Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Flow separation in undisturbed soil using multiple anionic tracers (2) steady state core scale rainfall and return flows.
AU - Henderson, D. E.
AU - Reeves, A. D.
AU - Beven, Keith J.
AU - Chappell, Nick A.
PY - 1996/11
Y1 - 1996/11
N2 - A series of experiments designed to study the separation of flow components from two large undisturbed cores under steady-state rainfall (downward) and return (upward) flows under near-saturated conditions is summarized. The experiments were conducted on soil columns collected from Lancaster University and the Slapton Wood catchment, Devon. The use of the relatively conservative tracers, potassium bromide, o-(trifluoromethyl)benzoic acid and 2,6-difluorobenzoic acid and a combination of application rates made it possible to quantify the different sources of water contributing to the discharge hydrographs. There is significant retention of tracer within the cores, despite the application of several pore volumes of water. The use of steady flow conditions allowed the determination of dispersion coefficients, dispersivity and proportion of mobile water content parameters of the advection-dispersion equation. It was found that there were significant differences between the dispersivities at different flow-rates under upward and downward flux conditions and that in the undisturbed cores studied here the apparent proportions of mobile pore water ranged between 0.33 and 1.0, with an apparently complex relationship to flux rate. Prediction of transport in undisturbed soil remains problematic and tracer experiments will continue to be needed to provide a fundamental understanding of the complex flow processes involved.
AB - A series of experiments designed to study the separation of flow components from two large undisturbed cores under steady-state rainfall (downward) and return (upward) flows under near-saturated conditions is summarized. The experiments were conducted on soil columns collected from Lancaster University and the Slapton Wood catchment, Devon. The use of the relatively conservative tracers, potassium bromide, o-(trifluoromethyl)benzoic acid and 2,6-difluorobenzoic acid and a combination of application rates made it possible to quantify the different sources of water contributing to the discharge hydrographs. There is significant retention of tracer within the cores, despite the application of several pore volumes of water. The use of steady flow conditions allowed the determination of dispersion coefficients, dispersivity and proportion of mobile water content parameters of the advection-dispersion equation. It was found that there were significant differences between the dispersivities at different flow-rates under upward and downward flux conditions and that in the undisturbed cores studied here the apparent proportions of mobile pore water ranged between 0.33 and 1.0, with an apparently complex relationship to flux rate. Prediction of transport in undisturbed soil remains problematic and tracer experiments will continue to be needed to provide a fundamental understanding of the complex flow processes involved.
KW - anionic tracers • soil water • solute transport • multicomponent mixing • breakthrough curves • undisturbed soil columns
U2 - 10.1002/(SICI)1099-1085(199611)10:11<1451::AID-HYP384>3.0.CO;2-C
DO - 10.1002/(SICI)1099-1085(199611)10:11<1451::AID-HYP384>3.0.CO;2-C
M3 - Journal article
VL - 10
SP - 1451
EP - 1465
JO - Hydrological Processes
JF - Hydrological Processes
SN - 0885-6087
IS - 11
ER -