MT3D-USGS capabilities and features include:
- unsaturated-zone transport;
- transport within streams and lakes, including solute exchange with connected groundwater;
- capability to route solute through dry cells that may occur in the Newton-Raphson formulation of MODFLOW (that is, MODFLOW-NWT);
- new chemical reaction package options that include the ability to simulate interspecies reactions and parent-daughter chain reactions;
- new pump-and-treat recirculation package that enables the simulation of dynamic recirculation with or without treatment for combinations of wells that are represented in the flow model, mimicking the above-ground treatment of extracted water;
- reformulation of the treatment of transient mass storage that improves conservation of mass and yields solutions for better agreement with analytical benchmarks;
- separate specification of the partitioning coefficient (Kd) within mobile and immobile domains;
- capability to assign prescribed concentrations to the top-most active layer;
- change in mass storage owing to the change in water volume now appears as its own budget item in the global mass balance summary;
- ability to ignore cross-dispersion terms;
- definition of Hydrocarbon Spill-Source Package (HSS) mass loading zones using regular and irregular polygons, in addition to the currently supported circular zones; and
- ability to specify an absolute minimum thickness rather than the default percent minimum thickness in dry-cell circumstances.
Software License and Purchase Information
This software is a product of the U.S. Geological Survey, which is part of the U.S. Government.
This software is freely distributed. There is no fee to download and (or) use this software.
Users do not need a license or permission from the USGS to use this software. Users can download and install as many copies of the software as they need.
As a work of the United States Government, this USGS product is in the public domain within the United States. You can copy, modify, distribute, and perform the work, even for commercial purposes, all without asking permission. Additionally, USGS waives copyright and related rights in the work worldwide through CC0 1.0 Universal Public Domain Dedication (https://creativecommons.org/publicdomain/zero/1.0/ ).