DOI: 10.5194/hess-20-3005-2016
Scopus记录号: 2-s2.0-84980000713
论文题名: Assessment of land use impact on hydraulic threshold conditions for gully head cut initiation
作者: Nazari Samani A ; , Chen Q ; , Khalighi S ; , James Wasson R ; , Rahdari M ; R
刊名: Hydrology and Earth System Sciences
ISSN: 10275606
出版年: 2016
卷: 20, 期: 7 起始页码: 3005
结束页码: 3012
语种: 英语
Scopus关键词: Erosion
; Flow of water
; Forestry
; Landforms
; Shear stress
; Soils
; Uncertainty analysis
; Aggregate strength
; Critical shear stress
; Environmental conditions
; Ephemeral gully erosions
; Soil-erosion model
; Surface vegetation
; Threshold condition
; Threshold phenomena
; Land use
; discharge
; environmental assessment
; environmental conditions
; environmental modeling
; Froude number
; gully erosion
; land degradation
; land type
; land use change
; shear stress
; soil erosion
; water flow
英文摘要: A gully as an accelerated erosion process is responsible for land degradation under various environmental conditions and has been known as a threshold phenomenon. Although the effects of gullying processes have been well documented, few soil erosion models have taken into account the threshold condition necessary for gully development. This research was devoted to determining the effects of land use change on hydraulic threshold condition and stream power of water flow through an in situ experimental flume (15m × 0.4 m). Results indicated that head cut initiation and detachment rates showed a better correlation to stream power indices than shear stress (τcr). The threshold unit stream power value (ωu) for head cut initiation in rangeland, abandoned land, and dry farming land was 0.0276, 0.0149, and 4.5 × 10-5ms-1, respectively. Moreover, the micro-relief condition of soil surface and surface vegetation affected the flow regime of discharge and velocity. It is seen that the composite hydraulic criteria of Froude number (Fr) and discharge (Q) can clearly discriminate the land uses' threshold. In fact, the remarkable decrease of τcrin dry farming was related to the effect of tillage practice on soil susceptibility and aggregate strength. The findings indicated that using the unit steam power index instead of critical shear stress could increase the models' precision for prediction of head cut development. Compared to the Ephemeral Gully Erosion Model (EGEM) equation for critical shear stress, it is important to point out that for modelling of gully erosion, using single soil attributes can lead to an inaccurate estimation for τcr. In addition, based on the findings of this research, the use of threshold values of τcr= 35 dyne cm-2and ωu=0.4 cm s-1in physically based soil erosion models is susceptible to high uncertainty when assessing gully erosion. © 2016 Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/78777
Appears in Collections: 气候变化事实与影响
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作者单位: Faculty of Natural Resources, University of Tehran, Karaj, Iran; CEER, Nanjing Hydraulics Research Institute, Nanjing, China; RCEES, Chinese Academy of Sciences, Beijing, China; Institute of Water Policy, National University of Singapore, Singapore
Recommended Citation:
Nazari Samani A,, Chen Q,, Khalighi S,et al. Assessment of land use impact on hydraulic threshold conditions for gully head cut initiation[J]. Hydrology and Earth System Sciences,2016-01-01,20(7)