Arc Hydro
Free
Esri's free hydrology framework for ArcGIS Pro — terrain preprocessing and the data model behind many agency workflows.
12 tools · Topic
Terrain Analysis Software for Hydrology
Slope, aspect, curvature, wetness indices, flow accumulation — terrain derivatives feed every spatial hydrology workflow. This page collects the geomorphometry toolkits (SAGA, WhiteboxTools, TauDEM and friends) and the Python interfaces that script them.
Browser tool for estimating point terrain elevations globally by address, coordinates, or map click.
Copernicus DEM (GLO-30 / GLO-90)
Gov-Public
ESA's TanDEM-X-derived global DEM — the most accurate free global surface model available today.
GRASS GIS
Open Source
Four decades of geospatial engineering — r.watershed and the most battle-tested hydrology modules in GIS.
HydroSHEDS
Free
The global hydrography reference — basins, river networks, lakes and hydro-environmental attributes, free.
NOAA VDatum
Gov-Public
Transform elevations between vertical datums — the essential fix-up for US coastal flood and drainage models.
QGIS
Open SourceVerified
The free, open-source GIS that has become the default spatial platform for water engineers worldwide.
RichDEM
Open Source
High-performance DEM conditioning — Priority-Flood depression filling at scale, C++ with Python bindings.
SAGA GIS
Open Source
The geomorphometry powerhouse — hundreds of terrain and hydrology modules behind a free desktop GIS.
SRTM (Shuttle Radar Topography Mission)
Gov-Public
The original free global DEM — 30m/90m elevation from an 11-day shuttle radar mission, still a baseline today.
TauDEM
Open Source
Utah State's parallel terrain-analysis suite — D-infinity flow modelling and objective stream-network extraction.
WhiteboxTools
Open SourceVerified
500+ fast geospatial analysis tools with the best DEM hydrology toolkit in open source.