This is partly because water projects, almost by definition, represent a massive subsidy to farmers. But Beijing seems almost certain to push ahead on this one as it did with the Three Gorges dam the biggest such dam in the world by some measures despite international criticism. The basic idea is that the Yangtze is subject to flooding, while the Yellow River is running dry, so transferring water helps kill two birds with one stone. But the logic doesn't work for many experts. The only reason it's being considered is because there's no healthy, open, democratic debate.
Work is already underway on two south-north canals associated with the project.
In the east, engineers are rebuilding and expanding an ancient manmade waterway the Grand Canal which originally ran from the Yangtze to Shandong province. It will be extended north to the port city of Tianjin. The central route, which U.S. officials have seen under construction, is designed to take water from a tributary of Yangtze and deliver it to Beijing. These two cities combined population of about 20 million have been rationing water for several years. The third canal, the most controversial and expensive, would deliver water from the upper reaches of the Yangtze to the upper reaches of the Yellow River, where the two rivers are somewhat closer together.