HydroCAD
Commercial
The US land-development standard for TR-55/TR-20 hydrographs and detention pond design.
Urban Stormwater & InfrastructureActiveDetention DesignTR-55
2 tools · Topic
TR-55 Calculators & Software
TR-55 ("Urban Hydrology for Small Watersheds") remains the reference procedure for small-watershed peak flow and detention sizing across the United States. Indexed here: implementations of the graphical peak discharge and tabular hydrograph methods, WinTR-55 itself, and modern re-implementations you can script.
WinTR-55
Gov-Public
NRCS's official implementation of TR-55 small-watershed hydrology: peaks, hydrographs and storage.
Hydrology & Catchment AnalysisStableTR-55SCS Curve Number