地理学报 ›› 1995, Vol. 62 ›› Issue (4): 335-343.doi: 10.11821/xb199504005

• 论文 • 上一篇    下一篇

河漫滩地生态系统影响下的河型转化──以红山水库上游河道为例

许炯心, 师长兴   

  1. 中国科学院国家计划委员会地理研究所, 北京 100101
  • 收稿日期:1993-12-01 修回日期:1994-05-01 出版日期:1995-07-15 发布日期:1995-07-15
  • 基金资助:
    国家自然科学基金

RIVER CHANNEL PATTERN CHANGE AS INFLUENCED BY THE FLOODPLAIN GEOECOSYSTEM:AN EXAMPLE FROM THE HONGSHAN RESERVOIR

Xu Juongxin, Shi Changxing   

  1. Institute of Geography,CAS,Beijing 100101
  • Received:1993-12-01 Revised:1994-05-01 Online:1995-07-15 Published:1995-07-15

摘要: 将地生态学概念与方法用于水库修建后河床调整过程的研究。以老哈河红山水库上游为例阐述了河漫滩地生态系统影响下的河型转化过程。由于水库上游河漫滩地生态系统的变化,导致了河漫滩淤积过程的改变,使河岸组成物质变细,抗冲性增强,因而促使建库前的游荡河型逐渐转化为弯曲型。

关键词: 河漫滩地生态系统, 河床调整, 河型转化, 红山水库

Abstract: The floodplain geoecosystem can be defined as a system composed of factors such as floodplain morphology,alluvial materials,soils, groundwater and vegetation. A strong coupling relation between the floodplain geoecosystem and the channel system is established by the matter and energy fluxes through their interface.After the construction of the Hongshan Reservoir,a dramatic change of the upstream-reservoir floodplain geoecosystem has taken place.Before and after the reservoir construction,the succession of the floodplain geoecosystem can be generalized as 3 stages, namely,the semi-desert geoecosystem,the marsh and swamp geoecosystem,and the agricultural ecosystem.After the upstream-reservoir floodplain geoecosystem turned from a semi-desert to a marsh and swamp,the dynamics of matter exchange between the floodplain and the channel has been changed significantly,leading to a strong reform of the composition of floodplain material.Before the growth of aquatic and marsh weeds,the clay content in the bed material was very low, ranging from 5%to 7.5%.After dense weeds appeared, the water flow velocity declined greatly,a factor favourable to the fine sediment deposition. So the clay content of the bed material increased rapidly up to 45%on average.Adjusting itself to accommodate the reworked channel boundary conditions, the channel reforms its bed morphology and tends to re-establish the balance among the material, process and morphology. Consequently, the pre-dam wandering braided channel pattern has been gradually transformed to a meandering one. With the narrowing of the channel due to the strong sedimentation induced by aquatic and marsh weeds growth, the width-depth ratio tends to be much smaller,associated by a lower and lower degree of braiding. Finally the channel becomes a singethread one. In the meantime, the channel sinuosity increases continuously, from 1.06 in 1961to 1.27 1n 1985, and the channel is turning to a meandering one.

Key words: Floodplain geoecosystem, Channel adjustment upstream from a reservoir, River channel pattern transformation, Hongshan Reservoir

中图分类号: 

  • X171