topic Re: Stream Order (Strahler) and Flow Direction in Water Resources Questions

Stream Order (Strahler) and Flow Direction

PeterWilson — Fri, 07 Jan 2011 04:04:12 GMT

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.

Re: Stream Order (Strahler) and Flow Direction

BiniamTes — Tue, 16 Aug 2011 10:38:40 GMT

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.

Re: Stream Order (Strahler) and Flow Direction

PeterWilson — Sun, 01 Jan 2012 19:12:09 GMT

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

Re: Stream Order (Strahler) and Flow Direction

JanSlaats — Wed, 23 Jan 2013 19:30:51 GMT

Peter,
Did you develop any code to create a Strahler Stream Order attribute
for vector streams?
Just wondering.
Thanks,

Re: Stream Order (Strahler) and Flow Direction

MarkBoucher — Thu, 24 Jan 2013 13:43:55 GMT

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=stream+order

Re: Stream Order (Strahler) and Flow Direction

ChristineDartiguenave — Tue, 19 Feb 2013 20:38:32 GMT

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

Re: Stream Order (Strahler) and Flow Direction

NicoleCarlozo — Mon, 15 Apr 2013 14:35:30 GMT

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

Re: Stream Order (Strahler) and Flow Direction

MarkBoucher — Mon, 15 Apr 2013 15:18:08 GMT

There is one in SA:
Toolboxes\System Toolboxes\Spatial Analyst Tools.tbx\Hydrology\Stream Order

Re: Stream Order (Strahler) and Flow Direction

ZichuanYe — Mon, 22 Apr 2013 16:55:51 GMT

(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)

Re: Stream Order (Strahler) and Flow Direction

NicoleCarlozo — Tue, 23 Apr 2013 12:40:18 GMT

Mark - I see the SA tool, but it requires a flow direction raster and a stream raster. I don't see a "Flow Direction with Streams" tool. There is a "Flow Direction Tool" that requires a hydro DEM, but I only have a stream polyline/shapefile.

Zye - The "Create Drainage Line Structures" tool requires a Raw DEM. Do you have any more information about the DEM specifics? Does resolution matter?

Re: Stream Order (Strahler) and Flow Direction

ZichuanYe — Thu, 25 Apr 2013 15:53:21 GMT

the Create Drainage Line Structures function needs a DEM for it's cellsize and as a snapgrid.
In that sense, any DEM that provide correct cellsize and coordinate snapping will work.

Re: Stream Order (Strahler) and Flow Direction

DuncanHornby — Fri, 16 Aug 2013 09:18:44 GMT

There is a more efficient Strahler ordering algorithm created by Gleyzer et al 2004 which is implemented in an ESRI 10.1 AddIn tool called RivEX, worth a look?

Re: Stream Order (Strahler) and Flow Direction

NicoleCarlozo — Thu, 05 Sep 2013 16:56:21 GMT

After attempting to create stream order attributes via Lidar processing using the Hydrology Toolbox, I have circled back to this. Due to low coastal elevations and landuse changes, the lidar output isn't lining up with the stream polyline data that I already have.

I have a stream polyline, but I need stream order attributes. I have lidar, which I have used to create flow direction and flow accumulation grids. I attempted to use the "Create Drainage Line Structures" tool, however I received an error due to missing HydroIDs. I used the Assign HydroID tool within the Attribute Toolbox and tried again. It is still failing to execute. Am I missing something? Should I be using the lidar data as the raw DEM instead of the flow direction or flow accumulation grids? Do I need to specify file type?

If anyone has any experience with identifying stream order using known streams and lidar, I would really appreciate the help.

Thanks,
Nicole

Re: Stream Order (Strahler) and Flow Direction

MarkBoucher — Thu, 05 Sep 2013 17:11:04 GMT

Should I be using the lidar data as the raw DEM instead of the flow direction or flow accumulation grids? Do I need to specify file type?

The LiDAR data (points, I assume) must be converted to raster data. The rawdem is a raster file not a point file.

My experience is most polyline data fails to always follow the creek/river/stream (stream) idenditified via raster DEMs. This is because they are likely created by tracing over old maps that inaccuratly depict the streams or over ariel photos where the stream is hidden by trees. So, I use the raster with Arc Hydro to determine where the creeks are w/o the streams layer. Then I correct that where there stream is vauge in the DEM and where there are bridges/culverts, etc. that "mask" the creeks. This is where I burn in stream with the DEM reconditioning.

I suppose if you wanted to keep your stream polyline layer, you could do the Arc Hydro process create the stream order field inthe drainage layer and then transfer the stream order to your stream polyline layer.

