地理学报 ›› 2020, Vol. 75 ›› Issue (7): 1494-1511.doi: 10.11821/dlxb202007012

• 气候变化与地表过程 • 上一篇    下一篇

黄河下游主槽断面形态对水沙变化响应过程的模拟

王彦君1,2(), 吴保生1, 钟德钰1   

  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. 长江科学院水利部江湖治理与防洪重点实验室,武汉 430010
  • 收稿日期:2019-05-27 修回日期:2020-04-05 出版日期:2020-07-25 发布日期:2020-09-25
  • 作者简介:王彦君(1989-), 女, 河北邢台人, 博士, 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:
    国家自然科学基金项目(51639005);国家重点研发计划(2017YFC0405202);国家重点研发计划(2016YFC0402406);中央级公益性科研院所基本科研业务费(CKSF2019214/HL)

Simulation of the main-channel cross-section geometry of the Lower Yellow River in response to water and sediment changes

WANG Yanjun1,2(), WU Baosheng1, ZHONG Deyu1   

  1. 1. State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China
    2. Key Laboratory of River Regulation and Flood Control of MWR, Yangtze River Scientific Research Institute, Wuhan 430010, China
  • Received:2019-05-27 Revised:2020-04-05 Online:2020-07-25 Published:2020-09-25
  • Supported by:
    National Natural Science Foundation of China(51639005);National Key R&D Program of China(2017YFC0405202);National Key R&D Program of China(2016YFC0402406);Central Public-interest Scientific Institution Basal Research Fund of China(CKSF2019214/HL)

摘要:

准确把握环境变化下前期水沙条件对当前河床形态调整的影响,建立非平衡态河床形态调整的模拟方法,对深化河床非平衡调整过程的认识至关重要。基于黄河下游花园口—利津河段1965—2015年的水沙和沿程82个大断面数据,首先统计分析了不同河段主槽断面形态参数(面积、河宽、水深和河相系数)的调整过程及其对水沙变化的响应规律;进而以水沙因子作为主槽断面形态调整的主控因素,采用滞后响应模型的多步递推模式,建立了其对前期水沙条件变化的滞后响应模型。结果表明,各河段面积、河宽和水深经历了减小—增加—减小—增加的变化过程,并且其与4 a滑动平均流量和含沙量之间分别呈正相关和负相关;而河相系数孙口以上段整体减小,孙口以下段呈增加—减小—增加—减小的变化过程,除花高段1965—1999年外,其与流量呈负相关,与含沙量呈正相关。滞后响应模型在黄河下游主槽断面形态对前期水沙条件响应过程的应用表明,各参数模型计算值与实测值符合程度均较高,模型能够很好地模拟主槽断面形态对水沙变化的响应调整过程,模型计算结果显示主槽断面形态调整受当年在内的前8 a水沙条件的累积影响,当年和前7 a水沙条件对当前断面形态的影响权重分别约为30%和70%。本文模型有助于深化前期水沙条件对当前河床形态调整影响机理的认识,并为未来不同水沙情形下主槽断面形态的预测提供了有效计算方法。

关键词: 黄河下游, 水沙变化, 主槽断面形态, 滞后响应模型

Abstract:

To understand the non-equilibrium morphological adjustment of a river to environmental changes, it is essential to (i) identify accurately how previous water and sediment conditions have impacted the current morphological adjustment of the river to environmental changes and (ii) establish a corresponding simulation method for non-equilibrium conditions. Based on water-discharge and suspended sediment concentration (SSC) data and 82 cross-sectional data for the Huayuankou-Lijin reach of the Lower Yellow River for 1965-2015, the adjustment processes of the main-channel geometry (area, width, depth, and geomorphic coefficient) and their responses to changes in water discharge and SSC for different reaches are analyzed statistically. Then, with the water and sediment conditions as the main controlling factors, a delayed response model (DRM) of the main-channel geometry subjected to previous changes in water discharge and SSC is established using the multi-step analytical model. The results show that the main-channel area, width, and depth decreased initially, then increased, then decreased again, and finally increased again. They were correlated positively with the 4 a moving average discharge and negatively with the 4 a moving average SSC. The main-channel geomorphic coefficient for the Huayuankou-Sunkou reach exhibited a decreasing trend, whereas that for the Sunkou-Lijin reach decreased initially, then increased, then decreased again, and finally increased again. Except for the Huayuankou-Gaocun reach for 1965-1999, the coefficient was correlated negatively with the 4 a moving average discharge and positively with the 4 a moving average SSC. In applying the DRM to the response of the main-channel cross-sectional geometry to previous water and sediment conditions in the Lower Yellow River, the calculated values of the main-channel morphological parameters for all the sub-reaches agree well with the measured values. This indicates that the DRM can be used to simulate the response adjustment process of the main-channel cross-sectional geometry to variations in the water and sediment conditions. The results of the established model show that the adjustment of the main-channel cross-sectional geometry is affected by the current discharge and SSC (30%) and those of the previous seven years (70%), where the numbers in brackets are the respective weight factors. The established model offers insights into the mechanism whereby previous water and sediment conditions influence the current morphological adjustment of the river, and it provides an effective method for predicting the magnitude and trend of the main-channel geometry under different incoming water and sediment conditions.

Key words: Lower Yellow River, water and sediment changes, main-channel cross-section geometry, delayed response model