DOI: 10.5194/hess-19-3771-2015
Scopus记录号: 2-s2.0-84941244011
论文题名: Transit times from rainfall to baseflow in headwater catchments estimated using tritium: The Ovens River, Australia
作者: Cartwright I ; , Morgenstern U
刊名: Hydrology and Earth System Sciences
ISSN: 10275606
出版年: 2015
卷: 19, 期: 9 起始页码: 3771
结束页码: 3785
语种: 英语
Scopus关键词: Catchments
; Groundwater
; Land use
; Ovens
; Rain
; Runoff
; Stream flow
; Water quality
; Water resources
; Alluvial gravel
; CL-concentrations
; Headwater catchment
; Headwater stream
; Ion concentrations
; Low flow condition
; Mean transit time
; Rainfall variation
; Rivers
; alluvial deposit
; baseflow
; catchment
; flow pattern
; headwater
; rainfall
; seasonality
; transient flow
; tritium
; water chemistry
; Australia
; Ovens River
; Victoria [Australia]
英文摘要: Headwater streams contribute a significant proportion of the total flow to many river systems, especially during summer low-flow periods. However, despite their importance, the time taken for water to travel through headwater catchments and into the streams (the transit time) is poorly understood. Here, 3H activities of stream water are used to define transit times of water contributing to streams from the upper reaches of the Ovens River in south-east Australia at varying flow conditions. 3H activities of the stream water varied from 1.63 to 2.45 TU, which are below the average 3H activity of modern local rainfall (2.85 to 2.99 TU). The highest 3H activities were recorded following higher winter flows and the lowest 3H activities were recorded at summer low-flow conditions. Variations of major ion concentrations and 3H activities with streamflow imply that different stores of water from within the catchment (e.g. from the soil or regolith) are mobilised during rainfall events rather than there being simple dilution of an older groundwater component by event water. Mean transit times calculated using an exponential-piston flow model range from 4 to 30 years and are higher at summer low-flow conditions. Mean transit times calculated using other flow models (e.g. exponential flow or dispersion) are similar. There are broad correlations between 3H activities and the percentage of rainfall exported from each catchment and between 3H activities and Na and Cl concentrations that allow first-order estimates of mean transit times in adjacent catchments or at different times in these catchments to be made. Water from the upper Ovens River has similar mean transit times to the headwater streams implying there is no significant input of old water from the alluvial gravels. The observation that the water contributing to the headwater streams in the Ovens catchment has a mean transit time of years to decades implies that these streams are buffered against rainfall variations on timescales of a few years. However, impacts of any changes to land use in these catchments may take years to decades to manifest themselves in changes to streamflow or water quality. © Author(s) 2015. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/78432
Appears in Collections: 气候变化事实与影响
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作者单位: School of Earth, Atmosphere and Environment, Monash University, Clayton, VIC, Australia; National Centre for Groundwater Research and Training, Flinders University, GPO Box 2100, Adelaide, SA, Australia; GNS Science, Lower Hutt 5040, New Zealand
Recommended Citation:
Cartwright I,, Morgenstern U. Transit times from rainfall to baseflow in headwater catchments estimated using tritium: The Ovens River, Australia[J]. Hydrology and Earth System Sciences,2015-01-01,19(9)