Burning stream network into DEM layer in QGIS

This video demonstrates how to perform catchment delineation by burning a river into a DEM to force the water to follow the main hydrography. We first download river data from OpenStreetMap and preprocess it. The GRASS r.carve algorithm from the processing toolbox is used for burning the river in the SRTM DEM.
Credits for OpenStreetMap data: © OpenStreetMap contributors
SRTM data available from USGS Earth Explorer: earthexplorer.usgs.gov
The catchment delineation procedure is based on Chapter 4 of the book "QGIS for Hydrological Applications - Recipes for Catchment Hydrology and Water Management" by Kurt Menke and Hans van der Kwast. More information about the book can be found at the website of Locate Press: www.locatepress.com/hyd2
This video is part of IHE Delft OpenCourseWare. More free resources can be found at www.gisopencourseware.org
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[@samhuddy5951]

Hans you're a legend! all your videos are so relevant to my work! Keep it up

[@drewfrench8784]

Thank you, this was one of the most helpful vids on QGIS I have seen so far

[@drewfrench8784]

r. carve is still not working for me - is there something I'm missing? Mainly - is it only able to work on one vector line at a time? I am trying to have it carve several lines at a time into a DEM. Are there other issues I should be aware of?

[@HansvanderKwast]

@@drewfrench8784 I also tried a bit. It only works if you do the corrections that are mentioned in the video and dissolve the river into one feature. Maybe for the whole river network you can use the other approach: kzbin.info/www/bejne/oHm3kIaqhceSpa8 or use PCRaster Python.

[@AlejandraGomez-lr9ol]

Hi Hans, I really have to say Thank you! You have saved me with this clear and practical material. I would recommend to you a higher resolution on future videos, just for beginners like me.

[@HansvanderKwast]

Thanks. The resolution of the video is already HD 1080p. It's not possible to increase that. Or do you mean something else?

[@mlfb01ag]

Some bookmarks in this video: 2:19 extracting thematic layers from OSM (Open Street Map) 7:57 burn streams with r.carve 8:57 assign a classic topographic-style palette to the DEM (fabulous! I would never have discovered it) 10:08 fill depressions with Fill sink (Wang&Liu)

[@miraclebuoy]

Hi Dr Hans. Thank you for the guiding videos you produce. I am working on my project to delineate a lake watershed, where all the surrounding subcatchments are draining directly to the lake. I have been following your steps on all tools (PCRaster, SAGA, GRASS, Whitebox) to delineate, but none are working. I even tried using SWAT. Including this video (burning my own streams). Every step goes well until DEM fill. I think the tools are filling up the lake and nearby wetland area, finally giving me wrong output at "strahler" step. Water does not flow out of the lake. So, i wish you do a video on how to delineate a lake watershed (if possible with Whitebox tool) so we can follow your steps. Many thanks.

[@christinethomas6433]

Hi Hans, thanks for your brilliant tutorials! When I run r.carve, the river cells are just getting clipped out of the DEM instead of subtracted by x. So the result has nodata values corresponding to the river. Do you know why this could be happening? I’ve followed the steps you outlined here exactly.

[@AK-me3vb]

Hello, what values for stream width and additional stream depth (applying r.carve) should be chosen? I tried different values but no burned dataset is created. My dissolved river network dataset has multiple river and stream arms and is more branched than shown in the video.

[@AbdullahSalimalig]

Thanks for the upload. Can this be applied to data-scarce region?

[@HansvanderKwast]

This method applies when you have a river layer available or you can download it from OpenStreetMap as demonstrated in the video. If that's not available, you can digitize the river in OpenStreetMap or use the procedure without burning the river network. This video shows how to do that with GRASS tools in QGIS: kzbin.info/www/bejne/l4W8eaOcqZaaq9U This video shows how to do that with SAGA tools in QGIS: kzbin.info/www/bejne/iKCQg4WwgrKqY8U

[@r_2148]

Stream network by qgis found to be correct.but found incorct in hechms and arcgis.what should I do to match in HEC HMS.

[@maiyourathaankarunanandara3382]

Hi Hans, can I use r.carve to burn not only main river but also other hydraulic structures (Eg: Underpass of the Bridges (Brückendurchlass) or Railway (Bahndurchlass), culverts) on the foreland, which define the correct flow path of the rain. In other words, I do not want to burn those structures just assigning a specified depth value in the r.carve tool, but I wanted to select these Structures as a vector layer (line), and then extract the Z value of this line layer (Single line which consist of 2 points) from the DEM at the beginning and the end, thereafter use these interpolated or given Z values between these 2 points of line to burn the DEM

[@HansvanderKwast]

You can do that, but it depends on the purpose of your study and the detail of the DEM (DSM?) if it makes sense. Also check this tool from WhiteBox: www.whiteboxgeo.com/manual/wbt_book/available_tools/hydrological_analysis.html#BurnStreamsAtRoads. There's also an interesting reference on the page. The tool can be used from QGIS with the WhiteBoxTools plugin.

