Storm Water Management Model

The United States Environmental Protection Agency Storm Water Management Model (SWMM) is a dynamic rainfall-runoff-subsurface runoff simulation model used for single-event to long-term (continuous) simulation of the surface runoff/subsurface runoff quantity and quality from primarily urban/suburban areas. The runoff or hydrology component of SWMM operates on a collection of subcatchment areas that receive precipitation and generate runoff and pollutant loads after simulation evaporation and infiltration losses from the subcatchments. The routing or hydraulics portion of SWMM transports this runoff and possible associated water quality constituents through a system of closed pipes, open channels, storage/treatment devices, pumps, orifices, weirs and regulators. SWMM tracks the quantity and quality of runoff generated within each subcatchment, and the flow rate, flow depth, and quality of water in each pipe and channel during a simulation period comprised of multiple fixed or variable time steps. The water quality constituents can be simulated from the subcatchments through hydraulic network with optional first order decay, BMP and LID removal and treatment at selected storage nodes. SWMM is one of the hydrology transport models which the EPA and other agencies have applied widely.

History

SWMM was first developed between 1969-1971 and has undergone several major upgrades since then. The major upgrades were: (1) Version 2 in 1975, (2) Version 3 in 1981 and (3) Version 4 in 1988. The current SWMM edition, Version 5, is a complete re-write of the previous Fortran release in programming language C. Running under Windows XP and Vista, EPA SWMM 5 provides an integrated graphical environment for editing watershed input data, running hydrologic, hydraulic, real time control and water quality simulations, and viewing the results in a variety of graphical formats. These include color-coded thematic drainage area maps, time series graphs and tables, profile plots, scatter plots and statistical frequency analyses.

This latest re-write of EPA SWMM was produced by the Water Supply and Water Resources Division of the U.S. Environmental Protection Agency's National Risk Management Research Laboratory with assistance from the consulting firm of CDM Inc under a Cooperative Research and Development Agreement (CRADA).

The update history of SWMM 5 from the original SWMM 5.0.001 to the current version SWMM 5.0.013 can be found at the [http://www.epa.gov/ednnrmrl/models/swmm/index.htm#Downloads EPA SWMM 5 Downloads] in the file epaswmm5_updates.txt.

Integrated Solution

One of the great advances in SWMM 5 was the integration of Urban/Suburban Subsurface Hydrology with the Hydraulic computations of the drainage network. This advance is a tremendous improvement over the separate Subsurface Hydrologic and Hydraulic computations of the previous versions of SWMM because it allows the modeler to conceptually model the same interactions that occur physically in the real open channel/ shallow aquifer environment. The SWMM 5 numerical engine calculates the surface runoff, subsurface hydrology and assigns the current climate data at either the wet or dry hydrologic time step. The hydraulic calculations for the links, nodes, control rules and boundary conditions of the network are then computed at either a fixed or variable time step within the hydrologic time step by using interpolation routines and the simulated hydrologic starting and ending values.

An example of this integration was the collection of the disparate SWMM 4 link types in the Runoff, Transport and Extran Blocks to one unified group of closed conduit and open channel link types in SWMM 5 and a collection of Node types.

Batch Versions of the SWMM 4 and SWMM 5 Engines

How to Use the SWMM 4 Dos Engine

SWMM499.EXE SWMM4.DAT SWMM5.OUT

* SWMM Engine Name Name of the SWMM 4 DOS Engine * SWMM Input File - SWMM 4 Input file * SWMM Output File - SWMM 4 Text Output File (.OUT Extension) * Alternative SWMM Output File - Reduced SWMM 4 Output File (.RPT Extension) How to Use the SWMM 5 Dos Engine

SWMM5.EXE SWMM5.INP SWMM5.OUT SWMM5.RPT

* SWMM Engine Name Name of the SWMM 5 DOS Engine (usually called SWMM5.EXE) * SWMM Input File - SWMM 5 Input file * SWMM Output File - SWMM 5 Output Binary Graphics File (.OUT Extension) * Alternative SWMM Output File - SWMM 5 Output Text File (.RPT Extension)

SWMM 5 Engine Solution

ee also

*DSSAM Model
*Hydrology
*Hydraulics
*Surface runoff
*Precipitation (meteorology)

External links

* [http://www.epa.gov/ednnrmrl/models/swmm/index.htm EPA SWMM 5 page]
* [http://www.swmmconversion.com/ SWMM 3,4 to 5 Conversion Tools]
* [http://www.swmm5.com SWMM 5 Tools, Google Groups and Other Links]
* [http://www.swmm5.com WWW.SWMM5.COM]
* [http://www.swmm2000.com/ SWMM 2000+]
* [http://sites.google.com/site/swmm2000/ Google SWMM Site]
* [http://swmm5.blogspot.com/ SWMM 5 Blog]
* [http://swmm50.ning.com/ SWMM 5.0.013 Spanish]

SWMM 5 Vendors

* [http://www.bossintl.com/stormnet-overview.html StormNET]
* [http://www.mwhsoft.com InfoSWMM and H20MAP SWMM]
* [http://www.computationalhydraulics.com PCSWMM.NET]
* [http://www.xpsoftware.com XP-SWMM ]