The entire world is filled with concrete. Natural water system is disregarded. In the meantime, extreme weather conditions — floods, droughts — are frequent because of climate change. China has been hard hit by this. To solve this problem, they came up with the idea of Sponge City in 2015. No no, it isn’t the place where Spongebob Squarepants lives. Instead, it is a city structured to absorb and capture rainwater. It helps in flood prevention. It is a sustainable, regenerative, eco-friendly, low-impact, future-proofed, zero-carbon solution for the drainage system at urban scale.

Before explaining more about what Sponge City actually is, let us first understand what issues does Sponge City intends to solve.

  • Water Scarcity in urban and semi-urban areas — Most of the time we get water from aquifers underneath us. The rainwater is absorbed by the ground and is filtered through. This water reflourishes the aquifers. With extreme urbanization and impermeable concrete structures, the aquifers cannot restore to their levels. Thus less water is available.
  • Polluted water discharged into the rivers and seas — Now that water cannot be absorbed, it gets drained into sewage. This mixture is more polluted.
  • Degradation of urban ecosystem and increase in the intensity of flooding — Because of urbanization and industrialization there is a drastic change in the climatic conditions. This leads to extreme weather conditions. Flooding leads to water clogging and disturbances in the natural water cycle.

To deal with these problems, the idea of Sponge City has surfaced. The idea of Sponge City is to create a pervious system to allow the flow of water. The water is absorbed in the sponge-like environment and is stored in urban aquifers which can be used by the city.

A sponge city needs to be abundant with space that allows water to seep through it. Besides the permeable asphalt and water-absorbing materials, a sponge city requires contiguous open green spaces, interconnected channels and ponds that can naturally store and filter water. Green roofs can retain and filter water before releasing it into ground. More importantly, moderating the usage of water is very important.

The sponge city provides a wide range of advantages. More clean water, Cleaner groundwater, reduction in flood risks, greener and healthier environment. Inspired by this model, lately, many countries are studying and trying to incorporate this system into their environment.