DOI: 10.5194/hess-20-257-2016
Scopus记录号: 2-s2.0-84957041404
论文题名: Time series of tritium, stable isotopes and chloride reveal short-term variations in groundwater contribution to a stream
作者: Duvert C ; , Stewart M ; K ; , Cendón D ; I ; , Raiber M
刊名: Hydrology and Earth System Sciences
ISSN: 10275606
出版年: 2016
卷: 20, 期: 1 起始页码: 257
结束页码: 277
语种: 英语
Scopus关键词: Aquifers
; Catchments
; Chlorine compounds
; Groundwater
; Groundwater resources
; Igneous rocks
; Isotopes
; Rivers
; Runoff
; Stream flow
; Time series
; Tritium
; Wave propagation
; Alluvial aquifers
; Complex relationships
; Convolution model
; Groundwater residence time
; Hydrological tracers
; Pressure wave propagation
; Short-term variations
; Temporal variation
; Residence time distribution
; catchment
; chloride
; concentration (composition)
; groundwater
; headwater
; rainfall
; recharge
; residence time
; stable isotope
; time series
; tritium
; water quality
; wave propagation
; Australia
英文摘要: A major limitation to the assessment of catchment transit time (TT) stems from the use of stable isotopes or chloride as hydrological tracers, because these tracers are blind to older contributions. Yet, accurately capturing the TT of the old water fraction is essential, as is the assessment of its temporal variations under non-stationary catchment dynamics. In this study we used lumped convolution models to examine time series of tritium, stable isotopes and chloride in rainfall, streamwater and groundwater of a catchment located in subtropical Australia. Our objectives were to determine the different contributions to streamflow and their variations over time, and to understand the relationship between catchment TT and groundwater residence time. Stable isotopes and chloride provided consistent estimates of TT in the upstream part of the catchment. A young component to streamflow was identified that was partitioned into quickflow (mean TT ‰ 2 weeks) and discharge from the fractured igneous rocks forming the headwaters (mean TT ‰ 0.3 years). The use of tritium was beneficial for determining an older contribution to streamflow in the downstream area. The best fits between measured and modelled tritium activities were obtained for a mean TT of 16-25 years for this older groundwater component. This was significantly lower than the residence time calculated for groundwater in the alluvial aquifer feeding the stream downstream (‰ 76-102 years), emphasising the fact that water exiting the catchment and water stored in it had distinctive age distributions. When simulations were run separately on each tritium streamwater sample, the TT of old water fraction varied substantially over time, with values averaging 17 ± 6 years at low flow and 38 ± 15 years after major recharge events. This counterintuitive result was interpreted as the flushing out of deeper, older waters shortly after recharge by the resulting pressure wave propagation. Overall, this study shows the usefulness of collecting tritium data in streamwater to document short-term variations in the older component of the TT distribution. Our results also shed light on the complex relationships between stored water and water in transit, which are highly non-linear and remain poorly understood. © 2016 Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/78944
Appears in Collections: 气候变化事实与影响
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作者单位: Queensland University of Technology, Brisbane, QLD, Australia; Aquifer Dynamics Ltd and GNS Science, P.O. Box 30368, Lower Hutt, New Zealand; Australian Nuclear Science and Technology Organisation, Kirrawee DC, NSW, Australia; School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia; CSIRO Land and Water, Dutton Park, Brisbane, QLD, Australia
Recommended Citation:
Duvert C,, Stewart M,K,et al. Time series of tritium, stable isotopes and chloride reveal short-term variations in groundwater contribution to a stream[J]. Hydrology and Earth System Sciences,2016-01-01,20(1)