FLOTRAN, a three-dimensional ground water model, with comparisons to analytical solutions and other models

FLOTRAN is a ground water ̄ow and transport model developed in the past few years which takes advantage of recent advances in numerical methodology. FLOTRAN solves the governing equations for ̄ow and contaminant transport using Godunovmixed methods, in which a higher-order Godunov method is used to approximate the advective ̄ux, and a mixed ®nite element method is used for the dispersive transport. A mixed ®nite element method is also used to solve the ̄ow equation. As part of the development of this new model, we have tested it against known analytical and numerical solutions to the equations approximated by the model. In this work, we have tested FLOTRAN against 1-D and 2-D analytical solutions, Galya's 3-D horizontal plane source solution, two radial semi-analytical solutions, and two numerical models, BIOPLUME II and MT3D. We have also tested FLOTRAN on a hypothetical partially saturated ̄ow problem. FLOTRAN performed well on these tests, generally matching analytical solutions to within a few percent, and matching as well as or better than the other numerical models in most cases. Ó 2000 Elsevier Science Ltd. All rights reserved.