Please read it first before contacting the support. If you have any suggestions for content that may be helpful for others, please let us know.


Firewall warnings at startup

There are many firewall warnings when you start Flow-R: mpiexec.exe, ctfxlauncher.exe, FlowR.exe, app.exe and smpd.exe. These are due to the Matlab Compiler Runtime. Flow-R does not send, download, nor collect any data. The availability of new versions is not even checked automatically.

The startup is very long

Yes, the startup can be very long. This is due to the initialization of the Matlab Compiler Runtime, and we can do nothing about it.

Flow-R does not start on Windows

If you get an error saying (for Windows) "Could not find version XX of the MCR. Attempting to load mclmcrrtXX.dll. Please install the correct version of the MCR. Contact your vendor if you do not have an installer for the MCR.", it's because you do not have the correct Matlab Compiler Runtime installed. Please install the version from the download page that corresponds to your operating system (Windows 32 bits / 64 bits or Linux 64 bits).

Flow-R does not start on Linux

If you get an error saying (fof Linux) "Fatal error loading library [...]/libmwmclbase.so Error: libXt.so.6: cannot open shared object file: No such file or directory", install the following libraries: libXt6, libXmu6.

Data importation

Spatial domain issue

"The import of data has failed as the spatial domain is too large…"

It is possible to import data of any size. If an error occurs, it is necessary to adjust a parameter in the preferences. Follow these steps:

  1. Go to : Options > Preferences

  2. Enter a smaller value under Split data in rows of x meters.

Coordinates issue

"The importation of data is not accepted as the grid’s reference coordinates are not a multiple of the cell size…."

You should update your version of Flow-R !


What are the river and buffer layers ?

The river identification is used to create the buffer layer and nothing more. The buffer layer is what it says, a buffer around the identified rivers with the given size. The buffer layer has an influence on the source identification only if selected, else it is ignored. When selected, it limits the sources identifications within the buffer. It is only for source areas identification and has no influence on the runout computation. This approach is for debris flows only; do not use it for rockfall for example.

Can I also use the curvature threshold of -2/100 m-1 ?

No, you shouldn't. Here is why:

  • This threshold was calibrated based on historical events in Switzerland. This is not a value that will be valid worldwide, and you should not use it without testing. We know no better option than calibrating this threshold for every new region where Flow-R is applied.

  • The second problem is that it depends on the DEM resolution, as the details on the gullies will vary according to resolution. This value was established on a 10m DEM and should not be used with another resolution. You can even consider that if your DEM has a coarser resolution (for example 25m) and if you want to capture events in small to medium gullies, you should not use the curvature, as it will not contain enough information.

Is the flow accumulation mandatory ?

No, flow accumulation is not mandatory if you don't use it as input in the source areas assessment.

I cannot see new datasets

"I have imported new data but they are not displayed in the dropdown list…"

You should update your version of Flow-R !

The run button is disabled

It is mandatory to give a name to the run before being able to start the simulations. This name is used to save the resulting files.

My simulation seems never ending

If the calculation seems to never end, there is probably a problem with the choice of the energy algorithms. Actually, if the travel angle is too low and there is no energy limit, the processing can be long and nonsense values will result. In this case, increase the travel angle values or set energy limits.