HYDRUS

HYDRUS

HYDRUS is a Windows application for simulating water, heat, and solute movement in one-, two- and three-dimensional variably saturated media. The program can be extended with a number of special add-on modules. HYDRUS is currently being used by more than 3000 companies and institutions from around the world - see the list of selected customers. This list also includes almost 50% of the World's top 100 universities 2014.

HYDRUS version 5 was released in April 2022 and it merges two previously independent software packages HYDRUS-1D (version 4, for one-dimensional applications) and HYDRUS (2D/3D) (version 3, for two- and three-dimensional applications). See new features in HYDRUS 5.01.

September 2024: New version HYDRUS 5.04 has been released - see New Features

Animation of Infiltration

3D-Layered Domain

Introduction

The HYDRUS program numerically solves the Richards equation for variably saturated water flow and advection-dispersion equations for both heat and solute transport. The flow equation incorporates a sink term to account for water uptake by plant roots. The heat transport equation considers transport due to conduction and convection with flowing water. The solute transport equations consider advective-dispersive transport in the liquid phase, as well as diffusion in the gaseous phase. The transport equations also include provisions for nonlinear nonequilibrium reactions between the solid and liquid phases, linear equilibrium reactions between the liquid and gaseous phases, zero-order production, and two first-order degradation reactions. In addition, physical nonequilibrium solute transport can be accounted for by assuming a two-region, dual-porosity type formulation which partitions the liquid phase into mobile and immobile regions. Attachment/detachment theory, including filtration theory, is additionally included to enable simulations of the transport of viruses, colloids, and/or bacteria.

HYDRUS may be used to analyze water and solute movement in unsaturated, partially saturated, or fully saturated porous media. The program can handle flow regions delineated by irregular boundaries. The flow region itself may be composed of nonuniform soils having an arbitrary degree of local anisotropy. Flow and transport can occur in a one-dimensional vertical or horizontal direction, a two-dimensional vertical or horizontal plane, a three-dimensional region exhibiting radial symmetry about the vertical axis, or a fully three-dimensional domain. The standard modules (not the specialized add-on modules) of this program also includes a Marquardt-Levenberg type parameter optimization algorithm for inverse estimation of soil hydraulic and/or solute transport and reaction parameters from measured transient or steady-state data. Details of the various processes and features included in HYDRUS are provided in the Technical Manual [Šimůnek et al., 2022].

The main program unit of the HYDRUS Graphical User Interface (GUI) defines the overall computational environment of the system. This main module controls execution of the program and determines which other optional modules are necessary for a particular application. The module contains a project manager and both the pre-processing and post-processing units. The pre-processing unit includes specification of all necessary parameters to successfully run the HYDRUS FORTRAN codes, grid generators for relatively simple rectangular and hexahedral transport domains, a grid generator for unstructured finite element meshes appropriate for relatively complex two-dimensional and three-dimensional domains, a small catalog of soil hydraulic properties, and the Rosetta Lite program for generating soil hydraulic properties from soil textural data. The post-processing unit consists of simple x-y graphics for graphical presentation of soil hydraulic properties, as well as distributions versus time of a particular variable at selected observation points, and actual or cumulative water and solute fluxes across boundaries of a particular type. The post-processing unit also includes options to present results of a particular simulation by means of contour maps, isolines, spectral maps, and velocity vectors, and/or by animation using both contour and spectral maps.

Technical aspects of the HYDRUS software package such as the governing equations and details about the invoked numerical techniques are documented in the Technical Manuals [Šimůnek et al., 2022]. The Graphical User Interface of the HYDRUS software package is documented in a separate User Manual [Šejna et al., 2022].

Manuals and Main References

Technical and User Manuals

• Šimůnek, J., M. Šejna, G. Brunetti, and M. Th. van Genuchten, The HYDRUS Software Package for Simulating the One-, Two, and Three-Dimensional Movement of Water, Heat, and Multiple Solutes in Variably Saturated Media, Technical Manual I, Hydrus 1D, Version 5.0, PC Progress, Prague, Czech Republic, 334p., 2022. (HYDRUS_Technical_Manual_1D_V5.pdf 3.9MB)
• Šimůnek, J., M. Th. van Genuchten, and M. Šejna, The HYDRUS Software Package for Simulating One-, Two-, and Three-Dimensional Movement of Water, Heat, and Multiple Solutes in Variably-Saturated Porous Media, Technical Manual II, Hydrus 2D/3D. Version 5.0, PC Progress, Prague, Czech Republic, 283 p., 2022. (HYDRUS_Technical_Manual_2D3D_V5.pdf 3.6MB)
• Šejna, M., J. Šimůnek, and M. Th. van Genuchten, The HYDRUS Software Package for Simulating One-, Two- and Three-Dimensional Movement of Water, Heat, and Multiple Solutes in Variably-Saturated Porous Media, User Manual, Version 5.0, PC Progress, Prague, Czech Republic, 348 p., 2022. (HYDRUS_user_Manual_V5.pdf 9.6MB)

Peer-Reviewed Journal Articles

• Šimůnek, J., G. Brunetti, D. Jacques, M. Th. van Genuchten, and M. Šejna, Recent developments and applications of the HYDRUS computer software packages since 2016, Vadose Zone Journal, 23(1), e20310, 29 p., doi: 10.1002/vzj2.20310, 2024. (Supplementary Material)
• Šimůnek, J., M. Šejna, and M. Th. van Genuchten, New Features of the Version 3 of the HYDRUS (2D/3D) Computer Software Package, Journal of Hydrology and Hydromechanics, 66(2), 133-142, doi: 10.1515/johh-2017-0050, 2018.
• Šimůnek, J., M. Th. van Genuchten, and M. Šejna, Recent developments and applications of the HYDRUS computer software packages, Vadose Zone Journal, 15(7), pp. 25, doi: 10.2136/vzj2016.04.0033, 2016. (Hot paper according to Web of Knowledge (ISI))
• Šimůnek, J., M. Th. van Genuchten, and M. Šejna, HYDRUS: Model use, calibration and validation, Special issue on Standard/Engineering Procedures for Model Calibration and Validation, Transactions of the ASABE, 55(4), 1261-1274, 2012.
• 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). (Highly cited paper according to Web of Knowledge (ISI))