海勃湾枢纽对坝后河道冲淤的影响

随着黄河上游控制性水利枢纽相继投入运用，黄河内蒙古段河道冲淤演变格局得到重塑。利用水文站实测数据，系统分析了海勃湾水利枢纽建设运行前后坝后河道水沙变化特征。基于河道断面高程数据，从滩槽冲淤（横向）及沿程冲淤（纵向）两方面定性分析坝后河道形态变迁，采用断面地形法定量计算坝后河道冲淤变化量。结果表明：海勃湾水利枢纽蓄水运用后，坝后河道的水沙搭配条件显著改善，来沙系数、单位径流量的输沙量降幅较大，对坝后河道减淤冲刷作用明显。坝后河道横纵断面变迁以冲刷为主，冲淤演变过程经历了淤积（2004—2012年）、冲淤过渡（2012—2014年）、冲刷（2014—2020年）3个阶段。

Influence of construction and operation of the Haibowan Junction on the downriver channel erosion and deposition

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.