DOI: 10.5194/hess-20-4525-2016
Scopus记录号: 2-s2.0-84995483219
论文题名: Multiple runoff processes and multiple thresholds control agricultural runoff generation
作者: Saffarpour S ; , Western A ; W ; , Adams R ; , McDonnell J ; J
刊名: Hydrology and Earth System Sciences
ISSN: 10275606
出版年: 2016
卷: 20, 期: 11 起始页码: 4525
结束页码: 4545
语种: 英语
Scopus关键词: Agriculture
; Catchments
; Chemical activation
; Digital storage
; Groundwater
; Isotopes
; Moisture
; Process control
; Rain
; Runoff
; Soil moisture
; Soil surveys
; Soils
; Water levels
; Wetlands
; Agricultural catchments
; Antecedent soil moisture
; High intensity rainfall
; Hydrologic connectivity
; Preferential pathways
; Rainfall characteristics
; Runoff generation mechanisms
; Shallow groundwater levels
; Agricultural runoff
; agricultural runoff
; catchment
; groundwater
; hillslope
; hydrometry
; infiltration
; overland flow
; preferential flow
; rainfall-runoff modeling
; riparian zone
; runoff
; subsurface flow
; Australia
; Victoria [Australia]
英文摘要: Thresholds and hydrologic connectivity associated with runoff processes are a critical concept for understanding catchment hydrologic response at the event timescale. To date, most attention has focused on single runoff response types, and the role of multiple thresholds and flow path connectivities has not been made explicit. Here we first summarise existing knowledge on the interplay between thresholds, connectivity and runoff processes at the hillslope-small catchment scale into a single figure and use it in examining how runoff response and the catchment threshold response to rainfall affect a suite of runoff generation mechanisms in a small agricultural catchment. A 1.37 ha catchment in the Lang Lang River catchment, Victoria, Australia, was instrumented and hourly data of rainfall, runoff, shallow groundwater level and isotope water samples were collected. The rainfall, runoff and antecedent soil moisture data together with water levels at several shallow piezometers are used to identify runoff processes in the study site. We use isotope and major ion results to further support the findings of the hydrometric data. We analyse 60 rainfall events that produced 38 runoff events over two runoff seasons. Our results show that the catchment hydrologic response was typically controlled by the Antecedent Soil Moisture Index and rainfall characteristics. There was a strong seasonal effect in the antecedent moisture conditions that led to marked seasonal-scale changes in runoff response. Analysis of shallow well data revealed that streamflows early in the runoff season were dominated primarily by saturation excess overland flow from the riparian area. As the runoff season progressed, the catchment soil water storage increased and the hillslopes connected to the riparian area. The hillslopes transferred a significant amount of water to the riparian zone during and following events. Then, during a particularly wet period, this connectivity to the riparian zone, and ultimately to the stream, persisted between events for a period of 1 month. These findings are supported by isotope results which showed the dominance of pre-event water, together with significant contributions of event water early (rising limb and peak) in the event hydrograph. Based on a combination of various hydrometric analyses and some isotope and major ion data, we conclude that event runoff at this site is typically a combination of subsurface event flow and saturation excess overland flow. However, during high intensity rainfall events, flashy catchment flow was observed even though the soil moisture threshold for activation of subsurface flow was not exceeded. We hypothesise that this was due to the activation of infiltration excess overland flow and/or fast lateral flow through preferential pathways on the hillslope and saturation overland flow from the riparian zone. © Author(s) 2016. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/78690
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Infrastructure Engineering, University of Melbourne, Parkville, VIC, Australia; Global Institute for Water Security, University of Saskatchewan, Saskatoon, SK, Canada; School of Geosciences, University of Aberdeen, Aberdeen, United Kingdom
Recommended Citation:
Saffarpour S,, Western A,W,et al. Multiple runoff processes and multiple thresholds control agricultural runoff generation[J]. Hydrology and Earth System Sciences,2016-01-01,20(11)