China’s sponge parks

In 2013 China had a notably heavy monsoon season. Over 200 cities experienced flooding, and it prompted a rethink in urban planning. How could cities be more resilient to flooding?

An architect and urban designer called Kongjian Yu had a potential solution. He had developed an approach called ‘sponge cities’, and in 2015 China announced a pilot scheme that would try out these techniques across 16 cities – see this previous post, or a little summary below. It was very succesful, and sponge cities techniques are now widely used across the country.

One popular tool in the sponge city toolbox is the riverside park, and that’s what I wanted to highlight today. A growing number of towns and cities in China have invested in these, and there are dozens of examples on the website of Kongjian Yu’s agency Turenscape.

These parks include floating gardens, elevated walkways, and a whole range of clever landscape designs that allow them to flood and remain useable for local citizens. Trees are chosen that can stand in water if necessary. Water resistant materials are used for things, like park benches, that might be underwater for parts of the year. Rows of decorative stones reveal themselves as stepping stones when the rains come. Gardens are planted on elevations that are little hills in the dry season and islands in the wet season.

Another thing that I like about these parks – and this is very much a matter of taste – is that they are modern. There’s a distinctive style to Yu’s parks. They have striking pavilions and viewpoints in abstract shapes, and elements of bright colour. Plantings are deep and lush, with no grassy lawns in sight.

In Britain, our parks were mainly designed and built during the Victorian era, and it laid down a certain idea about what a park should look like. I like Britain’s heritage parks, and I don’t suggest we start sticking modernist bits and pieces in them. But I like these Chinese parks too, and I’d love to see a few more like this in due course. Very few councils get an opportunity to design a park from scratch today, and so contemporary park landscaping is quite rare. Olympic Park in London is one notable exception, and a very good park it is too.

Sponge parks like these are a form of climate adaptation, useful for managing seasonal floods. They also enhance the city with beautiful new public spaces, and improve biodiversity.

If you share my appreciation for China’s sponge parks, allow me to point you towards the extensive galleries at Turenscape, where there is much to enjoy.

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What’s a sponge city?

In traditional urban water management, the focus is on getting rid of excess water. When it rains, gutters and drains direct water into channels that flow out of the city. These work fine until there’s a very heavy rainfall – something that is increasingly likely as climate change makes weather more extreme. If too much falls at once, drainage systems are overwhelmed.

Sponge cities start with a different goal in mind. They attempt to absorb and soak up water. Green roofs and walls slow the rain’s progress to the ground. Grass verges and rain gardens catch and hold water to soak away slowly. Public squares and riverside parks are designed to flood in controlled stages.

There are two advantages to the sponge city in a changing climate. The first is that they help to avoid and manage flooding. The second is that by absorbing and soaking up water, they repelenish aquifers beneath the city. This helps to prevent shortages during dry spells. Sponge cities can help with both too much and too little water, so it’s an ingenious urban design solution.