FAQ 01-10
1. Problem with Hydrus-1D installation
After the Hydrus-1D installation, the folder into which the model was supposed to be installed is empty. This is likely due to the incorrect prior Hydrus-1D installation.
Remedy – Remove the old installation:
- Go to “Start->Control Panel->Add or Remove Programs” and remove the old Hydrus-1D installation.
- If the first way does not work, do the following:
- Run REGEDIT program as follows: Start->Run->RegEdit
- Delete the item Hydrus-1D from HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\
- Search in RegEdit for the string 50723e08-57bf-11d2-b51b-00609750c485 and delete all items with this name.
- Start Windows Explorer and show all Hidden files (Tools->Folder Options - Tab View – Hidden Files and Folders – Show Hidden Files and Folders).
- In the folder “C:\Program Files\InstallShield Installation Information” delete item {50723E08-57BF-11D2-B51B-00609750C485}
2. Instalation and Use of HYDRUS 2D/3D on Windows Vista
HYDRUS 2D/3D, version 1.05 or later is fully compatible with the Windows Vista operating system. However, when testing previous versions of HYDRUS (1.04 or earlier) on this operating system, we encountered several minor problems described below together with their solutions:
1. Problem with Authorization.
Description: When starting HYDRUS under Windows Vista, an error message appears
“Unable to access authorization information!”
“Error No. 103-9”
At the same time one can not open a dialog for HYDRUS authorization.
Cause: HYDRUS does not have sufficient rights to access system tools for verification of authorization.
Solution: It is necessary to run HYDRUS at least once with administrative rights. Go to the folder where HYDRUS is installed (usually "C:\Program Files\PC-Progress\HYDRUS"), click with the right mouse button on Hydrus3D.exe and in the displayed popup menu select "Run As Administrator". This single HYDRUS run with administrative rights will establish all necessary access rights. This should solve the problem, i.e., the next HYDRUS run can be without administrative rights.
2. Problem with Access Rights to Project Data Files.
Description: When saving a project, a warning appears informing that data can not be saved (no access to save).
Cause: A user does not have rights to store data in the folder with HYDRUS projects.
Solution: There exist two solutions:
- Change attributes of the folder with HYDRUS projects. Click with the right mouse button on the folder, in which HYDRUS projects are stored, and select “Properties -> Security”. In the “Users” group, set “Full Control”.
- Move HYDRUS projects to another folder, to which you have a full access. Set up access to this new folder using the Project Manager (Menu File -> Project Manager).
3. Graphics is Slow
Description: Drawing of the Scene (in the View Window) is very slow.
Cause: Drivers for the OpenGL hardware acceleration (for the video card) are not installed. Drivers of the graphical card, installed when the Windows Vista operating system was installed, were developed by Microsoft (not by the producer of the graphical card) and do not support the hardware acceleration. HYDRUS will display a warning that OpenGL hardware acceleration is not available and that graphics will likely be slow. Unavailability of hardware acceleration can be confirmed in the following way: Select the dialog window “Program Options” (HYDRUS Menu -> Options -> Program Options) and on the Tab “Graphics” the OpenGL Hardware Acceleration is set at “OFF”, while the radio buttons are disabled.
Solution: It is necessary to install the original graphical drivers for Windows Vista. These can be obtained (downloaded) from the producer of the graphical card.
4. Graphics Contains Various Errors
Description: The Scene (in the View Window) is not displayed correctly. Errors may be different.
Cause: These problems usually occur after installation of drivers for the OpenGL hardware acceleration (see 3). This is usually due to errors in newly developed drivers (software is provided by producers of graphical cards), that are not yet unfortunately bugs free.
Solution: Turn off the hardware acceleration. Run the dialog window “Program Option” (HYDRUS Menu -> Options -> Program Options) and on the tab “Graphics” set the OpenGL Hardware Acceleration “OFF”. Then restart HYDRUS. This should solve the problems, but the graphics will be unfortunately slow. We recommend updating drivers of the graphical card as soon as newer versions become available.
3. ORTHOMIN Terminates – too many iterations, time step reduced
ORTHOMIN is an iterative solver for the system of linear equations that results from the numerical discretization of the Richards or CD equations. When the system of equations is not well defined (which typically signifies that the problem is not well defined physically (e.g., unrealistic BCs); although this can occur also when the entire system is close to saturation or when there are parts of the domain that are saturated), then ORTHOMIN may have problems to converge. When that happens, the code issues the warning (above), reduces the time step, assembles the system of equations, and tries to solve it again. Thus this warning does not represent a major problem, unless the time step is reduced down to the minimum time step allowed.
4. How to run computational modules outside of GUI ?
Hydrus computational modules (e.g., h1d_calc.exe, h2d_calc.exe, h3d_calc.exe, HP1.exe. HP2.exe, etc) can be run either
(a) Directly (Internally) from the HYDRUS GUI, or
(b) Externally from any other location by simply clicking on the computational module.
(a) Internally:
When these modules are run from the Hydrus GUI (option a), the GUI will send them as a parameter the path to the folder, in which the input and output files are located (the working folder; the path to the working folder is displayed in the project manager or in the project information dialog window (only for h2/3d)).
