China’s sponge city model can reduce urban flooding: Experts

Beijing: Adopting China’s sponge city model in major cities of Pakistan may reduce urban flooding by 90%, and this may also help to absorb carbon dioxide, increase animal and plant life and expand green spaces.

The sponge city model aims to use previous pavements, rain gardens, green roofs, urban wetlands, and other innovations to absorb water during storms. The soil then purifies that water and gradually releases it – much like a sponge, CEN reported.

Faced with worsening urban floods, cities in China are embracing nature and building what is termed “sponge cities.” Instead of relying on the “grey infrastructure” of levees, pipes, dams, and channels, sponge cities allow urban areas to absorb water in times of high rainfall and release it in times of drought.

The 34-hectare “Qunli stormwater park” in the city of Harbin in northern China is one example of a successful sponge city. It collects, cleanses, and stores stormwater, while also protecting the native natural habitat and providing a beautiful green public space for recreational use.

The government of Pakistan in the past adopted various strategies to avoid urban flooding including the installation of a rainwater harvesting system and the construction of large underground water tanks.

The first urban rainwater harvesting system was installed in the capital city of Islamabad in 2010 at the iconic Faisal Mosque to conserve 3 million litres of water.

On the other hand, in 2020 the Lahore city management launched its first underground water storage system to collect rainwater for reuse and reduce flooding in the city of over 11 million.

The Lahore Development Authority (LDA), in collaboration with its subsidiary Water and Sanitation Agency (WASA), developed the first rainwater storage in the city to recharge the depleting groundwater resources. So far, 3 out of 22 underground tanks have been constructed successfully.

Experts believe that climate change is the major cause of the heavier than average downpour in Pakistan. In the months of June-July, continuous rain in Pakistan has killed more than 150 people, triggering flash floods and affecting millions more.