Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: March 11, 2010
Publication Date: April 21, 2010
Citation: Pan, F., Guber, A.K., Pachepsky, Y.A., Gish, T.J., Nicholson, T.J., Cady, R.R. 2010. Numerical simulations of water flow and tracer transport in soils at the USDA-ARS Beltsville OPE3 field site. BARC Poster Day, .
The objective of this study was to develop a realistic model to simulate the complex processes of flow and tracer transport in USDA-ARS OPE3 field site and to compare simulation results with the detailed monitoring observations. The site has been studied for over 10 years with the extensive available database on geophysical, biophysical, remote sensing, soil water and groundwater monitoring. High soil spatial heterogeneity and shallow groundwater were encountered at the site. A pulse of KCL solution was applied to the irrigation plot with an area of 13x14m, and then the plot was irrigated twice a day for three months using the tap water. The chloride concentration was measured at three sampling depths of 12 observation wells at 7 m and 14 m distances from the irrigation plot. The three-dimensional flow and transport model, TOUGH2 code, was applied in this study to simulate flow and chloride transport for the tracer experiment. The atmospheric boundary condition was applied at surface of the model domain and no flux boundary was set at the bottom. The spatially variable and temporally constant pressure heads were specified along the lateral boundaries. The trial-and-error calibration based on zonation of the flow and transport domain was reasonably successful. The dynamics of observed groundwater depth were well reproduced by the flow model. The maximum concentration levels and the 50% concentration arrival times were described satisfactory. The simulation results will be used to develop a strategy of combining monitoring and modeling to improve the understanding of subsurface properties.