Submitted to: American Chemical Society Symposium Series
Publication Type: Abstract Only
Publication Acceptance Date: March 22, 1999
Publication Date: N/A
This paper presents the application of a physically based two-domain model of water flow and solute transport (MACRO) in a sandy loam soil. First, six most sensitive input parameters for the model were identified by sensitivity analysis. Second, the model was calibrated using the field data collected for 1992. Finally, the model simulations of atrazine concentrations for 1993, 1994, and 1995 were compared to the means of observed concentrations. The results indicated a reasonable agreement between simulated and measured atrazine concentrations in the vadose zone. About 76 to 100% of the model predictions of three years fell within the 95% confidence intervals of the means of field observations. When run in one flow domain,the model overall underestimated atrazine concentrations at six soil depths in 1993, 1994, and 1995. This study concluded that preferential flow plays an important role in water movement and solute transport in the Coastal Plain soils.