage, such as reservoirs and lakes. There are permeable pavement, underground water cellar and other underground water storage.
The water flowing from the local area must be as clear as a spring. This is commonly known as sewage treatment. Sewage produced locally must be treated on the spot. The burden of sewage treatment cannot be left downstream.
Stay in the local area for surface water storage and groundwater storage, which must be used repeatedly and efficiently.
Every block of sponge city should try to meet all local water demand.
Gradually improve the ecological and environmental functions of sponge cities.
The ideal goal of the sponge city is to build the sponge city into a new green mountain and green water, and let the sponge city return to a part of the natural ecology.
References:
Baidu encyclopedia-sponge city