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I am using ArcGIS Desktop 10.4.

I have to calculate the upstream river catchments of all my small river catchments. As you can see in the picture below, there are catchments missing in a weird looking shape. Created with Arc Hydro tool "Adjoint Catchment Processing" after I created the catchments following the usual way from a DEM.

Do you have any idea why there are no adjoint catchments included at these white strips?

The white stripes seem to follow some, but not all, of the channel network. I add a picture of the stream network here below.

I don't really know the size of the river. It is a whole catchment, so the widths will vary a lot between the main stem and smaller tributaries. The polygons have a size of a few hundret sqm to maximum 2.5 sqkm. The DEM has a resolution of 25m*25m.

We are looking at the full catchment in the picture, its roughly 132km x 64km.

Adjoint Catchments

Adjoint stream

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  • Looks like the white strips are (possibly) following a channel network? What is the size of the river (width) relative to the individual polygons? What is the resolution of your DEM? What scale are we looking at here?
    – Jon
    Mar 20, 2018 at 23:37
  • They seem to follow a stream, yes. But not the whole stream. I add a picture of the stream in the original post. Sorry I did not mention all the details. I will add them to the original post as well! Thank you!!
    – Canna
    Mar 21, 2018 at 9:20
  • I don't use Arc products, so I might be barking up the wrong tree. Did you fill your DEM's holes? Also, is your DEM clipped to the shape you show here, or is it a rectangle? It looks like all the holes are connected to the extents of the watershed, so it could be that the algorithm can't find a drainage divide along the river.
    – Jon
    Mar 21, 2018 at 14:50
  • Yes, I did fill holes (so called sinks) in the DEM before starting the river and catchment delineation. The DEM is clipped in the shape you can see here.
    – Canna
    Mar 21, 2018 at 15:24
  • If I were you, I'd try again without clipping the DEM to the extents of the watershed. I would do that as a final step.
    – Jon
    Mar 21, 2018 at 15:28

1 Answer 1

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After a few days of trial and error, and help from @Jon, I somehow got it fixed.

I am guessing my (stupid) mistake was that I manually had split an upstream-catchment, which was too big. This resulted in a double ID and probably confused the whole tool. Unfortunately I could not remember I even did that until I spotted it.

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