Authorities in Shanghai are contesting claims that the city is vulnerable to serious flooding, noting the city's work to build protective bulwarks in recent years and its capability of moving residents out of harm's way amid emergencies.

The city's ability to control floods came under scrutiny after a study appearing in the American journal Natural Hazards suggested that it is more vulnerable to serious flooding than eight other big coastal cities in the world.

Scientists from Britain and the Netherlands used a new measure called the Coastal City Flood Vulnerability Index to study Shanghai; Buenos Aires, Argentina; Kolkata, India; Casablanca, Morocco; Dhaka, Bangladesh; Manila, Philippines; Marseille, France; Osaka, Japan; and Rotterdam, Netherlands. They collected social, economic, political and administrative data for those places, and considered their geological features.

The authors of the study found that Shanghai is the most exposed of those cities to coastal floods, a result partly of its long coastline.

"From a social perspective, the population close to the coastline is high, but the city does not have high resilience and the number of shelters is low compared to the population density," they wrote.

Various scholars in Shanghai deemed the authors' methods to be "too simple", saying that only a rigid mathematical model was employed in the study.

In Shanghai, storm surges are far less likely to cause flooding than they are in places such as Dhaka and Kolkata, said Dai Xingyi, an environmental science and engineering department professor at Fudan University.

Among the events that can cause serious floods in Shanghai are earthquakes and tropical cyclones, he said. The city, though, does not lie on a main seismic belt and doesn't have a history of being frequently or directly hit by typhoons.

Historical data show that only one typhoon has directly hit Shanghai, making landfall on the city's Chongming Island in 1974, the professor said. He also said the study's findings ignored the central governments' ability to move the public out of harm's way during emergencies.

Li Ruichang, deputy director of Fudan University's emergency management research center, noted the city's experiences in controlling floods and preventing disasters.

"Shanghai has done a great job in disaster prevention and emergency relief, though it still lags behind other metropolises in the world such as New York, London and Paris," he said.

As an example of what Shanghai can do to prepare for the worst, he noted the city's preparations for Haikui, the 11th typhoon this year. Earlier this month, the storm made landfall in neighboring Zhejiang province, causing torrential rains in Shanghai.

In one and a half days, 370,000 people living in Shanghai's coastal areas, makeshift residences and construction sites were moved to safer places, he said.

The expert said improvements meant to better protect the city from disasters should be mainly made to new towns on the outskirts of Shanghai, adding that older parts of the city are in less need of such work.

On Thursday, Liu Shuguang, an official at the Shanghai Institute of Disaster Prevention and Relief, said the study's conclusion is "open to debate".

"As a coastal city, Shanghai is vulnerable to severe weather," Liu said. "But one important question is: How can we ensure the public is aware of the need for disaster prevention and relief?"

Officials charged with fighting floods in the city declined interview requests from China Daily.

During an interview with the Oriental Morning Post on Wednesday, Hu Xin, deputy director of Shanghai Flood Control Headquarters, called the study's conclusion "incomplete".

He told the newspaper that Shanghai began to build a flood control system along its coastline after a typhoon severely damaged the city in 1949.

So far, the city has built 523 kilometers of coastal levees. The city's flood control system was designed to withstand a once-in-200-year high tide and gale winds of up to 133 km an hour, the official added.

The Huangpu River's levee and various urban flood control projects are designed to protect the city from a once-in-1,000-year high river level, he said.

The city also has a highly capable team working at its Shanghai Flood Control Headquarters and has established a means for it to communicate with people working in its district and county sub-headquarters.

wangzhenghua@chinadaily.com.cn