HPx – Coupled Hydrus and PHREEQC model
Hydrus has been coupled with the PHREEQC geochemical code (Parkhurst & Appelo 1999) to create a new comprehensive simulation tool, HP2 (acronym for HYDRUS-PHREEQC-2D), corresponding to a similar one-dimensional module HP1 (Jacques and Šimůnek 2005; Jacques et al. 2006; Šimůnek et al. 2006, 2008). HP2 has, apart from the dimensionality (2D), the same capabilities as HP1. HP2 contains modules simulating (1) transient water flow, (2) the transport of multiple components, (3) mixed equilibrium/kinetic biogeochemical reactions, and (4) heat transport in two-dimensional variably-saturated porous media (soils). HP2 is thus a significant expansion of the individual Hydrus-2D and PHREEQC programs by preserving most of their original features. The code still uses the Richards equation for simulating two-dimensional variably-saturated water flow and advection-dispersion type equations for heat and solute transport. However, the loosely coupled program can simulate also a broad range of low-temperature biogeochemical reactions in water, the vadose zone and in ground water systems, including interactions with minerals, gases, exchangers and sorption surfaces based on thermodynamic equilibrium, kinetic, or mixed equilibrium-kinetic reactions. HP2 (similarly as HP1) uses the operator-splitting approach with no iterations during one time step (a non-iterative sequential modeling approach). Jacques et al. (2006) evaluated the accuracy of the operator-splitting approach for a kinetic reaction network (i.e., sequential and parallel kinetic degradation reactions) by comparing HP1 with an analytical solution for TCE-degradation, as well as for mixed equilibrium and kinetic reactions involving different flow conditions (steady-state and transient).
Jacques & Šimůnek (2005), and Šimůnek et al. (2006) and Jacques et al. (2008ab), demonstrated the versatility of HP1 on several examples, which included a) the transport of heavy metals (Zn2+, Pb2+, and Cd2+) subject to multiple cation exchange reactions, b) transport with mineral dissolution of amorphous SiO2 and gibbsite (Al(OH)3), c) heavy metal transport in a medium with a pH-dependent cation exchange complex, d) infiltration of a hyperalkaline solution in a clay sample (this example considers kinetic precipitation-dissolution of kaolinite, illite, quartz, calcite, dolomite, gypsum, hydrotalcite, and sepiolite), e) long-term transient flow and transport of major cations (Na+, K+, Ca2+, and Mg2+) and heavy metals (Cd2+, Zn2+, and Pb2+) in a soil profile, f) cadmium leaching in acid sandy soils, g) radionuclide transport, and h) long term uranium migration in agricultural field soils following mineral P-fertilization. Most of these examples have been rerun using HP2, which verified correct implementation of various components of the coupled program.
Note that the HP2 code is fully incorporated into the HYDRUS (2D/3D) software package, and hence will be installed automatically, together with selected examples, when you obtain HYDRUS (2D/3D) and HP2 licenses and download HYDRUS from our website. The user manual and notes on how to use HP1 and HP2 can be downloaded below.
Manuals and Notes
Download the HP2 Program Manual and Related Documents
- Šimůnek, J., D. Jacques, M. Šejna, and M. Th. van Genuchten, The HP2 Program for HYDRUS (2D/3D), A Coupled Code for Simulating Two-Dimensional Variably-Saturated Water Flow, Head Transport, Solute Transport and Biogeochemistry in Porous Media, (HYDRUS + PHREEQC + 2D), Version 1.0, PC Progress, Prague, Czech Republic, 76 pp., 2012.
- Jacques, D., and J. Šimůnek, User Manual of the Multicomponent Variably-Saturated Flow and Transport Model HP1, Description, Verification and Examples, Version 1.0, SCK•CEN-BLG-998, Waste and Disposal, SCK•CEN, Mol, Belgium, 79 pp., 2005.
- Jacques, D., and J. Šimůnek, Notes on HP1 – a software package for simulating variably-saturated water flow, heat transport, solute transport and biogeochemistry in porous media, HP1 Version 2.2, SCK•CEN-BLG-1068, Waste and Disposal, SCK•CEN, Mol, Belgium, 113 pp., 2010.
Related References
- Šimůnek, J., D. Jacques, M. Th. van Genuchten, and D. Mallants, Multicomponent geochemical transport modeling using the HYDRUS computer software packages, J. Am. Water Resour. Assoc., 42(6), 1537-1547, 2006.
- Jacques, D., J. Šimůnek, D. Mallants, and M. Th. van Genuchten, Operator-splitting errors in coupled reactive transport codes for transient variably saturated flow and contaminant transport in layered soil profiles, J. Contam. Hydrology, 88, 197-218, 2006.
- Jacques, D., J. Šimůnek, D. Mallants, and M. Th. van Genuchten, Modeling coupled hydrological and chemical processes: Long-term uranium transport following mineral phosphorus fertilization, Vadose Zone Journal, doi:10.2136/VZJ2007.0084, Special Issue “Vadose Zone Modeling”, 7(2), 698-711, 2008. Download PDF (1.5 MB).
- Jacques, D., J. Šimůnek, D. Mallants and M. Th. van Genuchten, Modelling coupled water flow, solute transport and geochemical reactions affection heavy metal migration in a Podzol soil, Geoderma, doi:10.1016/j.geoderma.2008.01.009, 145, 449-461, 2008.
- Jacques, D., J. Simunek, D. Mallants, and M. Th. van Genuchten. 2008. Modelling the fate of uranium from inorganic phosphorus fertilizer applications in agriculture. In: L. J. De Kok and E. Schnug (eds), Loads and Fate of Fertilizer-Derived Uranium, p. 57-64, Backhuys Publ., Leiden, Netherlands.
- Šimůnek, J., M. Th. van Genuchten, and M. Šejna, Development and applications of the HYDRUS and STANMOD software packages, and related codes, Vadose Zone Journal, doi:10.2136/VZJ2007.0077, Special Issue “Vadose Zone Modeling”, 7(2), 587-600, 2008. Download PDF (2MB).
- Šimůnek, J., D. Jacques, N. K. C. Twarakavi, and M. Th. van Genuchten, Modeling subsurface flow and contaminant transport as influenced by biological processes at various scales using selected HYDRUS modules, Biologia, 64(3), 465-469, DOI: 10.2478/s11756-009-0106-7, 2009.
- Jacques, D., C. Smith, J. Šimůnek, and D. Smiles, Inverse optimization of hydraulic, solute transport, and cation exchange parameters using HP1 and UCODE to simulate cation exchange, J. Contaminant Hydrology, 142-143, 109-125, 2012.