极端降雨事件下三峡库区中部多尺度嵌套小流域径流泥沙特征分析  

Runoff and Sediment Characteristics at Multi-scale Nested Small Watersheds in the Central Region of the Three Gorges Reservoir Area under Extreme Rainfall Events

作　　者：闫洋洋 黄智华[3] 严坤[1,2] 王玉宽 逯亚峰[1,2] YAN Yangyang;HUANG Zhihua;YAN Kun;WANG Yukuan;LU Yafeng(Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu610299,China;The ComprenshensiveSafety Monitoring System of Three Gorges-Water and Soil Conservation Monitoring Station in Typical area of Wanzhou,Wanzhou404020,China;China Institute of Water Resources and Hydropower Rese arch,Beijing 100038,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,成都610299 [2]三峡工程运行安全综合监测系统万州典型区水土保持监测站,重庆万州404020 [3]中国水利水电科学研究院,北京100038

出　　处：《三峡生态环境监测》2024年第2期67-77,共11页Ecology and Environmental Monitoring of Three Gorges

基　　金：三峡工程运行安全综合监测系统,库区维护和管理基金项目(2136703);中国科学院战略先导专项A类项目(XDA23090501)。

摘　　要：为研究三峡库区中部泥沙来源及类型分布,本文基于中国科学院成都山地灾害与环境研究所万州典型区水土保持监测站多尺度嵌套小流域2003—2022年降雨极值与泥沙特征数据,利用Mann-Kendall秩相关检验,深入分析了库区流域内输沙量趋势变化及其与降雨极值之间的关系。结果表明:(1)三峡库区中部典型区小流域降雨天数和中雨、大雨以及暴雨天数有明显增加趋势;(2)支沟向出口汇聚过程中,部分推移质泥沙沉积,但在极端降雨时,沉积泥沙再次启动汇入下游,且极端降雨事件下流域坡面泥沙主要以悬移质形式流失;(3)由于人为活动的影响,嵌套小流域内各支沟和集水区的侵蚀模数存在显著差异,最大侵蚀模数与最小侵蚀模数之间的比值高达10.71。同时,小流域及其嵌套支沟的年侵蚀模数呈现不同程度增加的趋势,并在极端降水事件频繁发生的2020年达到最大值。(4)虽然三峡库区中部典型区小流域降雨整体上有降低趋势,但极端性的降雨频发仍是水土流失防治的重点区域。因此,针对频发的极端性降雨侵蚀特征及其小流域内泥沙迁移规律,加强小流域推移质与悬移质源头生态风险排除与治理,稳固河道沉积泥沙将有效降低小流域把口站泥沙的输出。To study the source and type distribution of sediment in the central region of the Three Gorges Reservoir Area,this paper utilizes the multi-scale nested small watershed rainfall and sediment characteristics data from 2003 to 2022 collected by Comprenshensive Safety Monitoring System of Three Gorges-Water and Soil Conservation Monitoring Station in Typical Area of Wanzhou,Institute of Mountain Hazards and Environment,Chinese Academy of Sciences.By applying the Mann-Kendall rank correla⁃tion test,the paper conducts an in-depth analysis of the trend changes in sediment discharge within the reservoir area watershed and its relationship with extreme rainfall.The results indicate that:(1)There is a significant increasing trend in the number of rainy days,moderate rain,heavy rain,and rainstorm in the typical small watershed in the central Three Gorges Reservoir area;(2)During the process of converging from tributary gullies to the outlet,some bedload sediment deposition occurs.However,during ex⁃treme rainfall events,the deposited sediment is reactivated and flows into the downstream,and the sediment on the watershed slope mainly loses in the form of suspended sediment;(3)Due to the impact of human activities,there are significant differences in ero⁃sion moduli among various tributary gullies and catchments within the nested small watershed,with the maximum erosion modulus being 9.71 times higher than the minimum.Meanwhile,the annual erosion moduli of the small watershed and its nested tributary gullies show increasing trends of varying degrees,reaching a maximum in 2020,a year with frequent extreme precipitation events;(4)Although there is an overall decreasing trend in rainfall in the typical small watershed in the central region of the Three Gorges Reservoir area,the frequent occurrence of extreme rainfall remains a key area for soil erosion prevention and control.Therefore,in response to the frequent extreme rainfall erosion characteristics and the sediment migration patterns within the small watershed,strengt

关 键 词：三峡库区中部典型区 极端降雨 悬移质 推移质 

分 类 号：P9[天文地球—自然地理学]