Vietnam.vn - Nền tảng quảng bá Việt Nam

Why can't China's sponge city prevent flooding?

VnExpressVnExpress11/08/2023


The sponge city was designed to prevent flooding, but because it can only withstand a maximum of 200 mm of rain per day, it cannot cope with record storms and rain.

Houses submerged in water in Poyang, Jiangxi. Photo: Yahoo

Houses submerged in water in Poyang, Jiangxi. Photo: Yahoo

China has suffered severe flooding in recent weeks, leaving cities submerged, many dead and infrastructure damaged, raising questions about the effectiveness of a 2015 “sponge city” initiative to reduce the risk of urban flooding, according to Reuters .

The initiative aims to make major cities more resilient to flooding and better utilize rainwater through architectural, engineering and infrastructure changes. But many cities remain vulnerable to heavy rains. In July alone, floods and related geological disasters left 142 people dead or missing, destroyed 2,300 homes and caused direct economic losses of $2.19 billion, China’s Ministry of Emergency Management said on Aug. 7.

China has long sought to improve its response to extreme weather, making its densely populated cities less vulnerable to floods and droughts. The “sponge city” initiative is designed to make better use of nature-based solutions to distribute water more efficiently, while improving storage and drainage.

The “sponge city” initiative’s solutions include using permeable asphalt, building new canals and ponds, and reclaiming wetlands, which not only release stagnant water but also transform the urban environment. Rapid urbanization has encased large tracts of land in impermeable concrete along major rivers that act as floodplains. As wetlands fill in and there is no place for excess water to settle, flooding has become common.

According to 2018 data, 641 of China’s 654 large and medium-sized cities are vulnerable to flooding and inundation, with 180 cities facing a risk of flooding each year. The study found that many recent local pilot initiatives have had a positive impact. Projects such as rooftop greening and rain gardens have helped reduce surface runoff.

However, implementation of the initiative has been uneven. A total of 30 pilot sponge cities were selected in 2015 and 2016. Last year, only 64 of China’s 654 cities had enacted laws adopting sponge city principles. So far, the government has paid little attention to sponge city development, according to researchers. They called on authorities to enact nationwide legislation as soon as possible.

Even if sponge city measures were fully implemented, they would not have been able to prevent this year’s disaster. Zhengzhou, in Henan Province, was one of the pioneers in actively building sponge cities, allocating nearly $8.3 billion to the program from 2016 to 2021. But Zhengzhou still could not cope with the heaviest rainfall on record in 2021.

Experts say sponge city infrastructure can handle no more than 200 mm of rain a day. At the height of a rainstorm that hit Beijing in late July, one weather station received 745 mm of rain in 3.5 days. In July 2021, Zhengzhou experienced more than 200 mm of rain in just one hour. Authorities are also considering climate change as a factor. This year’s heavy rains have hit already dry northern cities, where sponge city development is less advanced.

An Khang (According to Reuters )



Source link

Comment (0)

No data
No data
The powerful formation of 5 SU-30MK2 fighters prepares for the A80 ceremony
S-300PMU1 missiles on combat duty to protect Hanoi's sky
Lotus blooming season attracts tourists to the majestic mountains and rivers of Ninh Binh
Cu Lao Mai Nha: Where wildness, majesty and peace blend together
Hanoi is strange before storm Wipha makes landfall
Lost in the wild world at the bird garden in Ninh Binh
Pu Luong terraced fields in the pouring water season are breathtakingly beautiful
Asphalt carpets 'sprint' on North-South highway through Gia Lai
PIECES of HUE - Pieces of Hue
Magical scene on the 'upside down bowl' tea hill in Phu Tho

Heritage

Figure

Business

No videos available

News

Political System

Local

Product