File photo of Miyun Reservoir, Beijing's largest reservoir. [Photo: xinhua.net]

The water stored at Miyun Reservoir, Beijing's largest reservoir, is now over one billion cubic meters, a sufficient and reliable water supply source for the capital, Beijing Water Authority said on Wednesday.

Miyun Reservoir in northern Beijing has been at less than its capacity for years. Since the water began to be channeled from Hubei Province to the capital in December 2014, the reservoir's water level has gradually increased.

As of Nov. 21, the reservoir had received a total of 36 million cubic meters of "southern water", according to Beijing south-to-north water diversion office.

The first stage of the middle route -- one of three routes involved in the project -- starts at Hubei's Danjiangkou Reservoir, which stores water from the Hanjiang River, a tributary of the Yangtze. A 1,432-km-long canal brings the water to northern regions, including the cities of Beijing and Tianjin, and the provinces of Henan and Hebei.

Thanks to the water diversion project, Miyun Reservoir is expected to receive 250 million cubic meters of "southern water" each year.

To ensure water quality, Miyun District has closed more than 300 plants and an iron mine near the reservoir.