Despite damages to a key part of it incurred by the devastating May 12 8.0-magnitude earthquake, Dujiangyan, the 2,200-year-old water conservancy project near Chengdu, capital of southwest China's Sichuan Province, is still functioning well to protect millions of quake survivors from the threat of summer flooding.
"The earthquake caused damages to the fish mouth part of Dujiangyan, but after necessary consolidation efforts, we are sure that the project will function as perfectly as before in water diversion and flood control," a local water conservancy official told Xinhua on Sunday.
Meng Kunjian, head of the Dujiangyan monitoring station under the Sichuan Provincial Water Resources Monitoring and Survey Bureau, said that after the earthquake, the local authorities had taken immediate action to cement the cracks on the fish mouth, a sloping dyke that protrudes into the Minjiang River that flows across the Chengdu Plain.
The fish mouth divides the broad Minjiang River into Neijiang (Inner Course) and Waijiang (Outer Course). Only water that flows into the Inner Course could reach Chengdu and its surrounding plains, while excess flood water will be diverted into the Outer Course and denied access to the affluent and densely-populated plain area.
The simple yet effective design earned Li Bing, the local governor of Qin Dynasty (221-206 BC), the fame of "ancient water conservancy genius", and earned the project a place on the United Nations world cultural heritage list.
The May 12 earthquake, with Wenchuan, some 90 miles to the northwest of Chengdu, as its epicenter, has so far claimed nearly 70,000 lives and displaced several million people. In the worst hit regions, including Dujiangyan City some 40 miles from Chengdu, most quake survivors have to live in tents or makeshift board houses as the clearance of huge piles of rubble and debris is expected to take at least a few months.
"Having endured the tremor and the ensuing secondary geological disasters such as landslides and mud-rock flow, many quake survivors now face the threat of possible summer flooding," a source with the Sichuan Provincial Earthquake Relief Headquarters told Xinhua.
The high water season for the Minjiang River usually begins in May and ends in October, while the main flood season lasts from mid June to mid September.
At 2 p.m. sharp Sunday, the 50-year-old Meng Kunjian called his boss at the provincial bureau to report the latest water level at the Dujiangyan section of the Minjiang River.
"The elevation of the river surface at 1400 hours was 732.52 meters," Meng reported. According to his monitoring records, the water level was at 732.53 meters by 8 a.m. Sunday and 732.54 meters by 2 p.m. Saturday.
"The water level these days remains quite stable, and is almost the same as that in 2007, when no major flooding occurred," said Meng, adding that the water level forecast by the provincial bureau is "between medium and high levels".
However, he said that the earthquake made a big difference this year: the Zipingba Reservoir on the upper reaches of Minjiang also suffered certain damages, and had to stop water storage for dam checking and fortification.
"These days there is not much rainfall on the upper reaches, thus keeping the water level comparatively low," said Meng. "But if heavy rainfall occurs before the Zipingba dam resumes function, the risk of major flooding is quite high."
Meng's station, with three staff including himself, was ordered by both the provincial bureau and the State Headquarters for Flood Prevention and Drought Relief to "be on high alert" and keep a close watch on any major changes of the Minjiang water level.
Currently the station submits reports four times a day, once every six hours. If the water level further rises, the interval will be shortened to 3 hours. "When signs of major flooding show, we must make non-stop reporting around the clock," said Meng.
According to the veteran water watcher who had served in the same station for three decades, a timely early warning could give Chengdu and its adjacent areas 7 to 8 hours for emergency evacuation.
Though highly vigilant, Meng said he was quite confident in the ancient project's capacity to handle general floods.
"Isn't it amazing that it has been working so well for more than two millenniums?" asked Meng, pointing to the direction of the fish mouth with his bandaged right hand, which was wounded in the tremor. "It has such a great design that ever since its completion, the following generations could only maintain or fortify it, but not improve it."
His confidence was shared by many others in the quake-stricken areas.
In a tent set up in the center of Juyuan Town, Dujiangyan City, a family of 8, including a one-year-old baby, were enjoying their lunch Sunday while completely ignoring the swelling Zouma River, a tributary of Minjiang, that flows across just 30 meters away.
"It's weekend, so I cooked six dishes today to give us a small treat," said the smiling housewife, in her 30s.
"The water is rising these days, and we have been cautioned against possible flooding by the government," she said. "We have checked out the routes from our tent to nearby safe, high places, just in case of emergency."
But no one at the table said they actually felt worried. "We have lived here for many years, and the river is always well-tamed by the ancient project, all the way through till it reaches Chengdu," the woman explained. "I don't think this time floodwater would be able to breach Dujiangyan."
(Xinhua News Agency June 23, 2008)