Testing and validation of FLOTRAN: A ground water flow and contaminant transport model
Holder, Anthony Wayne
Bedient, Philip B.
Master of Science thesis
scFLOTRAN, a code written by a Rice faculty member, is designed to solve the advection-dispersion-reaction equation for contaminant transport in three dimensions. In this thesis, scFLOTRAN is tested in several different scenarios to determine the accuracy of the code and to eliminate programming errors. The testing scenarios utilized include testing in radially dominated flow conditions, testing against analytical solutions, and testing against a three dimensional model of the Borden Landfill site. Overall, the testing was successful. In the tests with analytical solutions, scFLOTRAN matches the analytical solutions, generally within a few percent, and often within one percent, as measured by the average absolute error. In the testing against the Borden Landfill model, scFLOTRAN performed well, demonstrating the usefulness of its variable grid thickness option. As a final test, and as an exercise in itself, scFLOTRAN is also used to model trichloroethylene (TCE) contamination at a site in Arizona. TCE was discovered in two City of Phoenix water wells in late 1981, a discovery which led to placing the area on the National Priorities List, and extensive study of the area. The emphasis of the modeling is to determine conditions in the subsurface before the discovery of TCE in the water wells. Of the several possible sources of contamination in the area, modeling suggests that one in particular is responsible for the contamination in the city water wells prior to 1981.
Environmental Sciences; Hydrology