Kunming, China (Agencies) July 26, 2025 – China is nearing completion of the world’s longest water tunnel system, a colossal infrastructure project designed to address chronic water scarcity in Central Yunnan, a region that contributes nearly 70 percent of Yunnan Province’s economic output.
The Central Yunnan Water Diversion Project, launched in August 2017 and scheduled for completion by the end of 2025, spans 664 kilometers, including 612 kilometers of tunnels, crossing multiple watersheds and mountainous terrain. The tunnel reroutes surplus water from the Jinsha River — a tributary of the Yangtze that experiences frequent flooding — to Kunming, Chuxiong, Yuxi, and surrounding areas that have long struggled with drought.
With an estimated cost of US$12 billion, the undertaking is hailed as one of China’s most complex and transformative water infrastructure projects.
Central Yunnan suffers from per capita water availability of just 700 cubic meters annually — less than half the international standard for water security. This chronic shortfall has restricted urban expansion, industrial investment, and agricultural resilience. The region’s capital, Kunming, and adjacent cities have historically depended on seasonal rain-fed lakes, leaving them vulnerable to extended dry spells and water rationing.
Officials anticipate that the diversion project will unlock vast economic potential, supporting urban growth, ecological restoration, and food security across the region.
The project’s engineering feats are unprecedented. It includes 58 tunnels, 25 inverted siphons, 17 aqueducts, and 15 culverts, along with Asia’s largest subterranean pumping station and highest-capacity pump system. Constructed through the Hengduan Mountains and beneath fragile geologic zones, the tunnel also incorporates cutting-edge seismic and hydrological safeguards to ensure resilience under extreme natural conditions.
By 2040, the diverted water will be distributed across multiple sectors. Urban and industrial use will receive 2.231 billion cubic meters annually, agriculture will be allocated 0.5 billion cubic meters, and 0.672 billion cubic meters will be reserved for ecological restoration, bringing the total to 3.403 billion cubic meters.
Beyond its regional impact, the project showcases China’s ambition in hydraulic engineering. It is being positioned as a model for future water diversion schemes, including proposed transfers from the Tibetan Plateau to arid regions in western China like Xinjiang. Analysts note that the tunnel not only supports China’s 2035 modernization goals but also strengthens internal resource redistribution at a time when global freshwater access is increasingly strained.