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Simulation of reactive solute transport in the critical zone: A Lagrangian model for transient flow and preferential transport

Sternagel, Alexander; Loritz, Ralf; Klaus, Julian; Berkowitz, Brian; Zehe, Erwin

Abstract:
We present a method to simulate fluid flow with reactive solute transport in structured, partially saturated soils using a Lagrangian perspective. In this context, we extend the scope of the Lagrangian Soil Water and Solute Transport Model (LAST) (Sternagel et al., 2019) by implementing vertically variable, non-linear sorption and first-order degradation processes during transport of reactive substances through a partially saturated soil matrix and macropores. For sorption, we develop an explicit mass transfer approach based on Freundlich isotherms because the common method of using a retardation factor is not applicable in the particle-based approach of LAST. The reactive transport method is tested against data of plot- and field-scale irrigation experiments with the herbicides isoproturon and flufenacet at different flow conditions over various periods. Simulations with HYDRUS 1-D serve as an additional benchmark. At the plot scale, both models show equal performance at a matrix-flow-dominated site, but LAST better matches indicators of preferential flow at a macropore-flow-dominated site. Furthermore, LAST successfully simulates the effects of adsorption and degradation on the breakthrough behaviour of flufenacet with preferential leaching and remobilization. ... mehr

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Verlagsausgabe §
DOI: 10.5445/IR/1000131137
Veröffentlicht am 12.04.2021
Originalveröffentlichung
DOI: 10.5194/hess-25-1483-2021
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Wasser und Gewässerentwicklung (IWG)
KIT-Zentrum Klima und Umwelt (ZKU)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2021
Sprache Englisch
Identifikator ISSN: 1027-5606, 1607-7938
KITopen-ID: 1000131137
Erschienen in Hydrology and Earth System Sciences
Verlag Copernicus Publications
Band 25
Heft 3
Seiten 1483-1508
Nachgewiesen in Scopus
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