A healthy watershed will produce streamflow in local rivers that are based on several factors. The hydrology of a watershed can be assessed by looking at several elements:
Identify the size of the watershed – how to identify the boundaries of a watershed (delineate the size of a watershed using a topographic map)
Identify the typical rainfall amounts at different elevations
How much water evaporation occurs at different locations in the watershed
Watershed hydrology lecture series – https://youtube.com/playlist?list=PLfTUZSONTrFGQ1hhTMQLbzZwl1GYWVmIT&si=EnSIkaIECMiOmarE