China is looking to rework nature itself with a gargantuan project to divert water from its lush south to the parched and populous north which will take half a century and tens of billions of dollars to achieve.
But when test runs began this year, villagers along the route said the inflow polluted their lake, leaving it teeming with silvery rotting fish carcasses and killing their livelihood.
Officials in the eastern province of Shandong rejected their account, but the incident feeds into concerns that the behemoth South-to-North Water Diversion plan may be creating more problems than it solves.
The hugely complex geo-engineering project officially began in 2002, is scheduled to take 50 years and 500 billion yuan (USD 80 billion) to build, and requires feats including blasting channels through mountains in earthquake zones on the Tibetan plateau.
If it works, its three separate routes from different points on the Yangtze river will deliver 45 billion cubic metres (1.6 trillion cubic feet) of water a year across 4,350 kilometres (2,700 miles) of canals and tunnels to the Beijing area and vast swathes of the north.
The region needs the water. With just a fifth of the country's total supply, northern China supports nearly half the population and economy and two-thirds of the arable land, according to a 2009 World Bank report.
China already boasts a long history of water mega projects, with the Grand Canal stretching from near Shanghai to Beijing first dug 2,500 years ago and extended over the centuries.
The directive for the expanded South-to-North network came from Mao Zedong himself, the project's official website says.
The leader known for big -- and often counter-productive -- ideas remarked in 1952: "The south has a lot of water. The north has little. If possible, lending some water would be okay."
But troubles abound. Pollution could render the water unusable, long uphill sections will require tremendous energy for pumping, and reservoir construction has displaced communities.
Even if the full supply arrives as promised, rising demand in the still growing country could quickly render it insufficient.
The greatest pollution threat lies with the eastern route, set to begin carrying water at the end of this year from Jiangsu province to Shandong and a little further north.
Built upon existing waterways in China's highly-developed seaboard, including the Grand Canal, it risks picking up tainted supplies from start to finish.
