I follow Watershed and Stream Network Delineation, and here's my workflow:

  1. use Batch Point Generation to create batch points related to designated points(green dots)
  2. Batch Subwatershed Delineation using these batch points

and I got this:

enter image description here

It looks great, but I still can't clip existing subbasins using designated points to get smaller subbasins inside.

Are there tools in Arc Hydro Tools or any other tool like QGIS or GRASS that can help me get my goal?

I have got the subbasin area of every river segment using Arc Hydro Tools:

Martin suggested How to get the subbasin area of each specified river segment?

enter image description here

Now I have some sample stations(the green dots) in the river network, and I'd like to take them as the segment bases, thus I would get more segments, and I want to split the drainage line based on those points and calculate the subbasin area of these new segments:

enter image description here

I think the key is how to make ArcGIS take these green dots as confluences of rivers as well. And all I want is like this schematic photo: enter image description here

What can I do?

  • 1
    not sure if I understood it completely. But i think you want to use green dots (points) to get sub-basins and then stream reach network for delineated sub-basins with tabular information, is it correct?
    – Ibe
    Commented Jan 26, 2014 at 3:01
  • I want to get subbasin areas of every segment including the segment above the green dot.
    – Heinz
    Commented Jan 27, 2014 at 9:56

1 Answer 1


Ssee http://grasswiki.osgeo.org/wiki/Creating_watersheds in the Wiki. With r.water.outlet you can calculate a watershed "backwards" from its outlet point. Furthermore, see also http://grasswiki.osgeo.org/wiki/R.stream.*

The screenshot shows where to find r.water.outlet in "Processing" (former Sexante) in QGIS 2. Typing into the search field lists name matching commands.

enter image description here

  • Thank you very much!I have looked this website you gave me:grasswiki.osgeo.org/wiki/Creating_watersheds, but I used to use GRASS in sextante toolbox under QGIS2.0, I don't know where and how to type those code.
    – Heinz
    Commented Jan 27, 2014 at 10:08
  • 1
    I edited and added where to find it in QGIS...
    – markusN
    Commented Jan 27, 2014 at 21:55
  • thank you, it seems that I need to put the output of r.watershed module as the input of r.water.outlet, and now I am stuck in this problem:gis.stackexchange.com/questions/84456/…, could you give me some other advices? Thanks again!
    – Heinz
    Commented Jan 28, 2014 at 5:04
  • Thank you very much, with your guide, I successfully used r.water.outlet module, and got some results in this post:gis.stackexchange.com/questions/61152/…, but the result is still not what I want.
    – Heinz
    Commented Jan 29, 2014 at 2:19

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