雅砻江流域河道高程剖面上的堰塞坝印记  

Influence of natural dams on the river profile of the Yalong River Basin

作　　者：刘维明[1] 周丽琴[1,2] 陈晓清 周震[3] Wolfgang SCHWANGHART 胡旭东 李雪梅[1] 张小刚[1] LIU Weiming;ZHOU Liqin;CHEN Xiaoqing;ZHOU Zhen;Wolfgang SCHWANGHART;HU Xudong;LI Xuemei;ZHANG Xiaogang(CAS Key Laboratory of Mountain Hazards and Earth Surface Processes,Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610041,China;University of Chinese Academy of Sciences,Beijing 100149,China;China Railway Eryuan Engineering Group Co.,Ltd.,Chengdu 610031,China;Institute of Earth and Environmental Science,University of Potsdam,Potsdam 14476-14482,Germany;Hubei Key Laboratory of Disaster Prevention and Mitigation,College of Civil Engineering and Architecture,China Three Gorges University,Yichang 443002,China)

机构地区：[1]中国科学院、水利部成都山地灾害与环境研究所中国科学院山地灾害与地表过程重点实验室,四川成都610041 [2]中国科学院大学,北京100049 [3]中铁二院工程集团有限责任公司,四川成都610031 [4]Institute of Earth and Environmental Science,University of Potsdam,Potsdam 14467-14482,Germany [5]三峡大学土木与建筑学院防灾减灾湖北省重点实验室,湖北宜昌443002

出　　处：《地学前缘》2021年第2期58-70,共13页Earth Science Frontiers

基　　金：国家自然科学基金项目(41661144028,91747207,41771023,42071017)。

摘　　要：堰塞坝会对山区河流的纵剖面产生强烈扰动,在某些情况下,堰塞坝造成的河流纵剖面变陡很容易与构造作用下基准面下降的迁移裂点混淆。然而,在何种程度下堰塞坝会影响基于地貌测量的构造分析还没有系统的研究。因此本文选取青藏高原东缘的雅砻江流域为研究对象,利用遥感影像解译,结合数字高程模型(DEM),来研究堰塞坝对河流纵剖面的影响。通过遥感影像解译和部分野外判识,在雅砻江流域共发现了34个堰塞坝;同时利用TopoToolbox工具包,选用30 m SRTM DEM提取了雅砻江流域河流纵剖面、河流裂点、河流陡峭指数等地貌参数。分析结果表明,有18个堰塞坝与河流裂点在空间上重叠,其中有8个堰塞坝形成高差>100 m的裂点,对河流纵剖面有显著的影响,并发现滑坡坝比泥石流坝对河流纵剖面的影响更大。进一步分析雅砻江主干流及其支流力丘河,发现堰塞坝所在的河段河流陡峭指数相对较大;在排除岩性和断层活动的影响后,发现堰塞作用也能够解释河流裂点的成因。本研究结果指示,在利用DEMs来提取和分析区域构造信息时,必须考虑由堰塞坝引起的河流裂点的影响。Natural dams are known to impose pronounced and long-lasting perturbations on the river profiles in mountaineous areas.In some cases,the steepened profiles caused by natural dams are easily confused with the migrating knickpoints associated with relative base-level fall linked to tectonism.However,the degree to which natural dams may compromise geomorphomety-based tectonics has not been systematically investigated.In this research,we studied the Yalong River Basin on the eastern edge of the Tibetan Plateau.Our investigation of the relation between river dams and the river longitudinal profile relies on the interpretation and analysis of remote sensing imagery and digital elevation models(DEM).Through such analysis and field work,we identified 34 natural dams in the Yalong River Basin.We extracted the river longitudinal profile from 30 m SRTM DEM and calculated the locations of convex knickpoints,the channel steepness index,and other geomorphic parameters using TopoToolbox.Our analysis reveals 18 natural dams with locations coinciding with knickpoints that are over 30 m high.Among them,eight have a significant influence on the river longitudinal profile as they can form knickpoints with heights exceeding 100 m.Moreover,we show that landslide dams have bigger influence on the river profile than mudslide dams.Further analysis of the Yalong River and its tributary Liqiu River shows that the river steepness index attains higher values at the dams.Excluding the influence of variable lithology and fault activity on the river profile,there are several knickpoints along the river that can still be attributed to dams.Therefore,we conclude that to accurately and reliably extract and analyze information on regional tectonics from DEMs,the potential occurrence of river knickpoints due to dams must be taken into consideration.

关 键 词：河流纵剖面 堰塞坝 河流裂点 遥感解译 雅砻江流域 

分 类 号：P642.2[天文地球—工程地质学]