Koeniger Paul, Leibundgut Christian, Stichler Willibald
Leibniz Institute for Applied Geophysics, Geozentrum Hannover, Hannover, Germany.
Isotopes Environ Health Stud. 2009 Dec;45(4):289-302. doi: 10.1080/10256010903356953.
River water samples were analysed for stable isotopes (deuterium and oxygen-18) collected from 46 sites during spring 2008, and from monthly samples at the outlets of seven sub-basins of the River Weser (46,200 km(2) basin area in total) over a five year period from 2003 to 2007, to characterise temporal and spatial isotope patterns of river water. Results indicate a pronounced elevation effect (0.2 per thousand and 1 to 2 per thousand per 100 m for delta(18)O and delta(2)H, respectively) as well as influence of seawater mixing for a few coastal locations. A lumped parameter modelling approach was used to compare residence times and relative amounts of direct flow, fast and slow groundwater with those derived from a combined water balance and tritium balance modelling approach. Residence times of direct runoff were estimated to be between one and three and a half months. Much longer groundwater residence times are necessary to explain tritium recession in river water. The modelling fits for stable isotope data in river water, derived with residence times and base flow amounts combined from a water and tritium balance approach, emphasise that beneath a characterisation of a direct flow component, seasonal variations of stable isotope values in river water carry information on groundwater contribution.
对2008年春季从46个地点采集的河水样本进行了稳定同位素（氘和氧-18）分析，并在2003年至2007年的五年期间，对威悉河七个子流域（流域总面积46,200平方公里）出口处的月度样本进行了分析，以确定河水的时空同位素模式。结果表明存在明显的高程效应（δ¹⁸O和δ²H分别每100米升高0.2‰和1至2‰）以及一些沿海地点受海水混合的影响。采用集总参数建模方法，将直接径流、快速和慢速地下水的停留时间及相对量与通过联合水平衡和氚平衡建模方法得出的结果进行比较。直接径流的停留时间估计在1至3个半月之间。需要长得多的地下水停留时间才能解释河水中氚的衰减。通过水平衡和氚平衡方法结合停留时间和基流量得出的河水中稳定同位素数据的建模拟合结果强调，除了直接径流成分的特征外，河水中稳定同位素值的季节变化还携带了有关地下水贡献的信息。
