China will have invested a total of 140.5 billion yuan (about 21 billion U.S. dollars) in its ambitious South-to-North Water Diversion (SNWD) project from 2006 to 2010, the country's water diversion authority said Monday.

The investment accounted for 62 percent of the entire project's budget of 228.9 billion yuan, excluding the pollution control project of the eastern route and the project that protects the water supply source of the central route.

The SNWD project will take water from the voluminous Yangtze River in the south to satisfy demand in the north's drought-prone cities, such as Beijing and Tianjin.

The eastern, central and western routes will each stretch more than 1,000 km.

Construction on the water diversion system began in 2002. The eastern route will start supplying water in 2013 and the principal part of the central route is scheduled for completion by 2013. The central route will start supplying water in 2014.