An aerial view of the Danjiangkou Dam in Hubei province. The reservoir is the start of the middle route of the South-North Water Diversion Project. [Photo provided to China Daily]

Over the past six years, more than 120 million people in northern China have directly benefited from a massive water-diversion project that transfers water from the Yangtze River, authorities said on Saturday.

The South-to-North Water Diversion Project, the world's largest such project, has diverted 39.4 billion cubic meters of water to arid areas in the north in that time, the Ministry of Water Resources said in a news release.

Saturday marked the sixth anniversary of the joint operation of the project's middle and eastern routes. The western route is in the planning stage.

The middle route, which feeds water to Beijing, the nation's capital, starts from the Danjiangkou Reservoir in Hubei province and crosses the provinces of Henan and Hebei before reaching Beijing and Tianjin. It began supplying water on Dec 12, 2014.

The eastern route began operation in November 2013, transferring water from Jiangsu province to areas including Tianjin and Shandong province.

All 260,000 residents of Qiuxian county, Hebei, which used to be plagued by water shortages, now have access to water diverted from the Yangtze.

"Previously, we sometimes couldn't have a proper bath even once a year," said Jiang Shuhe, a resident of Qiuxian's Xichangtun village.

The 70-year-old said all the families in the village have now installed solar water heaters, and having a bath is no longer a luxury.

The project has also helped a lot in addressing the excessive exploitation of underground water, a problem that has been lingering for years, the ministry said.

With the help of the project, the ministry has been diverting water into many of the water bodies in North China since 2018 to remedy damage to aquatic ecosystems caused by water shortages. While contributing to environmental conservation, the efforts have also helped raise underground water levels.

In Beijing, for example, the average underground water level had risen to 22.49 meters by the end of September, 3.68 meters higher than in 2015. Many dried-up springs in the capital have begun to see water gush out again, it said.

The ministry has also used the project to launch many emergency water diversion operations to help drought-stricken regions. Water diverted to northern Jiangsu province in April, when it was enduring a severe drought, guaranteed the harvesting of rice grown on almost 1.1 million hectares of land in the area.

The ministry said it is promoting the extension of the middle and eastern routes to allow the project to benefit more regions. The major parts of the eastern route's extension project, which will increase the annual water supply capacity to the Beijing-Tianjin-Hebei province cluster by 490 million cubic meters, are expected to be completed by the end of this year.