China is about to realize a dream of communist leader Mao Zedong to redirect river flows to benefit Beijing and the dry north, but critics say the resource grab by the politically powerful capital will harm other regions.

The $62 billion South-North Water Transfer Project is one of the world's biggest infrastructure projects.

Starting in October, stage two will see 9.5 billion cubic meters of water per year pumped through 1,500 km (930 miles) of canals and pipes from the Danjiangkou reservoir in central Hubei province to the northern provinces of Henan and Hebei and to Beijing.