Photo taken on July 31, 2014 shows lake in Guoluo Tibetan Autonomous Prefecture, northwest China's Qinghai Province. Sanjiangyuan, which translates as "source of three rivers," is home to the headwaters of the Yangtze, Yellow and Lancang (Mekong) rivers in northwest China's Qinghai Province. Ecological construction has been going on since 2005. (Xinhua/Wu Gang)

Photo taken on Sept. 9, 2015 shows sand prevention and sand fixation installations in Guinan County, northwest China's Qinghai Province. Sanjiangyuan, which translates as "source of three rivers," is home to the headwaters of the Yangtze, Yellow and Lancang (Mekong) rivers in northwest China's Qinghai Province. Ecological construction has been going on since 2005. (Xinhua/Wu Gang)

Photo taken on May 20, 2015 shows Tibetan wild donkeys in Hoh Xil, northwest China's Qinghai Province. Sanjiangyuan, which translates as "source of three rivers," is home to the headwaters of the Yangtze, Yellow and Lancang (Mekong) rivers in northwest China's Qinghai Province. Ecological construction has been going on since 2005. (Xinhua/Wu Gang)

Photo taken on Sept. 15, 2015 shows scenery of Dari River in Guoluo Tibetan Autonomous Prefecture, northwest China's Qinghai Province. Sanjiangyuan, which translates as "source of three rivers," is home to the headwaters of the Yangtze, Yellow and Lancang (Mekong) rivers in northwest China's Qinghai Province. Ecological construction has been going on since 2005. (Xinhua/Wu Gang)