Stream Order (Strahler) and Flow Direction

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01-06-2011 08:04 PM
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PeterWilson
Regular Contributor
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.
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33 Replies
BiniamTes
New Contributor
hi peter ,

Though I did not see any reply to you post , I am sure u must have already solved your problem. I have somehow similar problem with your case.
I am using ArcGIS 10 for sewer network analysis. and i want to adopt river network ordering method(strahler order) to my sewer network(shape file). the sewer network is characterized by branched and mesh type. therefore, for ordering methods, i have to apply the ordering method for braided networks. I have found one algorithm below ....

http://onlinelibrary.wiley.com/doi/10.1111/j.1752-1688.1990.tb01432.x/pdf

that can exactly do the same for my network. can u give me little idea how to convert the algorithm to vba code.
thank you in advance for your assistance.
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PeterWilson
Regular Contributor
Hi Biniam

Firstly I must apologise for not getting back to you sooner. I'll gladly have a look at the algorithm, please can you email me a copy of the pdf as I don't have access to Wiley's site.

Regards
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JanSlaats
New Contributor III
Peter,
Did you develop any code to create a Strahler Stream Order attribute
for vector streams? 
Just wondering.
Thanks,
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MarkBoucher
Regular Contributor II
Spatial Analyst>Hydrology tools are able to create a stream order. They start with a stream raster AND you need a flow direction grid. So, if all you have is polylines of streams, you will need to make a raster with them. This should be an easy polyline to raster function. Once you have the stream raster, run stream order tool to get another raster that depicts the stream order. Then you need to convert the stream to a feature to get back in to vector data where you can symbolize the streams based on the stream order (grid code in resulting polyline feature class).

If you don't have a flow direction grid, or need to make sure you have one that exactly matches your stream polylines, you can burn the flow direction of the streams into a raster using Arc Hydro Toolbar>Terrain Processing>Flow Direction with Streams. I believe the direction of the polyline is key to making this work right. To check the direction of the polylines, change the symbology to show arrows on the lines. The arrows will point in a direction based on the direction the polylines are drawn. There is a tool to called Flip Line under Editing tools that allows you to flip the lines that don't point in the right direction.

Also, see this recent thread: http://forums.arcgis.com/threads/75629-Redrawing-rivers-in-proportion-to-their-discharge?highlight=s...
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ChristineDartiguenave
Esri Contributor
There is a tool in the Arc Hydro Tools toolbox > Attribute Tools toolset called Assign River Order that will calculates the stream order using 3 different methods:

  • Strahler: if different upstream orders, then maximum of the upstream orders, if more than 1 with maximum order, then max order +1.

  • Shreve: add upstream orders.

  • PU_Order: downstream feature river order = maximum of upstream features river order + 1 (PU stands for Processing Unit).


This tool uses the attributes HydroID/NextDownID in the input feature class to determine the downstream direction. It does not support flow splits or loops at this time.

Christine Dartiguenave
Esri Water Resources Team
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AslamHanief
New Contributor

Hi Christine,

I've seen you referring to the Assign River Order toolset; however, I'm unable to locate the Assign River Order toolset under the Attribute Tools. Has it been removed in ArcHydro 2? Please see image.

Thanks,

Aslam.

Attribute Tools.png

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NicoleCarlozo
New Contributor
There is a tool in the Arc Hydro Tools toolbox > Attribute Tools toolset called Assign River Order that will calculates the stream order using 3 different methods


I am interested in assigning river order to the NHD dataset. I just downloaded Arc Hydro for Arc 10.0, but I do not see the "Assign River Order" tool. I do see a tool for assigning a HydroID. Doe this need tobe used before determining river order, and where is the River Order tool located?

Thanks,
Nicole
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MarkBoucher
Regular Contributor II
There is one in SA:
Toolboxes\System Toolboxes\Spatial Analyst Tools.tbx\Hydrology\Stream Order
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ZichuanYe
Esri Contributor
(1) to to assign river order, you can use Assign River Order tool of ArcHydroToolbox (Toolboxes\System Toolboxes\Arc Hydro Tools.tbx\Attribute Tools).  This GP tool handles multiple river system at the same time, so you don't need to delete unconnected river lines.
(2) to make sure a known river line is considered in the flowdirection processing (burn-in river line), you can use the Create Drainage Line Structures tool (under Toolboxes\System Toolboxes\Arc Hydro Tools.tbx\Terrain Preprocessing\Create Drainage Line Structures)
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