[@maiyourathaankarunanandara3382]

@@HansvanderKwast Thanks for the link and I will have a look on it. I have used r.carve tool to burn my 3D Line (Line with Z Values) into the DEM. I assigned only the width of the raster and let the depth as default, and then the r.carve tool automatically interpolated the 3D lines linearly and burned it in to DEM.

[@mlfb01ag]

Hi Hans, thanks for your videos, a true QGIS Encyclopedia! You first burn the stream and afterward fill the sinks. Could you please explain why? I have no based opinion, but following my ...well, my instinct, maybe I would have done the opposite, because I don't know how r.carve would act if it comes across a sink just along the stream. I guess that r.carve would find it easier to carve a flat surface rather than a surface with holes. As you see, this is only a hypothesis (it would be true if instead of by an algorithm, the carve was done by a child on the sand...) Thanks again!

[@HansvanderKwast]

Hi Fabio, good question. Before I made the video I tried both workflows. Only the one in the video worked. Probably filling the sinks first and then burning the river still causes local depressions.

[@mlfb01ag]

@@HansvanderKwast Thanks a lot!

[@simonwendl8575]

Hello, is it possible to use this to correct your Strahler Orders? I have a problem with some small channels (1m width) which don't appear in my DEM so the Strahler Orders aren't totally correct, but it's a much smaller scale. Can I just burn them into the DEM an re-run the Strahler Orders? Thanks in advance.

[@HansvanderKwast]

With burning the rivers in the DEM you can indeed get closer to the real channels and possible improve the Strahler orders.

[@GeneralFlop]

Hi Hans, a very useful video, thank you. I am having some issues with r.carve. I have followed all of the steps up to using that point, but in addition to the errors which appear in your log, I also get the following: ERROR: North must be north of South WARNING: Unable to determine input map's vector feature type(s). WARNING: Output layer is empty, no features written The resulting tiff has values of -34*10^-38 to 34*10^-38 and nothing appears. Any ideas?

[@HansvanderKwast]

Hard to tell what the reason is. The result means that all pixels probably have missing value (I guess you read it from the legend. The correct place to read it is from the layers property). One reason can be that CRS is wrong. Make sure that DEM and stream have the same CRS and that it's not a GCS (so not EPSG:4326). Check also the manual page: grass.osgeo.org/grass78/manuals/r.carve.html. For an alternative robust method see tutorial 8 on this page: courses.gisopencourseware.org/course/view.php?id=10

[@GeneralFlop]

@@HansvanderKwast Thanks for getting back to me. I have followed the steps religiously and it still produces the same error. Even when I use the single SRTM image of interest. Essentially, I am trying to force the River Network algorithm to join two two sections of major river that it doesn't want to. Is burning the only way to do this? Is there another workaround?

[@HansvanderKwast]

I guess you want to burn in the river, because the study area is too flat. If it's really flat the algorithms will not work. Hard to judge from text messages what goes wrong. General checklist: 1. Use QGIS LTR version 2. Use a CRS, not GCS 3. Interpolate voids first (nodata pixels in DEM) 4. Mask sea, ocean, lake if your outlet is where the river enters the ocean. 5. If it's too flat, the algorithms don't work. They are gravity based. There are no automatic alternatives. 6. Try alternatives (SAGA, GRASS, WhiteboxTools, PCRaster). Videos are available. 7. Don't use spaces, accents, dots, minus or other strange characters in file, folder or profile name. 8. Don't use very high resolutions or too large areas. That's all I can say from here. Live support is possible at a charge.

[@GeneralFlop]

@@HansvanderKwast Thanks for the help. Lots of things to try. I really appreciate it!

[@GeneralFlop]

If my stipend would stretch I'd have no hesitation paying you, ha!

[@user-tj7qf9tu3g]

Excuse me can I know what is the name of the algorithm used in this tutorial, please?

[@HansvanderKwast]

Here's the link to the r.carve tool from GRASS that was used: grass.osgeo.org/grass83/manuals/r.carve.html

[@Zoe-kw6we]

Hi Hans, I followed all your steps but my river doesn't shop up in the burned DEM. I tried a few different settings and one time accidentally forgot to tick off the 'adjusted stream points', which did show the river in a different layer (but not burned into the DEM). Do you have any idea what I could have done wrong?

[@HansvanderKwast]

Hard to tell from your description what goes wrong. Are you sure the projection of the layers match?

[@cappikkk_24]

May I know how to create the boundingbox?

[@HansvanderKwast]

You need to estimate the approximate location of your catchment and digitize the bounding box polygon. An easy way is to zoom in to your approximate area and then use from the Processing Toolbox Vector Geometry --> Create layer from extent. Then you have a nice rectangle as a bounding box. Make sure your map canvas is already in the correct projection of your project.

[@cappikkk_24]

@@HansvanderKwast Thank you

[@benmissimer]

At the 9:15 mark you show how to stretch the statistics to the current extent, but I'm not seeing that in v3.22 can you throw me a bone please? Great video! Thanks in advance.

[@HansvanderKwast]

It's still there in QGIS 3.22. Layers panel, Singleband pseudocolor, expand Min / Max Value Settings. Then under Ststistcs extent change from Whole raster to Current canvas