BEIJING: A Chinese river basin where 110 million people live has been hit by the worst floods since 1963 despite massive mitigation efforts, particularly during the rule of Mao Zedong, overwhelmed by the impact of global warming and outdated infrastructure.
Typhoon Doksuri, the most powerful storm in China this year, churned north in late July after making landfall in the south.
It brought exceptional rainfall to the Hai river basin, a region where typhoons rarely hit, and precipitation that the Chinese capital has not seen since records began 140 years ago.
WHAT HAPPENED IN 1963?
Five rivers flow into the Hai river basin, the largest natural drainage system in northern China. The basin includes Beijing, Hebei province and the big port city of Tianjin.
In August 1963, the area was drenched by historic rainstorms, with 22 million people affected by flooding that killed 5,030 people and forced millions from their homes. More than 53.6 million acres of farmland, or 76 per cent of the sown area, was inundated.
In response, Mao Zedong, the founder of modern China, ordered that millions work to bring the Hai river basin under “permanent control”, raising thousands of kilometres of embankments and building new reservoirs and reinforcing old ones.
CURSE OF URBANISATION
Since then, China’s urban population has soared, from just 16 per cent of the population to 64 per cent in 2022. The Hai basin is now home to 25 large and medium-sized cities.
Rapid urbanisation has meant the spread of impermeable concrete surfaces and reduced natural wetlands and marshes that had in the past absorbed rain.
Urban migration has brought a construction boom in low-lying areas, including in flood storage areas and near lakes and rivers.
China’s Soviet-era urban drainage systems of shallow buried pipes leave cities vulnerable to waterlogging during heavy rain, in contrast with cavernous underground storm “corridors” in cities such as Tokyo.
Since 2015, some 30 Chinese cities including Beijing and Tianjin have tested various flood mitigation systems, including permeable asphalt and pavements to slow water run-off but severe floods have raised doubts about their effectiveness.
Source: CNA
