Reusing rainwater to benefit city, citizens and the climate

Using your car as a boat. This might seem like a futuristic idea, but many cars in China have had the need to drive through high waters. China’s cities often encounter heavy downpours and flooding which create its own problems.

Although rainwater needs to be drained quickly from cities, there is also a great demand for fresh water within cities. Cities drain large amounts of water while water, to supply for drinking water, is pumped or transferred from lakes and rivers at the same time. Would it not be much more convenient and sustainable if rainwater could be stored and retained underground to serve many different purposes within the city when needed?

The above description is exactly what Drainblock can do. Its main material is stone wool, a great insulator and often used for building purposes. Further research and development discovered that it could also be used for water management to prevent flooding in an effective and sustainable way. Stone wool has great load-bearing capacities and can also be used in parking lots and below highways.

Ivo Bastings was one of the players in the development of Drainblock. “We started in the Netherlands and have set up a joint venture in China about 1,5 years ago. We already have many interested parties and projects throughout the country. Cities all over China, from Beijing to Qingdao, from Hainan to Xiamen, are making use of our products.”

A good example of the use of Drainblock is in property development. Mr. Bastings mentions that they are used in the drainage system for new apartment buildings. “When it rains, the water is caught in our blocks instead of straining the drainage system. And the water can then be reused again, for example to water the garden.”

Reusing and harvesting rainwater

For cities and communities to become truly water-wise, the long-term benefits of using alternative water sources such as rainwater are key. Reusing and harvesting rainwater can become an important option to supply drinking water, develop rain-fed agriculture and improve the ecosystem. Cities can serve as a water supply catchment, increasing its use of invisible water to provide temperature control. Increasing urban green spaces, sponge city concepts and retrofitting buildings in cities, are all important methods to prepare for an uncertain future.

In a more practical sense, road design can also play an important role in ensuring a city is able to cope with rainwater. Mr. Bastings points out that there is quite a lot of private-public cooperation in this field in China. “The government hires private engineering firms to design roads and highways. Another one of our projects in Xiamen is the design for a new highway which includes our blocks in a small stroke on the verge. In this way, the rain is first trapped in our blocks and prevents the highway from flooding. Water trapped in the blocks can be reused for other purposes and replenish water resources at the same time.

Although China and the Netherlands are very different countries, mr. Bastings did not encounter cultural difficulties in his work. “The Chinese are very eager to learn and really go for it once they have a goal. You do not need to explain things ten times to them, they directly grasp it and then devise innovative solutions.”