强人工约束条件下黄河下游游荡性河道河床演变OA

With the improvement of river regulation works and the operation of the Xiaolangdi Reservoir,the Lower Yellow River is becoming a channel under strong artificial constraints.Understanding the riverbed evolution under these conditions provides a theoretical basis for effec-tive river regulation and flood control.The wandering reach of the Lower Yellow River was the focus of this study.Based on hydrological and sediment data and cross-sectional topography from Huayuankou(1950-2022),and records of regulation project construction(1949-2019),the riverbed evolution process in the wandering reach under strong artificial constraints was investigated.The results indicate that:The in-creased density of regulation works significantly enhances the confinement of the wandering channel.The swing range of the main stream no-ticeably narrows,while the length of projects adjacent to the flow substantially increases,effectively stabilizing the main flow.Under the regu-lated flow and sediment discharges from the Xiaolangdi Reservoir,the main channel experiences continuous scouring for many years.The me-dian size of bed sediment exhibits a spatial-temporal evolution pattern,coarsening over time and fining along the course.The coefficient of sinuosity generally shows an increasing trend,altering the formerly rapid and straight characteristics of the wandering channel,imparting some traits of a meandering river.The coefficient of fluvial facies generally decreases,improving the cross-sectional form towards a narrower and deeper shape.