Stream Order (Strahler) and Flow Direction

[PeterWilson]

I have generated a terrain dataset for South Africa from 20m contours and SPOT shots. In order to eliminate errors in the terrain where there isn't enough data especially low lying areas. I would like to make use of river centerlines to enforce the drainage within the terrain dataset. My proposed methodology is to intersect the river centerlines with the contours and extract the Z values of the contours into the river centerlines. I would then use the polyline Z river centerlines as hard break lines within the terrain dataset.

The problem that I have is that I need to ensure that the flow direction of the existing river centerlines that I wish to use is correct and secondly need to assign a stream order (Strahler) to the river centerline segments.

I've attached a screen shot of the river centerlines to help explain the problem that I have with the currently available river centerline dataset. There are numerous segments that should be tributaries but do not extended enough to link up with the main river. I'm looking for advice in how I can make use of the available river centerlines to embed into my terrain. Do I eliminate the segments that are not connected to the main river centerlines.

What is the most efficient methodology to rectify the river centerlines to a point that they won't add additional error to my terrain dataset, which I then would like to use to generate a river centerline network to build up an hydro data model. Any assistance will be appreciated.

[SeoyoungKim1]

Hi Nicole,

Did you solve the problem about producing the Strahler stream order using the stream shapefiles?

I also have same problems. Would you show me  your solution if you solved?

My email is

sykim2012@knights.ucf.edu

Seoyoung

[TRINY_GRACE_LORETLICERA]

Hi. Were you able to solve the problem? I need some help here. I digitized a river network out from georeferenced topographic map. Meaning the polyline river has no data. I'll be using the river for HEC-GeoHMS. But upon processing when I tried the command adjointcatchment it says that my river polyline has no GRID CODE/ID? How can I assigned GRID ID to my river polyline? I need to produce a Strahler stream order polyline? Kindly show me how to do it.

My email address is tglicera@gmail.com

Thanks,

Grace

[MarkBoucher]

Grace,

I haven't used HEC-GeoHMS for a while, but I'm very familiar with Arc Hydro. GeoHMS uses the same logic and tools as Arc Hydro for processing the watersheds. What GeoHMS does is take the processed grid and vector data and then allows the creation of an HMS model from that data.*

Normally, when using HEC-GeoHMS (and Arc Hydro), you start with a digital elevation model (DEM) and then process it through a few steps to create a flow direction from which you derive the rivers (drainage lines). I have started the practice of not digitizing or using existing river/stream polylines until I need them for correcting the DEM where the areas is flat or the DEM is not defined enough to put river/stream in the right place. In these cases I use the agreestream polyline layer to put the river/stream in the right place and then burn them in.  See this related discussion for more on my approach to burning in streams: Stream Definition threshold value​.

It looks like there is also some discussion about burning in streams in this thread. Wow! It started in 2011!!

Mark

*Footnote: The first generation GeoHMS tools relied on Arc Hydro tools to process the DEM before using the GeoHMS tools. Now, it appears the GeoHMS toolbar has the Arc Hydro tools needed to get to GeoHMS datasets that can be then used to build the HMS model. Likely, you would only need the GeoHMS toolbar if your goal was to create an HMS model from the GIS data.

[TRINY_GRACE_LORETLICERA]

Thank you for your help Sir Mark. I already figured it out