Aerial photo taken on Oct. 24, 2018 shows a view of the Liujiaxia reservoir in Yongjing County, northwest China's Gansu Province. The Liujiaxia reservoir has increased its water flow to support the irrigation on the middle and lower reaches of the Yellow River for the upcoming winter. (Xinhua/Chen Bin)

　　Two speed boats sail in the Liujiaxia reservoir in Yongjing County, northwest China's Gansu Province, Oct. 24, 2018. The Liujiaxia reservoir has increased its water flow to support the irrigation on the middle and lower reaches of the Yellow River for the upcoming winter. (Xinhua/Chen Bin)

　　Aerial photo taken on Oct. 24, 2018 shows a view of the Liujiaxia reservoir in Yongjing County, northwest China's Gansu Province. The Liujiaxia reservoir has increased its water flow to support the irrigation on the middle and lower reaches of the Yellow River for the upcoming winter. (Xinhua/Chen Bin)

　　Aerial photo taken on Oct. 24, 2018 shows a dam of the Liujiaxia reservoir in Yongjing County, northwest China's Gansu Province. The Liujiaxia reservoir has increased its water flow to support the irrigation on the middle and lower reaches of the Yellow River for the upcoming winter. (Xinhua/Chen Bin)

　　Aerial photo taken on Oct. 24, 2018 shows a view of the Liujiaxia reservoir in Yongjing County, northwest China's Gansu Province. The Liujiaxia reservoir has increased its water flow to support the irrigation on the middle and lower reaches of the Yellow River for the upcoming winter. (Xinhua/Chen Bin)

　　Aerial photo taken on Oct. 24, 2018 shows a view of the Liujiaxia reservoir in Yongjing County, northwest China's Gansu Province. The Liujiaxia reservoir has increased its water flow to support the irrigation on the middle and lower reaches of the Yellow River for the upcoming winter. (Xinhua/Chen Bin)