Stormwater Management Model (SWMM)

Purpose: Simulate hydrology, hydraulics and water quality in urban areas
Developer: US Environmental Protection Agency (US EPA)
Key Features: Hydrodynamic modeling; open source; import dxf file
Latest Release: 2015, Version 5.1.010
OS Platform: Windows
Cost: Free
Related Software: XPSWMM, PCSWMM, MIKE Urban
Website: SWMM Homepage

Introduction

The SWMM, developed in 1971, is a dynamic transport model that simulates runoff quantity and quality primarily from urban areas and combined sewer overflow. The SWMM categorizes drainage systems into four major components: atmospheric, land surface, groundwater and transport, though not all components are required for modeling. Through the land surface component, the SWMM models infiltration and runoff from the subcatchment. Subcatchment modeling uses a series of non-linear reservoirs. Transport modeling applies a variation of the dynamic wave equation. The SWMM has been used for flood control drainage systems and detention facilities, floodplain mapping, minimizing combined sewer overflow, floodplain mapping, and non-point source pollution modeling.

Key features of the SWMM includes the ability to model complex storm drain systems with backwater effects. The model imports storm drain data via a DXF file. The SWMM was developed by the United States Environmental Protection Agency and Camp Dresser and Mckee, and is supported only on the Microsoft Windows operating system.

Advantages and Limitations

Advantages Limitations
  • Software program code is available on the USEPA website
  • Program has been continuously upgraded
  • Simulate pollutant loading
  • Support provided via vendors or user forum
  • Import World Coordinate Files and export DXF
  • Model complex storm drain
  • Analytical tool and not design tool
  • SWMM engine slightly more unstable then other hydraulic engines
  • Economic analysis is no longer part of SWMM5
  • Cannot model manhole or inlet loss directly
  • Technical manual for Ver. 5.0 has been only updated for hydrology
  • No technical support provided by USEPA

Illustrative Screens

Sample Applications

Africa East Asia and the Pacific Europe & Central Asia Latin America & the Caribbean Middle East and North Africa South Asia
Vietnam (Improved Drainage) India (Climate Change)

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