摘要
高能洪水是地球上目前已知最大规模的极端洪水事件,其对全球地貌演化、气候变化等有着深刻的影响。高能洪水重建可以提高对极端洪水事件的认识,进一步探索高山峡谷地貌对于极端洪水事件的响应。然而,针对高海拔山区的高能洪水模型应用仍存在一定局限,无法得到高准确度的重建结果。为了研究雅江中游高能洪水规模,本研究在雅鲁藏布江中游宽谷加查—米林河段发现的代表古高能洪水的17个砾石洲/滩的基础上,采用HEC-RAS模型,结合ArcGIS平台下的HEC-Georas模块重建了古高能洪水洪峰流量;以±35%的变幅对曼宁糙率系数进行了敏感性测试,以保证重建结果的准确性。计算结果表明:(1)17个砾石洲/滩的模拟水位与野外调查所得标志水位能较好吻合,与实测结果相比误差均小于0.1%;(2)雅鲁藏布江中游古高能洪水洪峰水位为3047.09~3373.39 m,洪峰流量为0.2×10^(6)~1.8×10^(6)m^(3)/s,且最大淹没水深为366 m;(3)当曼宁系数处于±35%的变幅下时,洪峰水位的误差为-0.36%~0.17%,说明该模型对曼宁糙率系数的敏感性较差,采用此方法能够很好地恢复雅鲁藏布江中游古高能洪水洪峰流量。该研究对于充分认识雅鲁藏布江中游的洪水运动规律有重要作用,对于揭示高能洪水在高山峡谷区的特征及其地貌响应具有重要的现实意义。
High-energy floods are the largest extreme floods on earth and highly relevant to global landform evolution and climate change.The efforts to reconstruct high-energy flood occurrences can improve our understanding of historic extreme flood events and help us further investigate the responses of alpine and valley landforms to the strikes of extreme floods.Unfortunately,the research on the reconstruction of high-energy flood occurrences remains limited.There were less applicability of high-energy flood models to high-altitude mountainous areas,and high-accuracy reconstruction results were not available.In this study,high-energy floods occurred in the middle reaches of the Yarlung Zangbo River,China were reconstructed for estimation of their scales.HEC-RAS model was introduced and HEC-Georas module in ArcGIS platform was used to rebuild the peak flow of ancient high-energy floods based on current 17 gravel islands and shoals located in some wide valleys between the middle reaches of the Yarlung Zangbo River,which were believed to be relics or records of ancient High-energy floods events.Sensitivity tests were used to ensure the accuracy of reconstruction based on the Manning roughness coefficient with a variation of±35%.Results conclude:(1)The simulated water levels of the 17 gravel islands and shoals were consistent with the marked water levels obtained from field surveys.The discrepancies with measured results were all less than 0.1%.(2)The peak flow was between 0.2×10^(6)~1.8×10^(6)m^(3)/s,and the maximum submerged water depth was 366 m.(3)When Manning coefficient was in the range of±35%,the error range of the flood peak water level was between-0.36%and 0.17%,indicating that the model was less sensitive to the Manning roughness coefficient,indicated that the proposed method was appropriate to recover the peak flow of ancient high-energy floods in the middle reaches of the Brahmaputra.This research contributes to fully understanding the flood movement in the middle reaches of the Yarlung Zangbo River and has i
作者
蒋先刚
刘维明
文宿菘
吴朝华
JIANG Xiangang;LIU Weiming;WEN Susong;WU Chaohua(School of Civil Engineering,Sichuan Agricultural University,Dujiangyan 611830,Sichuan,China;Key Laboratory of Mountain Hazards and Earth Surface Process,Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610041,China;China-Pakistan Joint Research Center on Earth Sciences,CAS-HEC,Islamabad 45320,Pakistan)
出处
《山地学报》
CSCD
北大核心
2022年第2期276-288,共13页
Mountain Research
基金
国家自然科学基金(42071017)
国家自然科学基金重大研究计划(91747207)
国家自然科学基金(41807289)
中国科学院山地灾害与地表过程重点实验室开放基金(KLMHESP-20-05)。
