Analysis of long‐term dispersion in a river‐recharged aquifer using tritium/helium data
Analysis of long‐term dispersion in a river‐recharged aquifer using tritium/helium data
复制标题
使用氚/氦数据分析河流补给含水层中的长期扩散
DOI：
--
复制
发表时间：
2009
期刊：
影响因子：
--
通讯作者：
A. Pekdeger
中科院分区：
文献类型：
--
作者：
G. Massmann;J. Sültenfuss;A. Pekdeger
Large‐scale dispersion was studied in an unconsolidated, sandy, glaciofluvial, river‐recharged, and confined aquifer in Germany. Groundwater observation wells from a 3.5‐km‐long transect located in flow direction from the river Oder into a large lowland area (Oderbruch polder) were sampled for noble gases in order to date the groundwater with the tritium and helium (3H‐3He) technique. The apparent 3H‐3He ages of the groundwater increased from only a few months to >40 years along the flow path. Highest values for initial 3H (sum of 3H and its decay product tritiogenic helium, 3Hetri) were encountered in 2.6‐km river distance. Concentrations of 4He in the water increased to 1.1 × 10−7 cm3 STP/g with distance from the river. The initial 3H data enabled an estimation of the longitudinal dispersivity with a simplified one‐dimensional transport model. The best fit of modeled and measured initial 3H data was obtained using a dispersivity of 120 m. Deviations of modeled hydraulic ages and measured apparent 3H‐3He ages for older samples can be explained by dispersive mixing.
