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Interplay between Fingering Instabilities and Initial Soil Moisture in Solute Transport through the Vadose Zone

Cueto-Felgueroso, Luis and Suarez-Navarro, María José and Fu, Xiaojing and Juanes, Ruben (2020) Interplay between Fingering Instabilities and Initial Soil Moisture in Solute Transport through the Vadose Zone. Water, 12 (3). Art. No. 917. ISSN 2073-4441. doi:10.3390/w12030917.

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Modeling water flow and solute transport in the vadose zone is essential to understanding the fate of soil pollutants and their travel times towards groundwater bodies. It also helps design better irrigation strategies to control solute concentrations and fluxes in semiarid and arid regions. Heterogeneity, soil texture and wetting front instabilities determine the flow patterns and solute transport mechanisms in dry soils. When water is already present in the soil, the flow of an infiltration pulse depends on the spatial distribution of soil water and on its mobility. We present numerical simulations of passive solute transport during unstable infiltration of water into sandy soils that are prone to wetting front instability. We study the impact of the initial soil state, in terms of spatial distribution of water content, on the infiltration of a solute-rich water pulse. We generate random fields of initial moisture content with spatial structure, through multigaussian fields with prescribed correlation lengths. We characterize the patterns of water flow and solute transport, as well as the mass fluxes through the soil column. Our results indicate a strong interplay between preferential flow and channeling due to fingering and the spatial distribution of soil water at the beginning of infiltration. Fingering and initial water saturation fields have a strong effect on solute diffusion and dilution into the ambient water during infiltration, suggesting an effective separation between mobile and inmobile transport domains that are controlled by the preferential flow paths due to fingering.

Item Type:Article
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URLURL TypeDescription
Fu, Xiaojing0000-0001-7120-704X
Juanes, Ruben0000-0002-7370-2332
Additional Information:© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ( Received: 11 February 2020; Accepted: 18 March 2020; Published: 24 March 2020. Author Contributions: Investigation L.C.-F., M.J.S.-N., X.F. and R.J. All authors have read and agreed to the published version of the manuscript. Funding for this research was provided by Spanish Ministry of Economy and Competitiveness under grant CTM2014-54312-P (to L.C.-F.), by the Abdul Latif Jameel World Water and Food Security Lab (J-WAFS) at MIT (to R.J.), by the MIT International Science and Technology Initiatives (MISTI), through a Seed Fund grant (to R.J. and L.C.-F.), and by the Miller Fellowship for Basic Research in Science (to X.F.). The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
Funding AgencyGrant Number
Ministerio de Economía, Industria y Competitividad (MINECO)CTM2014-54312-P
Abdul Latif Jameel World Water and Food Security LabUNSPECIFIED
Massachusetts Institute of Technology (MIT)UNSPECIFIED
Miller Institute for Basic Research in ScienceUNSPECIFIED
Subject Keywords:vadose zone; solute transport; unsaturated flow; infiltration; preferential flow
Issue or Number:3
Record Number:CaltechAUTHORS:20200804-152305583
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Official Citation:Cueto-Felgueroso, L.; Suarez-Navarro, M.J.; Fu, X.; Juanes, R. Interplay between Fingering Instabilities and Initial Soil Moisture in Solute Transport through the Vadose Zone. Water 2020, 12, 917
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:104739
Deposited By: Tony Diaz
Deposited On:05 Aug 2020 15:50
Last Modified:16 Nov 2021 18:34

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