China is undertaking two huge projects to tackle flooding in the south and drought in the north.
The Three Gorges Dam under construction on the Yangtze River aims to control flood waters and generate power. But the project – the largest of its kind in the world - has been dogged by corruption scandals and criticised for its impact on the environment and the million people who have been uprooted.
In the north, all three rivers feeding China's Northern Plain are severely polluted, damaging health and limiting irrigation.
The lower reaches of the Yellow river, which feeds China's most important farming region, ran dry for 226 days in 1997. Between 1991 and 1996, the water table beneath the north China plain fell by an average of 1.5 metres a year.
To combat this, work has begun on China's biggest ever construction project - a massive scheme to channel billions of cubic metres of water from the Yangtze to the replenish the dwindling Yellow river.