Volker Wichmann

For a simplified analysis you can use the Flow Accumulation tool. Use the "Weight" grid to add the precipitation amount. Note that this simplified approach will not fill up and overcome depressions - water will simply accumulate in sinks but will not overflow. If you want the water to fill up and overcome the sinks, you must run a simulation with the Overland Flow tool. This is computational intensive, but allows you to simulate a selected time span with the specified precipitation (mm/h) and see...

Simply unload (close) all libraries you don't want to use. After a re-start, these closed tool libraries will not be loaded anymore. SAGA GUI stores this information in the saga_gui.ini file (located in your user folder or in the SAGA installation folder if you have write access). Of course you can also simply edit this file in a text editor and remove the tool libraries that should not be loaded. These entries are at the bottom of the file.

There are many things which can influence the startup time, most of them are not under our control. This includes: library dependencies: we rely on other libraries (like GDAL/PROJ and wxWidgets) and changes (mostly new functionality) in these libraries can cause slowdowns because the libraries get bigger the amount of additional libraries that need to be loaded (e.g. new dependencies introduced in GDAL) windows itself: SAGA is very modular and loads a lot of dlls ... and these are usually checked...

Hi, the error is about your input file ... it is not passed to the tool, so the tool has nothing to compute. Please check your input data and why this fails - usually the QGIS plugin converts your input data to a SAGA grid before passing it to the tool and it seems that there is a problem. If you can't get it working in QGIS, please try directly in SAGA ... I am very confident that the tool itself is working.

The seed point simply represents the location at which the flooding starts. Usually you specify the water depth "relative to the DTM". Then the specified water depth is added to the terrain height at the seed position and the surrounding is flooded with that water depth until DTM cells are reached where the terrain is higher (and therefore cannot be overcome by the water).

Hi Gerrit, I doubt that the "Terrain Flooding" tool can be used in this context ("flooding from a river") as the tool models a constant water height. Modelling the flooding caused by a river (with a gradient of the water surface) is a non-trivial task. You need to approximate an inclined water surface and then you must intersect it with the ground surface. This is difficult, but you could try with the Vertical Distance to Channel Network tool. Something similar has been described in a paper published...

Hi, this will depend on the kind of input data you use and the application you have in mind. I have not tried this, but since the tool will produce quite a lot of seed points (and does not remove the seeds of joined segments), I would expect that you will always have to apply some kind of pre-processing to the seeds before you can use them for terrain flooding. Best regards, Volker

changes.md: add coordinate transformation tool changes