DANJIANGKOU, China — North China is dying.

A chronic drought is ravaging farmland. The Gobi Desert is inching south. The Yellow River, the so-called birthplace of Chinese civilization, is so polluted it can no longer supply drinking water. The rapid growth of megacities — 22 million people in Beijing and 12 million in Tianjin alone — has drained underground aquifers that took millenniums to fill.

Not atypically, the Chinese government has a grand and expensive solution: Divert at least six trillion gallons of water each year hundreds of miles from the other great Chinese river, the Yangtze, to slake the thirst of the north China plain and its 440 million people.

The engineering feat, called the South-North Water Diversion Project, is China’s most ambitious attempt to subjugate nature. It would be like channeling water from the Mississippi River to meet the drinking needs of Boston, New York and Washington. Its $62 billion price tag is twice that of the Three Gorges Dam, which is the world’s largest hydroelectric project. And not unlike that project, which Chinese officials last month admitted had “urgent problems,” the water diversion scheme is increasingly mired in concerns about its cost, its environmental impact and the sacrifices poor people in the provinces are told to make for those in richer cities.

Three artificial channels from the Yangtze would transport precious water from the south, which itself is increasingly afflicted by droughts; the region is suffering its worst one in 50 years. The project’s human cost is staggering — along the middle route, which starts here in Hubei Province at a gigantic reservoir and snakes 800 miles to Beijing, about 350,000 villagers are being relocated to make way for the canal. Many are being resettled far from their homes and given low-grade farmland; in Hubei, thousands of people have been moved to the grounds of a former prison.