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Creating Watershed in ArcGIS

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ArcGIS can delineate watersheds directly from a DEM. Essentially, you will be needing a Spatial Analyst extension to do this. Below is the hydrologic modeling flowchart employed by ArcGIS to generate runoff characteristics Here's an image automating the entire Watershed modeling process: Important Notes from model above: GENERATING THE STREAM RASTER: To generate the Output Raster or the STREAM RASTER, use Raster Calculator CON tool and enter the expression below: Con("FlowAcc_Flow1" > 100, 1) The number '100'  states how many cells drains toward the stream network. This can be varied depending on the detail of stream network needed for modeling. The smaller the area, the smaller the number to be entered. GENERATING POUR POINTS In generating the watershed, pour point location is needed. To automatically generate pour points, use Stream to Feature > Feature Vertices to Points. (Note however that Feature Vertices to Points is only av