Solute Movement in Structured Soils: Two‐Region Model with Small Interaction

Skopp, J.; Gardner, W.R.; Tyler, Emily

doi:10.2136/sssaj1981.03615995004500050002x

Cited by 104 publications

(52 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Skopp et al (1981) have solved the advection-dispersion equation analytically for two interacting flow regions, each characterized by its own parameter set. The two regions were coupled by a mass exchange mechanism according to Eq.…”

Section: Mass Exchange Between Two Discrete Regionsmentioning

confidence: 99%

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

Flühler¹,

1996

View full text Add to dashboard Cite

Flühler, H., Durner, W. and Flury, M. 1995. Lateral Solute Mixing Processes-A Key for Understanding and Modeling Field-Scale Transport of Water and Solutes. Geoderma, 00: 000-000.Lateral mass exchange mechanisms affect the spreading of solutes in the main direction of flow. Modeling vertical solute spreading requires therefore an understanding of the lateral transport across regions of varying velocities. Experimental observations show that the variable extent and rates of lateral mixing cause dramatically different transport regimes, which can neither be predicted nor explained mechanistically in terms of known state variables. In this paper we show that the various solute flow regimes are sensitive to the relative magnitudes of the vertical and lateral solute particle velocities. We discuss the concepts of describing lateral mass exchange as used in conceptually different transport models, and we postulate that physically meaningful parameters describing the lateral mixing would be a clue for deciding a priori which solute transport regime is appropriate in a particular soil or soil horizon.

show abstract

Section: Mass Exchange Between Two Discrete Regionsmentioning

confidence: 99%

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

Flühler¹,

1996

View full text Add to dashboard Cite

show abstract

“…Previous research on two-domain soils has attempted to describe and partition the movement of water and solutes within and between the soil matrix and macropores (Anderson and Bouma, 1977;Rao et al, 1980a;Luxmoore, 1981;Skopp et al, 1981;Chen and Wagenet, 1992). Macrochannels, de®ned herein as well connected macropores, have been attributed to the preferential vertical movement of soil water and tracer.…”

Section: Introductionmentioning

confidence: 99%

“…In contrast, laboratory experiments of solute transport often neglect hydrometric analysis. Furthermore, subsequent modelling of the relative contributions to¯ow from the soil matrix and macrochannels is often based on qualitative analysis of breakthrough curves (BTCs) (Skopp et al, 1981;Smettem, 1984). Soil samples used in laboratory experiments are generally too small to comprise an adequate representative elementary volume .…”

Section: Introductionmentioning

confidence: 99%

Tracer and hydrometric study of preferential flow in large undisturbed soil cores from the Georgia Piedmont, USA

McIntosh¹,

McDonnell²,

Peters³

1999

Hydrol. Process.

View full text Add to dashboard Cite

Abstract:We studied the temporal patterns of tracer throughput in the out¯ow of large (30 cm diameter by 38 cm long) undisturbed cores from the Panola Mountain Research Watershed, Georgia. Tracer breakthrough was aected by soil structure and rainfall intensity. Two rainfall intensities (20 and 40 mm hr 71 ) for separate Cl 7 and Br 7 amended solutions were applied to two cores (one extracted from a hillslope soil and one extracted from a residual clay soil on the ridge). For both low and high rainfall intensity experiments, preferential¯ow occurred in the clay core, but not in the hillslope core. The preferential¯ow is attributed to well-developed interpedal macrochannels that are commonly found in structured clay soils, characteristic of the ridge site. However, each rainfall intensity exceeded the matrix in®ltration capacity at the top of the hillslope core, but did not exceed the matrix in®ltration capacity at the middle and bottom of the hillslope core and at all levels in the clay core. Localized zones of saturation created when rainfall intensity exceeds the matrix in®ltration capacity may cause water and tracer to over¯ow from the matrix into macrochannels, where preferential¯ow occurs to depth in otherwise unsaturated soil.

show abstract

“…A number of laboratory and field experiments have been conducted to qualitatively describe preferential flow through unsaturated soil and understand the mechanisms that control this type of flow (Quisenberry and Philips 1976, Bouma 1980, Hatfield 1988, Nelson 1990, Flury et al 1994, Quisenberry et al 1994, Flury 1996, Sadeghi et al 2000, Ersahin et al 2002. Even though many mathematical models have been developed to quantitatively describe preferential flow through macroporous soils (van Genuchten and Cleary 1976, Skopp et al 1981, Chen and Wagenet 1992, Durner 1992, 1994, Hutson and Wagenet 1995, Mohanty et al 1997, Zurmuhl and Durner 1998, none of them are complete for quantitative description and the incorporation of soil structures into these models. The mobile-immobile region concept of van Genuchten and Cleary (1976) and the application of this concept to a structured soil by Skopp et al (1981) were two of the earliest attempts to make these deterministic models more realistic by introducing these important soil characteristics into the models.…”

mentioning

confidence: 99%

“…Even though many mathematical models have been developed to quantitatively describe preferential flow through macroporous soils (van Genuchten and Cleary 1976, Skopp et al 1981, Chen and Wagenet 1992, Durner 1992, 1994, Hutson and Wagenet 1995, Mohanty et al 1997, Zurmuhl and Durner 1998, none of them are complete for quantitative description and the incorporation of soil structures into these models. The mobile-immobile region concept of van Genuchten and Cleary (1976) and the application of this concept to a structured soil by Skopp et al (1981) were two of the earliest attempts to make these deterministic models more realistic by introducing these important soil characteristics into the models. Since the soil structural features affect the transport of water and solute, mathematical models of soil transport processes require the relationship between the structural characteristics of the soil and these transport equations (Quisenberry et al 1994).…”

mentioning

confidence: 99%

Evaluation of MACRO model by short-term water and solute transport simulation in Maury silt loam soil

Merdun¹

2005

PLANT SOIL ENVIRON

View full text Add to dashboard Cite

Modeling preferential flow has been a concern of many academic fields in the past 30 years all over the world and helps to prevent groundwater contamination. A dual-porosity model, MACRO, was evaluated for short-term (less than 2 days) simulation of water flow and non-reactive solute (chloride) transport through the profile of six plots in well-structured Maury silt loam soil. Water flow in micropores is calculated by the Richards' equation while simple gravity flow is assumed in the macropores. Solute transport in the micropores is calculated by the convection-dispersion equation (CDE) while the dispersion and diffusion in the CDE is neglected for the solute transport in the macropores. The applied water and chloride reached the bo�om of the profile during the 2 and 1-hour(s) application periods in studies 2 and 3, respectively. There is a strong indication of macropore flow in this soil. Based on the statistical criteria, the model accurately simulated water flow and solute transport with depth and time in all plots. The mean values of three statistical parameters (coefficient of residual mass, model efficiency, and correlation coefficient) for water and chloride transport were -0.0014, 0.791, 0.903 and 0.0333, 0.923, 0.956, respectively. Preliminary studies showed that the model could not simulate flow and transport well enough with the one-domain flow concept. In the two-domain flow, effective diffusion path-length, boundary hydraulic conductivity, and boundary soil water pressure were the three most important parameters that control flow and transport between the two domains. The effective diffusion path-length represented the structural development with depth in the Maury silt loam soil.

show abstract

Solute Movement in Structured Soils: Two‐Region Model with Small Interaction

Cited by 104 publications

References 0 publications

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

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

Tracer and hydrometric study of preferential flow in large undisturbed soil cores from the Georgia Piedmont, USA

Evaluation of MACRO model by short-term water and solute transport simulation in Maury silt loam soil

Contact Info

Product

Resources

About