HEC-HMS
FreeVerified
The US Army Corps standard for rainfall-runoff modelling — event and continuous simulation, free to use.
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WinTR-55
StableNRCS's official implementation of TR-55 small-watershed hydrology: peaks, hydrographs and storage.
by USDA NRCS
- Pricing
- Gov-Public
- License
- US Government (public domain)
- Commercial use
- Permitted
- Ecosystem
- Standalone
- Platform
- Windows
About WinTR-55
WinTR-55 is the Natural Resources Conservation Service's Windows implementation of Technical Release 55, "Urban Hydrology for Small Watersheds" — the procedure a large share of US drainage manuals still reference for small-site peak discharge and detention sizing. It computes runoff by Curve Number, times of concentration by the NRCS velocity method, and generates hydrographs by the TR-20 engine that now runs underneath.
It shows its age, but it is free, official and universally accepted where TR-55 is specified. For modern workflows, the same methods are available inside HEC-HMS and most commercial drainage suites; WinTR-55 remains the canonical reference implementation.
Where it fits in the workflow
TerrainCatchmentRainfallRunoffRoutingHydraulicsMappingReporting
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