黄河下游河道断面形态参数变化及其水沙过程响应

基于1965—2015年黄河下游花园口、高村、泺口站的逐年水文和汛前河道断面的实测资料，分析了河道断面形态参数（河道断面面积，河道宽深比等）的变化，以及对河道断面形态与来水来沙间的关系做出定量化分析。结果表明：主槽断面形态参数与水沙搭配以及前期断面形态密切相关，沿程3个断面形态参数调整方式存在显著差异。河宽调整幅度沿程减小，辫状河段变幅最大，尤其在1986—1999年，辫状河段萎缩程度最为严重，其次为弯曲河段，顺直河段横向调整幅度最小。受到前期断面形态的影响，辫状河段河道断面调整方式既有横向展宽（萎缩）又有垂直加深（淤积）；弯曲河段河道宽深比与流量呈较弱的正相关关系，具有横向和垂向的调整方式；而顺直河段的宽深比与流量呈负相关关系，与来沙系数呈正相关关系，河道以垂直加深（淤积）为主。

Variation of Morphological Parameters of Channel Cross-sections and Their Response to Water-sediment Processes in the Lower Yellow River

The river channel of the lower reaches of the Yellow River has severely shrunk and the discharge capacity has been significantly reduced since 1990s, which directly affects the carrying capacity of flood-sediment and threatens the safety of flood control in the Yellow River. This article is based on the annual hydrology data of Huayuankou, Gaocun and Luokou gauging stations and the measured data of the river cross-sections before the flood season from 1965 to 2015, to reveal the response of channel cross-sectional shapes of the lower Yellow River to the incoming runoff and sediment. The variation of morphological parameters of typical cross-sections (cross-sections area, width to depth ratio, etc.) are mainly analyzed. In addition, the quantitative analysis of the relationship between channel morphological parameters and water and sediment conditions are made. The results show that the above-mentioned morphological parameters are closely related to the water and sediment combination and the previous cross-section shape, and there are significant differences in the adjustment of the morphological parameters of the three cross-sections along the river. The adjustment amplitude of channel width decreases along the distance, and the variation extent of braided reach is the largest, especially in 1986-1999, the most serious shrinkage degree of braided reach, followed by the meandering reach, and the smallest lateral adjustment range of straight reach. Affected by the early stage morphology, the adjustment modes of cross-section of braided reach includes both lateral broadening (shrinking) and vertical deepening (silting); The ratio of width to depth is weakly positively related to the discharge in the meandering reach, and the channel mainly adjusted by lateral and vertical migration; while the width depth ratio of straight reach has a negative correlation with the discharge, and has a positive correlation with the sediment inflow coefficient. The adjustment mode is mainly silting (scouring) in the vertical direction.