Watershed Model Basics




A DEM(Digital elevation model) which covers the area of interest is downloaded from the internet or other sources  (say srtm , aster gdem etc.)  

Raw DEM(srtm)
The DEM is then processed and errors should be removed for further analysis.
Processed DEM

 Delineation of Catchment

Catchment is delineated using Arc GIS and information such as Flow Direction, Catchment , Rivers etc. were fetched. After processing the area of interest(Tehri Dam Catchment in this case) is cut out from the DEM.
Extracting Project Area
                    The processed DEM will have all the processed layers and information required .
Tehri Catchment
Similarly by having DEM of different areas and you can extract other rivers as well e.g.  Satluj and Beas in example below.


Satluj Catchment

Beas Catchment
You can automate the process by using modelbuilder of ArcGIS as shown below.
Model Builder

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