TY - JOUR

T1 - Flow separation in undisturbed soils using multiple anionic tracers. Part 1. Analytical methods and unsteady rainfall and return flow experiments.

AU - Reeves, A. D.

AU - Henderson, D. E.

AU - Beven, K. J.

PY - 1996/11

Y1 - 1996/11

N2 - Tracers provide one of the few ways of obtaining realistic information on the flows of water and solutes in undisturbed structured soils. Three fluorinated organic acids [pentafluorobenzoic acid, 2,6-diflurobenzoic acid and o-(trifluoromethyl) benzoic acid] and bromide were tested as anionic tracers in situations where the separation of different flow components is of interest. The fluorobenzoates were relatively conservative (approximately 90% for loam soil) although, in some instances, co-elution or complexation may lead to apparently non-conservative behaviour. Tracer mixtures applied to soils, were separated and quantified by high-performance liquid chromatography. The relative mobilities of the tracers were studied during unidirectional steady flow in large undisturbed soil columns brought back to the laboratory. The breakthrough curves showed highly dispersive behaviour, with very early breakthrough of solute and a long tail. Contributions to the column outflow of different simultaneous applications of rainfall and return flow, labelled with different tracers, were separated using multicomponent mixing equations. The results show the importance of preferential flow and relatively immobile storage in the transport process.

AB - Tracers provide one of the few ways of obtaining realistic information on the flows of water and solutes in undisturbed structured soils. Three fluorinated organic acids [pentafluorobenzoic acid, 2,6-diflurobenzoic acid and o-(trifluoromethyl) benzoic acid] and bromide were tested as anionic tracers in situations where the separation of different flow components is of interest. The fluorobenzoates were relatively conservative (approximately 90% for loam soil) although, in some instances, co-elution or complexation may lead to apparently non-conservative behaviour. Tracer mixtures applied to soils, were separated and quantified by high-performance liquid chromatography. The relative mobilities of the tracers were studied during unidirectional steady flow in large undisturbed soil columns brought back to the laboratory. The breakthrough curves showed highly dispersive behaviour, with very early breakthrough of solute and a long tail. Contributions to the column outflow of different simultaneous applications of rainfall and return flow, labelled with different tracers, were separated using multicomponent mixing equations. The results show the importance of preferential flow and relatively immobile storage in the transport process.

KW - anionic tracers • batch sorption • soil water • solute transport • undisturbed soil columns • HPLC • dispersion • multicomponent mixing

U2 - 10.1002/(SICI)1099-1085(199611)10:11<1435::AID-HYP383>3.0.CO;2-5

DO - 10.1002/(SICI)1099-1085(199611)10:11<1435::AID-HYP383>3.0.CO;2-5

M3 - Journal article

VL - 10

SP - 1435

EP - 1450

JO - Hydrological Processes

JF - Hydrological Processes

SN - 0885-6087

IS - 11

ER -