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Basin, Watershed, or catchment?

Question asked by dschatt on Apr 7, 2015
Latest reply on Apr 7, 2015 by sephefox

I saw this question was asked previously but only in general terms.  I'm interested in the output from the ArcGIS tools that use these terms.  I'm just wondering what the difference is between the output from the Basin tool and the Watershed tool in ArcToolbox, and the catchment grids from the "Catchment Grid Delineation" in Arc Hydro.  The documentation does a poor job of explaining the distinction between them.  Is a "Basin" also a "Watershed", or vice versa?  And how does a "catchment grid" from Arc Hydro fit into that picture?


Before I knew all the various tools, I was just trying to create watersheds for a flooding study for a county and went through the procedure with Arc Hydro of create flow direction, flow accumulation, stream, stream link, and catchment grids.  But I was having an issue that some of the area of the county had no catchment grid assigned.  Then I saw the Basin tool which only needs a flow direction raster, and will always assign all cells to a basin.  And then there's the Watershed tool as well, requiring pour points.  But if I know the Basin tool is all I need, it's much simpler.


Thanks for any info!