‘Sponge cities’: China develops technology to reuse rainwater

China has revived the ancient practice of collecting rainwater to make buildings more environmentally friendly, The Guardian writes.

The northern regions of China are relatively dry, while the south receives more rainfall. To address these uneven water resources, many cities are implementing systems to collect and reuse rainwater.

Buildings are equipped with specialized systems that channel rainwater through pipes into storage tanks. The collected water is then filtered and reused for toilets, irrigation, cleaning, and other non-drinking purposes.

According to local authorities in Beijing, the city reuses 50 million cubic meters of rainwater annually. Combined with other water sources, such as runoff from bathrooms, over 30% of Beijing’s water needs are met with recycled water.

China is also promoting the “sponge city” concept, which involves designing urban areas so they absorb rainwater like a sponge.

Sponge cities use green spaces, parks, and traditional drainage systems to reduce the risk of flooding.

Managing water flows has been a challenge for Chinese rulers for millennia. Historical records show that even during the Qin and Han dynasties, small ponds were constructed to collect rainwater.