DOI: 10.1016/j.earscirev.2020.103086
论文题名: Frequency of boulders transport during large floods in hyperarid areas using paleoflood analysis – An example from the Negev Desert, Israel
作者: Greenbaum N. ; Schwartz U. ; Carling P. ; Bergman N. ; Mushkin A. ; Zituni R. ; Halevi R. ; Benito G. ; Porat N.
刊名: Earth Science Reviews
ISSN: 00128252
出版年: 2020
卷: 202 语种: 英语
中文关键词: Boulders transport
; Desert flood
; Flood frequency analysis
; Geomorphic effectiveness
; Paleoflood hydrology
; Shear stress
; Stream power
; Ungauged catchments
英文关键词: arid environment
; boulder
; catchment
; entrainment
; flood frequency
; geomorphology
; paleoflood
; paleohydrology
; sediment transport
; shear stress
; streamflow
; Israel
; Negev
; Southern District
英文摘要: Direct measurements of boulder entrainment in desert wadis are not available. The 2004 flood (peak discharge – 470 m3 s−1; recurrence interval – 120 years) in the hyperarid, ungauged Nahal Hatzera ephemeral stream (45 km2), transported and deposited 0.85–2.1 m concrete boulders and slabs detached from infrastructure upstream and natural boulders. EDM and drone air-photographic surveys documented the geometry of the study reach and the location of boulders. Analyses of flood slackwater deposits established a paleoflood record of 23 floods with peak discharges of 200–760 m3 s−1, during the last 600 years. 1-D HEC-RAS hydraulic analysis provided water surface profiles, discharges and hydraulics, along the study reach and velocity, shear stress and stream power for each boulder. MAX program and Pearson 3 distribution were used for flood frequency analysis. Most of the concrete boulders were deposited in the sub-critical backwater of channel constrictions where velocities were 1.5–2.1 m s−1. The largest boulders were deposited in super-critical flow where velocity was 8–9.2 m s−1. The alluvial channel enabled to transport these concrete boulders, reflecting the unstable, active sandy layer of the channel bed over which the boulders moved. The maximum flood shear stress and stream power characterize medium-large floods with return period of 20–120 years and not for the largest floods, as expected. Boulders about 2.1 m and weighing about 15 t can be transported at least once in 120 years. The shear stress and stream power indicate that the moderate-large floods are the most geomorphically effective floods rather than the largest floods in Nahal Hatzera basin. Nevertheless, the ‘geomorphic effectiveness’ of the 2004 flood – a typical desert flash flood with high peak and short duration, was small based on the minor changes along the channel and banks indicating that their resistance thresholds were not exceeded and energy expenditure was mainly on boulders entrainment and transport. © 2020 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/166093
Appears in Collections: 气候变化与战略
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作者单位: University of Haifa, Mt. Carmel, Haifa, 3498838, Israel; University of Southampton, Southampton, SO17 1BJ, United Kingdom; Geological Survey of Israel, Jerusalem, 9692100, Israel; Nehara, Misgav, Israel; Museo Nacional de Ciencias Naturales, CSIC, Madrid, 28006, Spain
Recommended Citation:
Greenbaum N.,Schwartz U.,Carling P.,et al. Frequency of boulders transport during large floods in hyperarid areas using paleoflood analysis – An example from the Negev Desert, Israel[J]. Earth Science Reviews,2020-01-01,202