Contribution of glacier meltwater to streamflow in the Wind River Range,Wyoming, inferred via a Bayesian mixing model applied to isotopic measurements   总被引：3，自引：0，他引：3  

Jessica Cable  Kiona Ogle  David Williams 《水文研究》2011,25(14):2228-2236

The Wind River Range (WRR) of Wyoming has the largest concentration of alpine glaciers in the American Rockies and contributes to several major river systems in the western United States. Declines in the areal extent and volume of these glaciers are well documented, and eventual loss of alpine glaciers will reduce the amount of water available for agricultural and domestic use. The contribution of glacial melt to streamflow remains largely unquantified in Wyoming. We used isotope measurements and Bayesian modeling to estimate the fractional contribution of glacier meltwater to Dinwoody Creek (DC) in the WRR on bi‐weekly and seasonal (spring, summer, and fall) time scales over 2 years. In 2007 and 2008, we made temporally intensive measurements of the stable isotope composition of water from the DC watershed. Samples of the primary sources of streamflow (snowmelt, glacier melt, rain, and baseflow) were collected during field campaigns, and automated collection of stream samples occurred over the melt season. Isotope data (D and ¹⁸O) were analyzed within a hierarchical Bayesian framework that incorporated temporal and spatial correlations. Glacial melt contributed a significant proportion (～53–59%) to streamflow in a low‐flow year (2007) or when streamflow was low during a high‐flow year (2008). In 2008, a large and persistent snowpack contributed significantly (～0·42–51%) to streamflow in mid‐summer. The large contribution of glacial melt to streamflow suggests that the loss of glaciers may impact riparian ecosystems and human water supplies in the late summer and in years with low snowpack. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

聚合膜电解浓集法测量低水平氚环境水样的氚比活度   总被引：2，自引：1，他引：1  

王华  殷建军  杨会  林宇  应启和  文云朝 《岩矿测试》2011,30(6):745-750

随着氚同位素电解浓集技术和测量仪器的发展,对低水平的氚比活度可以进行准确测量,但由于现行的氚处理方法的差异,导致氚比活度测定的不确定性增加。本文采用现行的两种氚比活度测量方法碱式电解浓集法和聚合膜电解浓集法测量低水平环境水样的氚比活度,并将结果进行比对。针对聚合膜电解法,通过使用优化结构的装置提高可靠性;对于使用国家标准方法计算出现较大误差的情况下,在氚水回收率的计算数据处理方面提出了死体积的概念,改善了聚合膜电解法测量低水平氚样品的稳定性,使氚比活度的计算结果更加精确。  相似文献   

Contaminant transport in fractured media: analytical solution and sensitivity study considering pulse,Dirac delta and sinusoid input sources     

David Ching‐Fang Shih  Gwo‐Fong Lin  I‐Sen Wang 《水文研究》2002,16(16):3265-3278

The analytical solution of one‐dimensional transport for a single species radioactive nuclide, considering the decay term in a single fracture for pulse, Dirac delta, and single sinusoid input sources, has been studied using the Laplace transform method. The dimensionless concentration of the radioactive nuclide in the fracture appears to be a function of space, elapsed time, dispersivity, retardation factor, half‐life of the nuclide, and release time. By comparing different values of groundwater velocity, retardation factor, dispersivity, and release time, the results show that the c/c₀ ratio agrees with the nature of the physical and chemical characteristics of the nuclide in fracture transportation. The dimensionless concentration peak value from a small retardation factor is found to be more sensitive, within a time frame ranging from 10 years to a few hundreds years, than the case with a larger retardation factor for H‐3. Except for a small variation in the peak value, the result is almost the same for pulse and sinusoid inputs when considering the H‐3 nuclide. Analytical solutions during the preliminary screening phase are suitable for performance assessment on radioactive waste disposal sites under a one‐dimensional single fracture condition. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

Input function and simulated distributions of tritium in the North Pacific     

BA Qi  & XU YongFu State Key Laboratory of Atmospheric Boundary Layer Physics  Atmospheric Chemistry 《中国科学:地球科学(英文版)》2010,(3)

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Rapid recharge of fresh water to the halite‐hosted brine aquifer of Salar de Atacama,Chile          下载免费PDF全文

David F. Boutt  Scott A. Hynek  Lee Ann Munk  Lilly G. Corenthal 《水文研究》2016,30(25):4720-4740

