Arc Hydro
Free
Esri's free hydrology framework for ArcGIS Pro — terrain preprocessing and the data model behind many agency workflows.
14 tools · Topic
Watershed Delineation Software
From a DEM to a catchment boundary: fill or breach the depressions, compute flow direction and accumulation, snap the outlet, extract the divide. The tools below automate the chain — GIS plugins, standalone terrain engines and Python libraries — each with different trade-offs in speed and control.
BASINS
Gov-Public
EPA's watershed assessment suite — HSPF continuous watershed-quality modelling with GIS and data access built in.
Delta Hydro Studio
FreemiumVerified
Browser-based hydrology and hydraulics calculators for practising engineers — no install, report-ready output.
GRASS GIS
Open Source
Four decades of geospatial engineering — r.watershed and the most battle-tested hydrology modules in GIS.
Click anywhere on earth, get the upstream watershed in seconds — free delineation in the browser.
HydroSHEDS
Free
The global hydrography reference — basins, river networks, lakes and hydro-environmental attributes, free.
QSWAT+
Open Source
The QGIS interface for SWAT+ — delineate, discretise and build a watershed model without leaving the GIS.
SAGA GIS
Open Source
The geomorphometry powerhouse — hundreds of terrain and hydrology modules behind a free desktop GIS.
TauDEM
Open Source
Utah State's parallel terrain-analysis suite — D-infinity flow modelling and objective stream-network extraction.
USGS StreamStats
Gov-Public
USGS web tool for basin delineation and regression-based flow statistics at any US stream point.
WEAP
Freemium
Integrated water resources planning and policy analysis framework for basin-scale supply and demand modeling.
WhiteboxTools
Open SourceVerified
500+ fast geospatial analysis tools with the best DEM hydrology toolkit in open source.
delineator
Open Source
Fast global watershed delineation in Python — the MERIT-Hydro engine behind the Global Watersheds web app.
pysheds
Open Source
Watershed delineation in pure Python — DEM conditioning to catchment boundary in a dozen lines.