Lateral solute mixing processes — A key for understanding field-scale transport of water and solutes

Flühler, H.; Durner, Wolfgang; Flury, Markus

doi:10.1016/0016-7061(95)00079-8

Cited by 125 publications

(92 citation statements)

References 56 publications

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“…An operational definition of preferential transport is a mixing regime that is not convective-dispersive, which assumes complete mixing in the directions transverse to the flow (Flühler et al, 1996). For a convective-dispersive mixing regime, the transport is described by the CDE.…”

Section: Methodsmentioning

confidence: 99%

Meta-analysis of the effects of soil properties, site factors and experimental conditions on solute transport

Koestel

Moeys

Jarvis

2012

Hydrol. Earth Syst. Sci.

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Abstract. Preferential flow is a widespread phenomenon that is known to strongly affect solute transport in soil, but our understanding and knowledge is still poor of the site factors and soil properties that promote it. To investigate these relationships, we assembled a database from the peer-reviewed literature containing information on 733 breakthrough curve experiments under steady-state flow conditions. Most of the collected experiments (585 of the 733 datasets) had been conducted on undisturbed soil columns, although some experiments on repacked soil, clean sands, and glass beads were also included. In addition to the apparent dispersivity, we focused our attention on three indicators of preferential solute transport: namely the 5 %-arrival time, the holdback factor, and the ratio of piston-flow and average transport velocities. Our results suggest that, in contrast to the 5 %-arrival time and the holdback factor, the piston-flow to transport velocity ratio is not related to preferential macropore transport but rather to the exclusion or retardation of the applied tracer. Confirming that the apparent longitudinal dispersivity is positively correlated with the travel distance of the tracer, our results also illustrate that this relationship is refined if the normalized 5 %-tracer arrival time is also taken into account. In particular, we found that the degree of preferential solute transport increases with apparent dispersivity and decreases with travel distance. A similar but weaker relationship was observed between apparent dispersivity, 5 %-tracer arrival time, and lateral observation scale, such that the degree of preferential transport increases with lateral observation scale. However, we also found that the travel distance and the lateral observation scale in the investigated dataset are correlated, which makes it difficult to distinguish their influence on these transport characteristics. We also found that the strength of preferential transport increased at larger flow rates and water saturations, which suggests that macropore flow was a more important flow mechanism than heterogeneous flow in the soil matrix. Nevertheless, our data show that heterogeneous flow in the soil matrix also occasionally leads to strong preferential transport. Furthermore, we show that preferential solute transport under steady-state flow depends on soil texture in a threshold-like manner: moderate to strong preferential transport was found to occur only for undisturbed soils that contain more than 8 % clay. Preferential flow characteristics were also absent for columns filled with glass beads, clean sands, or sieved soil. No clear effect of land use on the pattern of solute transport could be discerned, probably because the available dataset was too small and too strongly affected by cross-correlations with experimental conditions. Our results suggest that, in developing pedotransfer functions for solute transport properties of soils, it is critically important to account for travel distance, lateral observation scale, an...

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Section: Methodsmentioning

confidence: 99%

Meta-analysis of the effects of soil properties, site factors and experimental conditions on solute transport

Koestel

Moeys

Jarvis

2012

Hydrol. Earth Syst. Sci.

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“…However, especially tracer experiments in soils (e.g. Flühler et al, 1996) showed a lower effective porosity than the total porosity or even a partitioning into a mobile and immobile fraction. HillVi simulates transport in several domains.…”

Section: The Model Approach For the Virtual Experimentsmentioning

confidence: 98%

Virtual experiments: a new approach for improving process conceptualization in hillslope hydrology

Weiler

McDonnell

2004

Journal of Hydrology

297

267

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“…Constructed soil columns, steady state flow Similar to investigations of water flow, studies of preferential solute transport involved repacked soil columns with artificial PF paths. Due to the impact of lateral concentration equilibration on solute transport in the vadose zone (Flühler et al, 1996), a common theme was the effect of the solute mass transfer term on PNE transport simulations. Steadystate flow conditions are considered below.…”

Section: Modelling Of Tracer Transport In Preferential Flow Systemsmentioning

confidence: 99%

A review of model applications for structured soils: a) Water flow and tracer transport

Köhne

Šimůnek

2009

Journal of Contaminant Hydrology

290

224

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Lateral solute mixing processes — A key for understanding field-scale transport of water and solutes

Cited by 125 publications

References 56 publications

Meta-analysis of the effects of soil properties, site factors and experimental conditions on solute transport

Meta-analysis of the effects of soil properties, site factors and experimental conditions on solute transport

Virtual experiments: a new approach for improving process conceptualization in hillslope hydrology

A review of model applications for structured soils: a) Water flow and tracer transport

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