Commentary: China struggles with ‘once-in-a-century’ floods that may be new normal
Aside from immediate disaster relief efforts, China should intensify infrastructure development and build new capabilities as climate change is likely to increase the frequency and scale of such floods, say Asit K Biswas and Cecilia Tortajada.
SINGAPORE: China is battling a serious flood that may have grave implications for hundreds of millions living in its Southern provinces.
As of mid-July, nearly 38 million people were affected in 27 provincial level regions, with 141 people dead or missing. This count is sure to climb.
China’s Ministry of Emergency Management said on Jul 9 that an estimated 1.72 million people had been relocated, 22,000 houses had collapsed, with direct economic losses estimated at US$8.81 billion.
Just three days later, 2.25 million people had been evacuated, 1.26 million people needed emergency assistance, 209 thousand hectares of crops had been damaged and direct economic losses had increased by nearly 30 per cent, to US$11.75 billion.
READ: Commentary: Rising temperatures, fires and floods highlight importance of understanding weather extremes
A LONG HISTORY OF FLOODS
China has suffered regularly from floods throughout its history.
In ancient China, a place where legend and history often intermingle, some 4,000 years ago, Emperor Yu The Great, founder of the Xia Dynasty, is said to have tamed the floods of the mighty Yellow River, saving citizens untold misery.
The Yellow River is the second largest river in China, after the Yangtze, and the sixth largest in the world. Floods are so regular and serious there that people call these incidents expressions of “China’s sorrow”.
China has had more than its fair share of world’s floods. Of the 10 largest floods around the world during the past 100 years, seven have been in China: Five in the Yangtze, in 1911, 1931, 1935, 1954 and 1998, and two in the Yellow River in 1887 and 1938.
In fact, the world’s most severe flood occurred in the Yangtze and Huai rivers in 1931. After two years of serious drought, extreme rainfall in the densely populated Yangtze basin contributed to this flood. The areas affected were as huge as all of England and half of Scotland combined.
Over 2 million lives were lost due to this flood, and the resulting disease and malnutrition. An estimated 40 per cent of the affected population had to leave their homes.
There’s no denying that floods are one of nature’s most powerful destructive forces.
Between 1995 and 2015, there were some 3,000 flood disasters all around the world, affecting nearly 2.3 billion people. Since 1980, floods have contributed to well over a trillion dollars in global economic losses.
With climate change bringing more erratic weather patterns, countries like China must do more to prepare populations for more of such floods.
A COMING CATASTROPHE
The impacts of these latest floods have demonstrated how far reaching the consequences can be.
Just this past week, four cities, Xianning and Jingzhou of Hubei province, and Nanchang and Shangrao of Jiangxi province, have declared their highest levels of emergency alert. In Jiangxi province alone, 5.5 million people have been affected. Nearly 500,000 had to be evacuated as of July 13.
The most dangerous period of the flooding may be ahead. Past experiences indicate major floods are most severe in late July and up to mid-August, as heavy rains subside after the South China monsoon season is over.
The latest flood has almost reached the scale of the historic flood in the middle and downstream reaches of Yangtze river in 1998 which lasted from mid-June to early September. The 1998 flood impacted over 180 million people and damaged 13 million homes.
In Poyang Lake, the country’s largest freshwater lake, water levels rose to 22.6m on Monday (Jul 13), its highest ever recorded in history.
Premier Li Keqiang, during a meeting of the State Council on Jul 8, called for national efforts in rescue and relief work to be intensified to save lives as top priority. He noted there should be zero complacency in flood control and disaster relief works.
The Chinese National Cultural Heritage Administration has noted that over 500 immovable cultural monuments, including ancient bridges, citywalls and historic buildings in 11 provinces, have suffered varying degrees of damages making it the worst year for relics.
MANAGING THE NEXT EXTREME FLOOD
Immediate humanitarian and disaster relief endeavours aside, China must accelerate long-term infrastructure plans to mitigate the impacts of floods.
This has to be combined with a razor sharp focus on building new capabilities like good land use planning, early warning systems and effective evacuation systems when catastrophic floods strike.
The Three Gorges Dam has played important an important role in mitigating floods in the Yangtze River.
Between 2003, when the dam was completed, and 2019, it stored excess flood water during the monsoon seasons 53 times, and then gradually released this after floods were over.
Over the years, China has also invested significant work into assessing risks by identifying developments in flood-prone areas, their vulnerabilities and possible ways to reduce flood risk to build resilience.
These include sponge cities programmes, the rehabilitation of natural wetlands and construction of artificial wetlands in new cities and rain gardens in old and new cities.
The use of big data and artificial intelligence in weather forecasting, flood monitoring and warning have helped China to warn regional authorities of upcoming floods much faster. During the current floods, China's Meteorological Administration had warned regions in the south of the country to prepare.
The country also continues to build, extensive flood control infrastructure along rivers to rapidly channel flood waters from the cities. These include dams, walls, drainage systems, flood retention tanks, canals and flood-proof buildings.
In recent years, these infrastructures have been complemented with green solutions such as the sponge city programme, artificial wetlands, rain gardens, and permeable pavements.
China’s sponge cities programme now covers 30 cities, including Shanghai, Wuhan and Xiamen. By the end of 2020, these cities are expected to be able to absorb at least 70 per cent of rainwater.
They use porous surfaces and plan for large spaces to contain rainwater. These include permeable roads and sidewalks, green roofs, wetlands and natural vegetation to absorb, store and drain rainwater.
These cities have essentially made flood risk management a central pillar of their urban planning.
Additionally, with floods increasing in frequency and intensity, sponge cities also require all new and large construction projects – such as buildings and factories – to have storage areas for rainwater to temporarily hold flood waters.
China now leads the world in implementing sponge cities programme and managing catastrophic floods.
A major problem China and the rest of the world face is how to determine the magnitude and duration of extreme floods likely to happen in the future because of climate change.
The harsh reality is that there is not enough knowledge at present on how to estimate reasonably accurately magnitudes of extreme floods which may become national emergencies. China’s cities can set a global example.
Even then, it is no panacea when a country, so used to battling floods for centuries, struggles against an enemy growing in scale, strength and frequency.
One thing is clear: It is high time for major cities in China and all over the world to start planning to protect their populations from major floods likely to occur in the coming decades, with a judicious mix of infrastructure and innovative green policies.
Prof Asit K Biswas is Co-founder, Water Management International Singapore, and Distinguished Visiting Professor, University of Glasgow, UK. Dr Cecilia Tortajada is Senior Research Fellow, Institute of Water Policy, Lee Kuan Yew School of Public Policy, NUS, and Editor-in-Chief, International Journal of Water Resources Development.