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How groundwater seepage and transport modelling software can be useful for studying gaseous transport in an unsaturated soil
Author(s) -
Chesnaux R.
Publication year - 2009
Publication title -
water and environment journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 37
eISSN - 1747-6593
pISSN - 1747-6585
DOI - 10.1111/j.1747-6593.2007.00106.x
Subject(s) - vadose zone , groundwater , hydrogeology , water table , aquifer , environmental science , soil water , diffusion , porous medium , atmosphere (unit) , oxygen transport , soil science , environmental engineering , hydrology (agriculture) , oxygen , geotechnical engineering , geology , chemistry , porosity , thermodynamics , physics , organic chemistry
The aim of this paper is to show how standard hydrogeologic software, usually used to model contaminant transport in groundwater under unsaturated conditions, can also be used to model gas transport in unsaturated porous media. Physical processes involved in the interaction between the atmosphere and the unsaturated soils are considered: transport by diffusion through the air and the groundwater, exchange between the liquid and gas phases and consumption. These physical processes are incorporated into the governing equations of a groundwater numerical code; by considering air, contained in the unsaturated soil, as water in the seepage numerical model, the air effectively becomes fluid within the numerical code. Then, the investigated gas is defined as the contaminant in the transport model, which is transported by ‐the air for the modeller‐, and ‐water for the numerical code‐. The over‐riding assumption is that the air profiles and, therefore, water profiles of volume contents remain constant. The approach is illustrated using two examples, which consider the transport of oxygen. The first deals with oxygen distribution through a laboratory‐cell diffusion containing reactive mining tailings. The second deals with the oxygen fluxes through the vadose zone, between the atmosphere and an unconfined aquifer's water table. Both examples consider different cases of oxygen consumption.