ORD Stormwater Management Model (aka "SWMM")
This is the official SWMM source code repository maintained by US EPA Office of Research and Development, Center For Environmental Solutions & Emergency Response, Water Infrastructure Division located in Cincinnati, Ohio.
SWMM is a dynamic hydrology-hydraulic water quality simulation model. It is used for single event or long-term (continuous) simulation of runoff quantity and quality from primarily urban areas. SWMM source code is written in the C Programming Language and released in the Public Domain.
The source code distributed here is identical to the code found at the official SWMM Website.