We document, analyse, and interpret direct and rapid infiltration of precipitation to the southern margin of the Salar de Atacama halite‐hosted brine aquifer during two intense precipitation events in 2012–2013. We present physical, geochemical, and stable and radioactive isotope data to detail this influx of water. The two events differ distinctly in the mechanisms of recharge. The 2012 event did not produce direct precipitation onto the salar surface, while the 2013 event did. Both events are recorded by abrupt changes in head in observation wells along the halite aquifer margin. Spatially distributed water levels rose by over 30 cm during the larger 2013 event consistent with remotely sensed observations of surface water extent. The lithium concentration and stable isotopic composition of water indicate dilution of brine and dissolution of salt with fresh water. Tritium measurements of precipitation, surface water, and groundwater all indicate modern influx of water to the halite aquifer along the southern margin. We extend these observations by examining the response of the halite aquifer as a whole to precipitation events during the period of 2000–2010. This study suggests that local recharge to the aquifer during sporadic precipitation onto the halite nucleus is an important component of the modern water budget in this hyper‐arid environment. The rapid dissolution and salinization along the southern margin of the salar halite nucleus are aided by such precipitation events contributing a modern fresh water component to the water budget of the economically valuable lithium‐rich brine. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Vegetation water sources in California's Sierra Nevada (USA) are young and change over time,a multi-isotope (δ18O, δ2H, 3H) tracer approach.     

Melissa Thaw  Ate Visser  Richard Bibby  Amanda Deinhart  Erik Oerter  Martha Conklin 《水文研究》2021,35(6):e14249

Sierra Nevada forests transpire a significant amount of California's water resources, sparking interest in applying forest management to improve California's water supply. Determining the source water of evapotranspiration enables forest managers to make informed decisions. To this end, a significant interest in critical zone science is to develop new methods to work across time scales to predict subsurface water storage and use. In this study, forest vegetation accessed young water and switched sources depending on availability, suggesting that forest drought vulnerability may depend on the range of water sources available (rain, snowmelt and deeply stored water). This finding also suggests that changes in transpiration rates may have immediate effects on water sources in close proximity to vegetation, and delayed effects on storage and runoff. New δ¹⁸O, δ²H and ³H data were used to track precipitation, runoff, evapotranspiration and storage through the critical zone seasonally, including seasons where evapotranspiration and snowmelt were in phase (winter snowmelt) and out of phase (seasonally dry summer). The main source of this headwater catchment's runoff is derived from its meadow saturated zone water, which was dominated by snowmelt. Water that originated as snowmelt contributed to transpiration, unless other sources, such as recent rain, became available. In cases where xylem δ¹⁸O and δ²H signatures matched those of deeper saturated zone water, ³H data showed that xylem water was distinctly younger than the deep saturated zone water. During 2016, which experienced relatively normal snowpack in winter and seasonally dry summer conditions, mean summer saturated zone water and vegetation water were similar in δ¹⁸O, −12.4 ± 0.04 ‰ and − 12.5 ± 0.3 ‰, respectively, but were distinctly different in ³H, 5.5 ± 0.2 pCi/L and 13.7 ± 1.1 pCi/L, respectively. While δ¹⁸O shows that vegetation and meadow saturated zone water have similar origins, ³H shows they have dissimilar ages.  相似文献   

Review on soil water isotope‐based groundwater recharge estimations          下载免费PDF全文

Paul Koeniger  Marcel Gaj  Matthias Beyer  Thomas Himmelsbach 《水文研究》2016,30(16):2817-2834

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Tritium balance in macro‐scale river basins analysed through distributed hydrological modelling     

