MIN3P is a general purpose flow and reactive transport code for variably saturated media providing a high degree of flexibility with respect to the definition of the reaction network. Advective-diffusive transport in the water phase and diffusive transport in the gas phase are included.  Equilibrium reactions considered are aqueous complexation, gas partitioning between phases, oxidation-reduction, ion exchange, and surface complexation. The reaction network is designed to handle kinetically controlled intra-aqueous and dissolution-precipitation reactions, and the dissolution of non-aqueous phase liquids (NAPLs). All reactions can be defined through a database, not requiring external code generation by the user.


Subsurface fluid migration and geochemical conditions may be impacted by a variety of interacting physical and chemical processes, including density-dependent, variably-saturated groundwater flow, heat transport, mass transport, mixing of waters of different geochemical compositions, water-rock interaction, and mechanical loading. Understanding the interactions among these processes is important when investigating contaminant migration in groundwater, natural attenuation processes, or site remediation alternatives, and when assessing the long-term hydrogeological and geochemical stability of rock formations. MIN3P is a three-dimensional (3D) numerical model that has been developed to simulate the processes that are most relevant to these types of subsurface flow and reactive transport problems, and is primarily used to aid in the quantitative assessment of laboratory experiments and field studies. For examples and verification studies, refer to the Verification Examples.

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Development History

MIN3P has been used by numerous academic researchers and environmental professionals since the release of the original version of the code in 1999. The development history of the code is briefly outlined below:

1999 Initial development of MIN3P at the University of Waterloo by U. Mayer as part of his Ph.D. thesis (Mayer, 1999; Mayer et al, 2002). At that time, the code was able to simulate multicomponent reactive transport in variably-saturated porous media. The applications of the code included the generation and fate of acid mine drainage in unsaturated porous media, the in-situ remediation of groundwater contaminated by inorganic (e.g. hexavalent chromium) and organic contaminants (e.g. chlorinated organic compounds).


1) Dual porosity model (MIN3P-DUAL) added by L. Cheng, (PhD work at University of Sheffield, UK) (Cheng, 2006). This model was used in the assessment of the fate and transport of MTBE in a Chalk aquifer. 

2) Gas exsolution, entrapment and release model (MIN3P-BUBBLE) incorporated by R. Amos (PhD work at the University of British Columbia; Amos and Mayer, 2006). The problems investigated with this version of the code were primarily related to bubble growth and contraction due to in-situ gas production or consumption, bubble entrapment due to water table rise and subsequent re-equilibration of the bubble with ambient groundwater, and permeability changes due to  gas formation and entrapment.

2007 Multicomponent gas phase diffusion and advection model (MIN3P-DUSTY) added by S. Molins at the University of British Columbia (Molins and Mayer, 2007). The model was used to simulate gas attenuation in partially saturated landfill soil covers, methane production, and oxidation in aquifers contaminated by organic compounds (e.g. an oil spill site) and pyrite oxidation in mine tailings.

2009 Density coupling between flow and reactive transport included by T. Henderson as part of his Ph.D. thesis at the University of British Columbia. This code version was named MIN3P-D (Henderson et al., 2009) and was used to simulate permanganate-based remediation under free convection conditions, considering contaminant treatment, and geochemical reactions including the oxidation of naturally occurring organic matter (e.g. DNAPL) using the oxidant (KMnO4), mineral dissolution and precipitation, and ion exchange reactions.

2012 Pitzer equations for activity corrections, energy balance, and a formulation for 1D vertical stress were implemented by Bea et al. (2011, 2012). The resulting code was renamed to MIN3P-THCm.

2014 Multicomponent diffusion to account for the species dependent diffusion coefficient and to maintain local charge balance and multisite ion exchange models were implemented by Rasouli and Xie (Xie et al., 2015; Rasouli, 2016). The code is also parallelized using thread acceleration and domain decomposition methods (Su et al., 2015).

2016 Salinity dependent SRB model was added. Development of MIN3P unstructured capability was initiated. 

2017 LIS iterative solver was implemented to the current version. First order gas decay model was added to the current version. SIT model and pore clogging function was added to the code.

2018 MIN3P-HPC code was released. The unstructured capabilities support different mesh types including triangular mesh, quadrilateral mesh in 2D and prism mesh, hexahedral mesh and tetrahedral mesh in 3D. The new code has been optimized for OpenMP parallel version based on thread acceleration, MPI parallel version based on domain decomposition and hybrid MPI-OpenMP parallel version.

2019 ArchiSimple, a dynamic root architecture model was added to the MIN3P-HPC code. 

Present Ongoing work in code advancement and user accessibility initiatives. For more information on current projects, refer to Current Work.