1988-2018年黄河内蒙古段河道边界演变特征及影响因素

River Boundary Evolution Characteristics and Influencing Factors in Inner Mongolia Reach of Yellow River During 1988-2018

[目的]获取河道边界演变特征,为黄河内蒙古段的堤岸防护建设提供重要的理论依据。[方法]基于1988—2018年期间7期Landsat卫星影像,利用修正的归一化水指数(MNDWI),对黄河内蒙古段7期的河道边界信息进行提取,并计算不同时期河道摆动面积、最大摆动面积、摆动方向等指标,分析近30 a河道的时空变化特征。[结果]黄河内蒙古段在上游巴彦高勒—三湖河口和三湖河口—包头弯道区域曲率较大的河段摆动较严重,整体呈现向右岸迁移的趋势。河道摆动的时空差异受河床物质组成、水动力条件、水利工程、水土保持工程等人类活动因素的综合影响。[结论]黄河内蒙古段的堤岸防护建设重点应集中在巴彦高勒—三湖河口全段以及三湖河口—包头弯道曲率较大的河段。

[Objective]The boundary characteristics of the Inner Mongolia reach of the Yellow River were studied in order to provide an important theoretical basis for the construction of embankment protection in the reach.[Methods]The river boundary information of the Inner Mongolia reach of the Yellow River for the past 30 years was extracted based on the modified normalized difference water index(MNDWI)and seven phases of the Landsat satellite images taken from 1988—2018.After calculating the swing area,the maximum swing area,the swing direction,and the other indicators of the river in different periods,the spatial-temporal variations of the river were analyzed.[Results]The upper sections of the Inner Mongolia reach of the Yellow River in the Bayangaole-Sanhuhekou and the Sanhuhekou-Baotou bend(both with greater curvatures than other locations)section oscillated more seriously than the other sections,and the whole reach showed a trend of migration to the right bank.The spatial and temporal differences in the channel swing were influenced by the material composition of the riverbed,hydrodynamic conditions,water conservancy projects,soil and water conservation projects,and other human activities.[Conclusion]Embankment protection construction in the Inner Mongolia reach of the Yellow River should focus on sections of Bayangaole-Sanhuhekou,and the Sanhuhekou-Baotou bend,with their large curvature.