P. Koeniger  M. Schwientek  S. Uhlenbrook  Ch. Leibundgut  W. J. Krause 《水文研究》2008,22(5):567-576

The recession of bomb tritium in river discharge of large basins indicates a contribution of slowly moving water. For an appropriate interpretation it is necessary to consider different runoff components (e.g. direct runoff and ground water components) and varying residence times of tritium in these components. The spatially distributed catchment model (tracer aided catchment model, distributed; TAC^D) and a tritium balance model (TRIBIL) were combined to model process‐based tritium balances in a large German river basin (Weser 46 240 km²) and seven embedded sub‐basins. The hydrological model (monthly time step, 2 × 2 km²) estimated the three major runoff components: direct runoff, fast‐moving and slow‐moving ground water for the period of 1950 to 1999. The model incorporated topography, land use, geomorphology, geology and hydro‐meteorological data. The results for the different basins indicated a contribution of direct runoff of 30–50% and varying amounts for fast and slow ground water components. Combining these results with the TRIBIL model allowed us to estimate the residence time of the components. Mean residence times of 8 to 14 years were found for the fast ground water component, 21 to 93 years for the slow ground water component and 14 to 50 years for an overall mean residence time within these basins. Balance calculations for the Weser basin indicate an over‐estimation of loss of tritium through evapotranspiration (more than 60%) and decay (10%). About 28% were carried in stream‐flow where direct runoff contributed about 12% and ground water runoff 13% in relation to precipitation input over the studied 50‐year period. Neighbouring basins and nuclear power plants contributed about 1% each over this time period. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

九江庐山地区地下水水文地球化学特征及成因     

鲍志诚  查小惠  赵影  赵爱平  向阳  蒋雨函 《大地测量与地球动力学》2021,41(5):471-577

分析九江环庐山地区观测井水、大气降水、冷泉水、地热温泉水及地表水水样的常量化学组分和氢氧同位素及氚活度,结果表明,庐山地区地下水主要分为西北、东南两个水文地质单元,西北侧以九江台2号井井水、东林寺泉水为代表,水化类型为HCO3-Ca;东南侧以地热温泉井水、观音桥泉水为代表,水化类型为HCO3-Na,离子组分主要来自风化壳岩石风化。氢氧同位素显示,九江庐山地区地下水均属于降水成因型,部分井泉具有深循环的特征;氯离子估算结果显示,大气降水直接补给率约为4.5%~33.27%。大气降水下渗补给形成裂隙承压自流井泉是庐山地区地下水主要成因,另有部分为降水经长时间深循环形成地热温泉水,而九江台2号井既有浅表水特征又有深循环水的特征,暗示两个不同补给源的含水层通过不同循环路径上升到浅表地层,携带有部分深部构造活动信息,有利于获取地震前兆异常信息。  相似文献   

Hydrometric and natural tracer (oxygen-18, silica,tritium and sulphur hexafluoride) evidence for a dominant groundwater contribution to Pukemanga Stream,New Zealand     

Michael K. Stewart  Jens Mehlhorn  Sandy Elliott 《水文研究》2007,21(24):3340-3356

Pukemanga is a small (3 ha) steep headwater catchment at the Whatawhata Research Station near Hamilton, New Zealand. The water balance (1996–2002) shows average annual rainfall of 1640 mm producing annual runoff of 440 mm (baseflow 326 mm, stormflow 114 mm) and ‘deep seepage’ loss of 450 mm (i.e. 450 mm of water not appearing in the stream). Oxygen-18 (¹⁸O) concentrations were measured at weekly intervals for 8–15 months at six sites, ranging from Pukemanga Stream baseflow through wetland seepage to ephemeral streams and surface runoff. The first two showed no significant ¹⁸O variations. Inferred mean residence times within the catchment ranged from at least 4 years (for the stream baseflow and seepage) to a few weeks (for the ephemeral flows and surface runoff). Silica concentrations could also be used to distinguish deep flowpath water from near-surface flowpath water. Tritium concentrations gave an estimated mean residence time of 9 years for Pukemanga Stream baseflow. Sulphur hexafluoride tended to give younger ages, while the chlorofluorocarbon ages were older, but are not considered as reliable for dating streamflow in this time range. These results show that deep pathways predominate with over 74% of runoff deriving from deep hillslope flowpaths via the wetland, and 87% of total drainage (baseflow and deep seepage) travelling via deep hillslope flowpaths. Our conception of the deep drainage process is that there is a large volume of slowly moving water in the system (above and below the water table), which reaches the wetland and stream via an unconfined groundwater system. Subsurface water equivalents are estimated to be 2·9 m for drainage at the weir and 4·1 m for drainage bypassing the weir, giving a total of 7 m depth over the catchment. The unsaturated zone plays an important role in storing water for long periods (about 4 years), while linking the surface with the groundwater water table to contribute to the fast streamflow response to rainfall. A schematic model of the various pathways with indicative residence times is given. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献