title: The characteristics of extreme erosion events in a small mountainous watershed.
abstract: A large amount of soil loss is caused by a small number of extreme events that are mainly responsible for the time compression of geomorphic processes. The aim of this study was to analyze suspended sediment transport during extreme erosion events in a mountainous watershed. Field measurements were conducted in Wangjiaqiao, a small agricultural watershed (16.7 km(2)) in the Three Gorges Area (TGA) of China. Continuous records were used to analyze suspended sediment transport regimes and assess the sediment loads of 205 rainfall-runoff events during a period of 16 hydrological years (1989-2004). Extreme events were defined as the largest events, ranked in order of their absolute magnitude (representing the 95(th) percentile). Ten extreme erosion events from 205 erosion events, representing 83.8% of the total suspended sediment load, were selected for study. The results of canonical discriminant analysis indicated that extreme erosion events are characterized by high maximum flood-suspended sediment concentrations, high runoff coefficients, and high flood peak discharge, which could possibly be explained by the transport of deposited sediment within the stream bed during previous events or bank collapses.
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A & F University, Yangling, PR China ; Institute of Soil and Water Conservation of Chinese Academy of Sciences and Ministry of Water Resources, Yangling, PR China.
authors.forename: Nu-Fang
authors.initials: NF
authors.lastname: Fang
authors.forename: Zhi-Hua
authors.initials: ZH
authors.lastname: Shi
authors.forename: Ben-Jiang
authors.initials: BJ
authors.lastname: Yue
authors.forename: Ling
authors.initials: L
authors.lastname: Wang
mesh_terms: D002681:China; D016002:Discriminant Analysis; D017753:Ecosystem; D055868:Floods; D005843:Geography; D019015:Geologic Sediments; D011891:Rain; D012987:Soil; D014867:Water
chemical_list: D012987:Soil; D014867:Water