GRASS GIS
Open Source
Four decades of geospatial engineering — r.watershed and the most battle-tested hydrology modules in GIS.
Geospatial & Hydro-GISActiveWatershed DelineationDEM Processing
3 tools · Topic
QGIS Plugins for Watershed Delineation
Delineating a watershed in QGIS used to mean a chain of GRASS or SAGA steps; today several plugins do it in one pass from a DEM. This page compares the QGIS-native options for catchment and stream-network delineation, plus the terrain engines they wrap.
QSWAT+
Open Source
The QGIS interface for SWAT+ — delineate, discretise and build a watershed model without leaving the GIS.
Geospatial & Hydro-GISActiveQGIS Watershed DelineationQGIS Hydrology
SAGA GIS
Open Source
The geomorphometry powerhouse — hundreds of terrain and hydrology modules behind a free desktop GIS.
Geospatial & Hydro-GISActiveTerrain AnalysisDEM Processing