It might be the most ambitious construction project in China since the Great Wall.

The Chinese government is planning to reroute the nation’s water supply, bringing water from the flood plains of the south and the snowcapped mountains of the west to the parched capital of Beijing. First envisioned by Mao Tse-tung in the 1950s and now coming to fruition, the South-North Water Diversion – as it is inelegantly known in English – has a price tag of more than $62 billion, twice as expensive as the famous Three Gorges Dam. It is expected to take decades to complete.

“This is on a par with the Great Wall, a project essential for the survival of China,” said Wang Shushan, who heads the project in Henan province, where much of the construction is now taking place. “It is a must-do project. We can’t afford to wait.”

Even by the standards of a country where moving heaven and Earth is all in a day’s work, it is a project of enormous hubris. In effect, the Chinese are “replumbing” the entire country, says Orville Schell, a China scholar and an environmentalist, something “no country has ever done successfully in the past.”

China is plagued by extreme weather. Vast river deltas in the south are inundated each year by deadly flooding, while the steppes of the north are swept by sandstorms. To remedy this, the engineers are creating a vast, hydra-like network of canals, tunnels and aqueducts that will extend thousands of miles across the country.