OUT OF THEIR DEPTH
The catastrophic rainstorm that killed 302 people in Zhengzhou exposed the city’s poor emergency response plans and flawed chain of command
Despite the clear skies, Zhang was in a raincoat. He sat in front of Shakoulu Subway Station in Zhengzhou, capital of Henan Province, next to his parked bike. He held a sign: “Niuniu, Daddy is here to take you home.”
Zhang's daughter was one of 14 people who drowned after part of Subway Line 5 flooded during a torrential rainstorm on July 20. Ever since rescue efforts ended, Zhang has come to the station every day. While no one has the heart to address the grieving father directly, many online have called on mental health professionals to help him.
At a press conference on August 2, Henan officials said the rainstorm so far killed 302 people in Zhengzhou, with 50 missing. The city's meteorological bureau said Zhengzhou had 201.9 millimeters of rain between 4 and 5pm on July 20, the most rainfall per hour ever recorded on the Chinese mainland.
Between 2am on July 20 and 2am on July 21, Zhengzhou, according to the National Meteorological Centre, was pummeled with almost 622.7 millimeters of torrential rain – nearly what the city sees in an entire year.
Line 5 was one of the worst-hit places after water collapsed a retaining wall between a nearby railyard called Wulongkou and the Shakoulu Station, causing torrents of water to cascade along the subway tunnel and trapping a train carrying about 500 passengers.
Some netizens accused Zhengzhou Metro employees of waiting too long to stop the trains, while others blamed the subway's flood prevention systems. In any case, the rainstorm exposed the city's poor preparation measures for extreme weather. China's State Council dispatched a team to investigate the effects of the catastrophic rainstorm, the Xinhua News Agency reported.
According to a Zhengzhou Metro statement on July 22, the subway flood was caused by accumulated rainwater in
Wulongkou railyard parking lot, three kilometers from Shakoulu station exit C. There the rainwater collected and eventually collapsed the 2.6-meter-tall retaining wall between the parking lot and the subway entrance.
“The wall did not collapse in an instant,” a man surnamed Liu told Newschina, who watched it happen from his 25th floor apartment window. “I saw water already pouring over the wall at about 6pm. Then cracks appeared and they grew until it collapsed,” he said.
“If a subway employee had discovered it earlier and stopped the train [from arriving], I don't think the consequences would have been so serious,” he added.
A subway employee, speaking to Newschina on condition of anonymity, said that 13 people were sent to block the subway entrance with sandbags and door panels. At one point, they tried to stop the water with their bodies. Another rescuer told Newschina the water rose so high outside Shakoulu Station that it prevented other rescuers from getting closer.
“The subway has a built-in system for daily water leaks and floods that pumps water into the city sewers. But the July 20 storm obviously went beyond the [drainage] system's capacity in both density and flow,” the subway employee told Newschina.
“Nobody expected the rainstorm to be that severe, and we didn't have time to react,” he added.
Trapped Below
Because the city's Line 1 and Line 2 were halted much earlier, many are blaming the late response of Line 5 employees for the tragedy.
According to Zhengzhou Metro's Weibo account, emergency procedures were enacted on the morning of July 20, which involved dispatching emergency vehicles and rescuers to subway stations and safety points, as well as increasing patrol teams. While subway authorities called to halt Line 1 and Line 2 trains at 3:40pm, Line 5 stations were slow to respond. According to the official statement, all subway lines stopped at 6:42pm.
Weibo posts from trapped passengers calling for help began around 6pm. “The rainwater is rushing into the train, and we can't open the doors. People are panicking,” read one post.
“I was in the last train car and saw the flood waters seeping under the doors. The conductor came to try and drive the train in reverse, only to find that the controls had seized after something sparked between the rail and the tunnel wall,” a passenger surnamed Wang told Newschina.
According to Wang, his train stopped at Huanghe Station at about 4:50pm for more than 10 minutes. Before reaching Haitansi, one stop before the ill-fated Shakoulu Station, the train had stopped several other times. It was finally forced to stop operating less than one kilometer before Shakoulu because the rails were submerged in water.
The conductor tried to evacuate some
of the passengers, but the rushing water hindered efforts. It took the first group of rescued passengers one hour to walk 200 meters on the emergency trackside pathway.
After the first group evacuated, the conductor closed the doors to stop the water. By 7:30pm, Weibo was full of distress messages from trapped passengers. Some said the water had risen from their feet to their chests within 30 minutes.
At about 9pm, the water level rose so high that people attempted to break the windows with fire extinguishers, umbrellas and even their keys.
Rescuers eventually broke the windows and doors from the outside. Wang recalled that his train stopped at about 7:10pm, 30 minutes after the time local transit officials claimed they had taken all the trains offline.
When asked why Line 5 trains were not stopped earlier, a director from the Zhengzhou Metro's safety department told Newschina on condition of anonymity that the subway was the commuters' “only hope of getting home” in the storm.
“Line 5 is the only loop line in Zhengzhou. During extreme weather, Line 5 has to alleviate some of the above-ground road traffic and transport more passengers back home [than usual],” he said. “We had to hold out until we couldn't,” he added.
Line 5 trains have six carriages and a capacity of 2,592 passengers, about 700 more than Line 1 and Line 2 trains. By the time it was stopped on July 20, Line 5 had serviced 374,200 passengers. Interviewed passengers told media that the streets were in gridlock.
