The terrain makes most rivers in China flow from west to east; witness the Yellow, Huaihe, Haihe, Yangtze and Pearl rivers. “Making the water flow from south to north is a proposition the Chinese government has always approached with caution. The authorities spent 50 years on the preparatory work before construction began. It has been almost 60 years since the project idea was conceived,” Shen reminded China Today.

China has six percent of all global water resources, about 2,800 billion cubic meters of freshwater, ranking fourth in the world after Brazil, Russia and Canada, but the per capita water availability is only 2,163 cubic meters, representing one-fourth of the world average; and it has therefore been listed as one of the 13 countries with the lowest per capita water resources. To complicate matters, China’s geographical distribution of water is extremely uneven. An analysis on the water supply of the southern area suggests that the third-longest river in the world – the Yangtze – has a plentiful supply of water: an annual water volume that hits 960 billion cubic meters, with nearly 94 percent of it (about 900 billion cubic meters) flowing into the ocean.

Shen makes a calculation: “Even after the water transfer project is completed, its water consumption will be merely 44.8 billion cubic meters, far less than the total volume that currently flows into the ocean. What’s more, even incomplete construction, and even in the driest season,” Shen points out, “the water volume of the Yangtze River still reaches 650 billion cubic meters.” His conclusion is that diverting some water to the dry north has no downsides.

Only the first phase of construction on the eastern and central routes has been carried out. “Once completed, a massive volume of water will be transferred to about 250 cities, benefiting over 110 million people,” Shen tells China Today.

Is It Possible?

But as the project involves diversion over long distances, its construction has faced as many difficulties as its public relations. So far a lot of technical issues have been successfully tackled, such as bonding old to new concrete during the process of heightening the Danjiangkou Dam; acquiring key technologies for building the tunnel under the Yellow River under complicated geological conditions; achieving heavy-duty PCCP pipe manufacture and related quality control; low-lift and high-flow-rate pump manufacture; and the fundamentally formidable nature of large-scale canal design and construction.

Shen indicates five lingering challenges for the project.

The first is that they haven’t figured out a good way to maintain the stability of sections of canal built on expansive clay. Expansive clay has a high potential to absorb water. If the clay expands, the canal might collapse. To achieve good slope stability by using the natural foundation has remained a big challenge to dam and canal builders throughout the world. Part of the Central Route will be a 360-kilometer-long canal built on expansive clay. “Our solution is to change the layer of expansive soil near the slope to non-expansive soil; what’s tricky is to decide how much soil we need to change as the new layer should be neither too thick nor too thin,” Shen explains. If it is too thin, it will be insecure; but if it is too thick, a lot of construction is involved and it may produce a lot of waste. “To find a balance,” says Shen, “we have performed experiments in two sections – one of 2.1 kilometers and another of 1.5 kilometers – and after comparing various methods on those two sites, we hope to narrow it down in the near future to the best solution.”

The second difficulty is the elevated canal, for if too high, it will be very dangerous when it courses through cities. Any natural disaster may break the canal’s integrity and the city will be flooded. The major canal of the Central Route is simply huge with an accordingly impressive flow volume. “To control that flow,” Shen continues, “we divide the 1,000-kilometer long canal into about 60 sections using floodgates, with each section being around 20 kilometers in length. Nevertheless, the water volume of each section will still be 500 to 700 tons – enough to flood a whole city.”

The third issue revolves around groundwater. Groundwater reserves have been put to heavy use in many Chinese cities. It is possible that in the flood season, the groundwater might flow out and swamp canal construction. Shen doesn’t mince words, “We have to make an accurate estimate of groundwater levels wherever we are building; if overestimated, unnecessary construction ensues, but if underestimated, the canal might collapse when the groundwater gushes up.”

Shen is optimistic that these technical problems will be solved in the near future.

The fourth is a people issue – relocating families in the path of the canal. A total of 450,000 people along the major routes and in the reservoir areas of the Central and Eastern routes need to be moved to new homes. So far about 219,000 people, representing 49 percent of the total population slated for relocation, have already been resettled. The resettlement work has been carried out smoothly on the whole, meeting the demands of the project construction. But bridging people across a change in their lives and doing it smoothly is a task that demands continuous attention and empathy. With the aim of safeguarding people’s interests, government departments have conducted inspections and strictly implemented the relocation policies. In addition, they work hard to make sure that even reluctant people are finally willing or at least contentedly resigned to the change, then do what they can to help them improve their living conditions in the new location.

The last one, and a tough one, is reducing and controlling pollution of the diverted water. Shen confesses the nature of the setbacks: “The task of dealing with water pollution along the Eastern and Central routes was very demanding during the first-phase construction because our time was limited. Currently the focus is on reducing pollution along the Eastern Route and protecting water sources along the Central Route. Next we need to step up industrial restructuring, reduce pollution caused by ships operating in the canal, and protect water sources. Moreover, we will put effort into non-point pollution control and wetland protection.