A finite difference model for flow of a pollutant through unsaturated porus [i.e. porous] media
Acharya, Binayak Prasad
MetadataShow full item record
The purpose of this study was to develop a two dimensional finite difference model to estimate the solute concentration at different depths in various types of soils. The results obtained with the model will be used to determine the potential of possible groundwater contamination due to the flow of pollutants through unsaturated porous media. Three different soils were studied. Inputs into the model were soil physical properties, grid sizes of the domain, and a specified time increment. The soil physical properties include the relationships between moisture content, pressure, hydraulic conductivity, soil porosity, and soil field capacity. Solute concentrations were estimated at different depths within a domain of 10 feet by 10 feet using a grid size of one foot in both the horizontal (X) and vertical (Z) directions. During the testing of this model for Amarillo silt clay soil and Poudar river sand, the solute was shown to reach a depth of two feet from the soil surface within a time period of 45 days after a one day application period. The computation showed movement of moisture as well as solute through a depth of soil and in X direction for continuous application condition. For the fine sand soil the flow was much faster compared to the other two test soils. Solute moved to a depth of seven feet and horizontally for a distance of three feet along the X direction within a time period of 60 minutes. The estimates which were developed with the model showed that the flow of solute through unsaturated soil were dependent on the initial soil moisture content. A variation in solute concentrations at different depths of the soil with the initial moisture content was established. The computed results for the fine sand soil showed a little deviation from the type of results expected. Hence necessary modifications are suggested for better accuracy and flexibility of the model. It is also suggested to test the model for more different types of soil. Then the model can be used to estimate the potential threat to groundwater Zpollution for different areas.