[Qgis-user] DTM/DEM - upstream delineation

[Kirk Schmidt]

Hello Tony:

To add to Chris's comment.  Depending on which version of QGIS you are 
using, SAGA is not automatically implemented.  In recent versions, I 
believe there is a plugin which allows for SAGA implementation.  Check 
out Geosearch's tutorial at:

https://www.youtube.com/watch?v=ceBOzPtQvms

Another work around is to install SAGA directly and use it to complete 
the watershed analysis.  SAGA is a powerful, fast raster analysis tool 
and QGIS can read the resultant binary rasters natively.

A nice tutorial by Random Topics in GIS is available at:

https://www.youtube.com/watch?v=eC_CONLzP8s

Kirk Schmidt


On 4/17/2026 1:39 AM, chris hermansen via QGIS-User wrote:

> Tony and list,
>
> On Thu, Apr 16, 2026, 14:49 Tony Shepherd via QGIS-User 
> <qgis-user at lists.osgeo.org> wrote:
>
>     Hi All
>
>     Just a question to see how others are achieving this.  I often get
>     asked to measure the area of a catchment, upstream of a particular
>     point. With a DTM/DEM I would have thought that there should be a
>     simple tool to do this - click a point, and then shade or draw me
>     a polygon of everything upstream of that point.  Sounds easy, but
>     achieving this isn’t so simple, or maybe I am missing an
>     easy-to-use tool or plug-in?
>
>
> Have you reviewed this documentation on the topic?
>
> https://docs.qgis.org/3.44/en/docs/training_manual/processing/hydro.html
>
>
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-- 
Kirk Schmidt, MScF, BScF, RPF
General Manager
Nortek Resource Solutions Inc.
26 Church Road
Sutherlands River, NS
B0K 1W0
Tel (902) 922.3607
Email:kirk at nortekresources.com
Web:www.nortekresources.com
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