(b) Externally:
When the program does not receive a path as a parameter, it will look for the text file called Level_01.dir (for HYDRUS) or Path.dat (for HPx) that needs to be located in the same folder as the computational module. This file can be written using any text editor, such as Notepad. This file must have one line, which provides the path to the folder, in which the input and output files are located.
Example of the “Level_01.dir” ("Path.dat") file:
c:\program files\pc-progress\hydrus3d\mydirect\run1
HYDRUS 2D/3D: The input files are available in the Working Folder. The Working Folder is either 'Permanent' (see the Project Information dialog), i.e., it exists even when a particular project is not opened in the HYDRUS GUI, or 'Temporary', i.e., the HYDRUS GUI (and a corresponding project) needs to be opened. In each case the text input files need to be created by the menu command "File->Import and Export->Export Data for HYDRUS Solver in Text Format". When calculation is finished, it is necessary to update the HYDRUS GUI project file by using the menu command "File->Save" (available also from the toolbar).
HYDRUS-1D: Input files are always available in the working folder Project_Name.
5. Could one use HYDRUS (2D/3D) for one-dimensional simulations?
HYDRUS-1D and HYDRUS (2D/3D) are two independent software packages, which are being distributed independently, i.e., HYDRUS (2D/3D) currently does not include HYDRUS-1D (which is in the public domain). One can obviously solve a lot of 1D problems with a 2D/3D package as well, although at the expense of computational time (2D will run about 3 times slower then 1D for 1D problems, since one needs to use twice as many nodes to solve the same problem, i.e., at least two vertical columns of nodes) and user convenience. Both packages solve flow and transport for almost identical processes. We would not recommend using a 2D code for many typical soil physics inverse problems (e.g., one- and multi-step outflow experiment, evaporation method, solute transport column studies) or for engineering problems, such as multi seasonal simulations of the recharge through landfill cover. We would, however, recommend HYDRUS users to first gain experience with HYDRUS-1D (and what type of temporal and spatial discretization one needs) before attempting complex 2D/3D problems. Thus, we believe that there is a reason to have both packages if you want to solve both 1D and 2D/3D problems.
6. Should I use solute flux or solute concentration boundary conditions?
The third-type (Cauchy or solute flux) boundary condition prescribes solute flux (not concentration) across the boundary. Then due to mixing with water (and solute) initially present in the profile, one will not get immediately c_0 concentrations on the boundary. Since one prescribes solute flux, one has a complete control over the mass balance and how much solute enters into the transport domain.
When one uses the first-type (Dirichlet or concentration) boundary condition, one prescribes the concentration at the boundary (not the flux into the domain). Since solute flux consists of two components, i.e., convective and dispersive solute flux, both these fluxes are active on the boundary as well. Initially there is a large concentration gradient and thus the dispersive solute flux is large. In this case one has much larger flux into the domain than if one uses the third-type solute flux boundary condition.
We always recomend using the third-type boundary condition since that is more physically realistic boundary condition. Dirichlet boundary condition is not a physical boundary condition (and for above reasons it does not conserve mass). One could use it only if there is, for example, large reservoir of contaminant in contact with the transport domain, and thus one can assume that boundary concentration is fixed.
7. What to do when x-y graphs do not show up?
Have you installed the program (HYDRUS, STANMOD, or RETC) using the installation (SetUp) program? That needs to be done since during installation the graph dll (vcfi32.ocx) and the grid dll (vcF15.ocx) are registered with the Windows registration database. These programs (vcfi32.ocx and vcF15.ocx) are stored in the Windows (or System) folder. Installation also copies the Chart.vtc file into the Hydrus folder (with executables). If this is not done one can not view the graphics and tables in the GUI. You can do manual registration of this graph (and grid) by dragging the dll (vcfi32.ocx and vcF15.ocx) and dropping it on regsvr32.exe. You should get a message that the registration was successful.
8. Notes on Spatial and Temporal Discretization
If you are unsure on how to discretize time and space for HYDRUS calculations, download brief Notes on Spatial and Temporal Discretization.
9. I cannot run HYDRUS-1D executable modules even for preinstalled projects
This problem is related only to HYDRUS-1D. Some older Intel Processors do not support all optimization options that we have started using after implementing Intel Fortran Compiler in January 2001, which made computational modules substantially faster. If this is the case, then you need to download and use version 4.07 of HYDRUS-1D, which was compiled with the older (and slower) Compaq Fortran Compiler.
10. I cannot modify intervals in the spectrum when displaying small values (e.g., for concentrations).
There is indeed a problem in HYDRUS when trying to display a variable, that has only very small values (e.g., all values smaller than 1e-4), which may occur for concentrations. There will be only one very narrow interval for spectrum (in the dialog Edit Isoband Values and Color Spectra) and it will be impossible to redefine this interval or split it into multiple intervals. There is a simple way of getting around this problem. a) Select another variable that is displayed correctly. b) Open the Edit Isoband Values and Color Spectra by clicking at the color spectra at the Tools bar. c) Define required Isoband vales. d) Click on the button "Save" and save the definition of the new isoband values under a new name, e.g., Scale for Small Values. e) Display a variable with small values, open the Edit Isoband Values dialog, and select "Scale for Small Values". f) All should be displayed well.