Central Yunnan Water Diversion Project

The Central Yunnan Water Diversion Project is a large-scale civil engineering project under construction that will allow water from the Jinsha River near Lijiang to be transported to Central Yunnan. The total length of the water channels will be 664 km, of which 612 km will be in tunnels.

The project has a cost of US$ 12.03 billion, largely funded by the Ministry of Water Resources. It is planned for completion by 2026.

Background
Central Yunnan is a dry region in China, where currently, only 700 m3 of water is available per capita annually, compared to a 1700 m3 recommended minimum. At the same time, Central Yunnan accounts for 68% of Yunnan's GDP. The region has suffered from long drought spells, such as a period of 30 months without heavy rains in Kunming. Water scarcity has been described as the "biggest bottleneck restricting the sustainable development of Central Yunnan." The idea of diverting water from the Jinsha River to Central Yunnan was first proposed by Yunnan's vice-governor Zhang Chong in the 1950s.

The water diversion project was included in the Thirteenth Five-Year Plan. In April 2017, it was approved by the State Council.

Construction
The project will include the world's longest water tunnel, the world's largest underground pump room, and largest pump capacity in Asia. In addition, it deals with challenging geological conditions due to passing through a number of faults. It crosses the four major watersheds of Yunnan: that of the Jinsha River, Mekong, Red River, and Nanpan River, as well as crossing the Hengduan Mountains in northwest Yunnan.

Construction commenced on 4 August 2017, with a planned construction time of 8 years. The project includes 58 tunnels with a total length of 612 km, 25 inverted siphons, 17 aqueducts, and 15 culverts.

Impact
Once completed, the project would improve water availability for 11 million people, spread over 35 counties in Yunnan and a total area of 36900 km2. Over 3.403 m3 billion of water would be transported through the channels annually by 2040. This water will be used for domestic and industrial water supply (2.231 m3 million), agricultural water supply (500 m3 million), as well as for improving the ecology of lakes in the region (672 m3 million).

Since the inlet at the Jinsha River does not include a dam structure, the impact on the source river is expected to be small.

The project is seen as a demonstration project for a future Tibet to Xinjiang water diversion project.