HEC-HMS
The US Army Corps standard for rainfall-runoff modelling — event and continuous simulation, free to use.
DHI's integrated hydrological model — coupled overland, unsaturated, groundwater and channel flow.
by DHI
MIKE SHE is DHI's fully integrated catchment model: overland flow, unsaturated zone, saturated groundwater, evapotranspiration and channel flow (via coupling to MIKE Hydro River / MIKE+) simulated together in one framework. Where most models pick a compartment, MIKE SHE's value is the coupling — irrigation, wetland, conjunctive-use and drainage questions that live at the surface-water/groundwater interface.
It is commercial software with commercial-grade support and training, licensed per module. For integrated studies where budget exists it remains one of the most complete platforms; open alternatives (GSFLOW, ParFlow) trade polish for freedom.
Other hydrology & catchment analysis tools covering similar workflow stages.
The US Army Corps standard for rainfall-runoff modelling — event and continuous simulation, free to use.
FAO's classic tool for crop water requirements and irrigation scheduling from climate and crop data.
Browser-based rainfall frequency analysis — fit and rank 11 distributions with confidence intervals.
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.
Deltares' Python framework that builds ready-to-run hydrological models from global and local datasets.