Beijing began replenishing the Yongding River with water from the Yellow River on March 14, according to the Beijing Water Authority. The move is in preparation for the upcoming Expo 2019 Beijing and the opening of Beijing Daxing International Airport.

According to the plan, water from the Yellow River will arrive at Guanting Reservoir on Tuesday and then be channeled to the Yongding River, the first time that a cross-basin replenishment transfers water from the Yellow River.

The replenishing period will last for three months, transferring a total amount of 160 million cubic meters.

Li Guangyuan, deputy director of Guanting Reservoir, said the water for the replenishment is from three sources: Wanjiazhai Reservoir at the border of Shanxi and Inner Mongolia, which would provide 100 million cubic meters; Cetian Reservoir in Shanxi, which would provide 50 million cubic meters; and Youyi Reservoir in Hebei, which would provide 16 million cubic meters.

By the end of May, Yongding Reservoir would receive water replenishment of 160 million cubic meters, the largest amount in history.

Known as the "mother river of Beijing," the Yongding River spans Inner Mongolia, Shanxi, Beijing, Tianjin, and Hebei, totaling 700 kilometers in length and serves as an ecological artery in the Beijing-Tianjin-Hebei region.

"At present, Guanting Reservoir has a water storage capacity of about 550 million cubic meters, reaching the highest water level in the past 20 years, which can provide adequate water resources for the ecological restoration of the Yongding River," Li said.

Since March 14, Guanting Reservoir has transferred water into the downstream Yongding River at a rate of 10 cubic meters per second.