TITLE:
Vadose Zone Heterogeneity Effect on Unsaturated Water Flow Modeling at Meso-Scale
AUTHORS:
Artur Paiva Coutinho, Laurent Lassabatere, Thierry Winiarski, Jaime Joaquim da Silva Pereira Cabral, Antonio Celso Dantas Antonino, Rafael Angulo-Jaramillo
KEYWORDS:
Architectural and Structural Indicators, Ground Penetration Radar, Numerical Modeling, Preferential Flow, Structural Heterogeneity, Unsaturated Flow
JOURNAL NAME:
Journal of Water Resource and Protection,
Vol.7 No.4,
March
16,
2015
ABSTRACT: The
understanding of unsaturated flow in heterogeneous formations is a prerequisite
to the understanding of pollutant transfer in the vadose zone and the proper
management of infiltration basins settled over such heterogeneous formations.
This study addresses the effect of lithological heterogeneity of a
glaciofluvial deposit on flow in the vadose zone underneath an infiltration
basin settled in the Lyon suburbs. The basin had already been the subject of
several previous studies, some of which demonstrated the impact of soil
heterogeneity. But all of them were only based on the sedimentological study of
a trench and no study addressed the potential spatial variability of results
due to the spatial variability of soil heterogeneity. In this study, we model
flow in the vadose zone for several case studies, including drainage, water
infiltration during a rainfall event, and a complete meteorological chronic.
These calculations were conducted for several sections, previously
characterized in the basin using GPR and sedimentological study and compared with
a blank (homogeneous section). The results clearly show that heterogeneity
impacts unsaturated flow and that these impacts depend upon the section
considered. Some geometrical architectural and textural parameters were
proposed to explain the spatial variability and effect of the soil
heterogeneity on unsaturated flow, thus establishing the first step towards
modeling unsaturated flow in the basin at the meso-scale.