Free water engineering tools

JAXA's 30m global DSM from PRISM stereo imagery — a strong third opinion alongside SRTM and Copernicus DEM.

Esri's free hydrology framework for ArcGIS Pro — terrain preprocessing and the data model behind many agency workflows.

ETH Zurich's free 2D hydraulics and morphodynamics simulator — rivers, sediment and hazard mapping.

The standard 2D reservoir and stratified-river water-quality model — temperature, DO and eutrophication.

Gauge-blended satellite rainfall at 0.05°, daily, since 1981 — the standard for drainage work in data-sparse regions.

FAO's classic tool for crop water requirements and irrigation scheduling from climate and crop data.

Browser tool for estimating point terrain elevations globally by address, coordinates, or map click.

Deltares' operational forecasting platform — the shell running national flood-forecast centres worldwide.

Near-real-time 10m land cover from Google/WRI, updated every Sentinel-2 pass — land cover that keeps up.

ECMWF's hourly global reanalysis — the default gap-free climate forcing record for ungauged catchments worldwide.

A consistent annual global land cover record at 300m from 1992 — long enough to trend land-use change against.

The longest satellite soil moisture record available — merged active+passive retrievals back to 1978, free, no login.

Global 10m land cover from Sentinel-1/2 — the highest-resolution free global land cover map available.

Rapid flood modelling in the browser — steady-state inundation estimates in seconds, anywhere on earth.

Browser-based rainfall frequency analysis — fit and rank 11 distributions with confidence intervals.

Click anywhere on earth, get the upstream watershed in seconds — free delineation in the browser.

The US Army Corps standard for rainfall-runoff modelling — event and continuous simulation, free to use.

The world's most used hydraulic model: free 1D/2D river analysis, sediment, water quality and flood mapping.

Reservoir system simulation from HEC — operating rules, flood control and multi-reservoir networks, free.

Statistical hydrology from HEC: Bulletin 17C flood frequency, volume-duration and general frequency analysis.

The global hydrography reference — basins, river networks, lakes and hydro-environmental attributes, free.

CUAHSI's platform for sharing hydrological data and models — DOIs, collaboration and linked compute.

Free Spanish 2D hydraulic model — flow, turbulence, sediment and habitat modules behind a full GUI.

CDM Smith's free rainfall statistics and STORM-method screening model — IDF analysis, disaggregation, CSO planning.

A neural-network satellite rainfall climate data record, daily, 0.25°, purpose-built for long-term trend studies.

Model-independent parameter estimation and uncertainty analysis — the calibration standard for groundwater models.

The classic river water-quality model — DO, nutrients and algae along a 1D stream network.

The US Bureau of Reclamation's free 2D river model — FHWA's preferred engine for bridge hydraulics.

Free 10-20m multispectral imagery, 5-day revisit — the imagery backbone under WorldCover and Dynamic World.

The Watershed Bounded Network Model — free Australian runoff-routing hydrology for flood estimation.

Free web tool for building synthetic design-storm patterns — 560+ temporal patterns, exportable to SWMM and HMS.

Programmatic access to ERA5 and the Copernicus Climate Data Store — the world's reanalysis workhorse.