Chen Yifei's oil paintings have helped give the small town of Zhouzhuang to the southwest of Shanghai the name "Oriental Venice" because of its houses of white walls and black tiles perched on a winding river bank.
For about 900 years, the rivers in Zhouzhuang had run clear, providing drinking water for the small town's residents.
But in the 1980s, a growing population and tourists exerted too much pressure on the fragile water system. The worsening environment in Taihu Lake's drainage area also made it difficult for Zhouzhuang to keep its water clean.
From December 2000, Zhouzhuang underwent a major project to clean the rivers. The result was a fresh-looking Zhouzhuang which smiled at tourists from around the country and the world during the recent week-long "May Day" holiday.
The cleaning project cost Zhouzhuang 80 million yuan (US$9.6 million). But Zhuang Chundi, Zhouzhuang's town head, believes it was worthwhile.
"We are one step closer to being put on the World Cultural Heritage List of UNESCO," said Zhuang. "The project also caters for our residents. Tourism is the only way our town can really develop and sustain its development."
Officials from UNESCO inspected Zhouzhuang in 1997, but they were not satisfied with the water situation. They told Zhuang that Zhouzhuang would qualify as a cultural heritage site but for its lack of clean water - something vital for a town with water at its heart.
Cleaning the water would be easier than creating a long history and unique folk culture, they said.
But the actual cleaning proved far more difficult than expected.
"It was harder and harder!" said Zhang Shenghao, a senior engineer at the Shanghai Tongji Architecture Planning and Designing Institute under the Shanghai Tongji University, which masterminded the project.
He explained that the project consisted of three parts, which all posed difficult challenges.
The first was to stop sewage from entering the river system again. This meant a set of pipelines had to be laid down in the town to gather the sewage and send it to a treatment plant.
The second step was to build a sewage treatment plant at the southeastern end of the town to process some 2,100 tons of polluted water every day and turn it into clean water meeting national requirements.
The final step was to build five small dams where the water ran out of the town, to keep dirty water from entering and guaranteeing the town's river system stayed in a self-contained circle.
But there were conditions attached to the works. Not a stone of the 900-year-old town could be changed.
During the cleaning project, residents and tourists could not be disturbed and boats had to be allowed to continue gliding along the rivers.
The situation was made even more complicated because of the frailty of the town's architecture. In fact, some of the oldest and most beautiful buildings are even now actually on the verge of collapse. In the words of Zhang Shenghao, these houses are "structures made of bean curd."
Historical records show that Zhouzhuang was built on marshlands at the bottom of the ancient Dianshan Lake.
Early settlers rammed the mud into a solid base for building houses, but there was no actual strong support for them. For centuries, the sediment in the rivers has kept the buildings from toppling into the water.
This meant it was out of the question to dig sediment out of the rivers to lay down pipelines. Removing the tiniest bit of sediment could have led to the collapse of several buildings.
After numerous rounds of discussions, Zhang and other experts finally drew up a plan. All the pipelines would be laid according to the natural undulations of the river bed. Pumps were installed to push the sewage up the pipeline.
One construction team after another came to Zhouzhuang and left. They compared the project to catching mice in a porcelain shop. Everything in the town is a precious cultural relic.
One imprudent act could have had irrevocable consequences. Finally, the Fourth Project Bureau of the Railway Ministry took up the mission.
"We never slept a whole night during the project," said Wei Yichen, project manager of the Third Section in the bureau.
Wei's worries were not groundless. No big equipment could be sent to the town. All small and medium-sized equipment and materials like cement, pebbles and iron had to be carried by hand to the site.
"The night at the Qinglongqiao (Blue Dragon Bridge) almost drove us crazy," Wei recalled.
The Blue Dragon Bridge was a big test for the team before it worked on other parts of the town. Following traditional procedures, the workers started pumping water out of the river to start laying down the pipelines. But when cracks started appearing on the walls of the houses on both banks, it had to be stopped immediately. Workers jumped into the wintry river to work.
After a few days, it began to rain harder and harder. The rainwater made the cracks longer and wider, and the local government had to evacuate all the residents in the area.
Wei and his colleagues fought for a whole night to strengthen the buildings and the river banks. Their efforts proved successful.
Working deeper into the town, Wei and other experts in the team invented more and more methods to strengthen the buildings while laying down sewage pipelines. In some places, they had to put cement into the base of old buildings, while in others, they protected the river banks with steel boards.
"I hope we never have to work so gingerly again," Wei smiled.
Another reason for the deterioration of Zhouzhuang's water system was the processing of a local special food, the uppermost part of legs of pork.
To make this food, the pork is baked and stewed until the grease comes out and the pork skin becomes crispy and tasty. In the past, the grease went straight into the rivers of Zhouzhuang, feeding the algae and boosting its growth.
Mayor Zhuang said there were about 70 small pork processing sites registered in the town. If each site made just 50 legs of pork a day, the total would be more than 700,000 a year, and the pollution would be disastrous.
As a counter measure, the water-cleaning project installed strong oil filters in each of the pork processor's workshops. Larger processors were moved out of the town into a place especially set up for them, where a set of comprehensive treatment equipment was installed.
Dong Gengfeng is the owner of a handicrafts shop at the Shuangqiao (Double Bridges) scenic spot, which has inspired numerous painters. Most tourists like to spend a night or two in the small hotels of this area.
She said that before the cleaning project, even dragonflies would not hover over the river. The clothes she cleaned would be a tainted with the smell if she hung them over the river to dry.
"Now it's great! The terrible smell is gone. I hope I'll one day be able to catch fish in the morning, just like years ago," said Dong.
