The Storm Water Management Model (SWMM) is a widely used software application developed by the U.S. Environmental Protection Agency (EPA) for simulating the hydrologic and hydraulic processes in urban drainage systems. The first version of SWMM was released in the early 1970s, and since then, it has undergone four major upgrades, with the latest being Version 5, released in the early 2000s.
The current version of SWMM, Version 5/5.2.1, is written in the programming language C and can be run on various Windows operating systems and Unix platforms. The code for SWMM 5 is open source and can be freely downloaded from the EPA website.
SWMM 5 provides a comprehensive graphical interface for editing watershed input data, performing hydrologic, hydraulic, real-time control, and water quality simulations, and viewing the results in various formats such as thematic drainage area maps, time-series graphs and tables, profile plots, scatter plots, and statistical frequency analyses.
The development of SWMM 5 was carried out by the Water Supply and Water Resources Division of the EPA's National Risk Management Research Laboratory in collaboration with the consulting firm CDM Inc. under a Cooperative Research and Development Agreement (CRADA). The software is widely used as the computational engine for many modeling packages and some of its components are also incorporated into other modeling packages.
SWMM 5 has been approved by the Federal Emergency Management Agency (FEMA) for use in the National Flood Insurance Program (NFIP) modeling and has been included in the FEMA Model Approval Page since May 2005. The updated history of SWMM 5 from its original version to the current version can be found on the EPA website.
