The central, or middle, route is from Danjiangkou Reservoir on the Han river, a tributary of the Yangtze River, to Beijing. The project involves raising the height of the Danjiangkou dam (increasing the dam crest elevation from 162 m to 176.6 m above the sea level), in order to raise the water level in the reservoir from 157 to 170 m above the sea level.
The middle route is built on the North China Plain. The canal is to be constructed so that water can flow all the way from the Danjiangkou Reservoir to Beijing by gravity, without the need for pumping stations.The main engineering challenge is to build a tunnel under the Yellow River. Construction on the central route began in 2004. In 2008 the 307 km-long northern stretch of the central route was completed at a cost of US$2 billion. Water in that stretch of the canal does not come from the Han River but from reservoirs in Hebei Province, south of Beijing. Farmers and industries in Hebei had to cut back water consumption to allow for water to be transferred to Beijing.
The whole project was just completed earlier this year. This has recently been set back to allow for more environmental protections to be built. A problem is the influence on the Han River (below the Danjiangkou Dam), from which approximately 1/3 of the water is diverted. One long-term consideration is to build another canal to divert water from the Three Gorges Dam to Danjiangkou Reservoir.
