Discussion of Recent Optimal Operation of Xiaolangdi Reservoir

2.522 billion m3 of sediment had deposited in the Xiaolangdi Reservoir by the end of 2011 after 12 years' operation,the flowing and sediment transport conditions in the main channel in the downstream of the Yellow River had been changed dramatically,so the operation mode of Xiaolangdi Reservoir regulation was badly in need of adjustment in the following aspects: 1)raise the flood control level appropriately;2)set flood control level and limited water lever for sediment reduction separately;3)adjust the operation mode of water and sediment regulation before the flood season;4)adjust the discharge control indicator under the water supply operation mode;5)cancel the sediment concentration limit in the discharge of Xiaolangdi Reservoir.