Re: Stream Order (Strahler) and Flow Direction

NicoleCarlozo — Thu, 05 Sep 2013 17:43:35 GMT

Thanks Mark,

The lidar is in a raster format. I am having problems with the lidar results due to the ditching/artifical paths that are abundant in my study site. The Hydrology Toolbox first output "streams" in the middle of ag fields. I changed the CON value to produce an output more in line with my polyline file, but I still had the same problem. Now I am circling back to assigning stream order values to the polyline file I already have. If my study area was at a smaller scale, I think the lidar method could be used. But I am looking at county-wide data.

Does any initial processing need to be performed before running the "Create Drainage Line Structures" or "Assign River Order" tools? I feel like I'm missing something, but I haven't located any documentation that steps me through the process.

Re: Stream Order (Strahler) and Flow Direction

MarkBoucher — Thu, 05 Sep 2013 20:21:33 GMT

I normally use Arc Hydro that has several handy tools. You can use the Spatial Analyst (SA) tools but the process is not as well set up for someone doing it just once. This is a good link to review if you are using the SA tools. http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Understanding_drainage_systems/009z0000005m000000/

This link http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Deriving_runoff_characteristics/009z0000005p000000/ is a sub-section of the one above and shows a good flow chart of the process.

You can force the drainage lines to be at our polylines by "burning" them into the DEM (raster). You can do this by converting the polylines to a raster with a very low number (say -1000). Then add the DEM to the stream raster. The result is a DEM with the streams obviously below the surrounding terrain. Then you can run the fill tool and then the flow direction tool and this will set you up to create the stream features to which you can add the stream order because our flow direction grid will match the streams.

Arc Hydro adds a "buffer" the stream burning to ensure that the cells near the burned stream are lowered and you don't get parallel streams right next to the stream defined by your stream polyline based raster. This can happen if the polyline does not line up with the stream in the DEM. I'm sure you could figure out a way to lower the cells around the stream. Possibly you could create a small buffer around your stream polylines and then convert that to a raster with a smaller low number (-100). Then add the buffer based raster to the DEM and THEN the polyline based raster to that resulting DEM. This would take care of some parallel streams.

Some of this process will be influenced by the size of your DEM raster cells. If they are large, I don't think you will have many parallel streams. If the grid is small, you could have more.

Hope this isn't to confusing.

Best,

Re: Stream Order (Strahler) and Flow Direction

NicoleCarlozo — Mon, 09 Sep 2013 15:34:00 GMT

Thanks Mark. The SA Process you described makes sense, but when I followed it, the output did not make sense. Within a branch, the stream order values fluctuated (see attached for an example/screen shot).

Is this what you meant by parallel streams? I did use a small buffer as you suggested, but I could make it wider. Within the stream order tool, I used a raster version of the stream polyline and the flow direction output.

Is there an easier way to perform this analysis within ArcHydro?

Re: Stream Order (Strahler) and Flow Direction

MarkBoucher — Mon, 09 Sep 2013 17:49:58 GMT

If you use the Stream Link tool you should get a raster with just a stream defined by single grid cells (one cell wide). See example attached. Your image looks like the stream is defined by several cells wide. Your image is not an example of what I would call "parallel streams".

In my image, if you look at the confluence to the right of the center of the image, you will see parallel streams defined for a short distance (mine is a 10'x10' grid). They are only one cell apart. If I were to redo this one, I would add agreestream features to burn the DEM so the parallel streams merge (that is if I knew they should not be parallel and should come together sooner).

Re: Stream Order (Strahler) and Flow Direction

NicoleCarlozo — Thu, 12 Sep 2013 13:48:20 GMT

Thanks for the clarification. I tried what you suggested, but the result did not change. When creating the stream raster, I made sure the cell size matched the DEM. I also tried using the default cell size and a very small cell size. The same problem occurred. In environmental settings, I tried snapping the stream raster to the DEM during processing, as well as not snapping. Still no change.

My workflow:

1) Polyline to Raster conversion (1 on a background of NoData)
2) Burn the polylines into the DEM.
2) Fill the burned DEM
3) Flow Direction
4) Use the stream raster and flow direction outputs in the Stream Order tool.

Could this problem be due to a high resolution DEM? Since I am using a buffer (-100) around the stream lines, I'd think that the flow path/direction would not be a problem.

Re: Stream Order (Strahler) and Flow Direction

MarkBoucher — Thu, 12 Sep 2013 15:42:37 GMT

I tried using the SA Hydrology tools and Raster Calculator to do what you are doing. When I converted the stream polylines to raster I got a single cell pattern for the streams raster. I was not able to get all the tools to give me results I was expecting and then someone else doing "real work" needed the SA license and I had to stop investigating.

For your stream raster, you may need a value of greater than 1 to make the burn work. Use the Con() function to create another stream raster where 1 is changed to -1000, then add the two rasters. This will definitely burn the streams deep.