The hundreds of thousands of Chinese who spent more than 17 centuries building the country's Grand Canal received posthumous just reward when it was transcribed on the UNESCO World Heritage List on Sunday.

For all their toil, however, an arguably even tougher project awaits -- protecting their work. While the UNESCO honor in many ways serves to preserve historical sites, there are question marks over how the accompanying rush of tourists will affect the canal.

The section recognized by UNESCO runs some 1,011 km through 25 cities of two municipalities and six provinces from south to north China. With local governments competing to attract visitors and develop canal-side attractions, there are already concerns of over-commercialization and resulting damage. In modern, commercial China, it has proved difficult to coordinate management of the canal among the many local authorities that have jurisdiction over it.

In fact, that 1,011 km is far from the whole waterway. The original length of the Grand Canal, construction of which began in 486 BC to transport goods, mainly grain, exceeded 2,500 km. While some of that has vanished, other parts are in a sorry state.

"When we talk about the canal's protection, it means to protect it as a whole, not only the part listed by UNESCO," said Qi Xin, deputy secretary-general of the Grand Canal sub-committee under the China Association of Cultural Relics Preservation.

"It's not a piecemeal approach, but a massive project," said Qi. "More importantly, The canal's not a temple or a mountain. It's a complicated system involving many land resources, cultural relics and water conservancy projects as well as environmental concerns."

"In terms of time and space, its protection is an unprecedented challenge in the history of World Heritage. We have no model to follow worldwide," he added.

However, there's no time to mull the issue. Based on Qi's research, problems already exist.

The expert, who has been studying the canal since 2005 and traveled more than 2,000 km along it, tells of two pressing issues to deal with.

One is overdevelopment along the canal, mostly for real estate projects, which are harming the environment of the canal.

"The other is that in some places, a bunch of fake cultural relics -- for instance, a so-called ancient brothel -- have been built in the name of restoring original canal scenes to attract tourists, which indeed goes against our intention of the World Heritage application," Qi said.

In addition, pollution of this world's longest artificial waterway is in danger of worsening as tourists flow in.

"It's the fate of all World Heritage sites and a challenge to all their managers -- you have to balance development and protection," Qi noted.

Countermeasures

Shan Jixiang, curator of the Palace Museum in Beijing, described the protection of the Grand Canal as important but arduous, as over-exploitation of such areas has been rampant due to urbanization.

He suggested that the government could learn from the management of West Lake in Zhejiang, which was inscribed on the World Heritage List in 2011. It has established a monitoring and management center in charge of protection of the site.

The center has set up surveillance cameras around the lake for real-time monitoring to prevent manmade damage.

It has also built a database to analyze visitor flows and launch an early warning system to avoid overcrowding.

In addition, it issues reports on its work to the UNESCO World Heritage Center and exchanges information on a regular basis.

Actually, the government of Hangzhou has already taken action to protect the Grand Canal. The city is located at the waterway's southern tip and it has a section that is still in use today.

In 2003, the government set up a headquarters dedicated to managing the canal. By the end of 2013, more than 20 billion yuan (3.2 billion U.S.dollars) had been invested in protecting and enhancing cultural sites along its banks.

The Grand Canal section in Hangzhou attracted over 59,000 tourists in 2009, when annual tourism income rose 162.06 percent year on year.

Zheng Hanxian, manager of Hangzhou Canal Group, admitted there have been problems with over-commercialization and a lack of supervision at some spots along the canal.

But they have been seeking solutions to such dilemmas. Traditional enterprises featuring high pollution have been removed from the canal bank and replaced by those with low energy costs, less pollution and high added value, according to Zheng.

In the meantime, the company has adopted a slew of green measures. Cruise boats on the river are low-carbon and LED lights are used to save electricity. Public bicycle rental stations are also dotted about.

Locals are involved in the protection work, Zheng added. Residents by the canal have been encouraged to relocate, or they are allowed to stay there to run traditional businesses that it is hoped can both attract tourists and preserve local culture.

Zheng believes the secret of sound management of the canal is "to give back the waterway to the people."

"Our principles are protection, ecology, developing tourism for the people and emphasizing overall management," he said.

Overall design by law

As the waterway runs through eight provincial regions, a comprehensive management mechanism must be established to coordinate a variety of stakeholders to sort out problems in water conservation, transportation and protection of cultural relics.

Chen Tongbin, chief of the Institute of Historical Research of the China Architecture Design and Research Group, pointed out an irony in China now finding it difficult to communicate these points to all those interested parties.

"It is hard to imagine ancient China preserving peace and solidarity without the waterway's use in facilitating communication and cooperation among different regions," Chen said.

"But in today's China, a fast and massive urbanization is taking place and some officials who pursue personal career achievement have set their eyes on immediate interests, instead of long-term and overall gain."

"That explains the existence of some unqualified tourist projects along the waterway, such as the fake ancient brothel," said Qi Xin.

Qi believes China should create a special law to cover management of the Grand Canal as soon as possible to clarify "dos" and "don'ts."

In Yangzhou, a Jiangsu Province city through which the canal runs, the economic planning department must solicit the opinions of the cultural heritage protection department in writing and the latter may veto any project once it suspects that the historic area might be endangered.

"That's a good example from one city, but far more is needed in terms of the whole project. We need consensus among all the parties," said Qi.