# How to measure length of Sub-watersheds / Sub-Basins in ArcGIS Pro?

I am looking for guidance about reliable method of sub-basin length calculation.

I am a student and working on morphometric analysis for prioritization of sub-watersheds of a river basin. I am using White Box Tool Plugin for ArcGIS Pro for watershed delineation and stream network extraction.

I used this formula given by Schumm Lb=1.312*A^0.568 to calculate sub-basin length , length exceeded the actual length of basin. In literature this formula is mostly used in morphometric analysis. I am confused about measurement of length of sub-Basins in Morphometric parameters analysis. I want to know how to relate (how can I check / assess or verify) the length of sub-Basin obtained from this formula?

These are the some screen shorts about length calculation;    • To answer this question you need to do some research and report back the official definition of Basin Length. The straight line distance from the mouth is that to a point on the catchment boundary that is nearest to the longest flow or simply the longest straight line in the polygon but anchored to the pour point? Jun 22 at 11:44

The formula you are quoting `(Lb=1.312*A^0.568)` is a regression line developed by researchers looking at many watershed areas and their stream lengths. As such, it's just a correlation, to describe "average" watersheds. Not a magic formula that would let you skip actually measuring your flowpaths.