Appendix E: HYDRUS-1D

HYDRUS-1D is a forward model that handles one-dimensional groundwater flow and solute transport scenarios. This appendix is intended to discuss HYDRUS-1D features that are relevant to MAD#. See the HYDRUS-1D website for information on the software itself.

Origin convention

The HYDRUS project geometry is a single column with the origin of the coordinate system (Z=0, node=1) at the top of the column with decreasing values with depth. The MAD# origin convention is the same, except that MAD# uses the term ‘layer’ instead of ‘node’.

Variable naming convention

The Type-A and Type-B variable names used in MAD# are derived from the soil hydraulic model, material number, and hydraulic parameter that the driver is reading from the HYDRUS project you provide in the Project tab. For example:


indicates that the model is van Genuchten (one of the choices from HYDRUS’s Soil Hydraulic Model window), the material is the third kind (the row number in HYDRUS’s Water Flow Parameters window), and that the hydraulic parameter is residual water content (the first column in the HYDRUS’s Water Flow Parameters window for this model).

The hydraulic parameter name comes directly from the HYDRUS project input file, and these names vary slightly from both the notation in the Water Flow Parameters window in HYDRUS and that in the HYDRUS Help files.  In our example, the input file listed residual water content as thr, but the Water Flow Parameters window writes it as Qr and the Help files list it as θr

Last edited Sep 16, 2013 at 6:48 PM by frystacka, version 3


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