“We have to follow protocol. Conductors cannot unilaterally stop trains. Neither can metro authorities. They can't take trains offline without the government department's approval,” another Line 5 employee who declined to reveal his name told Newschina.
Local Codes
The tragedy raised concerns over the safety of Line 5's design. While officials assured media that the designs were standard, experts said China does not have national construction codes for flood protection.
In the case of the retaining wall, a railway engineer who declined to be named told Newschina that in many central and northern Chinese cities, which generally see less rainfall, water retaining walls in an all-inone structure are rarely built. Modular walls, which are mobile and less sturdy, are a common substitute.
“Every city has its own [flood protection] standards based on the city's annual rainfall and location,” an engineer with Zhengzhou Metro surnamed Zheng told Newschina. “Most subway designs are intended to last 100 years,” he said, adding that Line 5's flood protection is similar to those found in subways in most northern cities.
Zheng explained a subway entrance is usually raised three steps from the ground to make flooding less likely. While having seven to eight steps offers greater protection, it is less convenient for passengers, so few subways adopt such designs.
“Even if we have [more detailed] standards, it's hard to say whether they would work in such extreme weather,” he added.
“Drainage systems in subways are usually designed to handle a certain capacity. Even if the designers go beyond the code for extreme conditions, the municipal sewers they connect to may be unable to handle it,” Zhan Xuezhao, a deputy chief tunnel engineer at the China Design Group, told Newschina.
‘Sponge City’
Three years ago, Zhengzhou invested 53.5 billion yuan (US$7.9B) in drainage infrastructure. Billed as a “sponge city,” the construction involved installing minimally invasive systems that would protect the city during heavy rainstorms. The costly construction has since come under fire.
“The ‘sponge city' construction actually doesn't target extreme weather... Instead, it mainly deals with water accumulation caused by moderate or light rain, runoff prevention, and reclaiming rainwater for other uses,” Chen Qianhu, director of the Sponge City Institute, Zhejiang University of Technology, told Newschina. “It's a comprehensive concept that includes water conservation and civil engineering projects, and should not be confused with simple drainage,” he added.
Huang Guoru, a water conservation professor at the South China University of Technology in Guangzhou, agreed. He told Newschina that a “sponge city” is not completely protected from floods and only works when four sub-systems – runoff control, rainwater drainage, runoff discharge and urban flood protection – are well established.
Even then, the systems are not guaranteed to handle a rainstorm like the one that hit Zhengzhou, he said.
China classifies meteorological disasters by four alert levels – blue, yellow, orange and the highest, red. City and provincial meteorological bureaus issued five red alerts between July 19 and 20. However the Zhengzhou government did not order people to stop work on July 20 as it should have according to emergency response regulations.
An official from the Municipal Emergency Management Bureau of Zhengzhou told media that the decision to stop work and schools must be approved level by level and the government will not do so “unless absolutely necessary.”
“Zhengzhou had never seen such a torrential rainstorm and based on previous experience, the city's drainage capacity should have been enough to handle the heavy rain. Nobody thought that it would be an extreme weather event,” an official from the Zhengzhou government who did not reveal his name told Newschina. “We cannot assume to bring the city to a halt with every rainstorm,” he added.
Warning Signs
An official from Henan flood prevention command center told Newschina that
the provincial meteorological bureau had warned the incoming weather shared traits with the devastating storm of August 1975.
Brought on by Typhoon Nina, the devastating three-day storm caused extensive flooding across the whole of Central China and is among the most destructive weather events ever recorded in the country's modern history.
Weather authorities warned the rainstorm would severely challenge local reservoirs and cause floods in urban areas. However, the command center focused their efforts on reservoirs because no one expected rainfall in downtown areas would ever exceed that of the 1975 storm, the official said.
According to the statement from the Provincial Emergency Management Bureau of Henan, the command center did not raise the four-tier flood emergency level from IV to II until 6pm on July 20. The level was increased to I at 3am on July 21.
This means that during the storm's most intense rainfall on July 20, the level was still at the lowest, IV.
“Authorities did not heed the red alert. They should have made preparations as soon as the orange alert was issued to minimize risk,” Chen Lin (pseudonym), a researcher fellow at the Wuhan Academy of Social Sciences, told Newschina.
Chen blamed the rigid chain of command. “We should try empowering lower departments to make snap emergency decisions without fear of punishment or set up a green channel for fast reporting of disasters as well as an official accountability system for inaction,” he added.
Huang Guoru agrees. “I think subways should have an emergency response plan that grants them autonomy in determining whether to suspend trains in case of extreme weather and local governments should contact transport authorities directly when a red alert is issued,” he said.
“Besides hardware, the fight against extreme weather depends on public awareness and flexible emergency response systems... Avoiding danger should be the top priority during any natural disaster,” he added.
“I've talked about the [latest] rainstorm in Zhengzhou with many experts and they all called it ‘incredibly heavy.' It's like we were supposed to take a college entrance exam but sat for a master's degree exam,” Cheng Xiaotao, former director of the flood control research center under the China Institute of Water Resources and Hydropower Research, told Newschina.
“This time, we did poorly. This not only was a lesson for Zhengzhou but also the rest of the country. Every city should think about how they would respond to a recordbreaking rainstorm like the one that struck Zhengzhou and how they should adjust their emergency plans,” he added.