Have you heard of sponge cities? No? I hadn’t either until today.
Apparently, this is already a ‘thing’ in China. It is being practiced in some other parts of the world but under different names, such as ‘low-impact development’ or ‘sensitive urban design.’ In China, they have been experimenting with this type of urban design for twenty. An NPR report gives you an idea of how this works. The idea is to create spaces and conditions that allow for the absorption and redirection of water runoff.
Some of these designs are lovely. In the city of Jinhua, in eastern Zhejiang province, there was a flood wall at the confluence of two rivers that failed to protect the area from annual inundation. The concrete wall was replaced with a permeable landscape with overflow ponds and permeable footpaths, lined with grass, willows, and reeds. The designer Yu Kongjian, the godparent of sponge cities, even included an elevated walkway painted red and yellow to evoke the idea of a dragon.
"So instead of building the flood wall higher and higher, I removed the concrete wall and [terraced] the riverbank," he says.
This article contains some examples of this in cities such as Seattle and Berlin. And here is another one with some appealing images of sponge city designs.
Perhaps, it is too little and too late, but certainly those areas where these designs are put in place are considered more flood and drought resilient.
There are even standards of measure applied to determine the effectiveness. Check out this article.
“The seven cities analysed were New York, London, Singapore, Mumbai, Auckland, Shanghai, and Nairobi.
Each was given a “sponginess” percentage of 1-100%. Cities with higher ratings can absorb more water during rainfall.”
Sponginess as a desirable characteristic in urban design was new to me, but I’ll take it.