I have delineated the watersheds from DEM using r.watershed command. I have specified the Minimum Size of Exterior Watershed Basin as 1500. I have read the description of r.watershed as well. I am not able to understand why there is so much variation in size of watersheds. There are tiny watersheds even of the size of one cell. How can such small watersheds form after specifying criteria as big as 1500?
[GIS] How does “Minimum Size of Exterior Watershed Basin” work in r.watershed command in qgis 2.18.12
grassqgisqgis-grass-pluginr.watershed
Best Answer
Your result has sense since there is no threshold for interior drianage basins. Here I am quoting the man page of GRASS 7.4 link:
My guess is that you might get a better distribution of watershed with a lower value of the parameter threshold.