However, many of my watersheds cross DEM boundaries, rather than staying within a single DEM.
My goal: I want Arc Hydro to treat several DEMs (ideally the whole set--40 total) as one large unit, so that I can batch delineate all of my 70 watersheds in one fell swoop. That way it would include the watersheds that cross DEM borders.
I'm not sure how to go about doing this, or if there is a better way. I'm a bit skittish, because some of the terrain preprocessing steps (e.g., flow accumulation) take a long time, even for a single DEM... let alone dozens at once.
I'm sure that you've completed your DEM processing but for future reference. I've attached a document from ESRI ArcHydro Team "Global Delineation with EDNA Data" It explains how to using multiple tiles using ArcHydro.
