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README.md

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-# mt3dms
+# MT3DMS version 5.3
 A Modular 3-D Multi-Species Transport Model for Simulation of Advection, Dispersion, and Chemical Reactions of Contaminants in Groundwater Systems
+MT3DMS is the second generation of the modular three-dimensional transport model MT3D.  MT3DMS was developed with funding from the U.S. Army Corps of Engineers Waterways Experiment Station under the Strategic Environmental Research and Development Program (SERDP).  
+
+MT3DMS has significantly expanded capabilities, including the addition of, 1) a third-order total-variation-diminishing (TVD) scheme for solving the advection term that is mass conservative but does not introduce excessive numerical dispersion and artificial oscillation; 2) an efficient iterative solver based on generalized conjugate gradient methods and the Lanczos/ORTHOMIN acceleration scheme to remove stability constraints on the transport time stepsize; 3) options for accommodating nonequilibrium sorption and dual-domain advection-diffusion mass transport; and 4) a multi-component program structure that can accommodate add-on reaction packages for modeling general biological and geochemical reactions.  
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+Additional information on MT3DMS can be found at [https://hydro.geo.ua.edu/mt3d/index.htm](https://hydro.geo.ua.edu/mt3d/index.htm).
+
+--------------------------
+
+Downloaded as a self-extracting executable file (`mt3dms_530.exe`) on July 3, 2023 from [https://hydro.geo.ua.edu/mt3d/index.htm](https://hydro.geo.ua.edu/mt3d/index.htm).
+
+This repository was created to facilitate automatic builds of MT3DMS used in GitHub Actions CI workflows. Only the source files in the `mt3dms5.3.0/src/true-binary/` subdirectory available in the self-extracting executable file (`mt3dms_530.exe`), available from [https://hydro.geo.ua.edu/mt3d/index.htm](https://hydro.geo.ua.edu/mt3d/index.htm), have been included in this repository.