Stream and Catchment Delineation in QGIS 3 using GRASS tools

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[thewahface]

Big fan. Very helpful thank you very much sir

[nfysvrd]

Dear Hans
Thank for your tutorials, please how can delineate multiple catchments at once

[tzevoon]

Thanks for another great video! I see that we always have to specify the outlet. Is there a way to delineate sub-catchment for tributaries within a larger catchment, without specifying all its outlet individually?

[imtiazabdulgafur]

Hi, I have 2 points where I got different outputs. When I tried to change the values for flowdirabs it would not just change the label but the output as a whole, which was not in your case. The second was for the river, I got it on value 0 but not on 1.
I apologise if it's hard to read but let me know if you would like me to rephrase, thanks.

[ferdinanmanullang]

Thank you very much for the video Sir. Anyway, what is the unit of flow accumulation? Because on the channels creation step, you set the flow accumulation should be bigger than 50, 000. Is it in m3/s?

[abhimanyukumarbarnwal]

Hello Hans, would you help us to find command area from a given canal/river in QGIS??

[raidanmaqtan]

Dear Dr.Hans. Many thanks for the video and for all your continuous free support in this field. I have followed the steps in this video to extract the streams network of my study area ( big area). Please, is it possible to convert the extracted raster (the layer channels of values 0 and 1 only as described at time16.36 of your video) to a vector layer of streams network? How to do that and convert only the streams (the 1 value) to a vector without including the 0 value and no data value extent? with many thanks in advance

[TheSinured]

Thank you very much for the video! I've found all your video's extremely helpful! I've been trying it out for my own project in Uganda but the result (both through GRASS tools and SAGA tools) channels are not always accurate to rivers displayed on basemaps. Even though a lot of rivers are the same, others are split in two different big rivers while on the basemaps it's just one river. I was wondering how I can alter the results so the channels are displayed more realistically. I've tried different SRTM layers, different tools, etc. but they all display 2 different rivers instead of 1.

[Agi-otsc]

Hey thank you very much for this video. For me tho it’s still not working. I can’t do a vector of streams and r.stream.extract is too much processing for my pc.
The water outlet with my absolut flow direction (which is 0 to 128) is always 1-3 pixel big, what do I need to change?

[SuperDanisse]

I just discovered your channel and I love it. Does it matter the version of QGis?

[hanjostark]

Hi Dr Hans. I followed your steps on this video, but my projection might be off? when I ran the Fill on the cliped DEM it displays it at a nother location. Why would this be?

Kind Regards

Hanjo Stark

[moonlighttreasure]

Hi thanks for the tutorial. I was able to make it to almost the very end but when I run r.waterout it kept showing SetColorTable() only supported for Byte or UInt16 bands in TIFF format. How to solve it?

[jokojoko]

Hi! Great video! How can I remove bridges from DEM? Problem is that when channel hits a bridge it redirects to a nearby catchment area.

[AhmedAdelSaleh]

Thanks a lot dear Dr.Hans
Do you think that GRASS tools plugin is suitable to do the same process.

[miraclebuoy]

Hello Dr Hans. I have faced great difficulty of delineating watershed of a terminal lake, a lake which has inlets but no outlets (Lake Hawassa in Ethiopia). I tried repeatedly using all your suggestions, be it changing the DEM or alternating between PCRaster, SAGA, Whitebox, GRASS, SWAT and stream burning. I think the problem is with the filling process. But no idea how to go about it.
Unfortunately there is no any YouTube video on how to deal with such terminal lakes. Can you do one please. Thank you in advance.

[miraclebuoy]

Hello, Sir.
I can't produce a good watershed @ 20:15 because one of my streams wrongly flows to the opposite direction ( i also noticed it form the flow accumulation step). Is there any option to reverse its course? Thanks.

[sumanghimire]

After the Raster calculator step I am getting an error "Raster couldnot create destination file". How can I solve this problem?

[szarith]

hi, how to have QGIS with GRASS?, I've downloaded the latest one but I don't see the 'QGIS with GRASS', it only shows 'QGIS Desktop 3.22.2'

[abhimanyukumarbarnwal]

How can I delineate river and catchment area of a plain area using QGIS

[sankaraanu]

I am not getting osm standard map eventhough I had installed the latest version of plugins and the status of QGIS official plugin repository is unavailable....plzz suggest any solution for this problem..