I use the ArcHydro Toolbox and ArcGIS 10.4

I ran through the regular steps of Filling Sinks of a DEM, Flow Direction, Flow Accumulation, Stream Definition, Stream segmentation, catchment grid delineation and finally catchment polygon processing. My result looks like the following picture. As you can see the catchments are always a little off. From my understanding they should always cut the segments of a stream nicely. Any idea what might cause this error and what to do about it?


  • 2
    This is normal behavior due to raster nature of Hydrology analysis. – FelixIP Mar 19 '18 at 19:43
  • It looks quite good considering the coarse raster data. You will never get the watershed delimitation passing through the junction node, the delimitations follow the raster bonduaries and the streams the center – Marco Mar 19 '18 at 21:22
  • I see. That makes sense. Thank you. Is it possible to decrease the size of the rasters to make it a little more accurate? – Canna Mar 19 '18 at 21:34

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