The dam at a small reservoir in China's Guangxi region gave way last month after days of heavy rain in a collapse that could be a harbinger of sterner tests for many of the country's 94,000 aging dams as the weather gets more extreme.
Located in Yangshuo county, famed for its otherworldly karst landscape, the dam collapsed at around midday on June 7, inundating roads, orchards and fields in Shazixi village, residents told Reuters.
"I've never seen such flooding," said villager Luo Qiyuan, 81, who helped build the dam decades ago.
"The water levels were never so high in previous years, and the dam had never collapsed."
Completed in 1965, the dam, made of compacted earth, was designed to hold 195,000 cubic metres of water, enough to fill 78 Olympic-size swimming pools and meet the irrigation needs of Shazixi's farmers.
On a visit to the reservoir in mid-July, Reuters found the length of the dam, of about 100 metres, had largely vanished. It was reinforced 25 years ago.
The water went over the dam, which then collapsed, said a member of a survey crew at the reservoir, declining to be identified as he was not authorised to speak to media.
Shazixi residents said there were no deaths.
But the collapse, which was not reported by domestic media, suggests big storms might be enough to overwhelm reservoirs, especially if the design is inferior and maintenance has been patchy.
That raises the prospect of disaster in river valleys and flood plains that are much more densely populated than they were when the dams were built.
Environmental groups say climate change is bringing heavier and more frequent rain. Massive flooding could trigger unforeseen "black swan" events, the government says, with extreme consequences.
EXTREME EVENTS
Thousands of dams were built in the 1950s and 1960s in a rush led by Mao Zedong to fend off drought in a largely agrarian China.
In 2006, the Ministry of Water Resources said, between 1954 and 2005, dykes had collapsed at 3,486 reservoirs due to sub-standard quality and poor management.
It was unclear if record-breaking rains were to blame for the Shazixi collapse or if the dam's emergency spillway had been blocked by silt or if it was a design problem.
The water resources department in the area declined to comment. The county government did not respond to a request for comment.
In Guangxi, in southwestern China, rainfall and temperatures were on average significantly higher in 1990-2018 compared with the previous 29 years, official data shows.
It's the extreme events that put dams at risk, said David Shankman, a geographer at the University of Alabama who studies Chinese floods.
"But a dam should be able to withstand extreme events even if they become regular, and when the flood is over, it should be exactly of the same quality as before the event, if the dam was properly designed and built," Shankman said.
According to a notice at the Shazixi reservoir's monitoring station, the 151.2 metre-tall dam was built with a once-every-two-century worst-case scenario in mind in which water was expected to reach 149.48 metres. Last month, it overflowed.
In the county seat of Yangshuo in June, more rain fell in three hours than usually falls in two months.
The Ministry of Water Resources did not respond to a request for comment.
In what could be another sign of trouble to come, water behind a dam on a tributary of the Yangtze river rose so sharply that authorities on Sunday were forced to blow up part of the dam to lower the level.
'BLACK SWAN'
In China's worst dam catastrophe, the Banqiao on the Yellow River, completed in 1952 with Soviet assistance, collapsed in 1975, killing tens of thousands of people, official estimates published two decades later showed.
Ye Jianchun, deputy minister of the Ministry of Water Resources, told a recent news conference he was confident flood-control projects on major rivers were capable of handling the largest floods seen since the founding of the People's Republic of China.
But Ye was not so categorical about dams on other rivers, saying excessive floods may exceed the defence capability of the engineering to result in a "black swan" event.
Aware of the risks, authorities have been reinforcing and raising old dams and stepping up inspections. New dams are planned to increase storage capacity.
North of Yangshuo at Qingshitan is the biggest dam in the area. The banks of the river into which it empties have been shored up since last month, said a workman dumping rocks and soil with a wheel loader.
But climate change is bringing a new normal of extremes and flood-risk policies decided a decade or two ago are no longer sufficient, said Benjamin Horton, director at the Earth Observatory of Singapore.
