Delft-FEWS

Delft-FEWS is not a model but the operational system around models: it ingests real-time observations and NWP forecasts, runs any model chain (HEC-RAS, Wflow, SWMM, MIKE, custom binaries) on schedule, manages state and ensembles, and presents forecasters with a unified interface with alarms and dissemination. National services — the UK, Australia, the US National Water Model display chain, Rhine and Meuse authorities — run on it.

Licensing is unusual: free to use with paid support and setup typically via Deltares. Adopting FEWS is an infrastructure decision rather than a download, but nothing else in operational hydrology matches its install base.