DOI: 10.5194/hess-19-1871-2015
Scopus记录号: 2-s2.0-84928548949
论文题名: Detecting groundwater discharge dynamics from point-to-catchment scale in a lowland stream: Combining hydraulic and tracer methods
作者: Poulsen J ; R ; , Sebok E ; , Duque C ; , Tetzlaff D ; , Engesgaard P ; K
刊名: Hydrology and Earth System Sciences
ISSN: 10275606
出版年: 2015
卷: 19, 期: 4 起始页码: 1871
结束页码: 1886
语种: 英语
Scopus关键词: Agriculture
; Catchments
; Discharge (fluid mechanics)
; Doppler effect
; Groundwater
; Isotopes
; Nutrients
; Pollution detection
; Rivers
; Runoff
; Source separation
; Surface waters
; Acoustic doppler current profiler
; Agricultural catchments
; Concentrated groundwater
; Distributed temperature sensing
; Electrical conductivity
; Ground water discharge
; Groundwater-surface water interfaces
; Temporal and spatial variability
; Groundwater pollution
; Acoustic Doppler Current Profiler
; catchment
; discharge
; groundwater-surface water interaction
; stream bed
; tracer
; Denmark
英文摘要: Detecting, quantifying and understanding groundwater discharge to streams are crucial for the assessment of water, nutrient and contaminant exchange at the groundwater-surface water interface. In lowland agricultural catchments with significant groundwater discharge this is of particular importance because of the risk of excess leaching of nutrients to streams. Here we aim to combine hydraulic and tracer methods from point-to-catchment scale to assess the temporal and spatial variability of groundwater discharge in a lowland, groundwater gaining stream in Denmark. At the point-scale, groundwater fluxes to the stream were quantified based on vertical streambed temperature profiles (VTPs). At the reach scale (0.15-2 km), the spatial distribution of zones of focused groundwater discharge was investigated by the use of distributed temperature sensing (DTS). Groundwater discharge to the stream was quantified using differential gauging with an acoustic Doppler current profiler (ADCP). At the catchment scale (26-114 km2), runoff sources during main rain events were investigated by hydrograph separations based on electrical conductivity (EC) and stable isotopes 2H/1H. Clear differences in runoff sources between catchments were detected, ranging from approximately 65% event water for the most responsive sub-catchment to less than 10% event water for the least responsive sub-catchment. This was supported by the groundwater head gradients, where the location of weaker gradients correlated with a stronger response to precipitation events. This shows a large variability in groundwater discharge to the stream, despite the similar lowland characteristics of sub-catchments indicating the usefulness of environmental tracers for obtaining information about integrated catchment functioning during precipitation events. There were also clear spatial patterns of focused groundwater discharge detected by the DTS and ADCP measurements at the reach scale indicating high spatial variability, where a significant part of groundwater discharge was concentrated in few zones indicating the possibility of concentrated nutrient or pollutant transport zones from nearby agricultural fields. VTP measurements confirmed high groundwater fluxes in discharge areas indicated by DTS and ADCP, and this coupling of ADCP, DTS and VTP proposes a novel field methodology to detect areas of concentrated groundwater discharge with higher resolution. © Author(s) 2015. CC Attribution 3.0 License. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/78545
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Bioscience, Aarhus University, Silkeborg, Denmark; Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark; Department of Geosciences, Section of Geology and Geophysics, University of Oslo, Oslo, Norway; Northern Rivers Institute, School of Geosciences, Aberdeen University, Aberdeen Scotland, United Kingdom
Recommended Citation:
Poulsen J,R,, Sebok E,et al. Detecting groundwater discharge dynamics from point-to-catchment scale in a lowland stream: Combining hydraulic and tracer methods[J]. Hydrology and Earth System Sciences,2015-01-01,19(4)