In today's urban planning and construction, sponge city is not only a familiar term, but also a goal pursued by cities in their development. What is a sponge city? It is a very vivid metaphor. A sponge city means that urban construction should be built with sponge-like performance; it is a new-generation concept of urban stormwater management. It refers to a city having good "elasticity" in adapting to environmental changes and responding to natural disasters brought by rainwater. When it rains, it can absorb, store, infiltrate, and purify water; when needed, it can "release" the stored water and make use of it, taking in and discharging rainwater as freely as a sponge. Therefore, from the perspective of scientifically transforming natural ecology, a sponge city falls within the category of green cities.
The concept of the "sponge city" first appeared in April 2012, when it was initially proposed at the "2012 Low-Carbon City and Regional Development Science and Technology Forum." In December 2013, General Secretary Xi Jinping emphasized in his speech at the Central Urbanization Work Conference: "When improving urban drainage systems, priority should be given to retaining limited rainwater and to making greater use of natural forces for drainage, building sponge cities with natural storage, natural infiltration, and natural purification." Subsequently, the General Office of the State Council issued the Guiding Opinions on Promoting Sponge City Construction, pointing out that measures such as infiltration, detention, storage, purification, utilization, and drainage should be adopted to absorb and utilize 70% of rainfall on site. This year's Two Sessions attracted widespread attention and heated discussion among deputies and members.
Thinking in reverse, the proposal of sponge city construction also reflects the shortcomings of China's current urban construction, or rather, the unsatisfactory current situation we face. We often say that since reform and opening up, we have achieved remarkable accomplishments in various fields of construction. That is true, and urban construction is no exception: high-rises stand in great numbers, roads are broad, traffic and pedestrians flow, and the atmosphere of modernity is strong. But behind the bright and glossy exterior, there is shabbiness and disarray within. This is why, once rainstorms strike, cities reveal their true form and immediately turn from "beautiful cities" into "water cities." Beijing residents all remember that during a heavy rainstorm a few years ago, some streets appeared blocked by "rivers," creating the "spectacular" scene of people being ferried across the "rivers" by boat. If even the capital is like this, other cities can be imagined. This shows that in urban construction we mostly emphasize the "face" while neglecting the "inner core." Urban flooding has become a weak spot of cities and a pain point for people. The exposure of these fatal weaknesses strongly calls for sponge city construction. In this year's government work report at the Two Sessions, Premier Li Keqiang proposed: "We will coordinate aboveground and underground urban construction, begin construction of more than 2,000 kilometers of urban underground utility tunnels, launch a three-year action to eliminate key urban waterlogging-prone sections, and advance sponge city construction, so that cities have both 'face' and, more importantly, 'inner core.'" Here, Premier Li Keqiang's use of the word "more" illustrates the importance of the "inner core" in sponge city construction. It can thus be seen that to accelerate sponge city construction, on the one hand, laws and regulations on sponge city construction must be improved to ensure construction in accordance with the law and prevent arbitrary exercise of power and projects that only care about "face"; on the other hand, as the main force of construction, the construction industry should fully leverage its professional role in sponge city planning and construction, scientifically and meticulously making the "inner core" projects solid and well done. The "inner core" really matters too much!