Assistance in morphometric parameters determination of sub-watershed

[Sandip Pantha]

Hello Namaste everyone. I am actually determining morphometric parameters for several sub-watersheds and I had an issue on determining threshold on flow accumulation for stream orders determination. I have placed a threshold of 1000 upon reviewing some research papers. Is it a good placement for threshold or what determines the threshold I have to use.The overall watershed area is around 4792 km2 which will further be divided into sub-watersheds. 

Secondly, I have an issue on calculating the no of streams pertaining to a particular order . Calculating from the attribute table overestimates the number of higher order stream which can be validated by manual visualization of stream order.Could you please help shed light into these aspects.