S.S. Papadopulos & Assoc., Inc.
7944 Wisconsin Avenue, Bethesda, MD 20814 Phone: (301) 718-8900
3D transport model for simulation of advection, dispersion, and chemical reactions of dissolved constituents in ground-water systems. The model uses a modular structure that makes it possible to independently simulate advection, dispersion, sink/source mixing, and chemical reactions without reserving computer memory space for unused options. Intended for use with any block-centred finite-difference flow model such as MODFLOW and is based on the assumption that changes in the concentration field will not measurably affect the flow field. This allows the user to independently construct and calibrate aflow model. MT3D retrieves the hydraulic heads and the various flow and sink/source terms saved by the flow model, automatically incorporating the specified hydrologic boundary conditions. Although the documentation describes the use of MT3D in conjunction with MODFLOW, the transport model can be linked to any other block-centred finite-difference flow model. Simulates changes in concentration of single-species miscible contaminants in ground-water considering advection, dispersion, and some simple chemical reactions (equilibrium-controlled linear or non-linear sorption and first-order irreversible decay or biodegradation). Models confined,unconfined, or variably confined/unconfined aquifer layers; inclined model layers and variable cell thickness within the same layer; specified concentration or mass flux boundaries; and the solute transport effects of external sources and sinks such as wells, drains, rivers, areal recharge, and evapotranspiration. Runs in batch mode directly from the DOS prompt, or from under a shell program such as PM. Input files can be created by copying example problems and editing them with a line editor or by use of the MODELCAD or PM pre-processors (not included). Output files can be processed in any commercial contouring package.