Enhancement and application of a contaminant transport modeling program

Abstract

The purpose of this study is to resolve the problems involved with the correct visualization of contaminant transport in an aquifer. To resolve these problems an existing contaminant transport modeling program created by Bear and Verruijt was modified to increase the versatility and user-friendliness of the program. The program created by Bear and Verruijt visually models in 2-D the transport of a single contaminant source in the presence of a well field. The program is used to study the transport of a contaminant under different pumping rates, locations and aquifer characteristics. The existing program runs by specifying the characteristics of a well field and a tracer source in an input text file. The program models and records the amount of tracer source particles that reach the well(s) in an output text file. The objectives of this project are to increase the usability of the program by creating an interface for the input data and to display the output data as a plot. Also, the versatility of the program was increased by modifying the program to allow for more than one contaminant source. The modified program was applied and compared to two recovery well simulations performed by Keely (1984). At low flow velocities (0.0 m/day to 0.1 m/day) the recovery well layouts were effective. However, for moderate to high flow velocities (1.0 m/day to 10 m/day) the effect of remediation was compromised. The comparison of Keely's results and the results found using the modified program prove that the accuracy of the program was maintained. However, some stream lines were missing due to modifications made to the inputting method of stream line data and need to be corrected. The program was applied to well field data from Sussex, N.B. to determine what pumping rate would draw the contaminant to the well. The results of the simulations showed an initial breakthrough of the tracer at a pumping rate of 8000 m3/day. All of the tracer particles release during the simulation reach the well at a pumping rate of 8200 m3/day. The number of particles reaching the well increased with the pumping rate and, the amount and range of time the particle took reach the well decreased with increasing pumping rate. The simulation was effective in demonstrating the usability and changes made to the output file presentation.