Stroomrichting aanpassen in streams

Question

<\/HEAD>Hallo,<\/P> <\/P> Ik probeer te begrijpen hoe ik de tool "Adjust flow direction in streams" correct kan gebruiken. Voor zover ik begrijp, moet deze worden gebruikt bij het opleggen van een stroomstelsel (streams erin branden) dat circulaire gebieden bevat. Dit is mijn workflow:<\/P> <\/P> 1. Sinks vullen<\/P> 2. DEM herconditionering<\/P> 3. Sinks vullen<\/P> 4. Stroomrichting<\/P> 5. Stroomaccumulatie<\/P> 6. Streamdefinitie<\/P> <\/P> Vervolgens voer ik de tool "Adjust flow direction in streams" uit en als mijn "Stream flow direction grid" gebruik ik het resultaat van stap 6 in mijn workflow. Is dit de juiste aanpak?<\/P> <\/P> Hartelijk dank voor de hulp en mijn excuses als deze vraag al eerder is gesteld en beantwoord.<\/P> <\/P> Alex.<\/P><\/BODY><\/HTML>

ChristineDartiguenave · Answer

You will use if you have known Streams you want to use.

Create Drainage Line Structures will create a rasterized version of those streams.

This tool also create StrLnk which you can use as input Str raster in DEM Reconditioning (this way we use the same raster).

Christine

AlexanderVentura · Answer

Hi Christine,

Thanks a lot for your reply. OK, I was following this manual:

http://downloads.esri.com/support/datamodels/Hydro/Comprehensive_terrain_preprocessing_using_Arc_Hydro_tools_2008.zip

and as far as I had understood it the "Adjust flow direction in streams" tool is used when burning in streams into my DEM but the streams have "braids", but I guess I had gotten this wrong.

So essentially I need to "burn in" streams (ditches or drainage systems rather) to "force" the water to flow in these. I have a detailed network of drainage lines available in vector (polyline) format. So far I have been using "DEM reconditioning" for this but you mention "Create Drainage Line Structures". Is this a process that should be performed before running the "DEM reconditioning"  tool? Or is "Create Drainage Line Structures" used when a vector of drainage lines is not available and needs to be created?

Thanks again,

Alex.

ChristineDartiguenave · Answer

You do not need to run the tool "Adjust flow direction in streams" when the streams are generated using Stream Definition based on the flow accumulation raster. This tool is used when the Streams (Drainage Line) are created using Create Drainage Line Structures, i.e. you are trying to match the geometry and digitized direction of input vector streams, which may not match the direction provided by the underlying terrain. This tool ensures that once the water gets into the stream, it follows the direction of the digitized input streams. In flat area, the water may not go the right way otherwise.

Christine Dartiguenave

Esri Water Resources Team