An urban management officer warns visitors of danger at Tian'e Lake in Hefei, Anhui province. CHINA DAILY

Tian'e Lake in Hefei, Anhui province, can be deadly if visitors don't heed the warnings of Xu Jian and his fellow urban management officers, who patrol the waters day and night and point out its hazards.

A man-made reservoir in the city's Shushan district, Tian'e Lake was opened to the public in 2004. Since then, at least 66 people have drowned, according to media reports.

"Most of the victims were swimmers; others committed suicide," said Xu, deputy head of the Tian'e Lake team of urban management officers, who has been patrolling the lake for years.

When a heat wave hits the city, people flood to the lake. To keep them away from dangers beneath the water, 106 urban management officers are asked to stay on high alert, although the lake measures just 800 meters north to south and 1.5 kilometers east to west.

"Working in four shifts each day, the lifeguards patrol the lake 24 hours," Xu said－even at times in winter.

"The water is shallow in areas close to the lake's shore but deepens sharply after a few meters," said Xu, adding that the lake bottom takes the shape of a pot.

The lake was once a deep pond when the area was farmland 12 years ago, surrounded by high buildings. Then the city excavated to make it bigger and turned the area into a park.

A lot of sand was placed along the southern bank to make a beach, so residents would be able to enjoy the cool water on hot days.

Though there are signs reminding people of the dangerous underwater landscape, some swimmers pay no heed, overconfident about their skills, Xu said.

When he is on duty, he must walk continuously around the lake, more than 4 kilometers in circumference, or sometimes use a patrol boat.

Every time he sees someone cross the danger line－a rope with some floating balls attached－Xu gets nervous and shouts to them with a bullhorn.

"Most of the tourists will listen to us, while others just don't bother," Xu said.
"There are also people who not only don't listen to us but even attack us when we try to get them out of the water."

In May, a swimmer brought out of the danger zone attacked a colleague of Xu's with a knife. The wounded officer was sent to the hospital. The swimmer, who was in his 20s, was detained by the police.

If a drowning occurs, the officers on duty may be penalized. "As punishment our monthly salary could be cut," Xu said.