地理学报 ›› 2019, Vol. 74 ›› Issue (11): 2411-2427.doi: 10.11821/dlxb201911016

• 气候变化与生态环境 • 上一篇    

1986-2015年小浪底水库运行前后黄河下游主槽调整规律

王彦君1,吴保生1,申冠卿2   

  1. 1. 清华大学水沙科学与水利水电工程国家重点实验室,北京 100084
    2. 黄河水利科学研究院,郑州 450003
  • 收稿日期:2018-08-22 修回日期:2019-08-01 出版日期:2019-11-25 发布日期:2019-11-01
  • 作者简介:王彦君(1989-), 女, 河北邢台人, 博士生, 研究方向为河流地貌学和河床演变学。E-mail: yanjun1113@126.com
  • 基金资助:
    国家自然科学基金重点项目(51639005);国家重点研发计划(2017YFC0405202);国家重点研发计划(2016YFC0402406)

Adjustment in the main-channel geometry of the lower Yellow River before and after the operation of the Xiaolangdi Reservoir from 1986 to 2015

WANG Yanjun1,WU Baosheng1,SHEN Guanqing2   

  1. 1. State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084
    2. Yellow River Institute of Hydraulic Research, Zhengzhou 450003, China
  • Received:2018-08-22 Revised:2019-08-01 Online:2019-11-25 Published:2019-11-01
  • Supported by:
    Key Program of National Natural Science Foundation of China(51639005);National Key R&D Program of China(2017YFC0405202);National Key R&D Program of China(2016YFC0402406)

摘要:

基于黄河下游1986-2015年的水沙和沿程实测大断面数据等资料,统计分析了小浪底水库运行前后下游主槽断面形态参数(河宽、水深、河相系数)的调整过程。结果表明:1986-1999年小浪底运行前主槽持续淤积萎缩,主槽河宽和水深均减小,河宽与水深调整强度高村以上段河宽大于水深、断面河相系数明显减小,高村以下段河宽小于水深、河相系数小幅增加;2000-2015年小浪底水库运行后主槽持续冲刷,主槽河宽和水深增加,沿程各段水深调整强度均大于河宽,河相系数减小;各段断面形态调整方式淤积期表现为艾山以上游荡段和过渡段既有横向萎缩又有垂向淤高、艾山以下弯曲段以垂向淤高为主,冲刷期游荡段和过渡段为横向展宽和垂向冲深、弯曲段以垂向冲深为主;河宽淤积期减小速率明显大于冲刷期增加速率,水深淤积期减小速率略小于冲刷期增加速率,经过一轮淤积和冲刷后,断面形态向窄深方向发展;主槽断面形态调整规律与水沙条件密切相关,断面河相系数除游荡段淤积期与流量呈正相关、与含沙量呈负相关外,游荡段冲刷期、过渡段和弯曲段淤积与冲刷不同阶段,河相系数与流量呈负相关,与含沙量呈正相关。

关键词: 黄河下游, 水沙变化, 小浪底水库, 主槽断面形态

Abstract:

Previous studies indicate that the lower Yellow River experienced a continuous siltation period and a continuous scouring period during the past 30 years. However, the patterns of main-channel adjustments during these two periods are not clear. Based on measured discharge, sediment load, and cross-sectional data between 1986 and 2015, the changes in the morphological parameters (width, depth, and cross-sectional geomorphic coefficient) of the main channel were analyzed. The results showed that before the operation of the Xiaolangdi Reservoir (XLDR) from 1986-1999, the main channel shrunk continuously with decreasing width and depth. Because the decrease rate in width was greater than that in depth, the geomorphic coef?cient decreased in the reach above Gaocun. In contrast, for the reach below Gaocun, the decrease rate in width was smaller than that in depth, and the geomorphic coef?cient increased. After the XLDR began operating, the main channel eroded continuously, and the width and depth increased from 2000-2015. Because the increase rate in depth was obviously larger than that in width, the geomorphic coef?cient decreased in all sub-reaches. The cross-sectional geometry of the main channel exhibited different adjustment patterns during two periods. Before the XLDR operation, the main channel mainly narrowed in the transverse direction and silted in the vertical direction in the reach above Aishan (AS); in the reach below AS, the main channel primarily vertically silted. After the XLDR operation, the main channel adjusted by widening and deepening in the reach above AS; for the reach below AS, the main channel adjusted mainly by deepening. Compared to the decrease rates in main-channel width and depth during the siltation period, the increase rate in width during the scouring period was obviously smaller, while that in depth was larger. After continuous siltation and scouring, the main-channel cross-sectional geometry changed from relatively wide and shallow to relatively narrow and deep. The pattern of main-channel adjustment was closely related to the water and sediment conditions. For the braided reach, the geomorphic coef?cient was negatively correlated with discharge and positively correlated with suspended sediment concentration (SSC) during the siltation period. In contrast, the geomorphic coefficient was positively correlated with discharge and negatively correlated with SSC during the scouring period. For the transitional and wandering reach, the geomorphic coef?cient was negatively correlated with discharge and positively correlated with SSC.

Key words: the Lower Yellow River, changes in water and sediment conditions, Xiaolangdi Reservoir, main-channel geometry