HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Carminati, A. Articles by Flühler, H. Search for Related Content PubMed Articles by Carminati, A. Articles by Flühler, H. GeoRef GeoRef Citation Agricola Articles by Carminati, A. Articles by Flühler, H. Related Collections Hydraulic Conductivity Structure and Properties Infiltration

ORIGINAL RESEARCH

Water Infiltration and Redistribution in Soil Aggregate Packings

^a Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany
^b Institute of Terrestrial Ecosystems, ETH Zürich, Switzerland
^* Corresponding author (andrea.carminati{at}ufz.de).

Received 28 March 2008.

Aggregation of soil particles is crucial for water flow in the vadose zone. Recent studies demonstrated that the unsaturated water flow through an aggregate pair is controlled by the contacts between aggregates. In these studies, the hydraulic conductivity of an aggregate pair was calculated as the harmonic mean of the conductivities of one aggregate and one contact, and it was fitted increasing the tortuosity from 0.5 to 5. In the present study, we investigated whether the contacts between aggregates control the water flow also in large aggregate packings. Our hypothesis was that unsaturated water flow in aggregate packings is primarily a flow in series through aggregates and contacts, and therefore the hydraulic conductivity of the system is properly approximated with that of an aggregate pair. To verify this hypothesis, we used neutron radiography to image water infiltration and redistribution in a cylindrical packing of aggregates. Then we numerically simulated the experiment using the hydraulic properties obtained from the model of an aggregate pair—i.e., tortuosity equal to 5. The observed water flow showed that the water redistribution following infiltration was particularly slow and the wetting front was very sharp. These features are explained by the bottleneck effect of the contacts, which were rapidly drained and limited the flow. This flow behavior was well reproduced in the simulations with tortuosity equal to 5, while simulations with tortuosity equal to 0.5, which is the tortuosity obtained for the aggregates, could not reproduce the observations. This study shows that the contacts control the unsaturated water flow also in larger aggregate packings and the process can be in a first approximation modeled as a flow in series through aggregates and contacts.