Current Situation and Operation Effects of the Reservoir’s in the Middle Yellow River

In October 1999, the Xiaolangdi Reservoir was put into operation and since then it has played an important role in flood (ice flood) control, sedimentation reduction, water supply, irrigation, power generation and ecological improvement and other aspects through joint operation with reservoirs on the main stream and tributaries of the middle Yellow River. The effects of the joint operation of the reservoirs is detailed since 2000 in the paper, which has put forward the following conclusions: (1) The scientific scheduling of the reservoirs has effectively reduced the flood loss in the floodplain and alleviated the flood control pressure of the lower Yellow River; (2) The ice flood control by the Sanmenxia and Xiaolangdi Reservoirs greatly reduces the ice regime of the lower reaches and ensures the safety against ice flood; (3) Through the sediment storage and water-sediment regulation by the reservoirs in the middle reaches, the lower Yellow River has effective scoured as of the pre-flood season of 2017, a total of 2.90 billion tons of sediment has been scoured in the lower Yellow River and the minimum pre-flood bankfull discharge has increased from 1800 m³/s in 2002 to 4200 m³/s; (4) The joint operation has effectively safeguarded the water supply to the towns and cities on both banks of the lower Yellow River and its adjacent areas, brought about benefits through power generation and improved the ecology and environment of the downstream rivers and estuaries.