I have demarcated sub-watersheds using different tools like ArcHydro, ArcSWAT, and Hydrology tool (ArcGIS). The same input data have been used in all tools. There are 35 watersheds derived using ArcSWAT, 44 from ArcHydro and 50+ from the hydrology tool (ArcGIS).

Why are there are variations in the number of watersheds?

Which one is correct?

The area of the watershed is 1960 square Km.

How many sub-watershed can be there in this size of the watershed?

Is there any way to define the required number of sub-watersheds with the specific area range?

Because the 30+ sub-watershed for this watershed with 1960 square KM. seems too many.