Context: China has been hit by devastating floods in July, inundating cities and causing deaths and infrastructural damage, as well as raising questions about the effectiveness of its 2015 sponge city initiative to reduce urban flood risks.
About Sponge Cities
- It describes urban areas with abundant natural areas such as trees, lakes, and parks or other good designs intended to absorb rain and prevent flooding.
- It can alleviate urban flooding, water resources shortage, and the urban heat island effect and improve the ecological environment and biodiversity by absorbing and capturing rainwater and utilizing it to reduce floods.
- There are three main facets to developing such systems: protecting the original urban ecosystem, ecological restoration, and low-impact development.
- It is part of a worldwide movement that goes by various names: green infrastructure in Europe, low-impact development in the United States, water-sensitive urban design in Australia, natural infrastructure in Peru, and nature-based solutions in Canada.
- Associated techniques include permeable roads, rooftop gardens, rainwater harvesting, rain gardens, green space and blue space such as ponds and lakes.
Need for Sponge Cities
- A growing number of urban areas are experiencing devastating floods as climate change brings heavier rainfall and growing flood risk.
- A recent Intergovernmental Panel on Climate Change (IPCC) report said 700 million people already live in areas where rainfall extremes have increased, a number expected to grow as global temperatures rise.
- They can hold more water in rivers, greenery, and soil instead of losing it to evaporation, meaning they are more resilient to drought.
- Natural ways to absorb urban water are about 50% more affordable than man-made solutions and are 28% more effective.
Significance of Sponge Cities
- In the long run, it will reduce carbon emissions and help fight climate change.
- It can reduce the frequency and severity of floods and improve water quality.
- Helps in preventing beach pollution by capturing stormwater
- Associated strategies like green space can improve quality of life, improve air quality and reduce urban heat islands.
China's Sponge Cities
- A sponge city is a new urban construction model for flood management, strengthening ecological infrastructure and drainage systems, proposed by Chinese researchers in early 2000 and accepted by the Chinese Communist Party (CCP) and the State Council as urbanism policy in 2014
- The "sponge city initiative" undertaken by the Chinese government involves the construction of water-absorbent infrastructure in 30 different urban centers. This initiative aims to effectively manage and utilize 60% of the rainfall in these cities.
- The strategy includes creating ponds, wetlands, and installing permeable surfaces on roads and public areas, facilitating the natural infiltration of stormwater into the earth.
- China's goal is for 80% of its urban regions to have the capacity to absorb and recycle a minimum of 70% of rainwater by the year 2020.
With rapid urbanisation in India and increasing urban floods, it is time for India to move towards sponge cities.