"What really needs to happen is to work with the ecosystems, not against them by building dams, by extending flood wetlands and flood plains and allowing the water to naturally mix with the environment," he said.
Reuters
Wed Jul 22 2020
An aerial view shows the flooded Yangshuo town by the overflowing Li River, against the backdrop of the karst landscape in Guangxi Zhuang Autonomous Region, China June 7, 2020 - Chen Yan via REUTERS
Brazil's Lula says head injury 'serious,' with update from doctors in coming days
The president's injury forced him to cancel a trip to Russia for a summit of the BRICS group of major emerging markets being held in Kazan.
Blinken heads to Israel to revive Gaza ceasefire talks after Sinwar death
Blinken will focus discussions on how to end the war, plans for the enclave after the fighting ends and how to improve humanitarian assistance.
Facebook owner Meta restarts facial recognition tech in 'celeb-bait' crackdown
Meta said it will enroll about 50,000 public figures in a trial which involves automatically comparing their Facebook profile photos with images used in suspected scam advertisements.
BHP trying to avoid responsibility over Brazilian dam collapse, UK court told
More than 600,000 Brazilians, 46 local governments and around 2,000 businesses are suing BHP over the 2015 collapse of the Mariana dam in southeastern Brazil.
Minimum wage not benchmark for all employees' starting salaries - Sim
Steven Sim says the increase in the minimum wage is intended as a basic wage for workers with lower academic qualifications and skills.
Climate and China weigh on how the US views Pacific relations
Pacific leaders keep their preference for US President quiet, yet viewing relations only through the lens of China does nobody a service.
Gulen, the powerful cleric accused of orchestrating a Turkish coup, dies
Gulen was a one-time ally of Erdogan but they fell out spectacularly, and Erdogan held him responsible for the 2016 attempted coup.
[COLUMNIST] The reality of earthquakes in Malaysia: A threat we can’t ignore
The government needs to prepare the public to deal with such disasters in any way possible.
'PROTEGE-Veteran' provides job assurance for retirees
This is an aggressive step by the government to protect the welfare of retirees, said Dr Mohd Hasril Amiruddin.
US says THAAD anti-missile system is 'in place' in Israel
THAAD is a critical part of the US military's layered air defense systems and adds to Israel's already formidable anti-missile defenses.
IMAN Research calls for strengthening human security in 2025 Budget
IMAN Research identifies key areas for enhancement within the Malaysian government's Third MADANI Budget 2025.
Zambry assures academics of freedom of speech
Zambry says he is committed to preventing any actions that could infringe upon the rights and freedoms of academics across universities.
Media licensing framework development involves multiple consultations - Teo
Teo Nie Ching says the views of stakeholders have been considered through several engagement sessions and ongoing consultations.
ANALYSIS - World lags on 2030 nature goals headed into UN COP16 talks
A top concern for countries and companies is how to pay for conservation, with the COP16 talks aiming to develop new initiatives.
Situation in South China Sea safe, under control - Adly
Adly Zahari clarifies that reports of Chinese maritime assets near country's border mainly involve its Coast Guard, not its naval warships.
MOHE sets agenda to boost higher education cooperation ahead of ASEAN Chairmanship 2025
Datuk Seri Dr. Zambry said all higher education institutions must be involved to successfully implement the ASEAN chairmanship agenda.
King receives credentials of 12 foreign envoys to Malaysia
His Majesty Sultan Ibrahim welcomes nine new foreign envoys and appoints two Malaysian diplomats in a ceremony at Istana Negara.
Israel gives the US its demands for ending war in Lebanon, Axios reports
Israel demands IDF "active enforcement" to prevent Hezbollah from rearming and rebuilding military infrastructure near the border.
Indonesia's Prabowo swears in cabinet of over 100 ministers, deputies
Prabowo Subianto's cabinet has 48 ministries with over 100 ministers and deputies, including two re-appointments.
Freeze on foreign worker employment quota to continue - Saifuddin
Datuk Seri Saifuddin Nasution Ismail said as of Sept 15 the total number of foreign workers is nearing the stipulated ceiling.