海勃湾枢纽对坝后河道冲淤的影响

With the application of the control water projects in the upper reaches of the Yellow River， the evolution pattern of the channel erosion and siltation in the Inner Mongolia reach has been reshaped. Based on the measured data of hydrology station， the characteristics of river water and sediment change before and after the construction of Haibowan reservoir are analyzed systematically. Based on the elevation data of the channel section， the morphological changes of the channel were qualitatively analyzed from two aspects of the scouring and silting （transverse） and the scouring and silting （longitudinal） along the channel， and the variation of the channel scouring and silting was quantitatively calculated by the cross-section topographic method. The results show that after the reservoir is used， the water and sediment matching conditions of the downstream channel are improved significantly， and the sediment coefficient and sediment transport rate per unit runoff decrease greatly， which has obvious effect on reducing silting and scour of the downstream channel. The change of the transverse and longitudinal sections of the river is dominated by scour， and the evolution process of scour and silting has experienced three stages： silting （2004-2012）， scour and silting transition （2012-2014） and scour （2014-2020）. The results can provide a scientific basis for river course control and flood mitigation in Inner Mongolia.

Keywords： channel scouring and silting ; section topographic method ; water and sand conditions ; scheduling of water conservancy projects